Supra Forums banner

1 - 7 of 7 Posts

·
Supra Owner Since 1996
Joined
·
2,723 Posts
Discussion Starter #1
I thought I had read that 1mm+ over sized valves could not be run in conjunction with stock pistons due to not enough valve releaf. I have recently seen applications of stock pistons with 1mm over sized valves like Chris Johnsons old car. Was this a noobie trick I fell subject to? What about 2mm over sized? What's the limit before needing some after market dish?
 

·
Registered
Joined
·
1,196 Posts
You can always do it, but it may mean that the pistons could smash the valves if the timing belt lets go. I believe the same thing is true of HKS 272 cams. The valves move far enough to hit the pistons. Just keep the timing belt and tensioner in good shape.

Daniel
 

·
Supra Owner Since 1996
Joined
·
2,723 Posts
Discussion Starter #3
You can always do it, but it may mean that the pistons could smash the valves if the timing belt lets go. I believe the same thing is true of HKS 272 cams. The valves move far enough to hit the pistons. Just keep the timing belt and tensioner in good shape.

Daniel
Ha, I recently broke 2 in a week! Just replaced everything. Does anyone else concure that oversized valves will create an interference motor?

I thought it also held true that with the lift up to 272 cams, would not create an interferance motor as long as the head or block was not decked. Is this only true on stock size valves? Oversized and aftermarket pistons?
 

·
TH400 Club
Joined
·
809 Posts
I thought 272's were fine with +1 valves on stock, non decked head. I would also like to know, I know anything bigger with more lift= interference motor.

Someone with some knowlege let us know!
 

·
Exclusive 1000+ Post Club
Joined
·
3,488 Posts
Hmmm...this is interesting. I have stock pistons with 1mm oversized valves.
 

·
?!!?HABBA BABBA??!!
Joined
·
2,757 Posts
bump this up...thinking of taking the head off and doing new valves...trying to decide if I would want to go +1mm or not with HKS 272's... I want to stay non interference.
 
1 - 7 of 7 Posts
Top