Cracked Piston

[m6253816]

Hello All; I have a 1993 K2500 project which I purchased with a blown head gasket, #8 cylinder. The engine in this truck is a replacement from a mid 90's van, block casting #141. Just before installing the heads last night, I found a small crack on the top of #8 piston in the relief area under the precup. The piston has "OR" and "J" stamped into the top. Who is the manufacturer of this piston and where can I purchase a new replacement. RockAuto has a Sealed Power replacement, but I do not know if they are the same as OEM

[Robyn]

The Sealed power piston will work fine. ( The stuff on the top is select fit size notes)
Just swap out the bad one and be sure to keep the rod oriented as it came out and the bearings in the same location.

Best to mark the cap and rod as they are not marked from the factory.

Clean the cylinder good and use some 400 wet dry paper dampened with diesel to scuff the cylinder wall a bit all thoughout the ring travel area.

Install the new rings on the piston and stuff the asssembly back in and go with it.

No biggy.

Most of the aftermarket pistons are going to be just fine.

You should measure the original and make sure the new one is the same size.

Measure the skirt at 90 degrees to the wrist pin about midway on the skirt.

Just be sure the clearance is the same as the original or within specs

About .004" is in the ball park.

Good luck

Robyn

[Kennedy]

where can I purchase a new replacement.

This is not the answer. If one is cracked there is a good possibility that others have been heat stressed or are of inferior quality as well.

A set of poistons is about $400. Not exactly cheap, but better to do it once and be certain.

[Robyn]

I would agree.
If you are going to keep the rig, this is by far the best way to go.
Yank the engine and check the bearings and or better yet freshen the thing up while your at it.

If you are just patching it up to sell then that is a different story.

best

Robyn

[ak46champ]

I am going through that right now. Had a cracked #8 piston, Removed the head and found a cracked head. Removed the engine and checked the other head, its cracked as well. Removed the pan and what do you know! Cracked main webs! So what do I have left. About 700lbs of paper weights. Not to mention over a month and a half trying to find a usable block. Which I have found to be nearly impossible. I even looked into JK's Reman engines and Peninsular Diesels. Just can't come to accept paying $7000 for an long block engine without the improvements that JK offers. Although I am getting close to doing it. If you plan on keeping the truck I would check it out to make sure you are not just putting a band aid on a broke engine. I plan on keeping mine so I want it done right. and I am very glad I decided to take the engine out and check it over. I cant imagine how pissed off I would have been if the bottom end would have failed on me in 20K miles or so after I fixed the broke piston that I found first.