w250_93

I got my new main and rod brearings in an was just wandering how many miles I should baby it before I can play, 500 miles?. Anybody with over 200,000 on there engine should consider getting one of those oil test done that checks your oil for certain kinds of metal that indicate bearing wear. My truck only has 213,000 on it and several of the rod bearing were showing brass. Just figured I'd throw that out there, that little test might save your engine and it doesn't cost much and most cat dealers do it.

Riflemanusmc

Run it as normal. No boosted stop light launchs of course. What oil have you been using?

DNRCustoms

Was your truck not running good? Knocking or anything. I know I wouldn't let some oil analisis determine that my rod bearings are shot. Exspecially on a 12v cummins that run well over 200k before needing attention. Sounds like you are getting a sales pitch from somebody. IMO

Rick 12v CTD

I met a guy locally who lost the main bearing in his 91.5 truck and toasted the engine and it only had like 270k kms on it. I was totally shocked. I guess there are sometimes exceptions to the rule.

scottsjeeprolet

I send in a sample to Blackstone labs every other oil change.
They have nothing to gain by lying about the results. Crank bearings, cam bearings have different metallurgy so they know what's what in the sample. Why wouldn't you trust it?

w250_93

No man the truck was running just fine. I'm in the middle of a nv4500 swap and I figured while I was there I would replace the oil pan gasket then I figured while I was there I would roll in a new set of bearings, and I found several rod bearings that where showing brass. Nobody told me to get that oil test or anything lol. Those oil test must work cause alot of rental companys and cat do it to there own equipment, all they do is check for brass or copper or whatever that metal is in the bearings. I've been useing mobile1 fleet oil 15w40, I have no ideal what the previous owner used (I'd say rotella) but I know they worked the crap out of this thing maybe that's got something to do with it. When I done the headgasket the crosshatch marks were still in the cylinder walls so I doubt it has anything to do with useing bad oil, I know that you can get alot of miles out of these motors but there not invincible maybe this was just normal wear. Anybody else had one apart around to 200,000?

schamran

It probably isn't a good idea if you're in there and can do it yourself. What's it gonna hurt?

apwatson50

I put new rods and mains in mine. But that was only because the thrust bearing fell apart and the crank had an 1/8" of end play. (in and out) so it was throwing the belt off the a/c compressor. Other then that I wouldn't have changed them.

Riflemanusmc

^^ I would never use the factory Cummins three piece thrust bearing again. Have seen to many on teardowns that were in the pan. Have stuck with FP Diesels one piece.

w250_93

Yea I noticed that, seems like a bad design. I went to napa, they carry Sealed Power brand name but there manufactured Federal Mogual, says it right on the box.

Riflemanusmc

It is..And alot of folks don't know that...Members should do a search on bearings before they by OEM.

w250_93

You guys don't happen to know the torque spec for the engine adapter plate bolts do ya. I have access to that Mitchell online program but it's telling me 33ft-lb but I have a hard time believeing that cause those are around 1/2 Bolts they should be able to handle way more than that. Yea when I picked up that thrust bearing I thought it was broke untill I got to lookin at it lol.

apwatson50

The new cummins thrust bearing is a one piece. I believe 94+ engines all got the 1 piece bearing, because of the failures. I believe the biggest reason for the failures is the clutch safety switch. Since the bearing replacement, my safety switch has been bypassed.

wannadiesel

44 ft. lbs.

Riflemanusmc

Up until my last major overhaul on a 6bt. IIRC was 06. Factory supplied Cummins bearing were still three piece. BUT I have to add that they were Marine engines. Not that it should have made a differance. If they changed in 94? one would hope that they should have updated by 06..But they didn't in OEM bearings that I had seen. Our parts came from Cummins. Could have been an overrun to the off road side to get ride of stock..???