Correct the felpro 1074 has a crush thickness of .039.

Bill

 

ok, I have a question. let s say your goal is .040 for quench. What are the advantages/disadvantages (if any) to have the block zero decked and use a .040 gasket? Would having the block decked at .005 and use a .035 gasket have the same effect? Is one better than the other? and why?

 

From what I understand, the quench is important. I can't see any variance with a 0-Deck and 0.040 HG or a 0.050-Deck and a 0.035 HG.

 

The advantage of using a 0.035" gasket and an 0.005" deck is that there is still a little deck left for the next time you need to mill it for flatness or to remove scratches although 0.005" isn't much it might be just enough.

 

Tim, good to hear from you.... this is Greg from the SCCC. I can see you point about the 0.005 deck. Yes, it does leave some more meat for the next build. But, the 0.005 & 0.035 HG should not affect the quench "effect" differently than a 0.000 & 0.040 HG.

It would seem the safer bet to leave 0.005... I'd opt for that route.

Tangent - Tim, how is the build coming along? Will you be ready for the cruise tomorrow?

 

ok so logically thinking, the more metal you can leave on the block the more rebuilds it will last. the .005 and .035 were just examples I used. I was also wondering what would be the minimum head gasket thickness be? I guess at one point the gasket is too thin to compensate for block/head warp,shift caused be the heat up cool down cycles and the different expansion rates of aluminium and iron? What do you guys think?

 

No answers?
Ideas, maybe?

 

Those are great questions, I was waiting for some answers too. TTT for ya.

 

ok this may sound stupid but it has been bugging me for a while... what does " ttt" stand for ???

 

TTT is to the top.... to bring your post back to current.

As far as the thickness issue. A greater thickness will likely result in a weaker gasket as there is more surface area for the combustion pressure to press against. Remember a gasket of double the thickness also has double the force trying to push it out between the head/block.

A large deck/thin gasket combination will have more compression than a short deck/thick gasket combo as the gasket is larger than the bore adding combustion volume. This also has a drawback as some additional combustion residue (although small) remains in this area diluting the incoming charge.

Remember that you still have to achieve a suitable compression with a combination of heads, piston, gasket & deck height. Unless you are buying custom pistons, you will be limited to your choices.

For reference the stock LT1 gasket is not that strong & the 1074 has a copper fire ring which is also not severe duty but substantially stronger than the stock one.

Most severe duty gaskets have a stainless wire ring, but there is no direct LT1 gasket of this type that I am aware of (atleast in the FelPro catalog)...... although modifying the water passages in a standard small block gasket is a possibility.

An interesting side note is that a recent magazine article (I'll find & post the issue if anyone is interested... currently misplaced at the moment) using a Ford Turbo buildup from Bennett Racing. It said they routinely use large deck clearances to get compression down on their buildups. This contradicts most common thinking & honestly surprised me as well. They are one of the most desirable engine builders of Ford racing engines & have many winning engines in NMRA & Pro 5.0 classes so I'd hate to disagree with their philosophy. I'm sure this did not clear up the thread but is a reality that needs investigation.

 

thanks for your post.

I m still trying to figure this out, all help is welcome.

 

I looked into the cometic head gaskets and I believe that the part number is C5645 and was hoping that someone would verify this. I didn't find anyone that sells these for the LT1, were are you guys gettin um? Also, you stroker guys, what oil pan gasket are you using with a pan that has notches? Thanks

 

I went to the Cometic website and it was fairly sparse. I only saw two gaskets available for the LT1. Is there another place on their website to look? Neither gasket on their website mentioned the squish thickness.

 

Check with Sam at Combination Motorsports. That is where I got mine.

www.cmotorsports.com

Wingnut