Inliners International Forums General Discussion MOPAR Street Rodder magazine Plymouth

The current (August) issue of Street Rodder features a nice 49 Plymouth. It has a built 230 with twin carbs, Edgy head, Arias pistons (10:1 !) and a 52 Dodge truck crank. They make reference to 300hp.
2 questions...
1.) What is the max compression ratio usable on the street?
2.) What do you think this engine really makes...maybe 175hp?


It is a very nice car...

Leif

Nothing wrong with that compression ratio, except:
1. it restricts breathing in a flathead motor, 9:1 probably produces more power
2. it may knock if the intake valve closing point is conservative

No cam mentioned?
175 is possible (.76 hp/inch), 300 is complete fantasy without blower, nitrous, or both.
Considering the low state of development (long stroke limits engine speed, small siamese ports, limited cam lift) and casting limits perhaps 1 hp/inch is possible, but it would take a huge amount of R&D time.

Unless you already have a 230 engine is very good shape (i.e., no repairs needed, good oil pressure, good compression, low mileage) it's easier to find the similar but different 237, 251 or 265 DeSoto/Chrysler L6.

Is it one of the Edgy over head conversions? If so thats a whole new game.

Edgy has an overhead conversion? I didn't know that! This one is just a flathead.

He's done a few. I saw one in a push truck at Bonneville. I don't know anything about it. In fact I didn't know what it was when I was looking at it and no one was around to ask. It's in this pickup.

Leif, do you want me to check on that other 413?

Yes please!!!

Earl Edgerton made two of the overhead valve conversions... one for himself, and one for his crew chief Chris and his Dodge truck. Here's a few pics:





The car in Street Rodder belongs to Howard Tarnoff, and has an EDGY finned aluminum flat head with a 9:1 compression ratio.

According to Howard, the horsepower claims were editorial and they didn't ask him for the real numbers... Howard based his engine on mine, and I can assure you mine doesn't have 300 hp

Pete

The top photo looks like an "IOE", or pocket valve conversion (as opposed to OHV, since the original exhausts are still used), as done to some Indian 101. This was also a popular design before 1930 - the all-conquering 1928-31 Excelsior 45 used it, and all pre-1930 H-D big twins.
The intake valve is overhead with a pushrod and rocker arm, the exhaust valve is sidevalve and upside-down, running right off the tappet.
To convert a flathead engine, the original intake seats in the block are closed with plugs (which look like valves), then milled flat (so they don't interfere with the sealing of the new OHV castings). The ports are capped (as shown). The intake rockers are positioned directly over the flathead tappets for best pushrod alignment. The entire intake port is in the new casting, which uses as many of the original head bolts as possible (water also? not sure), and as you can see it can be several separate castings, 1 per cylinder etc. This is nice because it saves you from making a really big casting (they can be "modular"), but each motor will be different depending on the bolt patter, valve seat position, etc.
The compression can't be really high since the chamber still must cover the exhaust valve, but it's an improvement. The intake rocker ratio (if used - they didn't seem to do much with that back then) increases intake breathing, the port stays cooler, and of course the intake port can now be far bigger, more direct and the valve can be truly huge - almost as big as the piston (if you wanted).
There are still some IOE conversions made for the Model A.

The 230 (251?) engine shown appears to have siamese intake ports, where each new separate intake casting feeds 2 adjacent cylinders. From the bolts showing it looks like the 3 castings differ slightly.
Just a guess: he probably used a rocker arm from some existing engine by planning his positions carefully. There's probably a fitting you can't see that takes oil from an external source (pressure switch, filter?) and feeds the rocker shaft, etc.

Here's the "Riley" Model A head in section

The model a Ford guys love their Rileys and say that the "two port" which has siamese ports works very well and is a huge improvement over stock, with double the stock horsepower. Since it's a 4 banger the shared ports have more time between "sharing" than they would on a six. Still all but the most high performance designs had shared ports untill the '50's.

