Just got my engine done using SRP pistons, .035 PTW clearance. The engine isn't hella loud like a Vitara setup (had one) but its certainly noticeable to anyone listening that its not stock. Seems to be a dull like knocking more noticeable with load. Not something real loud, but there if you know what I mean. Windows up, you won't hear it. This normal for these pistons?

 

"dull like knocking more noticeable with load"
By knock do you mean, like a type of piston slap?
What did the piston to wall numbers look like when your engine was built?
Maybe the wrong rings?

 

I would say it sounds like piston slap yes... Just not the same as when I had my Vitara setup. More subtle I would say but it doesn't ever seem to go away...

PTW was .035"

I am 100% sure they correct rings are in there.

I don't think its an issue, just wondering. This is my first SRP setup. I kind of screwed up when I told the machine shop to shoot for .035 PTW.. I realized I read the wrong specs on the sheet. I should have gone for .025.. but I don't think its THAT much of an issue.. nothing thats going to kill the engine. I'm planning on going for 350whp.

 

i've been told that the high level of silicone content is what causes this. however this thread contradicts that. https://honda-tech.com/forums/tech-misc-15/silicon-content-forged-pistons-533078/

I've had an srp setup before and noticed the loud clanking noise you're describing. I took my motor apart and noticed scuffing on the cylinder walls. your clearances may be TOO tight and experiencing metal to metal contact.

 

i agree with ^^ im in the process of building my engine with srp pistons but im going with .045 ptw. Im also aiming for 350 whp.

 

I have a set of Arias pistons and they knock around a little bit on a cold start, but once the engine has warmed to operating temp, the noise ceases. I attributed it to the different metallurgic composition of the piston and different rates of expansion. If the noise you're hearing is constant whether its cold or not, then i'm not sure what to think. If you're 100% sure you're within spec for the P/W clearance and you know you have the correct rings, it may just be a normal noise. As i've never had a set of SRP pistons, i cant confirm or deny that they're louder than any other forged piston

 

That was my PTW clearance for my build (actually taking the stock sleeves and putting in the SRP's had a clearance of 0.035") I have 9.9:1 SRP's in my B16. I built it using 400whp ring specs but only got to 248whp.

I have a bit of slap in the cold morning, but goes away quickly. (my first build so maybe my rings weren't filed right? so when the cylinders get oil it quiets down.)

After the car has warmed up it almost sounds like a factory engine that has 100K miles on it...quiet, but you know it has some miles. My engine has been running for 47K miles with the SRP's and still sounds like the day it was built. I also had the engine tuned and broken in on the dyno.

The higher silicon (11%) in the alloy allows it to not expand like the 2xxx series pistons so you could effectively run a tighter PTW if you wanted. Rip it up and have fun.

If I ever get to turbo my car again I'm doing a refresh on the B16 and will post the results of my 50K+ SRP build with 17K turbo miles.