posted 08-22-2001 07:33 AM               

The ohv builders take alot for granted that just isn't a possibility with the flatties. On the other hand, flathead inlines possess some traits that that are seldom exploited or refined to compete with the ohv's

Let's hear what you have to say!

The discussion had started as follows:

Jim R

--------------------------------------------------------------------------------
Hudson,
Sounds like you have a heavily modified flathead. Would you care to share some of the details and performance with us?
Jim R
IP: Logged

Hudson
Active Inliner posted 08-21-2001 05:11 PM
--------------------------------------------------------------------------------
First, don't anybody jump out and bore your B&B carbs out to those dimentions. The step up jet is wayyyyy too big. Even though the tractor would run up and down the road like top fuel dragster, its too much fuel under the type of load a tractor pull inflicts on an engine. I buzzed down the track until the load popped up the step up jet - then billowing black soot rolled out, and the rpms stopped going up. I backed out to let the step up seat and hopefully gain my vacuum back, this may work on a drag strip - it won't on a pulling track. The main jet wasn't enough and the step up jet was too much. Ideally, the step up jet would pick up the load and additional fuel needed to sustain the engine. Mine is simply too rich.
Luckily, a new step up jet for these carbs comes with an overhaul kit from The Carburetor Shop in Eldon Missouri.
Now, as for modifications, nothing real outlandish has been done to the engine. It was noticed that is full potential should be gained at 5000 rpm, but the crank didn't seem to want to stand that.

The crank was fully cross drilled from the mains to each adjacent rod and from rod to rod between mains. An oil groove was cut in the main & rod bearings to allow continuous oil flow to the crank at all points. We are running stock stroke and had the entire rotating assembly balanced out to run 6000 rpm.

Another important modification to get this rpm is to plug all the oil bleeds from the rods. Depending on what type of chrysler engine it is, some have holes in the yoke to spray the cam, others have in addition ports drilled through the rod beams to lubricate the wrist pins and spray the piston head. Be sure and plug these up to conserve all the oil and associated cooling in the rod bearing. Almost all the engines we tore down had some degree of damage to #2 and #5 rods, attributed to poor oil distribution and the excessive bleeding of oil from the adjacent rod nearest the source oil port.

The rest is pretty vanilla in terms of hardware. '58 head cut .090, stock valve diameters, homemade split exhaust, and a custom grind on the cam 270 duration seat to seat with a .425 lift and 110 separation angle and centerline.

The valves were left stock because of the shrouding that would occur if they got nearer to the head relief at full lift. We could have ground this shrouding away for better flow, but that costs CC's in a situation that doesn't allow many compression boosts. Perhaps if we stroke it, these CC's can be made up with cylinder displacement. We run 9.5 compression and can burn 93 octane pump gas.

That's about it, nothing very elaborate - but we can turn some wicked sustained rpm's. Two years of some very hard, winding service without a hitch. We needed some more induction, just need to get it harnessed!

Hudson

IP: Logged

frank
Active Inliner posted 08-21-2001 08:24 PM
--------------------------------------------------------------------------------
Hey Hudson, would one cylinder be considered in-line?
I've had a lot of experiance with flathead one cylinder engines. We had a lot of restrictions on our rules so we had to get inovative.
One thing to improve breathing without disturbing the combustion chamber is to move the head off center towards the valves. By either necking down the head bolts or sloting the head bolt holes in the head. The more tne better, but in the Briggs, in order to still have enough gasket surface 0.070 to 0.080 was all we could go and it made a significant improvement.
Another thing we did was to reduce the head diameter on the valves, thus putting the margin near the edge of the valve. This seemed to work well also to increase flow.
These two things helped us get suspended from racing and asked to never return.
Frank
IP: Logged

Hudson
Active Inliner posted 08-21-2001 10:01 PM
--------------------------------------------------------------------------------
I hear you Frank, and the briggs is the defining flathead to me. I don't race them, but one has to admire their tenacity and durability! Not to mention their outright punch for such a little package.
You are exactly right about the valve arrangement and scooting the head over on the briggs. The '58 head already has that licked over the earlier heads for the little chryslers. The valve pockets are just enough around the stock valve diameters to flow good, but close enough for a good compression. Instead of the long air port over the top of the piston, it has a deeper, shorter air pocket that saves compression but flows better. Sometimes bigger isn't always better, especially when you consider the limitations of the simesed intake runners.

Our valves are setup just like yours in the briggs, barely grabbing the edge of a 3 angle job with plenty of meat in the valve head to keep the edge from rolling up. It may not be textbook, it was the machinist's doings - but it worked! (he had built a briggs or two himself)

To diverge from the mopar a little, my preoccupation with Hudson flatheads stems from the fact that their valves are canted towards the cylinder at an angle, they have 12 large ports, and you can run a higher compression with the ability to breathe better than the "big three" flatties.

To put that in Briggs perspective, wouldn't you love to regrind and reseat your valves right up to the edge of the cylinder at an angle and fill up all that backspace? Ohhhh Boy!

Keep them Briggs a rollin!

posted 08-23-2001 07:11 PM               

Glad you could get in on this flathead talk! I wonder if you could ask your dad which rods gave problems, or if he had done the same oil port modifications to his engine?

