Do I Need to Worry About Piston-to-Valve Clearance?
Do I Need to Worry About Piston-to-Valve Clearance? Hey guys,
I'm in the middle of rebuilding my motor. Here's a list of what's going back in..
Texas Speed Torquer V3 Cam:
231/234 .643"/.598" 111 LSA
7.4" Manley Pushrods
Speed Stage II 5.3 heads (862 casting number)
Stock rocker arms
Patriot Double Gold .650" Valve Springs:
My pistons are also flycut a little. I don't know the amount because I bought the motor like this.
Pistons:
Does anyone have an idea of whether or not I should check my PTV clearance before I put the heads on? Any easy & quick ways to check this?
And if I don't have enough clearance.. what are my options?
Thanks
I'm in the middle of rebuilding my motor. Here's a list of what's going back in..
Texas Speed Torquer V3 Cam:
231/234 .643"/.598" 111 LSA
7.4" Manley Pushrods
Speed Stage II 5.3 heads (862 casting number)
Stock rocker arms
Patriot Double Gold .650" Valve Springs:
My pistons are also flycut a little. I don't know the amount because I bought the motor like this.
Pistons:
Does anyone have an idea of whether or not I should check my PTV clearance before I put the heads on? Any easy & quick ways to check this?
And if I don't have enough clearance.. what are my options?
Thanks
Those aren't "flycuts". Looks like a notch where some valves kissed the pistons before. A real flycut is cut the width of the valve.
What size chamber your heads are, and which head gaskets you'll be using will determine the answer to your questions.
What size chamber your heads are, and which head gaskets you'll be using will determine the answer to your questions.
The head gaskets I'm using.. :
http://www.thunderracing.com/catalog...&sid=353#P3813
Part number: 20-12558810
GM LS1 Cylinder Head gasket, graphite
only real way to know would be to check it your self i would much rather do that and if there is a problem u will know instead of someone sayin it might be ok so u run it and u lose some valves/pistons
My heads are at the shop right now being cleaned up.. but I'm not sure what size the chambers are.
The head gaskets I'm using.. :
http://www.thunderracing.com/catalog...&sid=353#P3813
Part number: 20-12558810
GM LS1 Cylinder Head gasket, graphite
The head gaskets I'm using.. :
http://www.thunderracing.com/catalog...&sid=353#P3813
Part number: 20-12558810
GM LS1 Cylinder Head gasket, graphite
Do not use the graphite gaskets. Use the GM MLS gaskets.
Thanks Damian. I'll have to see if I can figure out how much milling has been done.. and if there's ever been any before this heads job.
Why shouldn't I use the graphite gaskets?
Why shouldn't I use the graphite gaskets?
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Verdad Gallardo But if I need more clearance, what do I do? Do I have to flycut them?
most likely but, i would do it anyway and clean up the piston just incase. it would be horrable if your motor let go cause of ptv clearance
btw i have never seen fly cuts that small not saying there could be but if i was going to flycut i would make sure there is more than enough room for the valve to clear
btw i have never seen fly cuts that small not saying there could be but if i was going to flycut i would make sure there is more than enough room for the valve to clear
I'm gonna go ahead and call the shop and ask them to do that. The shop also carries lightweight checking springs, so I'm gonna check the PTV tonight. I'll just need some clay..
More importantly.. if I need to flycut them, how the HELL do I do that? What do I need? Does anyone have any links to parts or anything? Or does someone rent them.. anything like that.
Thanks for everything so far guys
More importantly.. if I need to flycut them, how the HELL do I do that? What do I need? Does anyone have any links to parts or anything? Or does someone rent them.. anything like that.
Thanks for everything so far guys
Oh wonderful news.. Apparently they just noticed a guide was completely broken on my head? So it's gonna take EVEN LONGER now to get my heads back.
He said he'll measure the chamber size once the heads are done.. it's an extra $45.
He said he'll measure the chamber size once the heads are done.. it's an extra $45.
Why shouldn't I use the graphite gaskets?
-Clean up. If you ever have to pull the heads again, MLS gaskets leave a residue that takes 10 minutes to get off the block. If you have to pull the heads ever again with a graphite gasket, you'll be scrubbing the deck for a bare min of 30 minutes.
-Strength. Graphite gaskets have been much more prone to leak/blow out. Just 2 weeks ago I had a customer go ahead and do heads/cam, all because his graphite head gaskets were leaking on both sides.
And FWIW, I've successfully ran some 232/236'ish sized cams on 108-110ICLs with .020 cut off a 5.3L head. Granted space was a tad tighter than some people would run, but it worked just fine with no PTV issues. Judging from your circumstances, and the fact the heads needed a repair I would go ahead and measure.
Thanks Damian. Your posts are always helpful.
So as long as no more than .015-.020ish are milled off my heads, I SHOULD be alright? I'm gonna measure anyway, I'm picking up some lightweight springs and the clay.
So as long as no more than .015-.020ish are milled off my heads, I SHOULD be alright? I'm gonna measure anyway, I'm picking up some lightweight springs and the clay.
Your guide is broken from a valve tagging a piston which puts alot of stress on the guide trying to keep it in its intended position.....
You can rent flycut tools.....do a search on this board about flycutting. Alot of do-it-yourselfers who never did it before have successfully gotten it done....and most say it wasn't that big a deal when the smoke cleared.
You probably have .050 or so clearance on the intake....maybe less. To tight for a hyd roller cam application which tends to have valve control issues at high RPM.
-Tony
PS....And FWIW, the small eyebrows in your pistons were created from valves hitting them....not flycutting.
You can rent flycut tools.....do a search on this board about flycutting. Alot of do-it-yourselfers who never did it before have successfully gotten it done....and most say it wasn't that big a deal when the smoke cleared.
You probably have .050 or so clearance on the intake....maybe less. To tight for a hyd roller cam application which tends to have valve control issues at high RPM.
-Tony
PS....And FWIW, the small eyebrows in your pistons were created from valves hitting them....not flycutting.
The pistons are 250 thou thick. You are safe to give yourself an extra 50 thou clearance no problem.
I'm running a 234 lobe on a 107 icl with 58cc heads. I am going 100 thou deep personally. It's not hard to do.
I'm running a 234 lobe on a 107 icl with 58cc heads. I am going 100 thou deep personally. It's not hard to do.