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Discussion Starter #1 (Edited)
Motor Condition Evaluation thread...I want YOUR opinion

Ok, so I jumped in a little quick after seeing a local van come up for sale. The van is a 1980 Penn 20' Al. bread truck, GM 4speed . I suppose if I found the serial # on the motor I would have an idea of the era of the motor which is the 4BT. Today I tinkered with it and will list some of the things I saw and don't think it are good signs.
1. Oil seepage on the intake side of turbo, assume a seal has gone out.
2. Oil super dirty, oil pressure drops to 30 according to chevy gauges, at RPM it is at 60, didn't change oil but threw in a new filter. Wasn't any oil on rockers after a minute or two of running, a little throttle. After I changed the filter it started to trickle, #7 rocker was bubbling #8 was oozing . Oil pressure gauge seemed to bounce more after I changed filter. Non-bypass filter?
3. Blow by? With the #4 rocker cover off there was a fair amount of "blow"- same as the oil fill plug, but I assume some of this is due to the reciprocation of the pistons.. I guess I could put a plastic bag over the fill plug to see how much air was coming out.
4. Loose/missing bolt on tranny/bell housing to adapter, stripped bolts..I suppose some keyserts or helicoils will be employed.
5. Fuel running down driver's side below or from injection pump-saw someone else had this problem, found loose fuel cut-off or fuel supply pressure sending solenoid.( It sits on top of the injector pump and is almost impossible to get anything on it as the injection lines are on top and around it as well as a threaded stud with a nut... remember this is all new to me) I don't know if that is it though.
6. Valves loose, didn't seem to have much axial play but the #8 would dance fore and aft at a higher RPM. will adjust after I get my manual.
7. Oil line to turbo rubbing pretty good on intake plenum- this will probably change after the conversion.


Removed the intake plenum, turbo spins as motor runs, this rig blows black on accelleration and mildly black while running.. I plan on changing the oil, putting in some fresh fuel and changing the fuel filter, bolting things up tight again and seeing if it still blows black. Could this be oil from the turbo? I will check the oil pressure with a real guage. May look into a compression test. Any advice or input you have is greatly appreciated. I want to make sure I have a good solid motor or be ready to rebuild if that is the case or repair as necessary.
Another question.. How do I determine boost level and should I hear the whine of the turbo? Thanks and already gleaning a lot from your buildups!
 

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Discussion Starter #2 (Edited)
So far So ?

Changed the oil. Woohoo. I don't feel bad about turning it on now. Pressure appears to be 55-60 at speed, 30-40 at idle.
No ID tag.. looks like the PS hoses worked it off. Other emission tag has a 1988 or 89 tag. Any other spot that would have the number on it?
Found fuel leak, seems like the bolt with the hole squirts some out after letting off the throttle (See picture). Can't tell if it is coming off the stud/jam nut below or it is just dripping down.
Let Engine warm up, seems to blow black haze when I throttle up.
Found one bolt holding the tranny to the bellhousing, threads seem to be in the tranny so it must have a bolt on the other side...:rasta:
Found the tranny mount has no bolts... :confused:
Temperature sending gauge has two terminals with wires coming off both, gauge has read low, sending unit terminals were almost corroded off.
At this point I am thinking this motor need some serious attention, before I go too far. I am wondering if I would be better off with a better maintained unit.
Second picture is the lone tranny bolt, 3rd is the missing tranny mount bolts.. crazy.
 

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Discussion Starter #3 (Edited)
Is something else missing?

I noticed on dieselcruiser's post on 'mud that the injection pump has a cap over the bolt with a hole in it. Vs. where I have a little leak. I also think i am missing one of the bolts that holds it in place. I assume the PO didn't tighten stuff up right.
 

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Bummer.. Yes I would say a pumped being messed with is usually not a good thing. My motor runs great but needs all new gaskets, leaks like a sive.. Not sure if that is that bad or not..
 

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Discussion Starter #5
Bummer.. Yes I would say a pumped being messed with is usually not a good thing. My motor runs great but needs all new gaskets, leaks like a sive.. Not sure if that is that bad or not..
Hopefully that means that it isn't all sludged up and the sludge isn't plugging up the leaks!

When getting injector and a pump checked out do they outfits that do that want the hole rig?
 

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Discussion Starter #6
injection pump question.

Ok, so I talked with a nice guy at Oregon Fuel Injection in Medford. He seemed to think that if my pump was leaking at the place I pointed out that the o-ring associated with that is bad and that is a vent for the diaphragm and I need the filter on there so grit doesn't ruin anything. He stated that I am probably ready for a rebuild on the injection pump, about $800 off the shelf... YIKES! If it is leaking around the throttle shaft it may leak into the motor(?)
He stated that this is not uncommon when the newer fuels came on the market the older pumps are/were losing seals.
Cummins wouldn't talk to me without a motor serial #....
I guess I need to start looking to see what y'all have done for pumps.
 

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Discussion Starter #7 (Edited)
Compression test results

Well it started out going from #4 to #1, cold and no oil added (dry).

#4 300 to 310
#3 315
#2 320+
#1 360

I thought I would try again and make sure everything was lubed up good and I allowed 8-10 cranks per jug.

#4 340
#3 350
#2 350 and I skipped #1

I went back to #4 and pumped 360.

I don't have my manual so I don't know what the spec compression and when I talked to a cummins mechanic he said they always went by the blowby inches of water column method. As I pumped the oil was wetting the rings a little bit. I suppose if I had done it warm it would have been a lot higher. I debating on whether or not I should not sell it as I may have an interested buyer....:confused:
It looks to me like I need a pump and a turbo.. judging by the amount of oil in the tube from the turbo to the intake plenum/manifold I think either my seal is bad or the drain tube is plugged-this may be the source of my black haze.. Also need to test and possibly replace injectors.
Of course seals and gaskets are in order but that would be the same for any candidate. My thought was to sell this one and find another in better shape but I don't know what my odds are of getting one in better vs. worse shape not to mention prices seems to be very up and down. Any thoughts?
Thanks again guys, you have been most helpful.
Andre... thanks for the Harbor Freight Compression tester tip.. $25. That was a lot of fun for $25.. now I want to test my other motors.
 

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Discussion Starter #8
*ESN Help needed*

Well, live and learn. I scraped the back of the block off today and no number, I looked all around that flat portion around the freeze plug, above the adapter. Anything I am missing? I suppose they didn't do it on every engine?

Definitely need a number. :rasta:
 
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