Fed Up With MY CUCV...

[cam.man67]

Im getting real close to selling this pile o' crap. Don't get me wrong, I like the idea of owning a CUCV, but this is ridiculous. First, it was the leaky injection pump that I replaced. After getting it back together correctly and it not starting, I sent it to the shop for them to get it timed. As it turns out I static timed it perfectly without even trying.

That was the good news. The bad news from the shop was that I have only 1 cylinder with compression above 100psi, I have a broken timing chain (explain that one to me, the stupid truck ran before I took the injection pump out), and my lift pump may or may not be working. Not that they could tell, since the injection pump wasn't turning due tot eh broken chain.

Fed up.

[old Rusty C10]

I feel your pain. I had two 1986 CUCV M1008s. One of my trucks took forever to get the glow plus to work right now that I did the mod on em they work ok.. the other truck looked like a million bucks but I couldn't figure out the glow plugs there then like yours it stopped running well I put the old one on craigslist and this kid came ( im hoping hes gonna sign on here) his dad and him decided to make an offer on my non running million dollar looking truck that was what I had into it so I sold him the nice looking one. Getting back to your problem I would first do some research on steel soldiers .com they have all kinds of tms and parts books etc plus it gives you the part numbers so that you can try to find the correct gm parts.. Also if you decide to go with a used motor PM me and I can give you a guy in PA who is also a member here who has lots of parts for these trucks.. Also you may wanna PM Gerry GM72K10 maybe he can assist you
the last thing im going to say is make sure you take the truck to a competent diesel mechanic.. many claim to be yet so few seem to know their glow plug from their CDR valve . I have had several guys try to bluff their way trying to fix mine and it cost me more in the long run than if I spent the money on the real truck shop
good luck and let me know what happens

[nekkidhillbilly]

covert it to a v8 or cummins.

[DirtyLarry]

Sorry for your frustration. I bet it is frustrating and expensive if you are paying a shop to do this work for you.

The number 1 reality is if you’re going to own an old truck the only way you can really afford to have them and build them is to do the work yourself. That rules out any BS like all a sudden the truck needs a timing chain not to mention the ridiculous cost to pay someone to do the work you should be doing. Spending money while they spin their wheels equals more frustration for you.

Second, 6.2 and early 6.5L engines are pretty simple and actually pretty reliable once you get to know them (not Cummins-like durable but, the 6.2L was pretty reliable). Look at the military…..We all respect our men in uniform but you have to admit a great number of the gomers in the field working on 6.2L engines were not the sharpest knives in the drawer but yet they were able to keep them running. The more you study the manual and work on it yourself you will find they are very simple. Also remember the truck is OLD. While it may be an low mileage CUCV, it is still OLD. Old stuff needs attention.

Good luck!

[mattcrp1]

If you timming chain is bad your compression will be off won't it?

[nekkidhillbilly]

it could cause the valve not to close or open so yes it could. im sure the whole thing will need rebuilt still. timing chain usually means the valves smack the piston.

[Willowrun]

As mentioned above, Steelsoldiers.com. Sign up and after that use the search function to diagnose. I have Three CUCVs and just like anything old they need attention every now and then but mileage and fun to drive factor is right up there with a gas V8 (my opinion). If it ran before it will run again....study steelsoldiers and you'll figure it out.

[Wellgeo03]

Originally Posted by nekkidhillbilly

it could cause the valve not to close or open so yes it could. im sure the whole thing will need rebuilt still. timing chain usually means the valves smack the piston.

With the 6.2s and 6.5s if the valve train is out of time with the bottom end it WILL result in valve/piston contact. Hopefully it was being spun over by had when the timing chain broke, and not the starter or you will have piston and valve damage. I would suspect thats why your compression is now low and it won't run. It likely has bent valves.

These engines have 380-400 psi compression when new/rebuilt. At 140 or less they basically won't start.

I would be pulling the heads and having the valves checked out and checking the pistons for damage/cracks.

I am sorry to hear this has happened to you. Good luck with the rebuild.

[Zoomad75]

Larry has a valid point. CUCV's are over 25 years old now. Something smells fishy about the shop you took it to as well. If the timing chain broke how in the heck are they able to tell you the pump is in time? I find it would be pretty lucky to have the timing chain break at just the right spot you can install the pump in perfect timing.

I'd invest in the factory service manual for the correct repair details to aid in diagnosis of your problem. Steel soldiers is a good info source too. Your increase in knowledge will stop the need to farm out the work and give some guys an opportunity to put the screws to you.

[aotte1]

Glow plug issue mine had glow plugs not working, also. Do not remember exactly where on fire wall, I direct wired from battery with momentary switch inline to a terminal block that powered the glow plugs. That fixed my problem. Depending on temp I would run them for 8 to 12 seconds. Try starting it for for very short time ( equivalent to warm start). If it did not start I would try another 6 to 8 seconds. It almost alway started on second try. For mine I found you did not want to crank it for more then 1 to 2 seconds. Cranking for several alway messed it up and it would not start that day. Mine always started very quickly. Cold or hot. It has like 35k now. As other stated above, once working they usually last a long time. I have had mine for 12 years with no problems once I got it running. Learning starting procedures for me was most important and keep batteries well charged.

Just a note if you need second alternator, they were also used on 454 ambulance for that time period. Think mine came from Auto Zone.

Hope thing go better for you soon.
Les

[GM72K10]

Ahhh I feel your pain. CUCVs are not for the light of heart.

[cam.man67]

Thanks for the comments, guys. I'm a little more clear-headed about it now...looking back I think I know when the timing chain broke as I was turning the engine. I already had gotten the pump in and I distinctly remember hearing a quiet pop, then the engine turned a lot easier. Had to be it. Yes, that would explain the lack of compression as well, and likewise, I'm unfortunately well aware that I'm going to face valve/piston contact now. I know the engine was turned over after that point so I'm quite sure I'm SOL with this motor.

I guess now the question is, is it actually worth it to put another motor in it? How easy is it to swap another 6.2 into it? I mean, it should go pretty smoothly, but what things will I need to watch out for?

@old Rusty C10, I will be PM'ing you about your guy in PA with the motors, thanks.

[old Rusty C10]

Im thinking that if you get a used motor just for the fun of it you should prolly do a timing chain before you install it in the truck

[Wellgeo03]

cam.man67, did the timing chain break break before or after you installed the new pump?

[cam.man67]

Originally Posted by Wellgeo03

cam.man67, did the timing chain break break before or after you installed the new pump?

After. I think it went as I was bleeding the air out of the injector lines.

[Wellgeo03]

I would take a close look at the pump itself. I am not saying it's impossible, but there are lots of 6.2s around with 400 000K + miles on them with out being rebuilt including the timing chain.
Anything is possible, but I would wonder if something locked up the pump causing the chain to brake while you were cranking it.