Ls1 fly cutting pistons
Thread Starter
Teching In
Joined: Apr 2016
Posts: 23
Likes: 0
I'm going to fly cut. I'm going to have them mill them another .20 and I'm going to .40 gasket. I'm just wondering if I need to just bring piston up to where it will hit the cutter with headgasket on or off? Or do I need to rotate motor up to TDC as I'm cutting piston? I have a set of new gm MLS gaskets. Should I use these when cutting? There bigger than .40 cosmetic im going to run. I'm just wondering how to get my reliefs in the right spot .
I'm going to fly cut. I'm going to have them mill them another .20 and I'm going to .40 gasket. I'm just wondering if I need to just bring piston up to where it will hit the cutter with head gasket on or off? Or do I need to rotate motor up to TDC as I'm cutting piston? I have a set of new gm MLS gaskets. Should I use these when cutting? There bigger than .40 cosmetic im going to run. I'm just wondering how to get my reliefs in the right spot .
I'm going to fly cut. I'm going to have them mill them another .20 and I'm going to .40 gasket. I'm just wondering if I need to just bring piston up to where it will hit the cutter with headgasket on or off? Or do I need to rotate motor up to TDC as I'm cutting piston? I have a set of new gm MLS gaskets. Should I use these when cutting? There bigger than .40 cosmetic im going to run. I'm just wondering how to get my reliefs in the right spot .
When you check PTV use a headgasket that you are going to use.
Don't check PTV at max lift, that isn't where you are going to run into issues. At max lift the piston is way down the cylinder. The more aggressive the lobe and lift, the valve is "chasing" the piston so to speak. So the faster you open the valve at a higher rate, you are going to have PTV issues when the piston is closer to the cylinder head. BTDC and ATDC.
Everyone does it different and I'm not saying my way is the right way or the best way.
Decide what head gasket you are going to use. Slap it on there, snug the head down, check PTV.
I check it 15 degrees BTDC, in 5 degree increments to 15 degrees ATDC.
Bring the cylinder up to TDC, tape the cylinder up. Install the cutter in the head and cut whatever you need.
Don't check PTV at max lift, that isn't where you are going to run into issues. At max lift the piston is way down the cylinder. The more aggressive the lobe and lift, the valve is "chasing" the piston so to speak. So the faster you open the valve at a higher rate, you are going to have PTV issues when the piston is closer to the cylinder head. BTDC and ATDC.
Everyone does it different and I'm not saying my way is the right way or the best way.
Decide what head gasket you are going to use. Slap it on there, snug the head down, check PTV.
I check it 15 degrees BTDC, in 5 degree increments to 15 degrees ATDC.
Bring the cylinder up to TDC, tape the cylinder up. Install the cutter in the head and cut whatever you need.
Use a degree wheel and soft test springs to find the exact location in degrees where the piston is the closest to the valve and that is in overlap (one valve opening, one closing) usually 10* before to 10*after, the test spring allows you push down on the valve beyond what the rocker has moved the valve. Or you can use clay method. Either way fly cutting Hypereutectic pistons is a wrisky move, they’re brittle and not well if at all reinforced where you’ll be cutting the reliefs. Go forged.
Thread Starter
Teching In
Joined: Apr 2016
Posts: 23
Likes: 0
So I got my heads back with 2.02 and 1.57 valves I have the cutters. For that size. Has anyone used a old junk ls head to do it? Even with the stock xmaller valves on the old head? I'm assuming my cutters would stick out a little ?
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
