6.9 idi cylinder wall pitted

[Tylorg1999]

Was just planning on doing a reaseal before i put the new motor in my truck. Removed the head and a cylinder had rust all over the walls. Flex honed and walls are pitted. Im assuming i should do a complete tear down and send the block and heads out and go .10 over.

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[IDIBRONCO]

I may be wrong on this, but as far as I know, they don't make any +.010 pistons for these. I think that +.020 is the next size over standard. How deep are the pits? Maybe a good hone job would take care of them. Maybe you should take the engine to a trusted machine shop and get a second opinion. Of course an entire rebuild (including new pistons) would be "best", but if you're on a limited budget, then I'd go with the second opinion. Either way, you'd be completely tearing apart the engine and the biggest differences would be the reduced cost of not having to buy new pistons and only having the cylinders honed. Whether or not you tear the engine apart, one thing that you should do is to inspect your lifters. The earlier ones used a bushing for the roller to ride on while the later ones all used roller bearings. The bushings are known to fail after years of use and then they take out a lobe on the cam. If they aren't the roller bearing type, DEFINITELY replace them. I think that you can only buy the roller bearing type these days, but I've been known to be wrong on things like this before too. If you buy a big name brand of lifters, such as Sealed Power, etc., you'll be fine. Rock Auto usually offers brands such as "Engine Tech" as well as the bigger name brands. Even though they're cheaper, the quality just isn't there.

 

[Tylorg1999]

Thank you for the info. This is a later motor so it does have the roller bearings. I was doing some research and summit does offer .10 over pistons for the 6.9

 

[IDIBRONCO]

Good. I had no idea. Thanks for your info.

 

[IDIBRONCO]

Before you order them, you want to make sure that your cylinder will clean up at +.010.

 

[jaluhn83]

Yes, it need to be bored. Very unlikely it will clean up at 0.010, probably need at least 0.020 and maybe more. A 0.010 bore is difficult to do even just with normal wear, and those pits are at least 0.005" deep.

Check the oil squirters and see if they're press in or bolt in. They will have to come out for boring, and all but very late 6.9s are press in which are technically not reusable and require special tools/jig to install. It's possible to get them out in reusable shape, not that hard to make an install tool and you can eyeball it without the jig, but still a potential problem spot, and high risk of damage if they're not right.

 

[raydav]

I bought a 94 rebuilt about a year ago. Because of the combination of wear and pitting on the inside and cavitation damage on the outside, their standard rebuild is eight sleeves and standard pistons.