I've seen our 230 hit 6000 with the single carb, but never held it any length of time to know if we could go that far and sustain it (for one reason the single carb wouldn't let us!). Right now somewhere around 5000 is all I want to hold, as our cam really isn't giving us anything beyond that. I really don't think the valve springs will take the 6000 as when dad hit it, it stuttered a little and began leaning out, the exhaust was very very hot.

I've spec'ed out the bigger series mopar flatties (3.438" bore), and like what I see! There is a 265 version out there, used in ag machinery and industrial versions. I think a few were used in very heavy dodge trucks during '56-'60 also. The cranks from these engines will drop into any of the 3.438" bore blocks without modifications. These bigger engines have 2.125 rod journals compared to the 2.00 journals of the smaller engines of 3.25 bore.

The stroke of the 265 is 4.750, .125 larger than the little 230. With an offset grind on the bigger crank to shave it down to the 2.00 journal, the stroke can be increased to 5.00" gaining a total cid of 279 for the cheap, stroked flatty. Of course, there is room for more, as this mod will leave the outer clearances of rod to crankcase the same as before. But, you've just gone from a $400 mod to a $1200 situation.

The rod lengths in these engines, both series, differs in length according to stroke. The longer the stroke, the shorter the rod. Its possible to increase your torque output at lower rpms by simply swapping rods with a shorter stroke engine and shaving off the piston head a smidge. A very good rod length/stroke ratio is around 1.75:1. If you check out the rod lengths vs. stroke in most flatties - you'll find something close to this number, that's why they seem to lug so smoothly at lower rpms than their bigger cid ohv cousins, who consequently run ratios around 1.55 with not much room to improve.

In the tractor world, Minneapolis Moline tractors built pre '55 all had stock rod ratios of 2:1, this is the ultimate rod ratio - my stock 40 hp Moline 4 cly. can show up a 66 hp IH 6 cly. on the pto any day of the week grinding corn @ 1000 rpm less at the flywheel.

I can hear those gears turning in your heads even now!

Hudson

[This message has been edited by Hudson (edited 08-23-2001).]

posted 08-24-2001 12:19 PM               

The torrential rain we had this morning has nixed my plans, so what better to do than talk engine!

The 1.75 is not ideal, but the reasoning behind calling it ideal is that the greatest increase in torque is attained at this ratio. In other words, if the torque increase due to rod length was represented in a curve, 1.75:1 would be a short plateau at the end of a steep rise. The apex would be at 2:1 with less relative rise than up to 1.75. Any increase beyond 2:1 being very small and impractical with most engines.

Why does this become so important? Its part mechanical physics in relation to rod flex and power transmission from reciprocating to rotating, part hydrodyamics in relation to cylinder filling and scavenging, and part pyrotechnics in using the combustion gases to their best potential.

The basic physics of the matter: the longer the rod in relation to stroke, a lesser angle is present between the centerline of the cylinder and the centerline of the rod beam at any point in its travel: as it deviates from vertical at TDC and BDC. This characteristic allows more direct transmission of power to the crankpin, via the longitudinal length of the rod. In shorter ratio engines, more of this transmission is transferred to the lateral section of the rod, using up power by attempting to force the rod to bend rather than push the crankpin around.

Another enormous benefit is the increase in piston dwell near TDC and BDC. As the ratio increases the amount of crank degrees that the piston dwells near the terminal ends of the reciprocating path will increase also. In mechanical perspective, this allows the crankpin to change the direction of the reciprocating mass under less resistance. The crank also rotates more degrees past tdc before piston direction changes and reduces the relative piston speed at these two points. Put these together and you have a rod acting more directly against a crank that is already past TDC by more degrees per unit of piston travel and moving the piston slower at critical points in its travel.

Hydrodynamics? Gases and fluids share the same phyical properties with the exception of compressability. We express fluid/gas flow in CFM. We often catch on to the volume, but overlook the function of time in this expression of measure. To increase the amount of piston dwell at BDC during the intake stroke, is to allow a more complete filling of the cylinder at peak demand by allowing more "time" for the cylinder to fill at its maximum volume. In addition, to increase piston dwell at TDC during the exhaust stroke, is to maintain the cylinder's minimum volume longer for a more complete expulsion of gases through the exhaust valve. Although these properties do not change the cfm capacity of a group of cylinders, they definately change how effective an engine employs its theoretical capacity. This will effect the VE% in the classic formula ((CIDxRPM)/3456)VE%=CFM.

Now, we have exhausted the spent gases more completely, taken a denser charge into the cylinder - lets examine the pyro part of longer ratios. Again, we are dwelling at TDC longer with the wider ratio. This allows the combusting gases to reach more of their potential in a smaller space over a greater amount of time, and crank degrees. This really conserves the maximum force of the combustion at is most advantageous point against the piston head. Power is really only transmitted at its maximum at this point as the change in cylinder volume during the power stroke takes up the potential of the explosion rapidly.

The benefits of this are enormous, just ask the sbc builders how much improvement they get from just .300" of rod length. The first measurement I take on any engine is deck height above the mains' centerline. The stroke is then determined based on available rod length and piston combos to effectively use the available height.

