Ok, a bit of a story.

I was driving to my college class, noticed the 6.2 in my 84 M1009 was running a little rough. Nothing too noticeable. A cop was following me, and pulled me over for a license plate issue. While he was reviewing paperwork, I noticed my truck was smoking out the left side, noticeable more than normal. It hardly smokes at all normally. It started running a little rougher. I smelled the smoke, reeked of unburnt fuel. Drove to my class, by the time I got there it was making a ticking noise, and still smoking. Got towed to the mechanic and they said it had no compression on #7 cylinder, all other cylinders on the left bank had 400+ for compression. This happened friday of last week, and the mechanic said he would do a leak down, but hasn't gotten to it yet. I know this will pretty much tell me everything I need to know, but any ideas? It wasn't blowing air out the oil filler, etc, so I don't think its a hole in the piston or bad ring. When I ran it with the air cleaner off, it was very loud, like something wasn't right. I have dropped a valve before in a gas engine, and I know what thats like, it was smashing the valves to bits between the piston and the head. This doesn't sound like that at all, its like a tapping noise. I thought maybe a lifter went bad? How hard are the lifter to replace? Its not like the standard SBC where its below the intake? How do you get to them? I might have them pull the valve cover and see if that shows anything? It does still run, but A, sounds pretty bad out the intake, and B, runs rough, and smokes.

Thanks a lot everyone!

Caleb
84 M1009 CUCV

Almost sounds like a injector problem to me, well the more smoke that smelled like unburnt fuel does. Injectors will knock when they go bad too. I dont know if a bad injector would give you no compresion though, I wouldnt think so but im not a pro with these engines. Ive been lucky that all the diesels Ive been around, just tractors have never had engine problems. Hopefully somebody who has had this problem will help you out, just thought Id put my two cents in.

I think he probably pulled the injector to get a compression reading. If so that blows the injector theory.

I'd guess sticky valve. Try running injector/engine cleaner through it - Sea Foam is excellent (NAPA, etc - can about $6.00) - recommended by the mechanics that run the refineries where I lived in Washington - for all engines. Can put it in gas and/or oil I believe. Might take awhile - but before you pull anything apart, go simpler to more complex, eh?

Dennis

Could be a rocker retainer broke off and let the rocker slide over. Fairly common problem, pulling the valve cover and visually inspecting the rockers will tell you.

If you don't see anything there, then pull the rockers off and check the pushrods.

Still nothing then you probably have to pull the head to check for a blown head gasket, broken valve or collapsed lifter.

Hey,

Someone was telling me lifters can be replaced with the heads on? Is this true? He said it would be a pain, but could be done. Its at the shop, if they don't get on it, I'm going to tow it here and work on it. Also, I am having a leak at the IP, throttle shaft is leaking pretty good. Is this an easy fix I can do myself?

Thanks,

Caleb

Yeah, you 'can' change the lifters on with the heads on, but its more than a pain, its so bad you would probably save time pulling the heads. Wouldn't hurt to take them off for a visual inspection of the valves and to look for cracks and change the head gasket.

If your throttle shaft is leaking, the old brass bushing have to be replaced with steel ones. And that requires pulling the throttle lever and replacing the seals too.

I'm the guy who tries to fix things myself before I turn them over to a mechanic to mess up. I got an extra year or two from my leaky throttle shaft by tieing some thick thread around and around the leaking shaft and using a knife to push it over toward the body, then dripping some kind of goop that fuel doesn't cut into. Slowed the leak down for awhile. I think you can only do that on the driver's side of the pump. Can't get to the other side (If I remember right)

I don't know how you could replace the bushings without taking out the pump itself????? I'm not that up on it!

Dennis

I'm the guy who tries to fix things myself before I turn them over to a mechanic to mess up.
I'm not telling you to take the truck to a garage or a mechanic. You need a fuel shop to do the repair. And yes, the pump would have to be removed and disassembled to replace the bearings.

Hey guys,

Well its all fixed. Long story. I called the mechanic yesterday, and he said
the rings were bad. He said he did a leak down and that was the results, air coming out the crankcase. He taped both the intake and the exaust. I think this may have provided false results. Anyways, when I was talking to him, I asked him how long it would take to pull the valve cover. He said 2 hrs. I asked him to do it. He refused, and said the leak down told him everything he needed to know. I was very fustrated, as a leak down and compression test took him a week and a half. He said it would need a new long block or short block. I thought "BS" in my head, and went down there late last night after my night class, and pulled the valve cover. Took me and a friend about an hour. As soon as I got it off, I nooticed something. The shaft that the rear 4 rockers rock on, the tube that goes down the middle of the head, is held in by 2 bolts. The bolt near the rear, or #7 piston, the one that had lost compression, was loose. The bolt had worked itself out, and was cauing this metal tube to bounce up and down and cause the clicking noise I heard. This made the valves on #7 not work correctly. I tightened it, hooked the injector lines back up, and it ran fine. I left the valve cover off, drove a very short distance to home, and put a new valve cover gasket on. Put everything back together, and a few things happened. First, it seems to be fine. I seemed to get rid of a slight tick I have had for almost a year, I think. Second, it sounds like its running nice, with a nice rumble at higher RPM's. This seems to cause a very slight high speed vibration, at higher RPM's. I am not sure if this it good or bad. I have a feeling it might have been loose for a very long time, and when it broke down, the bolt finally loosened itself enough to cause major troubles. I will let you guys know how it turns out in the next few weeks. Second, I drove it back to shop last night, parked it, and this morning came in and old them I was taking it somewhere else, and wanted to settle up. $242 for a compression check and a leak down. And a false diag. I was not happy. They did not know I had fixed it. I waited till the service manager got back, and explained everything that had happened. He immediately dropped all service charges. So that fiasco is over. A big thanks to everyone on the board who helped out! Any thoughts on the vibration I'm getting? It seems to be before its about to kick into the next gear, so the rpm's are up a little. Its not a really bad vibration, it just sounds like a vibration, can't really feel it. Maybe thats normal now that the motor is how it should be?

Thanks again!

Caleb

Sweet, I love hearing stories like that.

I told you visually checking the rockers was the best place to start.

Have you looked at your motor mounts? I got one blown on mine and have a strong vibration, more noticeable sometimes than others, gotta get around to changing it soon.

Also, harmonic balancer will make some vibrations if its shot.