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Is there an easy/simple way to bump of the compression of an LY6 or L96 from a 9:6:1 to a 10-10:5:1 or better without having to replace the stock pistons, rods and L92 heads? If the answer is to mill the heads, how much should I mill using this cam 224/236 .600/.600 110 LSA or the Titan 3 from Cam Motion. I know I could buy some flat top pistons and that will do the trick but I really do not want to have to tear apart the lower end, rebalance the crank, and then put it all back together. Nor do I wanted to spend the money to do all of that. I am just looking to bump up the compression with what I have, do a cam swap, and call it good.
First you have to know how much the pistons are sticking out of the block. Once you have that measurement you can determine the proper head gasket thickness to maintain .040" from the piston to the head. Typically this will be a .051" stock head gasket with the pistons .010" above the deck giving you .041" clearance. Once that is determined, milling the heads is the only other way to increase the compression (aside from changing the valve head thickness or pistons themselves).
How much to mill is the question. You'll basically have to mill the heads as much as you need to get the compression you want. Assemble the engine and check piston to valve clearance and then fly cut the pistons if you need more clearance.
You'll be hard pressed to find all your answers from previous builds as each combination is different. Just take it step by step on your own build and know what you have and be certain that at the end of the day you know it is correct and will work.
Thanks buddy for all of the great info. It seems like after talking to a lot of sponsors and forum members on here, the best way to go is changing pistons. I am looking at either the Wiseco Pro Tru Series PTS523AS which is a 4cc dome that would give me about a 10:6:1 or some WS6store Heavy Duty Pistons which would give me about a 10:3:1. If anyone else has piston recommendations please let me know. Thanks.
Would ls2 pistons work.....I'm in the same boat, just picked up a l96 but I wanna bump up the compression like I did with my lq4 with ls2 pistons ....I also have 64cc ls3 style heads so I know if I just swap the heads I should be over 10.1:1, but with ls2 flat tops would that bring me closer to 11.1:1.....anybody have any thoughts on any of this...........thx in advance
After talking to a couple of the members on here and some vendors, it looks like I am going to be purchasing WS6Store's 6.0L Heavy Duty Pistons and head gaskets with a 4.085 bore and .040" thickness to replace the stock dish pistons with valve reliefs. The guys at WS6Store said that they have used their pistons on 6.0L iron blocks and they measure 0 deck. If my calculations are correct I should be around a 10:5:1 or a little bit higher with stock L92 heads. So with you using the LS2 pistons which usually stick out of the hole about .007 and a .051" head gaskets, you are correct 11:1:1.
After talking to a couple of the members on here and some vendors, it looks like I am going to be purchasing WS6Store's 6.0L Heavy Duty Pistons and head gaskets with a 4.085 bore and .040" thickness to replace the stock dish pistons with valve reliefs. The guys at WS6Store said that they have used their pistons on 6.0L iron blocks and they measure 0 deck. If my calculations are correct I should be around a 10:5:1 or a little bit higher with stock L92 heads. So with you using the LS2 pistons which usually stick out of the hole about .007 and a .051" head gaskets, you are correct 11:1:1.
Started to tear down my l96 today.....definitely gonna get ls2 pistons to get me into the 11:1's compression zone Now time to get the stand and picker and bring this mess inside and see what these bearings look like.......how did your pistons look? 225k mile $800 ebay l96 complete with intake to run lpg.....i can sell this top end and get my money back....lol!
I bought a brand new crate engine for a pretty sweet deal so the pistons were brand new. Doing the same thing you are doing in regards to replacing the pistons for more compression. Trying to sell everything that I don't need to buy parts that I do need. That way the wife doesn't get onto me about spending money on my car. lol
Spending an extra $20 to patg to get the same spec cam could be spent somewhere else.
Also, every ls deck height is different. I have assembled 4 or 5 iron 6.0s and had 0 deck but they may be a tad below or above, so please measure before buying gaskets.
You wont have to rebalance your crank if you just drop in flat tops. Ive had that checked.
Yeah that's what the guy at the machine shop guy told me when I did my 5.3 when he put them on the rods he weighed them and he had to use the 4.8 wrist pins instead of the new ones that came with the pistons to get the right weight. ....that motor runs hard!
Well they were cheap dnr flat tops if that makes a difference. ...like $140 for the set....lol. on another note .....got the l96 prepped up and painted ready for assembly. ....
04-16-2018, 10:14 PM
L96 Compression 