Offsetting the wrist pin center in the direction of crank rotation will accomplish the TDC effects of the rod ratio, but speeds up the BDC end of things. In high compression and forced induction engines, the increase in lateral force on the rod, due to the exaggerated angle during its upward stroke, can bite you on the touche'. But, all things considered, if I had to build and engine with a ratio less than 1.55 - I would seriously consider offsetting the wrist pin. Offsetting the wrist pin makes it important to degree your cam closely, as the crank position at TDC will change - altering everything from cam phase to timing marks by a smidge.

You fellas have a good day!

Hudson

[This message has been edited by Hudson (edited 08-24-2001).]

posted 08-24-2001 05:42 PM               

I'm going on a little family outing this weekend, I'll ask my Dad about the cooling tube. He did most all the work on the engine while I looked over the bigger ones laying in the shop floor. You might say I was the technical advisor. I paid attention to the components, he put them together. I do seem to recall him mentioning the water tube though. Pop has a few tricks up his sleeve as well.

You are right about the previous generation going through the "trial by fire". I try and listen to as much of that as possible to either avoid the same mistakes, or recognize it before something breaks.

I'll jump back in when we get back.

posted 08-30-2001 10:54 AM               

First, the bore of the bigger engines is not 3.5", its actually 3.438". I had made my notes based upon "what could be" as my dad's material is "as manufactured". I didn't have the mfg's spec data and used my incorrect bore info to deduce the stroke of the 265 engine. Its actually 4.750! I know this disappoints you *laughing*.

Why did I error in my measurement? Because the chrysler engines are actually a "dry sleeve" design, with a very thick sleeve. If you really clean your block deck good, you can see it, but it is a very good press fit. Dont automaticly assume that you can run without this sleeve, as it is very good hardness and the block is very soft.

The larger bore 4.750 stroke, a 250 crank offset ground to the small 218 rod, is my favorite compromise in relation to rod ratio, numerous parts sources, and cid. One could offset grind the 4.75 large journal crank out to 5.00, but the piston speed really robs Hp at this stroke in the higher rpm levels. If you were going for a low rpm torquer, the stroked 5.00" would be good, but with a loss in rod ratio that may not make up the extra cubes.

I'll edit my other posts accordingly

Have a nice day!

Hudson

posted 08-30-2001 11:50 AM               

The book is "DODGE Pickups: History and Restoration Guide 1918-1971" by Don Bunn and Tom Brownell. It is published by Motorbooks a link to them on the web: www.motorbooks.com

This is an excellent engine reference as the authors actually compare the engines, year by year, to the auto counterpart. Listing the modifications in detail and what models they were used.

The last chapter is an excellent guide for rebuilding the L6, regardless of application. They even delve into modifications for those so inclined.

To clear the muddy water regarding cid, block families, and applications: lets summarize according to this book (as my dad quickly pointed out to me!)

US made small bores:
3.125X4.375 201cid Plymouth 35-41
3.250X4.375 217cid DodgePlymouth 41-54
3.250x4.625 230cid DodgePlymouth 54-59

Canadian made small bores
3.375x4.060 201cid PlymouthDodge 38-39
3.375x4.250 228cid PlymouthDodge to 54

Production Hybrid:Canadian Block+US crank
3.375x4.500 241cid Chrysler early 40's

This runs down the little blocks, and similiar to the old "canadian chevy" Chrysler apparently produced a thicker block for the cold temps up north with a little more room for improvement.

The larger bore @3.438" engines:
3.438X4.250 236cid DeSoto autos
3.438x4.500 251cid Chrysler 46-51 and Dodge trucks 46-56
3.438x4.750 265cid Chrysler 52-54, Crown Marine, and Heavy Dodge trucks 54-60

The maximum "bolt together" of this interchangable series is the Crown Marine engine of 265.

Of course, we've already talked about mods from this point on.

Hudson

posted 08-30-2001 02:44 PM               

About all I can say is that it allows a person to mix and match to build something to suit the need. I am amazed that these engines had such rod length variations, a rod for each stroke variant. It would have been much cheaper to vary the piston's compression height to accomodate a +/- in stroke. Yet, for each bore series, you have only one piston of the same compression height - regardless of stroke, @1.978" from the wrist pin center.

I have never seen a canadian block, nor heard of one besides the truck book. I suspect them to be long blocks with thicker sleeves/cylinder walls than the US counterparts. The strokes of the Canadian and US long blocks look suspiciously similiar to me.

And I also agree, that really only four of these variations represent the majority of concerns to us, whether restoration or hot rodding a bit. The 217/230 short blocks and the 251/265 long blocks. The resulting differences in crankpin diameter in these two engine series are the source of my glee in concocting hop ups.

Its just nice to know, that within a particular series, a person can up the torque output over the range of the engine by swapping rods from lesser stroked engines.

Lets add a little more confusion to the mix, if that's possible. I was just cruising the Silvolite piston website, Chysler OEM in the 50's, and found a little morsel. Going back to Frank's mention of offsetting the wrist pin, the Slant 226 piston is listed as being slightly offset. The 226 slant piston is 3.400 bore, 1.740 comp height, and available up to .060 overbore. The amount of offset is not listed, just mentions "offset". It may be possible to set up a flathead engine combination that uses the best bore, rod, stroke combination and utilize this piston as an "off the shelf" component. A person could at least utilize a 251 rod length on a 265/4.750 stroke and get the advantage of a longer rod and a little wrist pin offset. By the way, a 226 piston will fit the 3.375 bore as the difference in fit is only .025".

