Re-Using Stock Bore Pistons....

[rn240sx]

Ok, I popped the ring lands on # 1 and # 4 pistons.. My compression tested 100 and 130 on the 2 bad ones...I pulled the pistons out and i had SMALL HAIR LINE cracks in the ring lands.. I mean TINY.. It took me 2-3 complete turns on those pistons to even find those hair line cracks..

I was told that i should NOT use stock bore pistons cause they would not seat well... I looked at the walls and they look MINT.... NO sign of damage, no cracks, no scrapes, nothing..!!

Can i use stock bore pistons again or do i have to go larger..??

[Structure240sx]

you can use stock bore again if the walls are in spec. all that would be needed is a hone for the cylinders. these questions would be better answered if you took your block to a machine shop

[Checkered-Member]

How much did you bore your block?

[WDRacing]

You can get away with buying a flex-hone and hiting your cylinders with that. That'll remove the old ring glaze. Then add new rings and stock pistons and roll on two. Assuming hte cylinders aren't out of round. How many miles are on the motor? Mine has 165,000 and still has great compression.

WD

[rn240sx]

How many miles are on the motor? WD

It had approx 45k miles when it popped the ring lands..

How much did you bore your block?

I didnt

[WDRacing]

If there are no scrathes then I can almosr guarantee the cylinders are in spec. I'd slap in some new pistons and rings and press on. You don't even have to hone the cylinders really. The new rings will wear in reguardless.

WD

[rn240sx]

If there are no scrathes then I can almosr guarantee the cylinders are in spec. I'd slap in some new pistons and rings and press on. You don't even have to hone the cylinders really. The new rings will wear in reguardless.

WD

^ thats what i wana hear !!!!

To refresh this i had 110,180,180,130 on the compression test. I pulled out all 4 pistons and looked at all the walls and they all looked IDENTICAL to each other. I even put my hands down the walls and felt around and didnt feel any scratches or anything. The walls are shiny and look mint.. Again, im no pro at this stuff but i can look at them and tell that all 4 walls are the same...

[Titan]

^ thats what i wana hear !!!!

To refresh this i had 110,180,180,130 on the compression test. I pulled out all 4 pistons and looked at all the walls and they all looked IDENTICAL to each other. I even put my hands down the walls and felt around and didnt feel any scratches or anything. The walls are shiny and look mint.. Again, im no pro at this stuff but i can look at them and tell that all 4 walls are the same...

Looks are nothing. You can't judge a few thousandths of an inch by "looking". And those few thousandths mean everything to the proper operation of a motor.

Before you get too excited, you need to grab a bore gauge and verify that the cylinders are in spec for taper (measuring deviation vertically) and out-of-round (measuring deviation radially). Only then can you be sure what is safe to do.

[WDRacing]

A motor with 45k isn't going to suffer from an out of round condition....so unless there are scratches I'd say your fine. Even small scratches can be honed out.

WD

[DRIFTEADOR]

you could also say a motor with 45k isn't going to have cracked ringlands but who knows what the motor's been through. wd, is probably right, it's probably fine, but why don't you take it to a machine shop and have it checked anyways. if anything for peace of mind. tell them you'll bring it back for assembly and they'll do it free.

[WDRacing]

I only say you probably don't need to have checked by a machine shop cause not everyone has a truck to transport the motor. Let alone a local machine shop.

The ring lands crapped out because of boost...Boost won't elongate the cylinder walls.

[DRIFTEADOR]

not boost alone but detonation and/or cracked ringlands can.

[Titan]

I only say you probably don't need to have checked by a machine shop cause not everyone has a truck to transport the motor. Let alone a local machine shop.

The ring lands crapped out because of boost...Boost won't elongate the cylinder walls.

Checking the cylinders takes 15 minutes. There is absolutely no reason not to check. Even if just for peice of mind. It certainly won't harm the motor to do so. If you look around, I'm sure you can borrow a bore gauge for free and perform the check yourself.

No if, and's, but's, or should have's... do the check, and be sure.

[rn240sx]

Well i found a machine shop 6 miles from my house. The next adventure is to get the block from the engine stand to my trunk... I had to use the engine lift to support it in the air so that i could mount it to the stand..!!