PTV clearance
PTV clearance I'm one of those people who second guesses myself into submission so I'll just ask. I've read for hours on here and calculated until my head hurts so here we go. My plan for my first LS1 build is to go with the stock bottom end. From reading on here the pistons generally clear the deck somewhere between .008-.010. I am going with the prc 5.3 heads from TSP with 62cc chambers, .045 gaskets and the TSP 228r cam. With all that in mind I've calculated I should be in the neighborhood of 11.1:1 cr with a quench of .035. I'm almost certain that with the 228r ptv clearance shouldn't be an issue. Any help?
You will have plenty of room there, you could even mill the heads down a little bit if you would like some more compression. To stay on pump gas we usually try and stay under 11.5:1 compression.
Awesome! Thanks John. So are you saying I could safely take it down to say 59cc with the 228r? I think the 228 is where I want to go as this is going to basically be a street dd only car. May only see the track once or twice. I'm planning on going with the TSP headers and true dual setup too. Can't beat your prices down there.
I'm one of those people who second guesses myself into submission so I'll just ask. I've read for hours on here and calculated until my head hurts so here we go. My plan for my first LS1 build is to go with the stock bottom end. From reading on here the pistons generally clear the deck somewhere between .008-.010. I am going with the prc 5.3 heads from TSP with 62cc chambers, .045 gaskets and the TSP 228r cam. With all that in mind I've calculated I should be in the neighborhood of 11.1:1 cr with a quench of .035. I'm almost certain that with the 228r ptv clearance shouldn't be an issue. Any help?
100% stock bottom end
Home ported 5.3 heads 62cc
Trick Flow .045 MLS head gaskets
TSP 228R cam " straight up "
I altered the cam timing and at 4* retard the exhaust valve hit the piston. The intake valve at 4* retard was only at .075 anyways.
I have this EXACT same combo, PTV on the intake was .041. Flycutting was neccessary.
100% stock bottom end
Home ported 5.3 heads 62cc
Trick Flow .045 MLS head gaskets
TSP 228R cam " straight up "
I altered the cam timing and at 4* retard the exhaust valve hit the piston. The intake valve at 4* retard was only at .075 anyways.
100% stock bottom end
Home ported 5.3 heads 62cc
Trick Flow .045 MLS head gaskets
TSP 228R cam " straight up "
I altered the cam timing and at 4* retard the exhaust valve hit the piston. The intake valve at 4* retard was only at .075 anyways.
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The answer to the PTV question is ALWAYS "You have to check for yourself." There is tolerance in everything.
Checking spring, adjustable pushrod length checker, magnetic base dial indicator.
Replace valve spring with a checing spring, so it wont collapse the lifter. Adjust the pushrod to the length between the rocker arm and the lifter. Setup the dial indicator off the top of the retainer.
Roll the engine untill the piston starts nearing TDC, this is no where near max lift. Check PTV by pushing down on the rocker arm untill it hits the piston. Check and recheck until you find the closest point for the intake. Repeat the entire process on the exhaust.
Typically you want .080 on the intake and .100 on the exhaust.
Replace valve spring with a checing spring, so it wont collapse the lifter. Adjust the pushrod to the length between the rocker arm and the lifter. Setup the dial indicator off the top of the retainer.
Roll the engine untill the piston starts nearing TDC, this is no where near max lift. Check PTV by pushing down on the rocker arm untill it hits the piston. Check and recheck until you find the closest point for the intake. Repeat the entire process on the exhaust.
Typically you want .080 on the intake and .100 on the exhaust.
Check don't go by what someone says...
for reference i had 230/230 111+2 with stock mls gaskets and stock unmilled heads and had .086 on the intake...so with milled heads and a smaller gasket i would have not had much clearance...
Check with clay or a checker spring and dial indicator...worth it to learn too
for reference i had 230/230 111+2 with stock mls gaskets and stock unmilled heads and had .086 on the intake...so with milled heads and a smaller gasket i would have not had much clearance...
Check with clay or a checker spring and dial indicator...worth it to learn too