The Silvolite link to chrysler 6 pistons: http://www.kb-silvolite.com/slvpg36.htm

Hudson

posted 08-30-2001 09:47 PM               

Thought I'd jump in for a few moments here when you guys started talking about the "oddball varieties" of flathead MoPar 6;

It's my understanding that in the European Countries, such as England & continental Europe, vehicles are/were taxed on Horsepower or Displacement, thus the Chrysler export models such as the Kew and the Wimbledon, as well as various "Plodges" and "Plysotos" seen farther East had tiny engines such as the 170 cid flat-head, and the cars bearing the Chrysler nameplate were really re-badges of the smaller Plymouth & Dodge.
I also recall reading (don't recall where) that when the "new generation" of engines were designed at Chrylser, around 1932 or '33, there was a goal to share as many internal parts as possible, such as common pistons, bearing shells, etc.
I don't have my shop manuals handy, but I believe the 323.5 straight 8 ('34 to'50) and the comparable 6 of '33-'34 had the same 3 1/4" inch bore, and had the same rod bearings, cam profile, etc.
It also seems that as the engines "increased" in size at the top (Chrysler), the previous displacements were "handed down" to the lower priced lines;
the Chrysler 241 was de-stroked to become the Chrysler Royal & De Soto 228, then bored to become the De Soto 236; then De Soto inherited the 250 from Chrysler when Chrysler went to 265.
Similarly, Plymouth "inherited" displacements from Dodge as Dodge got bigger engines: 230>217>201.
As far as I know, all of the "small"(170) export engines were based off of the 201 Plymouth engine.
It's kind of interesing how certain displacements have a way of "coming back"; the first Chrysler of 1924, the B-70 had a 201 ci. six, as did the Plymouth 6 of the late '30s (entirely different engine), and the 170 ci diplacement returned in the Valiant in the early '60's, in slanted form.

I suppose this isn't terribly helpful in terms of performance talk... more of a historical rambling gleaned from the foggy recesses of a sometimes faulty memory...
at any rate, I'm quite interested in this topic, and would like to learn what can be done with (or to) the larger Chrysler and De Soto sixes and possibly the 323.5 Straight 8, to get more from them.
I just loathe the thought of having to put a later model V-8 w/AT in my '41 DeSoto just to be able to "cruise in the left lane".
(and, if it comes to that, you can be assured it will be a MoPar engine)
So I'll sit back now for another while and learn some more...

My '41 De Soto has the original 228 six, and manual trans (no fluid-drive!)and 4.11 rear, and at 88,000 miles, it's tired! It is also not happy about being pushed beyond 45-50mph.
So, with an engine rebuild in my future, I'd like to know how to get the most out of my old girl.

Regards,
Frank McMullen

posted 08-31-2001 09:43 AM               

I'm curious, as I've never seen the 228 before. Is it a long engine? If it is, I think a very good combination exists for you to get into the "left lane" and run with the big dogs.

I think your gearing may be causing most of your troubles. I am by no means a gearing guru, I just deal with engines. 4:11 is very low for a road hawg, you spend alot of your time over the back edge of your torque curve - heading for peak hp. Acceleration is all about riding your torque curve upwards. I'm not saying you don't have the hp to play in the fast lane, but its takes a hard downshift to get back over your torque curve and run at a higher relative rpm to get to your desired mph. I don't care what engine you're talking about, the higher sustained rpm - the shorter life it has.

I was recently treated to a ride in Bob Criswell's Dodge Bros. Coupe (Thanks again Bob!). He installed a very tall gear in the coupe and hitched the stock 230 to a t-5 tranny. Peak torque on a stock 230 is somewhere in the 2500-3000 range with peak hp in the low 4000's

His coupe was cruising down the road at 2000 rpm in 5th,@60mph, and just begging for more rpm. A good lean on the pedal, and you could feel the little 230 climbing up the torque band with noticable acceleration. He had all the throttle response you would want with no downshift to get there. He leaned on the pedal and put us in high 70's @2500 in seconds and had more pedal to go.

It was sweet, I promise!

The ideal setup to me would be to cruise just before the peak of my torque curve, use the curve to help me accelerate without a shift. Then, if If wanted to get froggy, use the rest of my torque range to bang me into peak hp at a significantly higher mph - after a good shift to wake it up!

The "seat of your pants" feel Bob's coupe has is directly associated with his engine dwelling just at the front side of his torque curve, right below its peak. His engine wants to accelerate all the time, and your engine has already reached its peak looking for another gear.

Bob would likely show you his license plate on the big road, but you would probably show him yours on the strip!

I hope Bob chimes in and gives us a good talk on mopar gearing.

Hudson

posted 09-01-2001 08:55 PM               

My dad used a Petronix magnetic trigger type electronic ignition in the stock distributor. Works good, but has a very limited range of operation - about 16 degrees. He has the vacuum secondary off with the spark plate bolted together. With a few modifications on a points based setup, I can get about 40 degrees movement without the vacuum. That's not possible with the electronic due to limited pickup range in the magnetic field of the trigger.

