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I'm running a stock block 2001 LS1 with an MS3 112 LSA cam, PRC LS6 2.5 heads (bought new from TSP), stock head gaskets, 7.4 pushrods, ls7 lifters. I got the car on the dyno and it made ~440whp but towards the end of the session the motor let loose. I tore everything down and every intake valve hit their respective piston. #1 suffered the worse of it and that valve was completely bent. I sent the heads back to TSP to be redone and I decided to clay the motor this time around (kicking myself for not doing that the first time around) and confirmed I have no PTV clearance. TSP has reassured me that this setup should not have any PTV issues. Has anyone had similar issues? Does this setup require flycutting? Before you ask, yes, timing is correct. I clayed it three times with similar results. I intend on giving TSP a call when they open back up and they have been great with support but Im getting a little frustrated with this setup.
That’s interesting since that’s a very common build/setup for tsp. That setup has been run for 10 years plus now. Almost like something valvetrain is not right. Your shortblock is 100% stock? No decking of the block or anything?
If the block is stock the heads must be shaved more than what they were sold as or the push rods are longer than what they say. Quality is never 100% perfect from anyone.
If the block is stock the heads must be shaved more than what they were sold as or the push rods are longer than what they say. Quality is never 100% perfect from anyone.
Ill measure the pushrods tomorrow but I bought everything new even the heads directly from TSP.
Did you verify intake centerline by decreeing the cam? How much exhaust clearance do you have?
I havent gotten to degreeing the cam. I dont have an adjustable timing set and given TSPs reputability and how common this setup is i didnt think it would have been necessary. I also have no exhaust clearance. Im going to pick up more checking springs today and do more pistons at the same time.
I also verified/measured this morning that the push rods are indeed 7.4".
If you have no exhaust clearance either, I find it unusual that it didn’t bend any exhaust valves. Your pushrod length won’t have any effect on piston to valve clearance dynamically, but if you’re not using solid lifters when checking it, your results may very well be skewed. Either way, you don’t have enough. The heads have most likely been milled a bunch.
Get yourself a degree wheel, a dial indicator, an adjustable PR length checking tool and some light weight checking springs. You'll also need to make yourself some LS solid lifters but your closest P-V on the intake should be around +/- 10 degrees ATDC and your exhaust valve +/- 10° BTDC.
Might want to verify if the heads have been milled. A set of non-milled heads generally measure 1.625" from the mating surface of the head to the flats on the lower bolt holes.
Might want to verify if the heads have been milled. A set of non-milled heads generally measure 1.625" from the mating surface of the head to the flats on the lower bolt holes.
I measured 1.613". Im ordering a degree wheel. I already have checking springs, PR tool, and a dial indicator with a magnetic base. Do i need to get the comp cams crankshaft socket?
I measured 1.613". Im ordering a degree wheel. I already have checking springs, PR tool, and a dial indicator with a magnetic base. Do i need to get the comp cams crankshaft socket?
Don’t really need the Comp socket, but man you will be glad you bought it when you have to try to go back a degree and the stupid damper bolt loosens up.
[QUOTE=Che70velle;20364175]Don’t really need the Comp socket, but man you will be glad you bought it when you have to try to go back a degree and the stupid damper bolt loosens up
Been there and done that...LOL
[QUOTE=blueshark123;20364163]I measured 1.613"
Those aren't heavily milled at all so as of now everything points to verifying how the cam was installed and does it match the cam card.
07-03-2021, 08:00 PM
MS3 PRC LS6 2.5 PTV Issues 
