Used 3126b engine

Honest question for the OP: does it still run? Does it show any signs of catastrophic failure? If so...I wouldn't replace it, just run it and make sure to keep the oil topped off!

It tis interesting that it doesn't use anymore oil than it did 20K miles ago. It actually blows less on startup than before,but there is a lot of blowby. It runs down the road fine, but when you hit a hill you're in trouble and she slows down and starts heating up. I am doing a really better job about downshifting and keeping my foot out of the injectors.
The Cat guy told me it was ok to run it as long as I don't get too far from a major tow truck company.

Well, I guess that didn't work out too well.

If it doesn't burn oil I would get a second opinion. I seen a fairly new Cummins that had excessive blowby. Turned out the owner had installed one of those high performance air cleaners and dusted the engine. Cummins was not going to cover it because of not using an approved air cleaner. Also the Rock and Dirt magazine has a lot of engine vendors. Good luck.;)

http://nationalpowersupply.com/caterpillar3126.html Has them in WA or Or.

Bigdog wrote:
It tis interesting that it doesn't use anymore oil than it did 20K miles ago. It actually blows less on startup than before,but there is a lot of blowby. It runs down the road fine, but when you hit a hill you're in trouble and she slows down and starts heating up. I am doing a really better job about downshifting and keeping my foot out of the injectors.
The Cat guy told me it was ok to run it as long as I don't get too far from a major tow truck company.

Does it smoke from the exhaust? If so, when, how much, and what color? What, EXACTLY, happened to the engine?

I just emailed a link to this thread to my uncle (retired heavy truck mechanic, Cat certified), will pass along his thoughts.

Just got back from a little jaunt on a boat and train to Denali,so was gone for a bit.
1. Occasionaly it blows dark gray smoke from the exhaust on start up, but only a major puff and then done.
2. notice engine blowby only when at low idle and if you run it up over 800 RPM it won't blow.
3. It uses a minimal amount of oil, Drove to Portland and back a few weeks ago and barely moved.
4. CAT in Fife dropped the pan and checked the cylinders from underneath and also found sparkles in the oil filter and on the drain plug and power drop on all but the dusted cylinder. $1200 bill for that.
It runs ok on the flat, with or without the toad, but slows down and heats up on the hills. I wish there were some easy way to check the high speed fan on these things to see if it's kicking in. On my school bus, you could hear it cut in, but not this thing.

If the engine was dusted, wouldn't there be more than one cylinder involved?

The way your article is written leads me to believe you have one bad cylinder only. That one cylinder if not to bad might be saved by honing or at the worst boring it to cleanup which might only be .010 to .020 thousandths oversize. A new oversize piston could be used on that one cylinder. This is kind of a patch job but would give you a decent running engine for use until you decide if you are going to sell down the road. Take your time and shop around tho if you want another engine. That engine is quite common and there are a lot of them available.