Wiseco .030 second ring gap too big?

[REDspydergst]

Hi, im putting together a 6 bolt with wiseco pistons and im wondering if a gap of .030 is too big for the second rings? would I get a lot of blow by? The block was bored .20 over and the new set of wiseco piston rings measure .022 for the top ring and .030 for the second ring. Im just a little concern for the gap of the second ring. PLK Thank you.!!!!

 

[donniekak]

What is the exact size of your bores? The rings with wiseco pistons always have to be filed to open up the gap to fit. I'm wondering if the machinist bored your cylinders to large. Measure them to make sure, you may just have a bad set of rings.

 

[WES_393]

Are you measuring the gap swith the ring 1" down the bore, and squared using the piston top? A gap of .030 isn't insanely large. Most run somewhere in the .02X range for both rings. The more power (and heat) you plan to put on the pistons, the looser the gaps should be. You also have to consider that the ring gaps will expand slightly after break in.

But like Donnie said, it's concerning that the 2nd rings were .030 right out of the box.

 

[REDspydergst]

ooh ok, yea i was wondering the same thing about the size of my bore. can you guys tell me the correct tool used to measure the bore size?? this egine was running before i took it apart to rebuild it. there was nothing wrong with it i just wanted to rebuild it before i swap it in my car. i will measure the old rings to see if the gap is the same as the new ones.

thanks for the replys.

 

[WES_393]

A decent dial bore gauge would work. At least for the average guy who just needs to double check machine work. I'd also suggest a set of calipers to measure the pistons. Oreilly sells a decent set of digital calipers for around $20.

Did you just recently have the block bored .20 over? If so, did the machinist use or measure your new pistons? The piston-wall clearance should be based off actual piston size, so it's possible the machinist bored (actually honed) the cylinders too large.

I would measure the pistons and cylinders to make sure everything is within spec. If your PTW clearance is way off, you could have bigger problems than blow-by.