Shoud I relieve my block

[Ronnieroadster]

Here's one of them Ford flathead speed secrets learned some time ago a built not relived Ford flathead will rev to 5 grand. To get another thousand RPM a relief will get you there. And to get even more pay attention to what Dale wrote above.
Ronnieroadster

[Pete]

Originally Posted by tubman

Oh, so it's the old : "I could tell ya', but then I'd have to kill ya'".

Well, actually, I have seen on both this and the HAMB forums, a few years ago, pictures of several of the top fuel drag engines with the heads off.
In the old days I saw the Bean Bandits engine with the heads off several times.
Also several other record setters of the day.
The info is out there if people really want to get it.

The thing is, most people can not tell what they are looking at even if they have a caliper and can measure things. Modifying a certain area by even .010 can lose you 5 hp. Few people can discern .010 with the naked eye.

[Ol' Ron]

With the Gas allowed at Bvill I can't see that running ON14: 1 CR I know John looked at allot of chambers, His displacement was alittle over 300 not sure what and the Cr around 12 :1 I know what the power was, ans it was nowhere near 1 per cubic inch. Just what kind of gas do you run on 14:1Cr???? Or is that a secret also/???
Gramps

[Pete]

I don't think that any of my modern engines have run at Bonneville.
They are circle track engines for vintage racing.

Most run alcohol but I do know that a couple run 118 race gas because of rules.
It works fine.
I ran the old discontinued 115/145 av gas in the 50's and it worked fine also.
Gas is usually down in hp about 10% from alcohol.

[richard crow]

if you want a fast car buy a corvet. the more you do to a flathead the worst it runs if you want a smooth cool running eng leave it stock

[Jack E/NJ]

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RR>>Here's one of them Ford flathead speed secrets learned some time ago a built not relived Ford flathead will rev to 5 grand. To get another thousand RPM a relief will get you there.>>>


Interesting. I'd hafta guess that the Hudson racing cognoscenti had a few secrets like this as well.

[Ronnieroadster]

Ron at Bonneville VP racing fuels brand is the gas available.
Anyone running for a gas record must use the VP gas. Example of the octane grades available C-16 has an octane rating of 116 for compression ratios up to 17.1.
The actual altitude at Bonneville is just over 4000 feet for a flathead that has a hard time breathing at sea level this of course is a big issue. I've read for every 1000 feet of altitude an engine can see a reduction in power of 15 percent.
When other factors are added in the density altitude gets even worse early morning at Bonneville the density altitude is just under 6000 feet. That's why the backup runs for a record at Bonneville are held early morning so our engine's have the the best air possible.

Here's one example and some details from the fastest run to date we made with our stock block Ford flathead
{Note stock block means we use the three exhaust ports on each side of the block as designed we do not add any other exhaust port}

Our flathead is 292 cubes we burn C-16 VP gas the car weight is well over 3000 pounds.
The density altitude just after 2 PM in the afternoon was over 7000 feet the Ford flathead engine turning 6100 RPM ran 219.8 MPH . To get a speed this fast burning gasoline takes horsepower lots of it we always run a block relief to help the combination to survive. Hopefully this information will help others in the future who may one day decide to try and do this crazy stuff some of us are doing.
Ronnieroadster

[Ronnieroadster]

Originally Posted by richard crow

if you want a fast car buy a corvet. the more you do to a flathead the worst it runs if you want a smooth cool running eng leave it stock

Well I'm sure there's a few flathead blocks around that would easily put some agent orange corvet to shame in a side by side run
Ronnieroadster

[mhsprecher]

I don't know, but the Beach Boys seemed to think it made a difference. ;-)

Little Deuce Coupe, you don't know what I've got
(You don't know what I've got)
Little Deuce Coupe, you don't know what I've got
Well, I'm not bragging, babe, so don't put me down (Deuce Coupe)
But I've got the fastest set of wheels in town (Deuce Coupe)
When something comes up to me, he don't even try (Deuce Coupe)
'Cause if it had a set of wings, man, I know she can fly
She's my little Deuce Coupe
You don't know what I've got
Little Deuce Coupe
You don't know what I've got
Just a little Deuce Coupe with a flathead mill (Deuce Coupe)
But she'll walk a Thunderbird like it's standing still (Deuce Coupe)
She's ported and relieved, and she's stroked and bored (Deuce Coupe)
She'll do a hundred and forty in the top end floored
She's my little Deuce Coupe
You don't know what I've got
(She's my little Deuce Coupe)
(You don't know what I've got)
She's got a competition clutch with four on the floor
And she purrs like a kitten 'til the lake pipes roar
And if that ain't enough to make you flip your lid
There's one more thing, I've got the pink slip, Daddy
And coming off the line when the light turns green (Deuce Coupe)
Well, she blows 'em outta the water like you've never seen (Deuce Coupe)
I get pushed out of shape, and it's hard to steer (Deuce Coupe)
When I get rubber in all four gears
She's my little Deuce Coupe
You don't know what I've got
(She's my little Deuce Coupe)
(You don't know what I've got)
She's my little Deuce Coupe
You don't know what I've got
(She's my little Deuce Coupe)
(You don't know what I've got)
She's my little Deuce Coupe
You don't know what I've got, what I've got

[flatford8]

This whole thread was great reading on a cold rainy day......Thanks guys!!.......Mark

[John R]

Originally Posted by Bored&Stroked

Actually, you were not wrong - it is all about the application and usage of the engine. Relieving a Ford Flathead does nothing of value before about 4000 - 4500 RPM . . . actually it hurts low end power as it reduced compression (with everything else the same). Also, relieving is just one small piece of the overall puzzle - you have the ports to worry about (they take serious amounts of work), you have the cam to worry about, you have the valves, the chambers in the heads, etc.. As Pete noted - when all the things are specifically designed to work together (for racing) - then relieving is part of the "combo" that was typically used.

Also, typically these naturally aspirated engines were fuel injected - which surely adds horsepower over the typical Stromberg setup. And truth be told, the classical Hilborn flathead injector is too small for max HP. Guys like Don Ferguson Sr. cast their own injectors way back in the 80's - with big port/butterfly sizes more like a SBC injector (to get the flow they needed).

Then, one can start talking about oil-control, dry-sumps, crank scrapers, vacuum pumps, low-tension rings, straight-cut cam gears, etc.. A lot can go into one of these engines - and it is not for those "on the cheap".

Dale, Thanks for a very balanced and informative discussion of the topic!.
John

[Pete]

Originally Posted by Jack E/NJ

RR>>Here's one of them Ford flathead speed secrets learned some time ago a built not relived Ford flathead will rev to 5 grand. To get another thousand RPM a relief will get you there.>>>


Interesting. I'd hafta guess that the Hudson racing cognoscenti had a few secrets like this as well.

You are right there. I learned a lot from Smokey.

[Bored&Stroked]

Originally Posted by John R

Dale, Thanks for a very balanced and informative discussion of the topic!.
John

This has been a good thread - based on a lot of the folks contributing who have many years of experience with these goofy engines (not only Ford, but many other variants).

Like anything else, there is no one "right" answer . . . the answer is the usual "well, it depends".

[Zeke3]

I am not sure exactly how the rating system works on this forum, but if you have enjoyed this discussion I encourage you to rate this thread. The “Rate this thread” button is in the ribbon at the top of the thread. Normally I would rarely rate a thread, but there are special discussions that warrant a rating.

I have thoroughly enjoyed this discussion. Thanks to Ol Ron for kicking off this thread.

[Ol' Ron]

Well over 1400 people have looked at it so I guess you can take your pick RR , I appreciate your input, what you've done to improve the flathead in competition is impressive. What I learned from limited stock car racing has allot to do with my building knowledge. Right now I working on a street engine with Good performance, good economy, long life and under 3K$. That might be harder than running at Bivll.
Gramps

[Tim Ayers]

Originally Posted by Graeme / New Zealand

I have a 99A block sitting under a tarp that is factory relieved.

GB

To add to this, I have three 99A's. Two are relieved and one is not. I'd assume the two that are were in trucks. One of the relieved and the non-relieved are both crack in the #3 intake valve seat.

[38 coupe]

Is this a decent summary of the information in this thread?


1 - Below 4500 rpm there is no benefit to a relief.

2 - For motors built for competition use a relief can help, but must be carefully designed. The rpm range of competition will heavily favor whether a relief is helpful or not.

3 - For all out high rpm use such as land speed racing a relief is necessary.

[Tim Ayers]

Originally Posted by 38 coupe

Is this a decent summary of the information in this thread?


1 - Below 4500 rpm there is no benefit to a relief.

2 - For motors built for competition use a relief can help, but must be carefully designed. The rpm range of competition will heavily favor whether a relief is helpful or not.

3 - For all out high rpm use such as land speed racing a relief is necessary.

Thanks all for contributing to this thread.

[itslow]

Originally Posted by V8COOPMAN

...I've still gotta ask WHY did those Frenchmen go to the trouble on those beautiful French flatheads (one of which I just sold the last couple of days), as well as the relatively few that Henry Ford produced for buses and other industrial equipment?

Truck and industrial engines which see high load over extended periods of time will often have lower compression ratios. One way of doing this is to relieve the block. GM did this on the 348-409 Chevrolet truck and industrial engines. I'd suspect Ford did the same.

[Pete]

Originally Posted by 38 coupe

Is this a decent summary of the information in this thread?
1 - Below 4500 rpm there is no benefit to a relief.

2 - For motors built for competition use a relief can help, but must be carefully designed. The rpm range of competition will heavily favor whether a relief is helpful or not.

3 - For all out high rpm use such as land speed racing a relief is necessary.

1 - "Below 4500 rpm there is no benefit to a relief."
Wrong.

2 - "For motors built for competition use a relief can help, but must be carefully
designed.
You will be in the "C" main without it and there is no design to it. You just
go bigger.

"The rpm range of competition will heavily favor whether a relief is helpful
or not".
It helps over the whole rpm range.

3 - "For all out high rpm use such as land speed racing a relief is necessary."
Right.