3306 CAT 977 Block Corroded/Engine Rebuild

[jezow2010]

We are working on rebuilding a 3306 for our 977 and got into trying to install the sleeves today and noticed
1. when we drop our sleeves in we have about -0.032" or protrusion. That is, the sleeve is not protruding like it is supposed to, it is actually sunk in the block over 30 thou. I know Cat has shims listed but the largest one is 30 thou.... any ideas? I do not have a sleeve that was torn down from the engine to see if it was a special sleeve or had a shim under it. I will try and get one from the machine shop monday.
2. the lower boss where the o rings seal are corroded pretty badly on three cylinders. I do not think we would be smart to proceed like this. You can see that two were attempted to be repaired during the last overhaul with JB weld. What do you guys think and what are our options?

Thanks!! - Tyler

 

[jezow2010]

Pictures

 

[jezow2010]

More pictures

 

[OzDozer]

The lower seal ring area can be repaired with a metallic epoxy compound such as Devcon putty - but it needs to be very clean (sandblasting is good) before you start to apply the putty, or you'll get poor adhesion.

But the recess in the block for the liner flange needs to be machined and an insert fitted to take the wear out and to enable you to get proper liner protrusion.
From memory (and it's been a long time since I overhauled my last 3306), the liner protrusion is supposed to be around .005" to .006".

If you don't do this machining and install an insert, you'll only be "bodging" the engine repair and you'll blow a head gasket in quick smart time.
Far better to spend a few bucks and do the repair properly, this ensures you don't waste money on engine re-do's.
Nothing worse than having to repair an engine way too early. Do them right and they'll repay you in spades, with reliability in performance, and no further repair costs for many years.

 

[Dave Neubert]

There was probably shims on the old liners pull block out and have a machine shop do upper and lower repairs or get another block

 

[jezow2010]

Ok so yes, the block is out. What do upper and lower repairs entail?

Is just epoxy an acceptable repair for the lowers then just get a special sleeve/shim made for the uppers and have the top deck machined flat?

 

[OzDozer]

A good brand name metal epoxy should be quite satisfactory for the lower seals. It's not a high-temperature or high-pressure area, it just needs to hold the liner securely without movement and present a good sealing surface to the o-rings.

Talk to the machine shop when you get them to do the counterbores for the liner flanges, see what they recommend.
Yes, machine the top deck lightly to ensure it's flat, and that it presents a good smooth surface for the head gasket to seal on.

 

[56wrench]

If you want it to last, in my opinion, the block needs to have the upper and lower counterbores sleeved and the block decked. Might as well check the main bearing bores for alignment and size while you’re at it. Good used blocks are getting hard to find because, after all, they are 40 years old.

 

[kshansen]

Where I worked we did have tooling to bore and sleeve the lower bores. Only did a couple but seemed to work good. I have my doubts that anyone there now has any idea of what is in that box on the shelf!

 

[tctractors]

The top counter bore section is the important area to have cut and an insert fitted, the lower section you can have machined with an insert fitted or the J.B. Weld (or similar) treatment, on the lower area you might want to think about the metal you will have installed, I have seen lots of lower repairs done some metal rots away fast in this location.

 

[DMiller]

Cat DEVCON is the ticket on lower, can be bored like iron once set and hardened. used that for years on cat blocks where mechanisms came loose and shifted until wore the surfaces. Upper bores will HAVE to be Sleeved and recut to spec.

 

[Cat977]

I used a good metal repair epoxy in old cast iron pumps with good results. Mega metal, got it from the Exergon welding rep. Sandblasting then cleaning spotless with isopropyl alcohol/acetone would be a good idea. Start the aplication of the epoxy by rubbing it forcefully into the surface by hand (with gloves). This pushes it into the grains/pores of the metal for better bonding. I found many years latter a smooth solid surface with no rust on future rebuilds.