Should I worry about PTV?
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Should I worry about PTV? I just ordered a new cam that is 228/232 114 LSA and .598/.598 lift.
I am trying to figure out if I need to worry about any PTV issues. The heads I have were milled very slightly (trying to figure out exactly how much as I type this) and I am currently running an LPE GT 2-3 cam with stock length pushrods.
Here is the information on my heads:
64.5CC chambers
215 Intake Runner
80 Exhaust Runner
2.02 Intake valve size
1.57 Exhaust valve size
FelPro Head Gaskets
Just trying to get a general vote of confidence that I shouldn't have much to worry about as far as PTV since it is a pain to remove the heads to check on a GTO (Header clearance problem).
I know that you all will tell me you should ALWAYS check PTV but some cams obviously aren't extreme enough to cause problems.
Thanks.
I am trying to figure out if I need to worry about any PTV issues. The heads I have were milled very slightly (trying to figure out exactly how much as I type this) and I am currently running an LPE GT 2-3 cam with stock length pushrods.
Here is the information on my heads:
64.5CC chambers
215 Intake Runner
80 Exhaust Runner
2.02 Intake valve size
1.57 Exhaust valve size
FelPro Head Gaskets
Just trying to get a general vote of confidence that I shouldn't have much to worry about as far as PTV since it is a pain to remove the heads to check on a GTO (Header clearance problem).
I know that you all will tell me you should ALWAYS check PTV but some cams obviously aren't extreme enough to cause problems.
Thanks.
I like the specs of that cam. Who sells it?
What's the thickness of the head gasket? The amount milled is very important in your decision. It's really not that hard to check PTV clearance. It's just more money you need to spend to get the right tools. You probably won't have any issues, but if it were me, I'd check. Besides, you get to have another tool
FWIW, I have 243's milled .010, with bigger valves (2.02 and 1.57), a 224/224 cam, and I had plenty of room when I checked.
Here's a post I did about how to check PTV clearance. If you get the right tools to check, you can go more extreme later if you know your measurements. https://ls1tech.com/forums/showpost....64&postcount=6
What's the thickness of the head gasket? The amount milled is very important in your decision. It's really not that hard to check PTV clearance. It's just more money you need to spend to get the right tools. You probably won't have any issues, but if it were me, I'd check. Besides, you get to have another tool
FWIW, I have 243's milled .010, with bigger valves (2.02 and 1.57), a 224/224 cam, and I had plenty of room when I checked.
Here's a post I did about how to check PTV clearance. If you get the right tools to check, you can go more extreme later if you know your measurements. https://ls1tech.com/forums/showpost....64&postcount=6
Thread Starter
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Off hand I am thinking that the MOST mine were milled was .010
Everyone I have asked so far has said that I shouldn't have any issues.
What is the biggest factor in PTV? Lift?
Ed Curtis from flowtech inductions sells the cam.
Everyone I have asked so far has said that I shouldn't have any issues.
What is the biggest factor in PTV? Lift?
Ed Curtis from flowtech inductions sells the cam.
Originally Posted by Fast GTO
What is the biggest factor in PTV? Lift?
That's a common misconception though. Lift of a cam has almost nothing to do with PTV clearance because when the valves are at maximum lift the piston is pretty much at Bottom Dead Center.
Things that play into PTV clearance are duration of the cam, amount of milling of the heads, gasket thickness, valve diameter size, valve margin size (thickness of material that hangs down into the combustion chamber after the contact point with the seat;this is something you won't have to worry about with stock valves)
I'd say you're probably okay on clearance, but you should check so you know how much more you might be able to mill and how much more duration you can get away with before having to flycut the pistons.
Thread Starter
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Yeah, I just did some reading and noticed that PTV was related to duration and overlap more than anything else.
Thanks for the help, I also read that an alternative to claying would be to use a dial indicator and light weight spring.
Thanks for the help, I also read that an alternative to claying would be to use a dial indicator and light weight spring.
