flycutting limits?
Thread Starter
Teching In
Joined: Jul 2010
Posts: 3
Likes: 0
From: Washington IN
flycutting limits? Hey guys, brand new to the forum here. Have a question for you all: How deep can I flycut the pistons on my ls2?
A little bit of background for you all...06 M6 GTO. I am installing a cam and heads right now. Cam is in and has been degreed, checked out ok. Cam specs are: 239/247 .624 .624 114lsa It's a Comp LSR 54-461-11. (yes it is going to be a roll race car) 243 heads are milled .030, fully ported, 2.08/1.575 valves and will run on E-85.
My problem is that when checking PTV clearance, the intake valve actually left a witness mark on the piston (I did not feel it while turning the motor over).
From what I have read, I need .080 clearance for the intake valve. Being that the valve is already touching the piston, I will need to go just a tad further. I think I will start with a .085 cut (yes I already have the cutters from Lindy) and check it after that.
The exhaust measures in around .020 so it will also need a .080 cut to reach a clearance of .100.
Is it safe to cut that much material from the piston?
This car will never see nitrous.
Thanks for any input guys.
Clint
A little bit of background for you all...06 M6 GTO. I am installing a cam and heads right now. Cam is in and has been degreed, checked out ok. Cam specs are: 239/247 .624 .624 114lsa It's a Comp LSR 54-461-11. (yes it is going to be a roll race car) 243 heads are milled .030, fully ported, 2.08/1.575 valves and will run on E-85.
My problem is that when checking PTV clearance, the intake valve actually left a witness mark on the piston (I did not feel it while turning the motor over).
From what I have read, I need .080 clearance for the intake valve. Being that the valve is already touching the piston, I will need to go just a tad further. I think I will start with a .085 cut (yes I already have the cutters from Lindy) and check it after that.
The exhaust measures in around .020 so it will also need a .080 cut to reach a clearance of .100.
Is it safe to cut that much material from the piston?
This car will never see nitrous.
Thanks for any input guys.
Clint
you can't arbitrarily assign an exact number as to what is safe vs not safe. so at .126 cuts the engine will not run? the engine will be destroyed? there are way too many variables to give an exact number to this question. i think the poster was looking for real world experience and not internet expert opinions.
^ I agree with that to an extent, but to say there is not a close answer is incorrect. I'd cut to your .080 / .100 safe margins and add around .005-.010 to that. Mill appropriately and have fun.
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