Tar kettle 4.0

a_kelley

a_kelley

mechanical fixer
Joined
Jan 26, 2010
Location
Rutherfordton
I have a tar kettle 4.0.. decent oil pressure, top end was crusty. Cleaned it up and the oil pan, which didn't have much crap in it, surprisingly. What's the chances of the bores being serviceable enough to hone & re-ring the pistons? If I have to bore it, I'm as good off sending my spare block and stroker parts to the machine shop and building my stroker for a brand new rebuilt motor than dumping money in a stock motor. However if I can more than likely get by with a hone job and new rings, I will go that route. I'm not sure how many hundred thousand are on the motor.. but I do know it rolls coal almost with the best of the diesel home boys... What say ye experienced nc4x4 peoples? Not looking for a lifetime out of it, but a few years would be nice. Without fogging for skeeters everywhere I go.... Basically I ask because I don't want to tear it down if it's likely going to be too far gone to patch up.

maybe @Jody Treadway has some suggestions?
 
Unless they have been WAYYYY overheated, I have personally never seen a high mileage 4.0 that had egg-shaped cylinders. Generally speaking, they can be honed and ringed and give acceptable additional life.
 
Many years ago when considering new rings I would first examine the ridge at the top of cylinder. This was a good indication of cylinder wear. As Jody said the cylinders will wear egg shaped. What we did was cut out the ridge and it may be necessary just get the piston out. Then use a course hone only with cheap rings. The thought was to promote initial ring wear so the rings would fit the cylinder better. Once the rings break in and become smooth along with the cylinders if they don’t seal then they probably will not for a long time. I don’t know if newer block material or better rings would make difference to what I have stated
 
Jody Treadway said:
Unless they have been WAYYYY overheated, I have personally never seen a high mileage 4.0 that had egg-shaped cylinders. Generally speaking, they can be honed and ringed and give acceptable additional life.
Click to expand...
moldman05 said:
As Jody said the cylinders will wear egg shaped.
Click to expand...

Understood that they will egg shape at the bottom. What I wondered was is it worth it to pull it apart to check tolerances, hone, and re ring. I've not seen many 4.0s with ridges unless really overheated. Never measured a 4.0 block I pulled, I just stuck another motor in.

I'd hate to pull the head and pan off, get the pistons out and it be too far out of round to hone and ring. (Which is really what I was wondering if it was worth it in frame, or build a motor and swap it out. Seems it's worth the risk)
 
I would do a compression test. Also a leak down test if compression indicates a problem.
 
Agreed. I usually do leak down tests if I suspect head gasket failure (burning coolant). Compression test will show if it's even across the board or if some cylinders are weaker than others. I just didn't want to consider pricing and doing everything if there wasn't a reasonable possibility of fixing it without having to get it bored. At that point, I'd simply build the stroker I've got everything for except pistons. But if most of the time, they can be honed and ringed, I'll get everything to do it and be done in a day if it's not fubarred when I pull the head. Jody pretty much confirmed I will most likely not have egg shape cylinders, so tear down and check bores once I get my parts in.
 
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