compression ratio
Thread Starter
Staging Lane
Joined: May 2017
Posts: 52
Likes: 0
From: central ky
compression ratio Im assembling my ls1 back together and was wondering what my compression ratio will be now.
Im running a 243 head with a .030 cometic gasket and a tick sns stage 2 cam, 227/235 .618/.605 LSA 110+3
I bought the .030 gasket to bump my compression but keep reading about compression/quench/spuish and now am wondering if buying the .030 gasket was the right move.
Im running a 243 head with a .030 cometic gasket and a tick sns stage 2 cam, 227/235 .618/.605 LSA 110+3
I bought the .030 gasket to bump my compression but keep reading about compression/quench/spuish and now am wondering if buying the .030 gasket was the right move.
Use this:
http://www.wallaceracing.com/cr_test2.php
The pistons stick up above the deck on stock bottom end LS engines. The last one I checked was .006" out. With a .030" thick gasket, you're probably going to have problems.
http://www.wallaceracing.com/cr_test2.php
The pistons stick up above the deck on stock bottom end LS engines. The last one I checked was .006" out. With a .030" thick gasket, you're probably going to have problems.
10 Second Club
Joined: May 2009
Posts: 3,427
Likes: 226
From: over dere
You'll want a minimum of .033-.034 quench. Most most Ls have the pistons sticking out around.005 or so. Your pistons could end up hitting the heads. Ls are a lot different than sbc where the pistons were usually way down in the hole
Milling the head doesnt bring the cyl head deck any closer to the block deck and piston while using a thinner gasket does. Both change ptv but thinner gasket does both ptv and quench, piston to head clearance.
Valve angle will also change how much your ptv changes based off how much you mill.
Valve angle will also change how much your ptv changes based off how much you mill.
Thread Starter
Staging Lane
Joined: May 2017
Posts: 52
Likes: 0
From: central ky
okay thanks. this is my first build so I expected some errors. already torqued down both heads with new factory tty bolts, ordered wrong length pushrods, exchanged for correct length, and now may have to get a thicker head gasket...then will need those longer pushrods I originally ordered sent back to me lol
gonna have to measure ptv
gonna have to measure ptv
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okay thanks. this is my first build so I expected some errors. already torqued down both heads with new factory tty bolts, ordered wrong length pushrods, exchanged for correct length, and now may have to get a thicker head gasket...then will need those longer pushrods I originally ordered sent back to me lol
gonna have to measure ptv
gonna have to measure ptv
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Quench Distance Hi 99T/A, I would NOT remove your heads at this time.
I ASK :
Crankshaft Material and Stroke ?
Rods OEM/Forged ?
Pistons Cast/Forged (2618/4032) ?
Engine Operating Range/Max RPM ?
Pin Offset OEM/Custom ?
I can calculate your P/V using EAP
Guessed Facts = Your +3 Advance L 107 Intake C/L with MY 110 Intake C/L
L +3 (107) = E of .095" and I of .065" P/V
MY "0" (110) = E of .077" and I of .084" P/V
My RECOMMENDATION, do NOT BELIEVE the "hip shot" TECH, use Math.
My RECOMMENDATION, believe the Empirical Data, not guesses.
I have data with MY reports of piston/head contact, (my personal engines) you would be surprised, just ask ?
The difference in distance we are speaking about is the thickness of ONE of the hairs on your head ! (the quench distance)
Few here will state the amount the AL block grows (deck) when up to temp, then they state the timing chain will become "tighter" when the block is up to temp ?
I DO NOT create the "tech" reports here, just my own, with those other reports read found "funny" like the laugh is get when watching CNN.
Lance
I ASK :
Crankshaft Material and Stroke ?
Rods OEM/Forged ?
Pistons Cast/Forged (2618/4032) ?
Engine Operating Range/Max RPM ?
Pin Offset OEM/Custom ?
I can calculate your P/V using EAP
Guessed Facts = Your +3 Advance L 107 Intake C/L with MY 110 Intake C/L
L +3 (107) = E of .095" and I of .065" P/V
MY "0" (110) = E of .077" and I of .084" P/V
My RECOMMENDATION, do NOT BELIEVE the "hip shot" TECH, use Math.
My RECOMMENDATION, believe the Empirical Data, not guesses.
I have data with MY reports of piston/head contact, (my personal engines) you would be surprised, just ask ?
The difference in distance we are speaking about is the thickness of ONE of the hairs on your head ! (the quench distance)
Few here will state the amount the AL block grows (deck) when up to temp, then they state the timing chain will become "tighter" when the block is up to temp ?
I DO NOT create the "tech" reports here, just my own, with those other reports read found "funny" like the laugh is get when watching CNN.
Lance
Oh damn good catch.. I was reading the thread thinking, what is the problem?! Lol I did mean .040's.. i see the concern running .030s that would be an awfully tight PTV and quench . Total brain fart, I apologize for the confusion
Thread Starter
Staging Lane
Joined: May 2017
Posts: 52
Likes: 0
From: central ky
So after measuring ptv I have found it is tight. I used some playdough to measure. made up some solid ls1 lifters, dropped in my 7.375 pushrods and rotated the motor twice, removed the head and looked at the playdough.
i didnt measure but on the intake side the valve just barely cut through so that you could see the silver of the piston. but the motor turned freely, never felt the valve make contact. The exhaust came nowhere close.
So now my question is if I have basically 0 clearance, going to a .040 gasket would only give me .010 of slearance correct?
i didnt measure but on the intake side the valve just barely cut through so that you could see the silver of the piston. but the motor turned freely, never felt the valve make contact. The exhaust came nowhere close.
So now my question is if I have basically 0 clearance, going to a .040 gasket would only give me .010 of slearance correct?
So after measuring ptv I have found it is tight. I used some playdough to measure. made up some solid ls1 lifters, dropped in my 7.375 pushrods and rotated the motor twice, removed the head and looked at the playdough.
i didnt measure but on the intake side the valve just barely cut through so that you could see the silver of the piston. but the motor turned freely, never felt the valve make contact. The exhaust came nowhere close.
So now my question is if I have basically 0 clearance, going to a .040 gasket would only give me .010 of slearance correct?
i didnt measure but on the intake side the valve just barely cut through so that you could see the silver of the piston. but the motor turned freely, never felt the valve make contact. The exhaust came nowhere close.
So now my question is if I have basically 0 clearance, going to a .040 gasket would only give me .010 of slearance correct?