M1010 weird hum & vibration from motor

[squaretaper]

Hi all,

Approaching the 2 year mark of owning/working on my CUCV. It's been the first vehicle I've ever tried to work on, and that beast and this forum have been amazing teachers. I've rebuilt the front end- replaced the U-joints, rebuilt the bearings, and rebuilt the lockers on the Dana 60. I've replaced the starter, chased down 100 electrical gremlins, swapped GPs, rebuilt the alternator, and replaced the GPR with a push-button relay. I've built out half the box into a murphy bed camper with a kitchen and 12V system and done some awesome offroad camping with the wife. The truck has been halfway across the country back to WI to visit my folks and back to the East Coast TWICE. Now I'm trying to figure out a weird engine-related issue and I'm appealing to the greater wisdom of SS members.

A few weeks ago while I was hauling some equipment (I'm a welder and fabricator, and I use the truck for hauling work and gear, as well) I noticed a growing hum/vibration on the highway, starting about 35mph. Only had about 800lbs in the truck but I could feel it coming up thought the floor pan/bulkhead- it was a shudder/hum that would die down when I slowed. Thereafter, even in Park, the vibration is present, building at around 1500rpm and again at 2000rpm. Idle is rough and the beginnings of that hum is there. Did some research and checked out the motor mounts and harmonic balancer- both look ok to my eye. Took it to a guy and he looked at it for about 30 seconds and said he thought it was a bad cylinder or cracked piston, but he didn't even test drive it or run it at any RPM other than idle. It doesn't seem to "knock" or anything, just rough and loud at idle, and rougher and louder under way.

Obviously lots of things it could be, but I'm wondering if any of y'all have experienced anything like this and would have some ideas as to where to start. I'm in Rhode Island (just moved my shop down here) and time is tight with the buildout and work at the new place- I'd love to find a mechanic who could take on the stuff I can't in the area- the few times I've had a shop guy look at it they stinkeye it like it's a ****box, not the beautiful thing it is.

thanks in advance-

Josh

 

[dmetalmiki]

That harmonics balancer might look OK to the eye, but I would be checking it out further. With it sounding and running rough..Look at the drive plate coupling area as well as the flywheel. . You would not get a "hum" with a misfire.
Keep us informed on the checks, and hopefully the cause and eventual remedy.

 

[squaretaper]

Thanks for the leads, dmetalmiki. I'll pull the bell housing cover tomorrow and inspect the flywheel- would I be looking for missing teeth or other damage? As far as the HB goes- the one on the shaft certainly isn't new, but I don't any evidence of dry rotter rubber or rubber oozing out. Is there a good way to inspect or test the function of the balancer?

 

[llong66]

When you pull the bell housing, check for loose/missing bolts at the crank and between the flex plate and torque converter. If you havent had it off or worked on it I dont see how the flex plate could be bent but maybe before you put the inspection cover back on, look under the truck with it running, maybe shine a bright light on it and look for any "wobble" in the flex plate.
Good luck!

 

[Recovry4x4]

Loose air cleaner will cause a droning sound but not cause a miss

 

[jpg]

I took my M1010 to the service station that services all the landscapers' trucks. They're used to 1-ton diesel pickups. They thought the truck was way cool. They crowded around, checking out all aspects of the truck. They like the fact that it has no computers -- it lets them be mechanics. If you find the guy who services landscapers' trucks in your area, you may encounter better attitudes.

On my truck, loose belts have caused funny harmonic vibrations. It's worth checking your belt tensions. The M1010 alternators are very hard on belts.

 

[Drock]

I'm not familiar with how the harmonic balancers on our trucks are made. But I have had a couple shake loose on hotrods in the past. Those had a large counter weight pressed over a center hub with a strip of rubber glued in between. The rubber rots out and the counter weight slips a little. Sometimes you can't tell just buy looking at it. If it has timing marks you mite be able to tell with a timing light? But one rule of thumb here in my yard is, (If it's made of rubber, and 30+ years old replace it anyway). Another one is, (When in doubt, replace the cheap parts first). hope this helps, good luck and keep us posted.

 

[CUCVLOVER]

I would check the air cleaner nuts, the fly wheel, also run some injector cleaner through it.