Petronix is supposed to have a new "dual dwell" system out there to remedy this problem. I'm curious to see what improvements they employed to do this. If memory serves, I think the new setup will accurately allow up to 32 degrees movement by mechanical advance only.

posted 09-09-2001 06:47 PM               

I found a very good article that discusses many of the issues that effect the performance of engines and explains the differences between engine types. The article was orignally written to prove/disprove the worthiness of auto engines as aviation powerunits. What resulted was an excellent overview of engine theory. Had this author explored crank/cylinder arrangement and rod ratio, this would be a wonderful article.

This article is the kind of stuff that you print off and read over a period of time, one reading just isn't enough to digest all the info - or at least for me it isn't.

hope you fellas enjoy it! http://www.eaa1000.av.org/technicl/engemp/engemp1.htm

posted 10-17-2001 12:27 PM               

[This message has been edited by DEL (edited 10-18-2001).]

posted 10-21-2001 09:29 PM               

First of all let me say - nice to have you with us.

I would like to hear some "new school" thought on piston speeds. Since I have the carbs straightened out on the little 230, we're hitting 6000 rpm on the track. I really need to swap cams to use this to my advantage - but at least I know it can handle the rpm.

The 230 @ 4.75" stroke is hitting the 4750 fpm piston speed and making me nervous due the fact it has cast pistons. I'm not so concerned with bottom end failure as much as I am piston failure at this point. Cast is lighter, but I'm beginning to wonder how much punishment the molecular bond of cast can take.

Season is over for us, we'll tear this old horse down this winter for an exploratory look and maybe even a little improvement.

Hudson

posted 10-21-2001 09:58 PM               

There may be a slight problem with taking the mopar flattie out to .125 o/s. They have a very thin, replacable sleeve pressed in the bores. The maximum overbore on the sleeve is .060 after that it gets too thin to dissipate enough heat to hold up.

At first thought, I was going to eliminate the sleeve and overbore the block to really open up the bores in these engines. However, the block casting is really too soft to withstand that type of duty. Flat Ram made mention of engines wearing out very prematurely and I attributed that to either a sleeve bored too thin or running the block unsleeved.

All hope is not dead! I haven't tried this but have read about it. Some antique tractors are dry-sleeved and have the same soft cast problems as the mopar. The blocks have been "cryogenicly" treated to harden the surface of the cast much like "case hardening". The difference is that the machined dimentions are not distorted as in the radical introduction of heat. Cryogenics is a deep freezing of the block in liquid nitrogen to achieve the same net effect as the cooling phase of heat treating.

I don't think I'll ever go this far with the mopar as the overall increase in cid wouldn't be that great as with the tractors, achieving in some cases as much a .625 in additional bore diameter.

posted 10-22-2001 12:23 PM               

Are you sure the sleeved engines aren't just for ag/industrial use? I've never seen a car or truck engine with them. I don't think the block would be too soft to run without, although the sleeve material is probably harder than the iron in the block. Speaking of being too soft, I don't think anything could be softer than a 400 SB Chevy. On the stroking issue, I was looking the other day and found another interesting possibility. The little pre '42 Plymouth of 201 cid has rod journals that are 1.937 with the same length rod as the 217. You could offset grind the crank .187 on the big motors or .125 on the small ones providing the rods are the same width as the rest. Might be a little too far to go on big 2.125 journal motors though. Piston speed is just sort of a non issue these days. For example: an NHRA Pro Stock motor has a stroke in the range of 3.75 to 3.82 ( we built one with the 3.82 stroke ) turn 10,000 rpm plus. That figures out to 6366 @ 10000 rpm. Stock eliminator racers run cast pistons a lot because they are lighter. They do not turn a lot of rpm because the valvetrain is the limiting factor for NHRA Stock class ( have to run stock valve springs so they generally valve float in the 5500/6000 rpm range with the crazy cheater cams they use ). The strength of a cast piston is actually pretty strong considering what it is subjected to. Think of it this way, our old flatheads really don't make enough power to hurt themselves. That's why so many oldies are considered to be so sturdy. Think hp per cylinder and compare to anything else with ohv heads. Ohv engines in the 300 hp + range have cast pistons and are actually subjected to more stress over the long haul. Weight wise the 3.25 bore pistons are probably pretty light, of course there's always room for improvement.

Regards,
Del

posted 10-22-2001 07:34 PM               

We had to replace one sleeve in the block we are running as it was pitted very badly when we got it. The original block was destroyed by freeze cracking when we got the tractor. This is where we first discovered the sleeves, in the bursted block. The replacement sleeve was a Perfect Circle I believe, but I didn't check to see its complete listing of application. All the engines we have dealt with were the heavy duty series L-6's (there is a difference and I'll look up the id numbers for them).

The blocks seem terribly soft to me, a rotary file ripped through the bursted block almost as easily as aluminum it seemed. I don't know the exact metallurgical composition, but they seem the softest I've ever seen. I know what Del is talking about in the 400 sbc engine, and the siamesed cylinder walls too - most I've ever encountered on the street had a blue haze coming from them.

I spotted the 201 rods too, but really don't know if they are poured babbit or shell type bearings.

I think modern casting technology and metallurgical science has done much to bring the cast pistons up the the demands and piston speeds of the racing applications mentioned. I think the Silvolite pistons would be good choices for these engines. I would really like to have a hypereutectic alloy casting in the L-6 mopar pattern.

