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how bad is this engine?

imiceman44

imiceman44

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So I got this truck and so far everything in it has been bad, the engine supposedly was running, couldn't get it to run so I started testing:
compression test results:

8.......400 7.......400
6.......300 5.......400
4.......400 3.......450
2.......300 1.......500

I know 300 is minimum for a diesel, but the huge difference between 1 and 2, 6 makes me a little uncomfortable.
The others are 400 and one 450 I wouldn't be too concerned about that.
So what say the diesel gurus?
Should I try and get it running and run it till it dies or self destructs, or should I wait a week or 2 till I get my low miles engine and slp it in there?
 
I'm no expert,but I've had quite a few engines ,both in vehicles and small engines,that had "low" compression in one or more cylinders,that improved markedly after they were gotten running again and run for awhile--rings can stick from sitting,if the engine sat awhile rust may have formed in the bores and that takes time to buff off,etc..and if a few cylinders were running rich,or in the case of a diesel had excessive fuel being dumped in by a bad injector or a dead glow plug caused one to load up after a cold start,enough soot or carbon could build up to give a higher than normal compression test reading...

I'd try to get it running and use it awhile and take it from there...unless the "low" cylinders happen to be side by side,in that case a head gasket may be leaking between the two cylinders..
 
diesel4me said:
I'm no expert,but I've had quite a few engines ,both in vehicles and small engines,that had "low" compression in one or more cylinders,that improved markedly after they were gotten running again and run for awhile--rings can stick from sitting,if the engine sat awhile rust may have formed in the bores and that takes time to buff off,etc..and if a few cylinders were running rich,or in the case of a diesel had excessive fuel being dumped in by a bad injector or a dead glow plug caused one to load up after a cold start,enough soot or carbon could build up to give a higher than normal compression test reading...

I'd try to get it running and use it awhile and take it from there...unless the "low" cylinders happen to be side by side,in that case a head gasket may be leaking between the two cylinders..
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Well you mentioning the soot is interesting, when I removed the glow plugs, it was hard getting them out and I was afraid they were swollen, but it was just carbon deposit so I kept spinning and pulling slightly and finally they got out with lots of soot on them, only a couple were easy to remove they were lose and as soon as the threads ended they kinda fell out.
The all are in good shape but are Autolites 1110, I don't know if I wanna keep those especially that I plan on running them on manual control.
It did sit for almost a year after it was parked, so I expect some problems, I guess I could get it started, run some additives in the fuel and the oil and see how it does after a few months.
I just worry that the imbalance could make the cranck snap or destroy my balancer quick since it is a problem with these engines.
:dunno:
 
If you've got another motor lined up then I would put it in. #2 definitely has an issue. Thats a ginormous difference across the board...
 
Stomis said:
If you've got another motor lined up then I would put it in. #2 definitely has an issue. Thats a ginormous difference across the board...
Click to expand...

I know, 1 is too high and 2, 6 are too low, but the rest are good.
I think I want to at least get it started and run it a bit before moving ti to the vehicle I want it in, in that time I will have a low mileage engine ready and can decide which to put in.
I could use the extra engine in my waggy for trail use.:D
 
I would try to get it started before pulling it to swap out. Once it's running for a bit and warms up some, recheck the compression. The numbers should even out, if they don't then the engine has issues. But a low of 300 in nonadjacent cylinder isn't too bad.
 
KirsL said:
I would try to get it started before pulling it to swap out. Once it's running for a bit and warms up some, recheck the compression. The numbers should even out, if they don't then the engine has issues. But a low of 300 in nonadjacent cylinder isn't too bad.
Click to expand...

That's what I am hoping but the thing this engine is in a truck I parted out and it would be going in another truck that is just missing the engine, but since I have it now still hooked up all I need to put is wires to the glow plugs and IP and starter (no wiring at all in this truck now.)
If it doesn't vibrate then I will check compression again after it runs and idles for a bit, and we'll see.
 
An Autolite 110 glow plug is what nearly destroyed my 6.2.when its tip snapped off about halfway down one day while I was cruising along at 30 mph--engine still sounds sick to this day,like a tappet or push rod clatters now,and I bet the half that broke is still embedded in the piston..do what you like,but if I were you I'd use nothing but 60G AC's if you are manually "glowing" them!...older GM 9G's can swell and pop too,I have a bunch of those ,good used ones,that I wont use..

Perhaps a few cylinders that are low have valves that are sticking open ever so slightly from rust or soot too,thats why I'd get it to run awhile before condemming it--it might come out of it after some run time..
 
diesel4me said:
An Autolite 110 glow plug is what nearly destroyed my 6.2.when its tip snapped off about halfway down one day while I was cruising along at 30 mph--engine still sounds sick to this day,like a tappet or push rod clatters now,and I bet the half that broke is still embedded in the piston..do what you like,but if I were you I'd use nothing but 60G AC's if you are manually "glowing" them!...older GM 9G's can swell and pop too,I have a bunch of those ,good used ones,that I wont use..

Perhaps a few cylinders that are low have valves that are sticking open ever so slightly from rust or soot too,thats why I'd get it to run awhile before condemming it--it might come out of it after some run time..
Click to expand...


Yeah I am not planning on running the Autolites.
But I was thinking if I spray some WD40 or better product in the glow plug hole and let it sit overnight and then try to start it the next day, you think it might help dissolve anything?
 
I was reading this via the new posts link at the top, and when i saw the compression numbers at 300+, I was like "heck, i got 140 and i was happy :haha:



But then I saw it was a diesel, and was like oh :doah:


Yeah, they seem low on 2+6, but id run it for a while, or try a wet test, Could be any of the previously mentioned reasons, and it may pick itself up after running for a while.
 
imiceman44 said:
Yeah I am not planning on running the Autolites.
But I was thinking if I spray some WD40 or better product in the glow plug hole and let it sit overnight and then try to start it the next day, you think it might help dissolve anything?
Click to expand...

Yeah I've been using Seafoam spray (the "Deep Creep" stuff) around my 6.2 for everything and it works great...it seems faster and more effective than WD40.
 
cdoggwsu said:
Yeah I've been using Seafoam spray (the "Deep Creep" stuff) around my 6.2 for everything and it works great...it seems faster and more effective than WD40.
Click to expand...

I need to get this one.
I have some time now that I put my truck at my buddies place so no hurry to get it running.
 
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