 

[squaretaper]

I snugged down the air cleaner nuts, checked out the flexplate, everything looks good. Seems the HB probably should be replaced anyway, and pretty sure I have a HB puller in a box somewhere. Do you all have a recommendation for a replacement part? As far as injector cleaning goes- are we talking pulling each one and inspecting/cleaning or simply dumping some diesel kleen into the tank?

 

[CUCVLOVER]

I would start with diesel clean or sea foam. Them some stanydne brand cleaner/lube if the other doesn't help. I use sea foam and the other I'm not sure how much better one is over the other.
Also you could change your fuel filter. It might help with the running rough.

 

[Tinstar]

Amazon has a AC Delco HB for just over $90

Mine "looked" fine while on the truck, but once off
you could see where it was dry and cracked.

Really glad I took the SS members advice To change it because of
age and not appearance.

Make sure you have the gasket installed between the
air filter housing and the manifold.
Mine didn't and it hummed a bit with the nuts cranked down.
Installed one from fel-pro and noise went away

 

[squaretaper]

Taking her in to a local shop that does a good bit of diesel work tomorrow. Will report back with a professional opinion...

 

[Chaski]

It will be interesting to see what the shop comes up with. What is it like on a cold start? Does it smoke at all? If it does smoke does it just smoke from one side or both? Is the smoke white, blue or grey? Does it consume any fluids?

My wild guess would be injection issues. Take a minute to look at the top of your injection pump. Under one of the three screws that hold the lid you may or may not have a metal tag with the letter E stamped on it. Stamped "E" tag = good. No tag = bad. The tag designates that the pump has the newer style weight retainer that does not fail.

If the shop thinks it might be injection related you should give your engine a bath, Then pull the injectors. All you need is a 30mm deep socket for the injectors, and the correct flare nut wrench for the injector lines. You can drop your injectors by an injection shop, expect to pay $6-10 each for a clean and test. If the pump is the issue pull it and take it to a reputable Stanadyne repair shop. Make sure whoever works on it uses OEM parts.

 

[squaretaper]

Chaski- good info- thank you. Cold starts are rough but she does get going after 5-10 seconds of cranking. White smoke on startup that clears as it warms. Not consuming more oil or other fluids than usual. I'll take a look at the IP tomorrow before taking it in and I'll order the 30mm socket. Report to follow.

 

[squaretaper]

M1010 weird hum & vibration from motor

Also- what did you mean by give engine a bath before pulling injectors? You mean clean it to prevent crap from ending up in the cylinders when the injectors come out?

 

[Chaski]

I should clarify. You need a 30mm deep socket. Stahlwille 51-30 is a really nice socket for injectors, but it is spendy.

As far as the cleaning goes, you want everything to be a clean as possible before you start, getting a tiny bit of crud in the cylinder isn't good, but getting a tiny bit of crud in one of your injectors will cause it to stick. Just be clean and careful if it gets to the point where you have to pull everything apart.

 

[m1010plowboy]

Also- what did you mean by give engine a bath before pulling injectors? You mean clean it to prevent crap from ending up in the cylinders when the injectors come out?

I should have asked the same question. We used Simple Green, Super Clean and steam to sanitize the M1010 under the hood and everywhere else. It's so much better to work on and after a good bath it's easier to see problems. A clean engine runs cooler and all Chevy's run better after a bath.

This method of bath is fun and wrong at the same time.

https://www.youtube.com/watch?v=SZqvDw_vYDQ

 

[squaretaper]

Hahaha fun until you gotta figure out getting it out of the bath! Any issues with using the pressure washer and simple green to clean, you reckon?

 

[dmetalmiki]

Yep that a good technique, just keep on grinding away, and sinking deeper and deeper. How did you get it out of that predicament by the way?

 

[m1010plowboy]

Fords are a problem with a water under the hood but I've been lucky with Chev. I avoid direct high pressure spray on wires, computer boxes, distributor caps if cleaning a gas engine but aiming at a spot and short pulls on the high pressure washer limits problems. Bagging up the intake is an added step to make sure NO water gets in the motor.
It goes without saying that electrical lines that are exposed could absorb that moisture in the jacket. I accept that because there are very few things that are better than a spotless engine bay, am I right fellas?

I'm a bit of an MVironmentalist and using Simple Green is a bonus because it works great and is a little gentler on the ground.

My latest trouble shooting M1010 adventure was the GP relay under the hood so having it clean for our buddies to work on always brings them back. Really looking forward to see how you get this problem beat.