Now on to areas I haven't explored fully but represent the next phase in the little tractor. Has anyone done any flowbench work on the actual intake ports/valves. Of course, getting a velocity off the valve seat is one thing, the ability of the air to flow into the cylinder is another consideration for the flathead. Any ideas or numbers would be appreciated.

posted 10-23-2001 12:22 PM               

The biggest problem in flathead modification is compression vs. flow. In stock configuration the transfer slot is the main restriction to flow. When the head is milled for increased compression the transfer slot is decreased in height hurting flow. One newer idea some of the guys running Ford flathead V-8's is to raise the whole chamber roof and then run a hemi style piston that sticks way out of the block to fill the resulting void and maintain a reasonable compression ratio ( serious bucks ). The idea is that according to some including Barney Navarro is the flow wants to go up as it passes past the valve, not sideways, so the roof of the chamber is in the way. Also on this note is that relieving is a waste of time as it does nothing to improve flow even though it widens the transfer slot. Also, a long time ago I read something about valve seat angle and have never seen anything since. The theory was a 30 deg intake seat flows better at low lift than a 45 deg. The reason being that at 30 deg. the face of the valve and the seat are farther apart than at 45 deg. If you do a little trig. on it it makes sense. At .100 valve lift with a 45 deg seat you get .0707 gap between the valve and seat, with a 30 deg seat it is .086 ). Makes sense to me that this would help a flathead since a high valve lift is almost impossible given the lack of rocker arms to multiply the lift. I would like to offer some suggestions on engine building and go fast tips as I go ( I only do this at lunch at work so I don't have much time daily ). By the way, thanks for the warm welcome from you and Bo. Also, where did you get your cam done?

Regards'
Del

posted 10-24-2001 12:23 PM               

When building any motor, the place to start is at the bottom. Most guys are on the hunt for the magic cam,head, or intake manifold and carburetor but the most basic and most often overlooked is the block. Think about it; after all it is where all the action is going on, right? After a thorough cleaning and inspection to make sure it is healthy and useable, if you are going to drag race or use it for some other purpose that only subjects it to short run times, fill it. You do not want to do this on a street or circle track engine as the oil temperature gets high since there is no cooling going on at the bottom of the cylinders. This is not a new idea. It has been around since the fifties ( there was a product back then called tuf-block ). Filling strengthens the cylinder walls extremely. When an engine runs the cylinder walls flex and this prevents that. Less power is transmitted to the cylinder and more is used to turn the crank. Now you may not want to do this if it has some special collector value ( drag racers often race but worship their rare pieces ). We filled them leaving water space at the top for about an inch at the top. On a flathead where the ports are in the block, you might run into a little difficulty around or under the port area. We used a commercially available cable setting grout ( can't remember the name anymore ). It looks like concrete but is WAY stronger with it's own aggregate and metallic material already in it. Yes, it does add weight, but at the same time it is displacing water at eight pounds per gallon.

Next on the agenda, or first if you are not filling the block, would be align honing the main bearing bores. There has always been a lot of argument against this, mostly being " when I tore it down, the crank turned okay ". Well I would certainly hope so after a hundred thousand miles. An engine pretty well clearances itself. But try putting a correct set of bearings right back in it and torquing the caps and see how well it turns ( can you turn it with just your fingers on the crank snout ?). You won't believe the difference in how free the crank turns in a block that has been align honed. It is well worth the price. By the way, the other argument against doing it is mostly about the skill of the machinist doing the job. A common problem is when they remove the couple thousandths material from the parting line of the caps, they get the thrust cap crooked, so when you assemble the engine the thrust cap is in a bind and the crank won't turn.

Decking the block is done after this. For the optimum benefit, measure all the parts: crank stroke, rod length, and compression height of the pistons, and mill the top of the block to give about .035 piston to head clearance ( a good figure for an iron rod motor ). Of course, you have to be careful if there is a lot of material to remove because you don't want to mill away the valve seats. A side benefit of milling the block is getting a good gasket sealing surface.
Boring and honing the cylinders comes next. Measure all the pistons where the manufacturer says ( they aren't all measured in the same place ) and get an average number. They don't differ enough to bother selectively fitting a certain piston to a certain bore. Checking the cylinder wall thickness with a sonic tester is a good idea if you are going for a large overbore ( even if not going way oversize, it's nice to know what you have ). Leaving about .180 on the thrust side of the cylinder ( the right or passenger side ) is plenty adequate. You can get away with a little less if it won't be subjected to any real hard running ( many stock modern engines aren't this thick, for example the 305 Chevies made in the 80's with the one piece rear main bearing seal have only .090 thick cylinder walls ). Relieving the cylinder at the bottom of the bore if/where it runs into the top of the main web, is critical to getting a proper diameter at the bottom when honing ( this isn't a problem on all motors ). The block should be bored leaving .005 or so excess for final honing. Honing with a torque plate is highly recommended if it is available. On our flatheads this probably won't be available, but a creative type could make one for himself ( I really doubt BHJ Products makes one ). You can make one by using a piece of material ( iron or aluminum depending on your application ) using the head gasket as a pattern. The head bolts used during honing should have the same thread depth as you will use on the finished product. This could also be used for doing the valve job on a flathead. The torque plate simulates the stress placed on the block/cylinders when the head is torqued in place. Believe me, they move, especially in the area around the bolts. The same type of head gasket should be used for honing and assembly as the stress varies according to the type of material the gasket is made of. When the honing is done and the plate is removed, the cylinders won't measure correctly anymore because of the distortion being removed so don't panic. The cylinder finish varies according to which rings you will be using. Plain cast iron rings use a pretty rough finish while Moly rings use a finer one ( chrome is just no recommended ). An even finer finish is used on .043 and Dykes ( pressure backed ) rings for racing applications. While honing the machinist can control the taper in the cylinders, and they should be perfectly straight when done ( this is the reason for the relief above the main webs I spoke of earlier ). All the work should be done preferably on a Sunnen CK-10 or the CV-616 as Sunnen has honing down to a fine art.

