LQ4 L92 Dilemma
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LQ4 L92 Dilemma I picked up a 30k mile lq4 from an 04 truck. I also have a set of stock unmilled, l92 heads ready to go on. I'm at a crossroads on which direction to go with this build. Should I keep the heads and bolt them up or have them milled to bump compression? Or do I sell them and go with another head? Do I keep the lq4 pistons or ditch them and go with a piston that already have valve reliefs? I have a little over 3 grand to spend and still have to pick up a cam kit and a good stall. This is going in a weekend car and I'm really just looking for the best option with the money I have. Thanks in advance.
With the 70 cc chambers of The l92 heads you will have just a little more compression than the stock Lq4. Since it's a weekend cruiser, I would take about .010 off the heads and run a .040 gasket and keep the stock dished pistons. That would put you at 10:1 +/-. Combined with a good matching cam, and an ls3 intake and 90 mm throttle body, you will have a good easy driving cruiser.
The only benefit I can see from going with a different piston is being able to run a larger cam, but I think with a cam that will fit with stock pistons will give you what your looking for. It will also save you about 1k by the time you buy the pistons and have the crank balanced.
I've got the 229/236 cam in mine. I get my heads back this week from being milled .030 but I don't think I will have to flycut. I'm also running stock gaskets as well. Reason I don't think I will need to cut is I bolted the heads down and used my pushrod length checker and the valves didn't hit the piston and I will be adding .021 to that
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Teching In
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Bringing this back up, I'm not milling the heads but I keep seeing ls2 rods and pistons pretty cheap. Should I swap in the ls2 pistons and go n/a, or keep the dished and run a small shot? Kinda broken between the 2 right now.
ive got the ls3 heads on my lq4 with ls2 pistons and rods.. my cam is good sized and i fly cut .080 on the pistons and ended up with .116 ptv clearance with unmilled heads and factory gm .051 gaskets, so i could have cut alittle less but oh well live and learn i guess. im waitin on my last parts to get it runnin, so i cant tell ya how it runs yet. hope you get it runnin soon and good luck to ya on it. i hope i dont break a piston on mine since i cut them lol.
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Well I got the car all put back together and going. I cleaned up the heads, went with .040 Cometic gaskets, and 231/236 ls3 3 bolt cam. I'm still in the break in stages for everything but it sounds wicked and has some good mid range torque. After I get it broke in, I'll hit the rollers and let you know what I come up with.
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I'm going through my own L92 dilemma right now. I'm sitting on a 10k mi LY6 long block and i cant decide which top end to use. I have both all stock, LS3 intake/L92 heads or LS6 intake/799 heads.
So what did you decide for your internals, you where thinking about the LS2 stuff?
What are you putting your compression at?
I'm going through my own L92 dilemma right now. I'm sitting on a 10k mi LY6 long block and i cant decide which top end to use. I have both all stock, LS3 intake/L92 heads or LS6 intake/799 heads.
Well I got the car all put back together and going. I cleaned up the heads, went with .040 Cometic gaskets, and 231/236 ls3 3 bolt cam. I'm still in the break in stages for everything but it sounds wicked and has some good mid range torque. After I get it broke in, I'll hit the rollers and let you know what I come up with.
What are you putting your compression at?
Thread Starter
Teching In
Joined: Feb 2010
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subscribed..
I'm going through my own L92 dilemma right now. I'm sitting on a 10k mi LY6 long block and i cant decide which top end to use. I have both all stock, LS3 intake/L92 heads or LS6 intake/799 heads.
So what did you decide for your internals, you where thinking about the LS2 stuff?
What are you putting your compression at?
I'm going through my own L92 dilemma right now. I'm sitting on a 10k mi LY6 long block and i cant decide which top end to use. I have both all stock, LS3 intake/L92 heads or LS6 intake/799 heads.
So what did you decide for your internals, you where thinking about the LS2 stuff?
What are you putting your compression at?
On The Tree
Joined: Dec 2009
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From: Aurora IL
I read and researched until i couldn't stand the head ache anymore. I just went with the thinner gasket and that along with the heads is netting me just above 10.1 compression. That's not ideal, but my buddy who just finished his turbo build kept telling me how easy we could do a turbo set-up down the road. That was my deciding factor. I will be spraying the car for awhile so it works out anyways. I was looking into LS2 and LQ9 pistons. Couldn't find a deal on anything. No sooner I got the car together and running, a set of LQ9's were on craigslist with rods for $200. O well I guess. The car runs strong and when I get enough time, I'll report numbers back. I'm trying to work out some converter issues now.
So you've got LQ4 shortblock, L92 heads and .040 hg=just over 10.1 cr? I see you said you "cleaned up" the heads, did you mill at all?
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He did a very thin mill due to the head surface being uneven. He said it was between .005 and .008. With so little being removed, he said he had a hard time gauging it? Idk. He is an Old Timer. He said the chamber came in around 67-68cc. I don't know the hard math but from what I have read, that puts me in the area of 10:1. Other than that, yes, I've got a low mile stock bottom end lq4, ARP bolts in everything, L92 heads, .040 cometic gaskets, LS3 intake, 92mm throttle body, and then the other supporting mods. I drove it last night and had a little fun with the neighbor's GTO. Alot more power than what I was expecting.
