I'm not saying that it wouldn't drop his static compression, but since we don't know his mechanical ability or the resources that he plans to use, its more of a bandaid for such a drastic change in compression. Going from 11.0:1 - 10.0:1, sure I could see using it, but in this case with such a drastic change, AND a head mill, not the best idea.

It'd be safer to do it correctly once and change to a bit better piston. Remember, whenever you calculate the head mill into a calculator like zealautowerks , you also have to recalculate the cylinder size CC in the head. you'll see that he's a much higher than just what a headgasket would fix. Trust me, I made that mistake once when doing one of my other builds, and I paid dearly for it, just because I didn't account for the CC size change with the head mill

For example. Say a b16 head has a .0015" mill on it. Easy to calculate right? But what happens is the CC volume of the b16 head changes from 42.7cc down to 40.2cc when it's milled that amount; the result, higher than calculated compression. He's .0030" mill.. so he's wayyy up there. that's where a good piston would solve that problem more effectively than a headgasket switch.

He's got a high Comp NA motor, and needs to make it turbocharged without using exotic fuels. Put in the right pistons/rods, and call it a wrap.

 

You prove an excellent point about the CC and the head with a milling. I NEVER really considered or thought of it in that regard because typically people dont mill the head .030, usually just a clean up cut of 1 or 2 thousandths. Just learned something new today and very valuable. Great info. and insight on the issues. And yea I do realize the HG would be just a band-aid, and we all know they fall off eventually until its "healed" correctly.
He could possibly look into finding a virgin bare LS head and throwing all his stuff in it and the problem would be solved quite easily with a thicker headgasket thrown in as well. I used to have a bare head I would have given out for free, took it to the metal recycler. Sorry OP

 

Thanks for the advice guys. I think what I'll do is just run it for a while as it is. It has a pretty sick sound to it when it idles because of the cams. Honestly I like this motor the way it is. Its not that bad imo. When I get a little extra cash I'll get it tuned all motor just to see what kind of hp it can make. Then after a while I'll buy a stock bottom end or sell the motor and buy a stock gsr, then go for turbo.

 

Ok, I accomplished my goal. I got it running and I got it tuned all motor. Now, I wanna start planning for boost. The last few days I've been trying to think of the easiest way I can solve this high compression ratio problem, so I can go turbo. I was considering buying another head that hasnt been milled and then I remembered this thread...

If I can find another virgin ls head and use it on this bottom end will my compression ratio change enough to get a safe tune? what will my new compression ratio be after a virgin head is entered into the equation? Will I definitely need a thicker headgasket to lower the compression to where I need it to be for boost? How reliable are the thicker head gaskets? any issues with them? Anyone have suggestions on where to find a ls head in good condition? what should be the going price on them?

I want to avoid swapping motors entirely. I want to leave the bottom end in there if I can for several reasons.

 

zealautowerks b series comp calculator says with a oem headgasket my cr will be at 11.12 :1. Is this accurate? Is this still too high for boost?

 

Still Not learning, eh? ;-).. What you're proposing can work. That doesn't mean it will work.

Sell the block man. Get a stock one with the money if time and effort allow.

 

Take it easy on me. Of course I'm learning. I'm only asking for clarification because someone suggested it would solve my problem. I was hoping to keep the block in the car, because it would probably be easier and cheaper on me if I could get away with just swapping heads out plus the block was just built a few years ago with new bearings, arp rod bolts, etc. and has very low miles.

 

ok if I have no choice but to pull the engine, any suggestions on where to find an ls engine in good working order?

 

I'm not trying to give you a hard time. I'm really not. I'm just looking at this entire thread, and I know that we've all gone through this before and addressed it in the first 2 pages. Again, if your tuner and the change in the HG is even a possiblity, think about the power that you're trying to push out of this thing, (not just psi.. this is turbocharger size dependant). So unless this tuning and turbo sizing is dead nuts on, its not really saving anything.

I'm quite sure that there is a person on H-T in the marketplace that would be more than happy to take that off your hands, provided that you disclose everything that was performed (including who performed the build if possible), how many miles it was on, parts list, and be willing to ship it or at least be willing to meet halfway to sell it.

Mostly, be as honest as you can, even if it means you don't get top dollar. Or pull it apart and sell the rods and pistons, so you can get new ones. The more honest you are, the more serious offers you'll receive.

 

ok thanks, I'll start looking for a place to buy a healthy engine in the near future.