The valve work can be done either before or after the final hone work. Grinding the seats on a wet bench would be nice, but the sheer bulk of a block prevents that, so it will have to be done the old fashioned way, dry, on the floor. The seats should be ground so they are in the center of the valve face for good heat dissipation on a street motor. seat widths should be about .060 on the intake and .090 on the exhaust seats. On a more performance oriented application they are ground so the o.d. of the seat and valve are the same with a .045 width intake seat and .060 exhaust. This allows you to open up the bowl area a little with the bottom cut. By the way there is nothing fancy about a "3 angle valve job". It's the way it should be done in any case. The width of the seat is controlled by the top and bottom cuts. Lapping should NOT be done. This usually leads to the valves leaking more readily than if they had not been lapped. Any port work should obviously be done before the seats are ground to avoid any damage to the seats from a runaway die grinder. As I mentioned a torque plate could be used on the block when grinding the valve seats to simulate the stress caused by the head bolts near the valves ( they have them for Chevies ).

Now for the rotating/ reciprocating parts. The crank should probably be ground as after so many years of use and abuse it generally won't be round even if it doesn't have a lot of wear. It's also nice to have a nice fresh surface. The journals usually should be ground to middle/ bottom tolerance so bearing clearance won't be too tight ( .0015/.0020 is good for street use while .0025/.0030 is better for performance use ). The weight of some of these pieces can be downright monstrous and could probably easily shed a few pounds by judiciously grinding the counterweights and blending some of the material around the rod throws. All the extra weight is detrimental to actual engine acceleration. The more everything weighs the longer it takes to get moving and of course slow down ( the flywheel effect ). Knife edging the counterweights can also be done to improve windage ( a little more on windage and oil control later ). The rods should of course be straight. Too much emphasis is placed on fancy aftermarket rod bolts. ARP's are nice but in their absence don't sweat it as they probably aren't available, even after cross referencing, for our oldies . The big end of the rod should be reconditioned by honing. A few thousandths material is removed from the parting line ( after the rod bolts have been removed ), then the bolts are reinstalled and torqued properly and the big end is honed on a Sunnen rod hone. Again, as on the main bearing housing bores, you should go for top tolerance for performance ( .0020/ .0025 )and about nominal for street ( .0015/ .0020 ). The best way to set the clearances is to do the machine work first on the mains and rods, torque the bearings in place and measure the i.d. to determine the proper diameter to grind the crank. Polishing the side of the rod beams is optional. A lot of guys like to do it in the name of relieving stress, but any actual benefit other than getting rid of a little weight is up in the air ( they do look good that way ). Center to center length on the rods can be controlled when removing the material from the parting line prior to resizing. A little speed trick for high rpm operation ( and YOUR machinist may laugh at this ) is to hone the big end out of round ( big at the parting line ). This is done by squeezing the rod at the parting line with a pair of welder's vise grips when honing. Just a couple thousandths is good. By the way, the clearance at the parting line with a set of bearings installed is greater than with the length of the rod. When the engine revs, the reciprocating weight ( piston, pin, rings, and small end of the rod )works against the big end of the rod pulling the bore out of round. If it gets out of round far enough, the edge of the parting line of the bearing acts like a wiper on the crank journal removing the oil and POW. This is how most rod bearings are spun. In some cases where losing rod bearings can be a habitual thing, you can even pin the lower half of the bearing to the rod cap like in an aluminum rod. One main concern when resizing the big end though, is getting the bore straight. Many machinists don't have much understanding of this. They just place the rod on the gauge on the rod hone to check the diameter. This only checks the diameter in one place in the bore. You must pull the rod off the gauge slowly and watch to see if the bore is straight and not tapered or barrel shaped. This leads to poor bearing alignment with the crank journal and premature wear of failure.

Balancing everything is highly recommended. Although inlines are inherently smooth, ( they are neutral balanced because of the placement of the rod journals ) it's hard to believe what a difference balancing one makes. With an inline, all you have to do is equalize the weights of the pistons, big ends, and little ends of the rods. The crank is not bobweighted when balancing an inline, so the cost is less than for a V-8. Most serious imbalance problems are usually caused by the flywheel or most often, the pressure plate ( they always have a sticker claiming they are balanced, but that's on their fixture, not your flywheel ). The flywheel and pressure plate should be balanced on the crank for the best result and then marked so they can be reinstalled in the same position.( continued on page 2 )

Regards,
Del

posted 10-28-2001 10:01 PM               

The head reconfiguration was among my "to do" things and had already investigated how much material I had to work with in different heads to accomdate the "dome" above the deck and using about .035-.040 relief for expansion. Actually, I'm still working on it.

