boost & intake valve seating

Has anyone ever seen or heard of boost hampering the intake valve from seating on time causing it to lash the valve train ? I turned the boost up from 30 to 52% 38 psi I am only turning 8000 and have way more spring than the cam calls for. t&d rockers correct length push rods crower sev duty hippo lifters bbc oddy 722 lift cam I keep tearing up lifters I was tearing up rockers before the t&d rockers now its the lifters ???

 

what are you tearing up? what is your seat pressure?

 

seat psi

The seat psi is 290# we are tearing up lifters now we were tearing up lifters and rockers. Switched to T&D shaft and now only tearing up lifters and the stick.I have the heads off so if I need springs no prob.I just want to put this problem to bed.Boost was the thing I thought of but was not sure if it could be the trouble has anyone else had these kind of problems ?? I just figured the springs were stronger than the cam requires it was good to go. I guess I was wrooong !! thanks for the info Craig

 

Craig,
Valve spring pressure appears to be way down. Unsure of your operating perameters, but drag guys running that much boost tend to start seated presure around the 400+ nowadays.

 

I am running 38 to 45 lbs of boost on a BBC with BAC-MAN heads and I run 350 lbs of seat pressure with no problems

 

Boost pressure on the back side of the valve is trying to open it, multiply your valve area by your boost pressure and I bet you'll be suprised. On a 2.3 valve with 38 lbs of boost there is about 150 lbs of force trying to open the valve. That would take your 290 lb spring pressure down to 140, not a good deal.

 

With the info given the only difference that I can see between your setup and mine is that I have more lift and the same to more RPM. I don't tear up valvetrain, I would occasionally break rockerarms until I went to T&D.

Could it be the aggresiveness of the cam?

I understand the whole PSI on the backside of the valve thing and maybe more people are doing it than I think, but,,, that's alot of PSI.

 

without giving away tuning secrets- think about LOTS more spring pressure- Dave Germain

 

springs

I called Oddy's and they said a min of 360# on the seat. Stupid me when I bought the cam I wasn't running but 25 psi boost. I thought I had enough seat psi I guess thats a lesson learned sooo next time I will take the boost into consideration not just what the cam requires thanks a lot guys you are great!!