I think my engine is giving up

[RCCUMMINS89]

Um, what? I would rebuild the engine in my truck.


I think you got confused in my talking of the car and my truck......

[rockbuggy4x4]

haha Probably. My brain isn't completely there today. I think it went on vacation.

[Alec]

If you can slide the crank back & forth, it is pretty much a sure bet the thrust bearing fell off the #6 main upper shell. I probably put 30k on mine after the bearing failed, but it was not a good idea. I rolled that single shell in with the engine in the truck, gave up on the two cooling nozzles in the pan, and just shake my head every morning when she starts & the oil pressure comes up . . . That was maybe 10k ago.
Oil pressure is still within specs, but down around 12-15psi at idle when hot.
A cheap band-aid solution, but one that has bought me time I needed for other things.

[RCCUMMINS89]

I need to measure my crank end play...... spec is somewhere around 10 thou.... well, our intake valves move a long way at 10 thou.

What was your hot oil pressure?

My oil pressures are still 50-60 cruising when hot... and always at minimum 25 when hot. Which is exactly the same as every single cummins I've ever owned.....


edit - I read your post as it is down 12 psi from where it was....

[Alec]

Sorry, writing while tired does not always produce clear posts.

Oil pressure hot is 12-15 @ idle, and at least 45 at 1800 rpm. I blame this on the two missing piston cooling nozzles, not the worn main bearings.

I was just trying to say that these engines will put up with a LOT and still run reliably. So if a new bearing and a day's worth of work is worth another year before having to do the full re-build . . .

Hmm, I hope I'm not jinxing myself.

Alec

[RCCUMMINS89]

Ya, I follow you.

With everything that went down the last week with our vehicle situation........... I'm going to pretend it's fine and run it until it has very obvious signs.

As in burning oil, knocking, extreme blow by, etc.......

by me adding more fuel and a larger turbo, it'll decrease my cylinder pressures while giving a smoother running engine.

[dunes450r]

It's always cheaper to rebuild a running engine than put in another used one.

If the work is done yourself, you can completely rebuild a Cummins for a under $2k

you can buy a running cummins' all day for under $2k. not to mention little to no down time, no complications with cracked parts or having the machine shop mess something up or re-assembling something wrong considering most people don't rebuild cummins' very often.

http://portland.craigslist.org/clc/pts/3771201909.html

http://eugene.craigslist.org/pts/3773058878.html



i'd put the motor back closer to stock for longevity. say anything you want about decreasing cylinder pressures with mods and what not, but i'll stand by the cummins engineers every day of the week for longevity. stock is best.

[RCCUMMINS89]

Why would I spend money on a used motor? When I could have a rebuilt one for darn near the same cost?

Also, I don't go to normal machine shops...........the "man" that would actually do the work on my short block has built over 200 cummins motors, and not one failure yet.


- stock is just not an option, or were you being funny

[RCCUMMINS89]

Oh, and I'd be into a rebuilt short block for a lot less than 2k............. I'm just using "normal numbers"

[dunes450r]

not really being funny on the stock part. if you're having car issues and need your cummins to run as long as possible than throwing bigger injectors and whatnot at it is probly not the best option. if you have the fuel and power on tap then you'll use it, putting more wear and strain on your motor that may or may not be on its last leg.

[RCCUMMINS89]

I know, I know.

[4thesporty]

FWIW, I am rebuilding mine at the moment and $1100 got me a block tanked, magnafluxed, bored, honed, and decked, rods reconditioned, balanced and shot peened, crank balanced and polished, and pistons (I supplied) balanced. I had the head done by someone else (tanked, magnafluxed, valve job, surfaced, and oringed) for $600. Rebuild kit from Mumua set me back $700 including the pistons I wanted. I am assembling it myself and needed to buy misc stuff as I am starting from scratch, but assuming you go back with all your other parts (injectors, turbo, IP, etc) you are in a little over $2K.

Like I said, I am starting from scratch, RC has his head done already and i'm sure can assemble a short block pretty easily, so well under $2K gets you a brand new motor built the way you want it, not a take out with 300,000 miles with an unknown service history. I say run it till it blows, then rebuild it.

[Mark Nixon]

I've seen numerous engines lose the thrust bearing, not all THAT uncommon, since they are kinda' a rinky-dink set-up in the first place.

Just run it, I ran a 1996 engine with schit ton of blowby from California to here, went through 12 GALLONS of oil and found that you can sort of control oil loss by routing a big ol' piece of heater hose from the crankcase vent to a 1 gallon jug sitting by the battery.

Went to try to start that truck the other day, 70 degrees out and it would NOT fire, had to jump it and crank the hell out of it then it fired off.

I'd say she's pretty down on compression.

Mark.

[RCCUMMINS89]

Wow.... ya mine is not that bad yet. MIne has no ill signs of blow by, except well.... the blow by itself.

I found my tremendous oiling issue............... vacuum pump to timing case gasket. ripped in half. Fixed that and I'm not leaking it everywhere now. I still have lots of blow by, but it's not even losing oil yet out of the tube.

[Mark Nixon]

This one is kinda' comical, as it did the same thing when we installed it out in California at ~70 degrees.
I cranked and cranked on it to get it to fire, had nice fuel pressure, where the fuel was shooting out of the lines to the hood when you cracked and cranked, but IT WOULD NOT FIRE.
It was almost like the compression was so bad that it had to fill the cylinders with fuel to get that first fire off, it shook and white smoked like crazy until it warmed up a little.

I firmly believe that this engine has been severely overheated a few times and that might have taken out the rings.
I'm also fairly certain the injectors are looking to head to Mexico for retirement, as well.

Mark.