consistent engine vibration? long post

[Busted]

Hey y'all,

This isn't exactly a technical question, more looking for the voice of experience in diagnosis . . .

The engine in question is in my '82 crew cab, which I bought believing it was a 6.2, and I drove it accordingly. 65 and occasionally 70MPH with no overdrive, 4.10 gears and 33" tires=high rpms for hours at a time. Ran super smooth, wound up great. Sounded like a diesel, but the cab sure didn't vibrate.

When I ripped into a turbo conversion, I discovered the the block was a 6.5 (141 casting) with very low miles. Super clean inside, crosshatching in all cylinders, etc. However, the timing chain was on the sloppy side, and the IP was advanced maybe 3/16" toward the driver's side of the mark.

Put the engine back together with new timing chain, head studs, girdle kit, and IP exactly on the mark based on the new chain. She fires up within a turn cold or warm, idles properly, etc.

BUTTTTTTT, there is this constant vibration. With my limited diesel knowledge, knowing how the engine ran before is the only reason i don't write it off as "normal diesel" vibration. Sitting in the drivers seat (bucket from an '89 burb, nice and comfy) the vibe is enough to tickle/irritate. Rev up a little (maybe 300RPMS) and it smooths out, but then returns full force.

I haven't had a tach on it yet, planning that tomorrow morning, but with the NV4500 conversion (overdrive and no loss through TC) I can't go faster than 50MPH in OD--sounds like the engine's going to send parts flying.

I know it's not the drivetrain, as I can rev it up in neutral/sitting still, and still have the same noise/vibration. HB is the same one, in great shape.

Injectors came from the donor 6.5, IP is original. Any suggestions before I reinstall my original known good injectors?

[Robyn]

Try running the engine with the serp belt off so you can rule out the accessories.

If this does nothing then the possibility exists that the clutch/flywheel has an issue.

As long as the flywheel came from a 6.5 you should be fine.

These are externally ballanced engines and must have the proper ballancer and flywheel or flex plate.

Now a water pump that is going south will vibrate you right out of the seat.

Keep us posted
Robyn

[Busted]

The flywheel and clutch were both off the donor 6.5. It's a brand new single mass flywheel with LuK clutch--the clutch plate has a lot more springs in the center than I'm accustomed to seeing. Didn't even appear to have been run at all when I pulled it off.

This is the clutch plate, sorry for the lousy picture . . .
http://i20.photobucket.com/albums/b222/Byronm/DSCN0628.jpg

I bought the donor truck with the top end of the engine dismantled (IP, intake, injector lines, accessories removed) so it obviously had something wrong. I guessed IP and took a gamble on the injectors.

What would I be looking for in a worn water pump? I inspected it thorougly before installing--seemed fine to me--I removed the back plate, cleaned everything, and couldn't feel any play in the shaft at all. The impeller didn't seem worn or damaged either.

[6.5 Detroit Diesel]

Did you try to run it w/o the bet yet? Like I said, with NADP in town there, you could get them to test the injectors.
Man you just aren't having luck with that beast. Done the wiring again?:D

[Busted]

Yep, wiring is redone. For the rest of you, I was doing a test run and my temporary hot to the fuel pump fell down onto the turbo (FP is on the pass. fenderwell for now) and fried my fusible link. Rashly patched the link to get me home without looking for the cause, and roasted the inside cab wiring harness. Replaced with harness/fuse box from the wrecker that was in better condition than the original.

Anyhoo . . . ran without the belt, seemed to help a little . . . removed crank pulley, didn't make much difference . . . bolted on original v-belt pulley again for kicks, felt the same . . . bolted serp. pulley back on but rotated one bolt hole, seems a little smoother. Rubber seems to be in great condition on both HB and pulley, new ones on schedule within a month or two anyway just to be safe.

Jury rigged the 93 6.5 tach dash so that the tach would run off my alt. signal--for those of you looking for a simple tach for 80's diesel trucks, the 6.5 factory tach unit and the circuit board in the dash can be run by themselves with just the alt. signal wire, hot, and ground if you're already running the serpentine conversion with the CS130 alternator . . . .

Took another test run after all this and it isn't really a vibration that's making me nervous *anymore*, guess maybe it's improved a bit BUTTT--it's the sound like a JET taking off under the hood whenever I get past about 1600 RPM's. Maybe I'm just not used to a free-flowing turbo sound? Dunno, but it really howls. I'll see if I can record it maybe and post up.

Idles right around 650-700RPM once it's warm, which is about right . . . still haven't revved it over 2000 because of that jet under the hood . . . maybe my boost gauge should go in next, still haven't bought an EGT gauge.

I'll also head over to a buddy's house and spend some time sitting in his 6.5 revving it and just listening, see if I can't get a better feel for what a healthy engine should sound like . . ..

Will keep y'all posted . . . .

[6.5 Detroit Diesel]

Did you put in the whole dash unit? Or.....
I am kind of looking forward to seeing it, how it has gone so far.

[Busted]

Right now I just have the gauge cluster propped on top of the factory gauge cluster with just the tach running. I'll be figuring out some way of using just the tach though.

I did fix a number of things today, and the problem is solved. The howl was the open CDR port in the turbo boot:eek: I had the boot rotated so that the filter was atop the intake manifold, and didn't think about the disconnected CDR, so I rotated the boot back and re-rigged everything which solved the howl.

Also opened up my rear diff to check the oil and found that the two big carrier bearings were completely shot. Cleaned the housing out thoroughly, checked all other bearings, and replaced those two. 4-1/8" diameter tapered roller bearings are not cheap--I paid $85 for each bearing and race set. Filled up with clean oil and good to go.

I also discovered my diesel leak--the bottom of the fuel filter can was leaking where the thingamajobber screws on--water in fuel sensor perhaps? It had been slowly dripping and running down the back of the block from the valley drain, so I wasn't sure exactly where it was coming from. I'm wondering if perhaps air might have been leaking in through there as well and causing some vibration.

Anyway, just a few sloppy mistakes putting things together, I'm still more comfortable with bolts and torque specs than plumbing.

Also hooked up the new boost gauge today, and running empty in the dually I maxed about 5-6psi. I expect I'll need to turn fuel up a fair bit more to utilise all the changes I've made, but will need to have timing set properly and install a pyro as well before I start cranking things up.

Running good now, thanks for the help!! Even if the problem wasn't suggested, I always need a reminder to diagnose rather than start changing parts. Will continue to post as I experiment and learn :D

[Robyn]

The little round fuel managers (filter) that sit in the back are notorious for rotting out and leaking.
Take the thing off and throw it as far as you can and then go pick it up and throw it farther.

Get a good Racor 230R2 and bolt onto a little bracket under the hood in a handy spot and you will be far better off. These filters are a lot bigger than the dixie cup goodie that GM used.
The Racor also has a water bowl in the bottom that you can see any crap in, plus a drain too.

These can be ordered with a heater if need be.

Mine is such that when I check the oil I can see the bowl and know if I need to drain any water.

Clean fuel is the best $$$$$ you can spend. The DB2 and DS4 IP's are both good but will fall far short of a good life span if they have to suck dirty fuel.

The factory filter is little better than a CLOD sifter.

If you have a factory unit thats in good shape it can do a fine job as a pre filter and then run the fuel through the Racor before it hits the IP.

If the water pump is bad the shaft will usually wobble and the thing would be noisy when it is spun over.

Best

Robyn