I'll have to agree on the block reliefs as being of little benefit to overall performance increase. It may increase the flow, but at serious loss to static compression in a situation that doesn't lend itself to improvement in that area anyway. The die hard Hudson 308 builders would beg to differ(Jack Clifford) - but I just can't go for that huge cut in the block as being the right thing to do. I had much rather go with the area above a domed piston that takes up the space carved out; giving me both flow and compression.

I'll definately agree on the bottom end as being the differnce between an engine surviving or turning into shrapnel! We went through 12 rods before finding 6 that would do, then had them seriously reworked. Our block was thoroughly resurfaced and line bored & line honed. The real modification that allowed us to hit the high notes was the oil port modifications in the crank. We're hitting 6000 rpm regularly with the engine under load in runs that last 10-15 seconds.

The cam is a regrind done by a shop in Somerset, Ky: Reed Coronet's Auto Machine Shop.

It's possible to get some pretty radical lifts on flathead cams. One method would be to overbore the cam tunnel for a larger bearing from a different engine, sleeve the camshaft journal with a press fit bushing, Then build up the lobes with a sintered alloy by flame-spraying it on. The sintered alloy required just enough heat to bond rather than the radical heat of welding that may distort the cam and ruin the concentricity of the distributor/oil pump gear. One could also build up and regrind the journals to match the new bearing diameters. Remachine or swap lifters from another engine (Hudson lifters are shorter and same diameter as mopars). Just because you've been so good at sharing info - here's a link to my favorite sintered alloy applicators. I was treated to a demonstration in college and immediately thought of how to use this in engines.
http://www.castolin.com/Products/Coating/Coat_Prod.htm

Getting lifts of .500 are possible without all those radical mods. But, the stock cams are limited in the amount of material they can give up if you decide to shift the lobe separation angles very much. You might want to give us a refresher on the evils of small base circles in cam profiles.

It is one of my pet projects to "rollerize" a flathead engine. I would like to use the hollow body type lifter and machine a drop in adjustable slug in a remachined pushrod hole. I also like the "H" type link bars that trap the lifters from the top. I still have alot of planning and researching to do on this one so don't be too hard on me. But, the more I look - the more possible it seems.

posted 10-28-2001 10:20 PM               

Nice looking flatty!

I hope you have better luck with those Ball&Ball carbs than I have. I finally have mine straightened out.

One thing, You may want to notice the discussion of "long" vs. "short" engines in this thread. The spitfire engines that I've seen are the "long" versions of 250 cid. The trick head to have on the short engines is the '58 heads from HD series engines. However, the earlier ones may have value in the modifications Del and I have mentioned previously. By the way, the top hp listed for the 230 was 125hp in '58 which is the base engine we're using in the tractor.

As I've said before, the only real modifications to our engine, beyond blueprinting to exact dimentions, is the crank/rod work, a dual offy manifold with B&B carbs, and a regrind on the camshaft. We just wanted to see what we could do with the "basic" engine first - then get funky with it.

So far, its doing pretty good just like it is - but I want the next phase in the hopper and ready to go too.

posted 10-29-2001 12:13 PM               

Cool Dodge! My '47 Chrysler with the 250 looks like it has a different oil filter hookup than the short motors. It looks like it is a full flow system rather than the 'piddle' system like my '48 Plymouth has ( like the old Chevies and Fords that filter a little and run it back in the crankcase ). My plans for the '48 are installing a 265 Chrysler six w/speed mods. There's not as much cool stuff for the long motors, but I figure I can get a few more ponies out of it and still be able to make it look cool at the same time with the right kind of detailing. By the way, does anybody know if Phillips Performance is still in business? Someone said the E-mail address doesn't work anymore.

posted 10-29-2001 11:05 PM               

Check out the progress on my '50 Plymouth

http://home.rmci.net/blueskies/plymouth.html

posted 10-30-2001 12:13 PM               

It wouldn't be hard to make one up. All you need to do is put the PCV valve in the road draft tube, hook up it up with a vacuum line to the manifold, and filter the fresh air coming in at the oil fill cap. Someone has already done this on my '50 Ford pu flathead ( homemade ). I had a '51 Ford business coupe with the 226 flathead six that had a PCV system from wayback. It had a small oil bath breather cap and a fitting at a 45 deg angle on the road draft tube with a hose going to a vacuum fitting under the carb. The only thing to watch out for would be it sucking oil if the area around the PCV valve isn't baffled well.

posted 10-30-2001 12:16 PM               

Thanks for the hot lead on the head! I haven't seen too many of the Wayfarer coupes, but I have seen a few roadsters ( mostly hulks ).

posted 10-30-2001 11:01 PM               

come on over to the thread called B&B woes in this mopar forum. I've come to know the B&B far better than I really wanted to. But, I got 'em honking. Read through it and I think I have a good source for parts listed, but the Mgr is kind of asinine about exact carb #'s, you can swap far more than he allows. We can talk over little mods to get them set up for you.

posted 10-31-2001 03:21 PM               

[This message has been edited by carlo (edited 10-31-2001).]