F-Head Rebuild Questions

Okay. Although as you say, air-cooled is different. And VeeDubs work pretty hard at highway speeds.

 

Yeah it is certainly different Pete, but that is the only engine I had first hand experience with it. My uncle reckons his Flathead had problems as well but nothing critical

 

Yes, Most often the block is decked and the head is shaved roughly 10 thousands each.
That generally raises the CR to around 7.4 to 1 ratio.
Do not raise the CR above 7.8 to 1 unless you're developing an experimental F-134 engine.

Better is relative to ones intended useage.
Don't foolishly expect to double the engine power output without a total change of engine character.

Black Permatex

Yes you can drastically increase the power from an F-134 but it comes at a huge cost .
The engine thereby becomes specialized and overly expensive.
This F-134 Hurricane has its greatest value when maintained in stock standard condition.
It is basically a tractor engine with moderately high RPM capability and with multi-fuel; especially low grade fuel capability.

 

You can not put larger valves in and would gain nothing through higher lift on the cam. You do not need to change the pistons to get a higher compression, so long as you are aware of the valve clearance

Just wanted to mention that because I forgot

Oldtime and I have differrent views on the engine being left in stock standard condition. The kind of changes I outlined can be cheaper than a stock rebuild and I would say the engine is definitely improved if they are done - no matter what you intend to use the engine for unless the use is a restoration show vehicle or something similar.

 

Anybody know what the rationale was for the F-head in 1950? Chevrolet had been selling cars with OHV engines since 1914, and I would think it would be clear at the time that the valve-in-block design was doomed.

 

"Anybody know what the rationale was for the F-head in 1950?"

I would assume, more power than the flathead without a major re-design.
Interestingly in 1962 "the Jeep Tornado engine was the first post-World War II U.S.-designed mass-produced overhead cam (OHC) automobile engine." (wikipedia)



"Chevrolet had been selling cars with OHV engines since 1914, and I would think it would be clear at the time that the valve-in-block design was doomed."

On the other hand, Ford used the Flathead V8 successfully until 1953.

 

I sure do disagree on that statement.
If I recall correctly some IH tractor exhaust valves (about 1-3/4" diameter) can be installed in place of the standard 1-1/2"" diameter valves.
Intake valves are already relatively huge in diameter.
A custom camshaft can readily change the valve timing and duration but realize that's not nessicarily an improvement.
Some have even installed the L head camshafts. That's a HUGE change !

That goes direct to my understanding of physics and the stipulated military design.
In stock form the Hurricane has it's own unique set of attributes.
In truth it is neither worse nor is it any better than any other internal combustion engine.
It is merely unique via it's design.
The engineered design worked extremely well for its original application.
Todays fuel supply and the expectations notably differ from the era of it's conception.

If someone wants HUGE power from the Hurricane they would be wise to take full advantage of its unique design strengths.
The outcome is a radically modified Hurricane with attributes being very dissimilar to the original intended applications.

The Stock Standard Hurricane engine is perfectly acceptable (but not optimum) for those who expect maximum cruise speeds of 63 MPH or less.

 

Have you tried it because I have? A high lift cam did almost nothing, you could not even tell it was there other than it made getting an idle difficult. We are talking the FHead here not the Lhead. In my opinion there is no chance you could get a larger valve in the block side (which on this engine is where it would matter) and in truth the intakes are probably big enough. If you really wanted to you could put in a large intake valve and then bore that head to allow it to mean something but I doubt that would be a wise thing to do. Who knows maybe it would be great, maybe but from the experimenting we did more air through the intake means loss of torque and gain in rev's which is not really a good thing for this engine.

Just because someone does not share your opinion does not make them wrong. I don't know what you consider huge power but I have made 121 HP from a FHead. The engine was not much more useful than a 80 HP FHead and self destructed in under 3,000 miles. The stipulated military design is irrelevant to what I mentioned because those things were not mentioned in the design specs. I have no idea what physics you are talking about definitely nothing I suggested violated any rules of physics. In fact it is the laws of physics that allow the engine to run.

It sounds like to me you are suggesting that the 1920's designed FHead engine is perfect and cannot be improved upon. What I said was SMALL changes that do not radically change anything and the engine can be driven every day and perform just as well as it did before, but giving just enough extra HP to allow the Jeep to be driven closer to normal road speeds. In my opinion that is a good thing.

Simple truth is you are trying to make it out like I am suggesting something radical because I suggested something you don't agree with, not because I suggested anything radical

 

Getting chippy, no need......we're allowed to disagree with each other without it being personal...

 

:dead horse: