Need to lower compression > Are 6.0 heads the answer?
07-23-2002, 11:24 PM
#41
Re: Need to lower compression > Are 6.0 heads the answer? man, running .020 Quench area is pushing it!
How do you account for the rod strech?
I have always thought that .035 -.040 is the way to go.
So you are saying that with a zero deck height piston you are running a .020 thick gasket!
I gotta know how that's done?
Bret
How do you account for the rod strech?
I have always thought that .035 -.040 is the way to go.
So you are saying that with a zero deck height piston you are running a .020 thick gasket!
I gotta know how that's done?
Bret
07-24-2002, 04:39 PM
#42
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Re: Need to lower compression > Are 6.0 heads the answer? Hi Brett, LS1's have their pistons appx .008" out of the hole. My pistons are plus .020" comp height which equals .028" out of the hole. Available gaskets are appx .040" & .052" thick plus I can go custom if need be so my piston head clearance will be .022" as an upper starting point if I use the superior gaskets. I don't reckon the rods stretch that much within normal rpms which is why I shall test it out. The Cosworth rods are ok within 6500rpm. .020" is quite large when you look at a feeler guage. How much does the crank flex, .001-2" or so plus .001-002" piston rock. If I hear a tapping noise during a cold startup then I can pick thicker gaskets or recess the heads .005". The books always recommend .040" because it's safe in the same way they give you safe piston ring gaps but if your willing to experiment you can snug up those clearances etc. Manufacturers are down to .040", again because it's safe and because they have to consider worst case production tolerences and heathens who rev the nuts off cold engines. Mike.
07-26-2002, 03:24 AM
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Re: Need to lower compression > Are 6.0 heads the answer? Vince, you won't get a straight answer to that question as the shops in the know will want to keep it to themselves. They also won't want to be responsible for you damaging your engine if you go to tight. As far as my engine is concerned I shall be initially aiming for .020-.025". If I get a couple of thou more then I shall be happy to leave it like that until the next time I lift the heads when an inspection would reveal what's been going on in there. If you are more cautious then .030 to .035" I would have thought would be safe.
07-26-2002, 07:48 AM
#45
Re: Need to lower compression > Are 6.0 heads the answer? Its a secret.. One day I hope to see some reliable built FI setups. The ls1 can do so much, but it is funny the ones that claim to have reliable setups post rarely and the others just get fed up and sell everything b4 they've worked out all of their issues. Most go to the extreme with it b4 even knowing if a safet setup would even work. I always here this should.
