Inliners International Forums General Discussion Hi Performance Dyno day for a 250

Tom:

I have another check headed your way (via snail mail) today. Use it to finish up the 292 pulls or on this next project as you see fit.

I know this would NOT be a possible 250 configuration to test but the results (or lack of them) would sure be interesting:

Suppose you take the best 250 combination you achieve in your future dyno pulls and simply moved all the components over to the 292 tall deck block with the only change being a switch to the necessarily long (7.425" cc ? - yikes!) connecting rod to arrive back at a zero deck. I'd be very curious to see imperical dyno proof of the benefits (if there are actually any at all) of a long rod configuration and its significant improvement of the rod:stroke ratio.

If I did the math correctly, the resulting ratio would go from 1.6:1 for the 250 block to something like 2.1:1 for the 292 block - all other things remaining equal.

It may be that the better rod ratio will only show an increase in performance in a maximum effort race engine and show no measureable impact at all on a street motor. And even if there were a positive impact, is it even remotely worth what the cost of the custom rods (and perhaps piston package) would be? Probably not but it would be interesting to know for sure . . .

Russ

Thankyou Russk,

The dyno charges as of now were more than what I recieved from you guy's by abit.
Total recieved was an amazing 1405.00 from about 30 of you! So the charges are off by about 400.00. I am ok with that.

There is more running to be done yet and hope to get more clean runs this weekend.

Guy's the multicarb thing is a tough one. The only way I'd be interested in doing it is if someone had a good running setup to try. It would take alot of time for me to set one up (jetting and such). Tom

I have stated before ,,I ran 3 48 MM side draft weber DCOE's w/something around 46 MM choke tubes,(not much smaller than the throttle valves.

The carbs were too big for my 250,,,but,,, with those carbs,,that were even too big,,,made more power,,,more torque,,,better streetability than any 2 bbl ,4 bbl, clifford or offy intake combo I ever tried,,,& believe me I tried almost all popular carb combos & even not so popular carbs,(thermoquad)example) with both the clifford & offy intakes.

I just wish I started off with the Webers first thing,,I would have won a lot more races w/those ;-)

I think the 3 48MM webers flowed about 1100 SCFM.

It seems w/Webers,,,it's kinda hard to over carb.


MBHD

Hank, was there a ballance tube on your Webber setup, or was it like 'normal' Webbers? (ie, no ballance tube)

Nexxussian,,


no balance tube,,I had the Clifford/Weber intake.

With Webers,,I think it is as close as you will get to fuel injection & still be carburated.


MBHD

Here's Steve's Webbers. Webbers

This may be an area where Tom Langdon could help???? He's done enough of them by now he should have the jetting etc. pretty well base lined. Multi Webers are a nice carb but not as affordable for most of us as a standard Offy with 3 carbs. Now if we ever go for a race engine dyno test they should be included along with some big carb and mechanical fuel injection setups. My 1 cent.

Looks like we're headed for a third set of tests using the best set up from these and a bunch of carbs and injectors. Then there's the whole boost thing. Tom what are you doing for the next couple of years? Did you say your wife used the word "crazy"? I feel the best information to be gained in the 250 tests is to repeat the 292 tests as closely as possible. After all we don;t want to answer all the questions in the first episode. You've got to leave room for a sequel or two. Didn't you guys read Harry Potter? I see a trilogy in our future.:D Beater

Well, before we spend too much more dough, we could almost buy a dyno for what we will end up spending for several more dyno sessions....then you could test virtually any combo imagineable with only time being the main contribution to deal with.

I like that idea CNC. Dyno connections (harness, hoses, stands, etc.) all set up for inlines. No rush to get out of the way either.

Xactly, sometimes you just have to see if the end justifies the means, before you realize you could have bought one for what you payed someone else to do....just thinking ahead. Seems like this can be an ongoing R&D project for these engines, so why not!

Lets buy one and set it up at Tom's house. Then we could all use it when we want and Tom could help us. Oh yea, his family, well we could put it at my house. No help though. I think there's a chassis dyno around here that could be had for cheap. Beater

Tom, check your paypal, now to interject some probable faulty logic, if the Clifford produced more torque and hp across the board on the 292 if the same occours on the first few 250 tests do you need to change manifolds for each cam and/or head change on the next pulls? Trying to save you some labor and maybe free up some time for other tests.

I am interested in this effort and may contribute. I haven't been watching the 292 thread that closely, so I'd have to figure out what the plan is. I'm interested in the 260H cam since that's what I'm using and also the lump types and intake/exhaust options.

If we are trying to trade off different heads and cams for primarily street engines, why start with a relatively exotic short block with high end internals? Couldn't you do all the same with something closer to stock?

67pete,
We are testing this engine and the 292 for street driven/ proven combo's. Each cam, intake, head is tested. Idle vac readings are taken and pulls start at 2500 rpm and go till the hp falls off.

A stock built lower end would do the job. But repeatability is what is desired. After the dust settles, There would certainly be a home for the motor.
For the 250 build, the components would be setup for longevity. Crank/ rods/pistons balanced. Forged pistons, crower rods (have them).
With the time/labor invested, all would be wasted if the base of the test mule started to decline during running of all the pulls.

I am all for a test of the Comp series of cams for the 250. Can someone get them to donate them? I have tried and got no help. Tom

Tom, i've gotten Comp to contribute to several of my engine building tech articles in the past, i'll give my contact there a shout this week and bring him up to speed so far on what we have done with the 292. They have been pretty easy to get contributions from in the past, at least for me, so if you can get me some specific part #'s before I contact him, that will help me know how to proceed.

Guys, my 250 originally came with a .600 lift cam that I removed because it wasn't streetable. Appears to be barely broken in but I didn't see any markings or numbers so I don't really know what it is. I supposed it can be measured.

At any rate, if you want to add it to the mix, I'll be glad to donate it to the cause.

Tom, I have the CompCam 260 in mine along with the head you did... Alum pistons, 60 over. Offy intake, Clifford truck headers, Edelbrock 500. Is that close to one of the configurations in the plan?

Kerry, i'd say that combo is spot on for the components we have available, except for the camshaft. Tom sent me a list this morning of the Comp cams he would like me to try and get from them, the 260H being one of them. I'll make a call and see what shakes loose.

I'm not opposed to pulling my Edelbrock and loaning it for the test but it is on my car and I'd a short turnaround. Don't know the issue with shipping a gas smelling carb these days either.

Tom;
Money order is in the mail.
Thanks, Al #4802

Al, james, Jalopy, and others,
Thankyou again for your help. Glad to see the support!

Kerry,
I do have a Edelbrock 500 and 600 sitting here. Why don't you bring that roadster up and we will have some fun!

I am presently getting the pieces together to form up the 250 lower end. Try to pick a date in January. We will see what happens.

Tom

I wouldn't be surprised if you get a ride one of these days Tom.

Tom, on the 292 thread you mention that you're pushing the 292 to 5400 RPM and that's into the concern range.

Of course with all the problems and crap with my 250 I'm not sure what to believe but the guy I bought it from said that the builder said his engines (built for the Nascar dirt track series in VA) would turn 6000 all day.

I doubt that my engine will ever see close to 5000 but just wondering...given the shorter stroke, what is the RPM range for a flat top alum piston, small block rods, balanced 250?

I turn my 250 to 7000-7500 rpm ,w/supercharger. . flat tops w/stock rods.

If you have a good damper on the crankshaft,,,they will turn higher rpms.

My 250 engines would never want to go over 5500 with a stock damper.


MBHD

Hank, what's the failure mode associated with "would never want to go over 5500 with a stock damper"? Damper explodes, crank breaks, pistons self destruct, or?

No failure,,,it just would get so much harmonics going on you would be loosing power,,,you could go higher RPM,but would not get anymore HP by doing so.

Switching to a good damper would allow you to go higher RPM & actually make more power.

My engines were all balanced pistons & rods weighed exactly all the same.
Zero balance the crank assy's.

MBHD

I think unable to reach performance potential due to harmonics qualifies as a failure mode.

I do not see it that way,I'm thinking failure = broke something,,I changed the damper & then would go to 7500 RPM.Which reached beyond my performance expected,AKA potential.
But,,,to each his own.


It was a learning process,,no company tells you straight out,,,,,if you want to rev your inline over 5500,,,you must get a different damper,,,that was back when I used to talk to Jack Clifford for advise, & I must say,,,most advise I got from him & his staff was pretty bogus. IMO




MBHD

Kerry,
To answer your question. 6000 is a safe rpm for a 250 if built correct. They will go much higher in RPM but those are different engines than we run. The valve springs you have will also allow you 6K rpm. Tom

hello! i lurk on here from time to time but dont do much posting. But this seems like such a good cause I'm in too. I just sent some money via paypal. im interested especially because this fits in with my 63 nova. it currently has a 230 with clifford 270h cam, intake, and headers. It has the 390 holley and a head that i ported myself and shaped the intake boss into a wing with 1.94 valves. I have a 250 sitting in the garage so this will be great for a possible build down the road. Keep up the good work this is great stuff!

I ran a 57 Chevy 283 "270 hp" in Junior Stock back in the 60s. We were allowed 55 lbs. on the valve seats and I saw 7200 rpms every run. Of course that was a solid lifter cam and the springs would fall off real bad after 10 to 15 runs. I run 90 lbs.on the seats,194/160 valves, opened up pockets,NO LUMPS,zero deck,flat top pistons and 262/ 500 lift cam by Lanati in my 250 and like you say 6000 is no problem..but from 5000 on it just stops pulling hard. As some one on this board said "not too much cam..Just not enough motor".. The balancer issue is something I need to look into more... J

Ok guy's,
Pulling a greasy 250 down and going to document the build on it. This will be the 250 for the dyno tests.
It will be fully balanced with:
Custom pistons (flat tops)
Crower Billet rods (allready have them)
zero decked
Allign honed mains
Find out overbore after teardown, try to keep to a minumum. This lower end will be reved to a higher rpm on the dyno for testing.

Thanks for the contributions so far on this 250. Tom

Hey Tom:

I have a lot of other things right now pulling money out of the wallet but if the dyno run is not until Feb I'll send you some money. I'm getting the garage cleaned out so I can get my 250 built up too. First up.....balance rods and pistons.(cast flat tops) Box says that they are weight matched but,"I'll be the judge of that"! I will be keeping an eye on this thread!

Randy S. Hager
Venus, TX
Still designing the Berta type head!

Yeah, I think the 292 dyno testing came a little quickly for some that wanted to participate, but couldn't, because it did happen on short notice. Tom and I both wanted to test a new Hydraulic roller cam conversion on the 292 that I have developed, so maybe we can test it on the 250. I also have designed and prototyped some exhaust port plates for these heads as well that we didn't get a good chance to give a thorough shakedown either, but so far they look very promising. So there is still several new products being developed for these engines that hopefully will have a little more time to tweak and perfect this time around. So it just isn't existing products being tested, its also new technology being developed as well.

I was getting curious about the status of your Berta head project.

CNC-Dude:

Very interested to see how your hydraulic roller cam works out, as well as your exhaust port plates. Sure would like to see some photos of each when you have the time.

I'm also curious about the Berta head project. I think you suggested some reshaping of the ports to improve (lower RPM) velocity might be worth looking at. In any event, if a new aluminum version of this head were to come to market at a price point similar to the CI small Ford head, I can't imagine that it wouldn't be purchased in significant enough numbers to be profitable.

Russ

Russ, the exhaust port plates was something I threw at Tom in the last days of testing. He was already overwhelmed with combos we had pre-planned to test, so naturally, we weren't able to evaluate them to their fullest potential. But right off the bat, I saw several changes that needed to be made immediately with the initial design, so that will give me an opportunity to rectify them, and then test them further. Also, since you have interests in the Ford 300's, im already seeing crossover potential for these plates with that engine as well, so don't worry, im already thinking way ahead.

Clyde @ PES Made these same plates years ago.CNC dude is not the only one working on these.When clude first did these plates they were not ment to be bolted in. As He told me many yrs back.

Mine are designed similar to others that companies that also make them that require no welding at all. I have never seen the style that PES makes, so I can't say what is required to be able to use their brand. But like Larry mentioned, I have also heard they require welding for installation, so making a version that will allow them to be installed without welding, or even any machine work, as mine are, is going to increase the marketing potential, I think, because of the greater ease in which they can be installed by the end user. Also, patent protection will also be an added feature incorporated into mine, so before this product will be revealed, that will be in place first.

CNC-Dude:

The Berta head will take some time to get through the design phase. I have hand drawn some port sketches but still need to have them done with CAD and check it out in 3D. One of the design issues is that I want 360 degree water flow around the exhaust ports and I'm having a mental block about it. I hate getting old. I'm only half century old. I would like to check out your roller cam for my 250. Do you think that a profile similar to the 262 V6 would work for an inline engine? I'm only looking for max torque and I'm running a 4L60/700R4 trans and 3:73 gears with 28.7 tall rear tires. Well......as soon as I get it all together that is!

Tom; A C-note will be in tomorrows mail. Hurry! Wish I could afford more. (I do know how to pronounce Lowe)
SOB