So my build is underway and I'm at the point now where I need to figure out which head gaskets I need. The pistons are .20 over and have 4 thousandths protrusion. Which head gasket will be right for me?
Choosing correct gasket .20 over
- Thread starter dmaxbowtie
- Start date
Thanks, my only concern now is only having 4 thousandths protrusion and using a "grade c" thickness overbore gaskets.
I spoke with Lorenzo at SoCal diesel and was told that standard bore gaskets can be used up to .040 over bores is this correct? If so I'm going to order up a set of grade a gaskets.
The goal would be to have .030 quench when finished. Four thousandths with a C gasket is going to give you .037-.039 quench. I would use an A gasket to come close or deck the block more to accomplish a more desirable quench.
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.004" out i would run As it would give you .026" quench.. stock is .020"
i'm currently .020 over with piston flush with the deck.. i went from C's to A's and saw an increase in performance and mpg with nothing else changed.
i'm currently .020 over with piston flush with the deck.. i went from C's to A's and saw an increase in performance and mpg with nothing else changed.
stock is .020" quench.. as i posted in couple threads i saw increase in HP and mpg going from Cs (.045) to As (.030)... IF the engine gets torn down again i'm decking it ~.007" and run As again
Now why is it that your pistons were flat with the deck height and I'm .004 protruding? I asked jon for 16:1 and he did his calculations to get 16:1 using grade c gaskets and .011 protrusion. So I'm wondering where my ratio will be with the a's and .004 also.
Yes that us a stock quench but as you build a engine to increase HP you want to increase quench. If it is a mild build and you won't ever push the limits then staying .020 would be fine. Pushing the limits requires that safety factor being built in or you are going to ruin a good motor from pistons hitting heads. I was providing a experienced opinion for the op to help him with choices. He definitely has too much quench in his current configuration.
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I was in the same boat, I cut my pistons .010 but had to deck the block .006 which brought me back to 16.8 CR. I had to call Lorenzo and they figured out the new CR for me.
mine all i did was a bore n balance with fingers pistons.. the compression hieght (distance from wrist pin center to piston crown) turned out to be ~.015" shorter then stock..
deck was in spec so i left it alone
Cs (0.0394-0.0433) and .011" is ~..028-.032" quench
As (0.0354-0.0394) and .004" is ~.031-.035" quench.
estimated gues... between 15.9-16.1 is around the area of what its going to being
the increase in efficiency (mpg) is what i'm after with my engine..
building an engine of your caliber i would build on the looser side of the specs since efficiency is that high of a prioity
as of ~3 months ago all head gaskets have been swapped over to LML spec head gaskets. :thumb: