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Car has stock 241s, a btr stage 3 cam and MLS gaskets. I pulled the heads to swap on some 243s. And every piston has a light valve mark. I ran the engine like this for 5k miles. And never heard any weird noises, it also seemed to run fine. I also performed a compression test and had very good numbers. What would’ve caused this? I can see light marks on the valves but they don’t look damaged. Am I okay to run the engine with the pistons like this?
There shouldn't be any PTV with that cam, stock heads and gasket.
Either It's been over revved and got into some serious valve float, from either weak valve springs or improper spring height resulting in not enough seat pressure.
I "guess" if it's also possible that if the cam was installed far enough off, that effectively changed your PTV because the valve events weren't what they were supposed to be.
Years ago a buddy of mine put a cam in his LT1(95 Camaro)and misread the timing chain instructions (circle, square, triangle) on the crank gear and when he started it, it broke most of the intake valves.
There shouldn't be any PTV with that cam, stock heads and gasket.
Either It's been over revved and got into some serious valve float, from either weak valve springs or improper spring height resulting in not enough seat pressure.
I "guess" if it's also possible that if the cam was installed far enough off, that effectively changed your PTV because the valve events weren't what they were supposed to be.
Years ago a buddy of mine put a cam in his LT1(95 Camaro)and misread the timing chain instructions (circle, square, triangle) on the crank gear and when he started it, it broke most of the intake valves.
I installed BTR dual springs at the same time as the cam. Engine has never been over 6500 RPM. Which i don’t believe is too high but I don’t really know. I had installed a dual roller chain when I did the cam. I really don’t think I would have set the timing incorrectly. Would it make sense for me to pull everything apart and check?
Are the springs new? Did you buy everything from BTR?
What length pushrods did you use?
Have the heads ever been milled?
everything new from BTR, 7.4” pushrods. Heads were milled .005 just to make sure they were flat. I will say I just went with the recommended pushrod length I was told which I know isn’t a good idea, could my pushrods being too long cause this?
everything new from BTR, 7.4” pushrods. Heads were milled .005 just to make sure they were flat. I will say I just went with the recommended pushrod length I was told which I know isn’t a good idea, could my pushrods being too long cause this?
Absolutely no. Do both banks have witness marks? Looks like the contact was recent…there’s no carbon buildup in the indentions.
Without trying to delve too deep into "why" the valves are hitting the pistons, it's easy enough to rent a fly-cutter and add valve reliefs to your pistons. If you like the way it runs and don't think it could be improved upon, that's what I'd do.
Might be worth checking your timing set installation though. Since the valves are closest to the piston at TDC, "max lift" isn't the issue at all. Rather, it's what the valves are doing at the other instance of TDC besides the firing one; the one where the exh valve is closing and the int is opening. Advancing the cam tends to bring the int closer to the piston at that moment and retarding it brings the exh closer. If you have it installed too far advanced that could account for "why" it happened.
Without trying to delve too deep into "why" the valves are hitting the pistons, it's easy enough to rent a fly-cutter and add valve reliefs to your pistons. If you like the way it runs and don't think it could be improved upon, that's what I'd do.
Might be worth checking your timing set installation though. Since the valves are closest to the piston at TDC, "max lift" isn't the issue at all. Rather, it's what the valves are doing at the other instance of TDC besides the firing one; the one where the exh valve is closing and the int is opening. Advancing the cam tends to bring the int closer to the piston at that moment and retarding it brings the exh closer. If you have it installed too far advanced that could account for "why" it happened.
Valves are closest to the pistons down the hole a bit actually, anywhere between 5-15 degrees…depending on which stroke it’s on…
Valves are closest to the pistons down the hole a bit actually, anywhere between 5-15 degrees…depending on which stroke it’s on…
well I’m a little confused now. Got my adjustable pushrod. And I’m measuring 7.28. After adding the preload it looks like 7.35 is the proper length. Would this be enough to cause clearance issues?
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Ptv contact cammed ls1 
