So here's the thing, I've got marks in the Pistons from intake side valves only. The block is bone stock pr4. Crank, rods and Pistons. Head is b16a with b16 cams, valve train besides forged flat top valves. Motor ran great for about 3k miles until all of a sudden the valves were hitting the Pistons. Any ideas? This is my daily and building the motor further would come later down the road

 

The only time I've had stock sized valves hit Ls pistons is when using ITR/CTR or larger cams.

Could be possible the valve springs are tired and causing valve float

 

could have jumped a tooth on the intake cam gear for some reason

 

I've talked to a bunch of people and I think I'm leaning more towards this

 

I thought this as well, but it would probably be running like *** too. If your springs are THAT bad on B16 cams you are lucky you didn't hit more problems. B16 cams are tiny the and Pr4 pistons are considered "dished" or negative dome

 

Valve pockets on PR4 pistons are also tiny in comparison to VTEC pockets. And the dished area is too far in to effect piston to valve clearances.

I am a little skeptical about stock b16 cams creating valve float.. Seems like there is an underlying issue that needs to be resolved. Or someone needs to set a rev limit

 

This discussion almost makes me not wanna mess with this engine

 

How high are you revving it?
How old are your valve springs?

 

I agree with you, BUT I have NEVER seen an LSV on stock cams w/ PR4 pistons have a clearance issue...hell even on S2T2 run without issues for many years. Unless his head has been milled to the max, along with the block and there is a thinner than OEM HG...valves should never touch pistons on this build. Were talking B16 cams here...

 

It's a 90 year model head, who knows how old the springs really are and how many times it's been milled

 

I'm strapped for cash but I'm almost willing to work extra over time and getta another stock head but could run into different issues with that.

 

Wow. I also have a obd0 b16 head with the cast rails lol. Also on stock springs. Any loss of power? How high are you revving?

 

No loss of power and it revs to 8500

 

So what about just getting a thinker hg and replace the valve springs?

 

Check to see if tdc is still true. Only way a valve can hit a piston if the belt slipped and jumped a tooth, or the spring has been weakened due to you revving it so high..

Replace the springs first. As was said before, the pr4 pistons have a negative dome so you are most likelyexperiencing valve float at a lowered rpm. Stock head studs also? Change them along with the headgasket. See what happens.

 

I'm thinking about doing a thicker hg and the springs. I have arp head studs installed

 

Do the springs and get a regular oem spec headgasket.

 

Alright then #fingerscrossed