Although this (IOE or "F" head) conversion is inferior to a complete new OHV head in terms of power, it's still a very large improvement over a sidevalve, and much easier to construct.
Begin with a head, iron is OK but easier with aluminum since the chamber has to be welded. It's important that there be a "window" in the head above the cylinder which is dry (does not include any water or hollow space), since this will be bored straight through from the upper (bolted) surface to the gasket surface to permit the intake valve to open.
The existing head bolt pattern will determine how and where the new intake "module" (self-contained port, rocker arm housing, cover etc.) will go.
There must be oil to the OHV valve gear, so a pressure source must be tapped (like the stovebolt) and a line run up to each module. Oil drain can be done by contouring the "floor" (top surface of the head) with channels to direct spent oil to the "plug" which performs multiple functions:
1. closes off the original sidevalve intake valve seat
2. allows the new OHV intake pushrod to access the intake tappet
3. oil goes down the pushrod hole to the tappet gallery
The new static compression ratio could be quite high, but unless the cam is reground with the intake duration (especially the closing point) extended to OHV standards (no such cam exists) a conservative CR would be preferred to keep cranking compression suitable for pump gas (165-180 psi?).
A Schedule 80 90° "weld ell" should make an interesting start for a module, it's weldable, cheap, has excellent internal shape.

Panic:
You get the prize for best post of the month! Fascinating idea!

Thank you, kind sir!
Obviously, I'm just repeating things already done and adding what seems like productive methods of doing it again.
The Chrysler 218/230 look like the best candidates for actually making some of the parts, since they're the most popular L6 flathead engines and they're pretty durable AFAIK.
I'm sure a casting (like Edgy did) will work very well, but I tend to favor things that I can understand and control better, and making a "module" out of commercial shapes looks possible.
Use 2 90° Schedule 80 elbows (90° is, IMHO, a good compromise between flow, height, and carburetor fit since down-draft will make everything taller) for the port wall and ID of each module (total of 6 elbows, 3 modules), seat them the same distance apart as the intake guide centers on a piece of 1/2" plate.
The plate should be bigger than the bolt pattern around a pair of cylinders (that share an intake port: 1&2, 3&4, 5&6) so that these bolts (replaced by longer bolts or studs where needed) can be used to attach the module. The elbows must be rotated toward each other (the exact angle depends on the center distance, and how far the stubs protrude laterally) so that the ends can be joined to make a siamese port. It may be possible to use an actual (Offy, Edmund) 3 × 1 or 3 × 2 manifold if the port center distances match the original - saves buying a manifold!
Weld the elbows to the bases all around the exterior.
The commercial valve seats go underneath, tilted at an angle favoring the bore center (this is also the angle you want for your donated rocker arm, so pick a V8 etc. rocker with this valve stem angle).
Now the hard stuff: the guide boss has to be part of the roof of the port. A 1" cylindrical chunk of 6061 with a .625" hole in it (you need 6 pieces) can be placed in a hole at the stem angle in the port, aligned with the seat, and welded in place on the top only (it only sees vacuum - no pressure, no water, no oil) to make welding easier. The hole fits a 5/16" ID commercial valve guide (bronze = works with less oil?).
The rocker support will depend on what you want it to look like. A single piece could house all 6 rockers and span the length of the head, but looks weird. Individual rocker housing could top each elbow at the guide boss (2 per module), but it's more work. Having a pair of rockers in a single housing (1 per module) is a good compromise.

I have to say that it looks difficult to get around the water in the 230 head. If the jacket really extends across the width of the "closed" chambers, the section with the new valve seats will have to be sealed against water top and bottom which will be a lot of welding (and potential warpage).

This is so odd - none of my fans appear to have read this thread (missing: the usual "here's why you're wrong", "you don't contribute anything", etc. comments).

Wake up!

Is that what you want?

Meaning, would you take this opportunity to validate my remarks concerning your motives?

