SLP4CamaroSS

iTrader: (16)

how much should i flycutt my pistons wiht a g5x3 112 i got stock heads?

N4cer

iTrader: (11)

You'd have to measure, but LG told me to start at .080". We measured first and .070" was enough. If you're gonna flycut, might as well mill for optimal compression bro! Mine are milled .040".

HAMRHEAD

iTrader: (8)

Do a search on here as there is a write up I've seen on it but can't remember the link.

Thimble

iTrader: (2)

None.

Flycutting is a necessary evil that should only be done when needed. You don't need to.
The one and only purpose of flycutting is to create more p/v clearance. Since you'll have adequate clearance with stock heads, there's no need or reason to do so.

Flycutting will lower your compression slightly, a step in the wrong direction, unless you are milling the stock heads, and/or use a thinner head gasket.

Put the cam and springs in and enjoy. When you decide to get some big valve,small chamber heads that will cause clearance to be an issue, then go ahead and flycut.

N4cer

iTrader: (11)

I agree, if leaving the heads stock, then don't. But if pulling the heads, you'd be silly to not mill them. And with them off, you might as well flycut.

The biggest mistake I've ever made on my car was during my first h/c swap. I had a 224 cam, and AS stage 2.5 heads. The heads had very little clearance, but were great heads. My mistake:
I SHOULD HAVE FLYCUT THAT FIRST TIME
Because I didn't flycut, I couldn't go up to a bigger cam with those heads in the future. So I ended up just swapping heads as well as the cam on my swap, since they had to come off anyway. If I would've flycut, I could've swapped to this cam and saved some hassle.

In my decision to flycut, I learned something:
The only people who will tell you to not flycut are people who haven't done it, and who rely upon theory instead of reality. I heard that the piston will go if I spray, or that it'll weaken the piston. Then talked to guys in the N2O section who flycut and have no problems. It's accepted that the ringlands will go before the center of the piston. So if your heads will be off, and you might go up later, flycut. If you are dead set on never milling and never going up on a cam, don't flycut.

I just can't imagine wasting the potential that your cam choices have by not milling. They love the compression, and you'll love the way the car drives. Untuned there was minimal difference in it and my 224, even at low speeds.

Thimble

iTrader: (2)

I'm by no means against cutting, in fact I'll be doing it myself real soon, because I just bought a set of stage 2 (bigger valve) TEA 5.3 heads to use with my G5X4.

But, the assumption was stock heads, and for a cam install, I wouldn't touch the heads at all unless going in for some other reason.

Meegle

The correct method would be to mock assemble the combo and actually measuring the clearances(no guessing). You want to have at least .080 on the intake and .100 on the exhaust. If your clearance is tight, the proper choice would be to send your pistons to the machine shop and have them properly cut. They can measure the thickness and give you guidance on what is safe as well as providing a consistent uniform cut.

There are those who attempt to fly cut the pistons with the engine assembled, a word of advice...DO NOT DO IT!

N4cer

iTrader: (11)

Why could one not get a consistent uniform cut with the Isky piston notching tool? Have you even seen the tool so you'd know how to properly flycut? I'm not bashing you so please don't take it that way. I'm just curious how one could mess up with the tool, and you said it as a fact. So where have you seen someone mess that up, and why weren't they on the short bus?



Once again, what problems have you seen? Everyone has done it and had no problems, but you are stating this as if you are aware of some issue that nobody else has ever had. If nobody has problems, why would it matter? Please help me to understand.


I'm not trying to bash anyone. I just would hate to have someone talking about flycutting when they have no experience. Your info contradicts all experiences I've had and read, so I'd like to know where you got it. You are saying that the people who ACTUALLY HAVE DONE IT are wrong.

PREDATOR-Z

The PTV clearance on the 112 is around .070 on intake, acceptable by some standards but too tight for street IMO.

I would flycut about a nickle thickness (~.060). and use a thinner gasket without milling heads.
This way you increase compression by 3 points, tighten your quench and res in peace thaty you won't the pistons.
Also it gives you a chance to change the lifters for a set of the New high lift GM lifters (~125$) and your whole top end is as new.
Mark

Sneaky

Friend has a G5X4 111lsa installed heads up with no fly cutting.

I'd definitly clay it though.