I've got Toda B's in my gsr motor with JDM ITR pistons and a mugen gasket. I was wondering if any of you knew if i would have any clearance issues with this set up? Are the valve reliefs the same on both pistons?

I've been running on this set up for awhile now, but i have not tuned it yet. Was going to do it soon, but i don't want the motor to blow due to pistons smacking my valves.

 

claying your motor is the safest way.

 

 

claying is a pain in the ***. easier ways to check piston to valve clearance.

 

Care to share the other ways?

 

...uh? What you asking for got nothing to do with the post title.
The difference between the JDM ITR piston and the USDM is just compression, being the JDM higher compression.

The fellows above are right about claying your piston/valve clearance. Advance or retard your cam gears all the way and check what the clay tells you. (of course, by hand.)

 

keep playing with your gears till you hear an awful slap then you know you went too far. that will tell you your limits...

 

uh, how about install the head, install a helper spring on a intake and exhaust valve, and check clearance with either an indicator or feeler gauges while turning over the motor by hand.

 

My question regarding the difference between the two pistons is if the valve reliefs were the same size.

 

[QUOTE
My question regarding the difference between the two pistons is if the valve reliefs were the same size. [/QUOTE]

No, they're not.
Same dia., different depth.

 

Thanks for the info, do you happen to know which piston has a deeper valve relief?

 

I think you are going about this the wrong way... If you are sooooo worried maybe you should stay with stock slugs. It will make you sleep better.. plus whats so big about a little more compression anyway

 

The pistons are already in my block and i do not feel like swapping if i don't need to. Can someone just answer the question?

 

Niether. They are going to be the same. You should be fine assuming the head hasnt been milled.

I would be more concerned with what valvesprings and timing belt you are using.

 

Do you think running a mugen 2 layer gasket should cause a problem? Thanks SGT.

 

no. you should be fine as long as the head isnt milled