It's not up to me to "validate" your remarks, nor is it up to you to concern yourself with my motives. I come to this site to have a friendly exchange of ideas with like minded inline enthusiast. I come to learn and comment when I feel I have something to add. I love to joke with those who can take a joke. Those who can't take a joke are of no interest at all! Those who whine when questioned and then whine when they are left alone fit into the "can't take a joke" group. You are as smart as you are. Your information is as good as it is. Your social skills? I'm new at this, I didn't even own an inline Chevy 6 until '61 and no famous racers would know my name. Sadly your ideas on the flathead conversion were interesting but your need to be in a pissing match put me off! Tom

I'm trying to detect whether there is a pattern of content to the personal attacks - it appears that the more complex subjects are less controversial? I would have thought the opposite.

Carrying my warning forward: I tried a search for Chrysler 230 etc. posts looking for one that had pictures of a sectioned iron head to see if there is room for the new OHV intake valve without puncturing the water jacket - no luck.
Possibly it was another site?
If there's water over the entire bore area (I suspect not, but I've been wrong before!) this makes the whole thing considerably more complex.
I'm also focusing on fabricating the whole module-thingy out of commercial shapes, rather than obsolete parts or new special castings since they elevate the project to a level above many who might be interested.

Needless to say, this is also a potential method of upgrading your Ford L4 without looking for those original and now pricey Cragar, etc. conversions, or getting a new Riley ( http://www.secretsofspeed.com/RILEY.htm ) in a box (looks excellent, but expensive).

BTW: this is also possible with the Hudson, Ford 226, Pontiac 239 etc. but I have less data, pics, etc. on these and they seem to be less popular. I try to research the donor that would of the most use to the enthusiasts, rather than my favorite, or the cheapest. The Hudson does pretty well as-is since the porting is highly advanced for a flathead.

Yes, the Hudson has good porting...

But it's like the Chev of the same era, handicapped by lack of a proper oil supply to keep the big ends alive at revs.

While I see that your proposal has merit, I'm thinking it might be easier to go to a less complex casting, a sandwich casting that enables you to have less complex coring at the expense of a joint in the head top and bottom.

Of course, what was I thinking. Too bad I didn't learn anything from my pattern making and foundry classes.

So as not to waste your time, I'll spare you any more details.

Ray
This is an interesting idea. I was thinking you could use 2 copies of an existing aluminum head, mill the bottom off one copy and the top off the other. It would give you access to the inside to but in the port. I was also thinking that where you are sealing against water (not combustion) you could just use silicone. That stuff will take a lot if it's properly applied and the joint is the right size.

This is a good example of what should not be done on this website and why people are complaining.
Snarky, self-righteous, condescending, passive aggressive, narcissistic behavior is not part of the rules of this website.
You do this on other sites as well. It's not about what you know, it's how you present it. you just suck all of the positive energy out of everyone around you.

The irony of this post is that what Ray said didn't even warrant this kind of response.

Consider this a warning...

I believe this thread was to award kudos for a nice Plymouth that graced the pages of Street Rodder Magazine, why did it deteriorate into something completely different???

Earl 'EDGY' Edgerton, who is, by the way, active Inliner #2762, has been designing and building speed equipment for MoPar sixes for years. His F-Head he built, in my opinion, is a work of art and doesn't need anyone expounding on how it 'should have been done'. His conversion has 6 intake ports in the new head casting and uses the original 6 exhaust ports, those black thingys are the rocker arm covers.

I, as Administrator, along with our Moderators have the task to keep this Bulletin Board a pleasant and informative place to visit. I don't post much and rarely visit the other Forums, but I do read every post on this Bulletin Board. Gearhead, one of our Moderators, has issued a warning, so no further warnings need to be expected.

[/quote] Consider this a warning... [/quote]

Finally !

Thank you.

This has been very informative - all of my prior suspicions are completely confirmed.