How much to do with a CL engine?
 

Ok, so I know there is no right or wrong answer here, but here is the deal. I am swapping out a bad 360 that threw a rod for one I got off Craigslist. I was told it ran good and has 120,000 miles on it. I want to know what everyone here would do in terms of cleaning it up.

I am planning on changing all the gaskets, oil pump, rear and front main seals, plugs, wires, etc. Not sure if I should look into the bearings, piston rings, or anything more. If it were you, what would you change out?

It is from a 1997 Ram 2500.

suggest to do a leakdown test on the cylinders and check cam chain slack. also, use a fresh thermostat when you install the engine.

I would say it is mostly up to your wallet. If you can afford to do a complete rebuilt, then that would be the best choice. But that can be pricey. If you can just afford to do the simple gaskets then go for it.

I bought my 5.9 with about 120,000 miles on it. I just got the heads/valves done and the major gaskets. Within 3yrs maybe 30,000 miles I started getting a loose crankshaft bearing. So a full rebuild was in need then. So my point is do it right the first time.

Also 5.9 heads are notorious for cracks in between the valves, due to thin walls. Mine was when I first got it. Thanks to the yard I got it from I got a fully rebuilt head from factory since it was under warranty, so I only needed one head to get valve seals done. One valve was burnt and needing replacing. There was no way to tell it was without a shop to test it for leaks. And I got it milled down .030 to help the compression ratio.

So if you don't rebuild defiantly send in the heads to get new valve seals installed and to get the heads/valves inspected.

Never rebuild the lower without doing the upper.

My next question is. Is there proof that the engine only has said mileage?

Well, if I do get the heads done, I am already right there. Mind you, I am doing this for a friend, so it isn't my truck...but I have a vested interest in seeing it done right. So really if i just took it all apart and brought it to a shop, after the heads, I am only looking at getting the crank checked, new main bearings and cam bearings, and pistons/rings. I am just wondering if I would need new pistons, I guess that comes down to how bad the cylinders are.

I'm doing a seal-n-shine on my 160,000 mile '95 3.9L, as we speak. Stripped it down to the shortblock. New gaskets, timing chain set, oil pump, etc. Popped the freeze plugs and ran high pressure water through the water jackets. Wire wheeled all the carbon off the tops of the pistons. Pulled the rod and main caps to check bearings. All good. Very little ridge on the cylinders and still showing a crosshatch pattern. Call it good. Sent the heads out for a valve job and found they're both cracked! $600 for new castings (ouch)!

Pull the rod and main caps to check the bearings. Unless there's big gouges or lots of copper showing, let 'em be. No major scratches in the cylinders and a minimal ridge, let it go. Otherwise, you're into a full rebuild with machine work and new pistons. Then it gets expensive! Pick up a rebuild kit for the injectors. O-rings and pintle caps. Replace some of the easier/cheaper sensors. Engine coolant temp sensor, O2, etc. Pull the IAC apart and clean it with Brakekleen.
Replace the clutch, seals and change tranny fluid if 5-spd. Filter, seals and fluid if auto. Check your motor mounts. Good luck!

My old boss does CAT engine rebuilds and have seen a 1.2 million mile engine have blow-by and still have good cross hatch. All he had to do was realign the rings and down the road it went for another 500k miles.

So until you crack it open. You wont know what you have.