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chasing E7-427 vibration


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I have a vibration..maybe 2 of them. Its a remanufactured engine by Mack , E7-427 in a 1998 CH613. Reman engine installed in 2008. Has 97,000 miles on it now.

The first vibe is at idle. Idles fine (not lopey) and engine runs good ( had 6 injectors that were bad last week). New injectors didnt change the vibe. It rattles everything to death. Motor mounts look good. Oil changed at 10,000 miles ( I do dump work, alot of off road.) I also run a bypass oil filter. Oil samples indicate high lead. Lab that tests my oil thinks the main bearings are wearing prematurely.

Vibe #2 is when I'm loaded. It gets bad between 4th and 7th (10 sp Eaton) and between 1400-1800 RPM. past 1800 it goes away). If i'm easy on the throttle its not as bad but still there. Climbing a grade its pretty bad.

I lost a carrier bearing 2 months ago...actually not the bearing but the bracket had cracked and came off. Ive had 2 different types of center bearing, a vented type and solid rubber. With a vented center bearing the vibe in the above mentioned gears is so bad the truck is almost undriveable. A solid rubber bearing makes it better but the vibe is still there. (New drive shafts, bearing and u-joints balanced and installed).

I think the solid rubber masks the problem coming down the drivetrain.

Another problem I had 2 years ago....the front motor mount fell off. Engine fell down on to crossbrace, just a few inches. Had it replaced. Not sure if this had any thing to do with whats happening.

The vibe while driving actually started when the reman motor was installed.

I need help and looking for ideas.

Thanks

.

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Jack er up, get plenty o daylight under wheels, get it point n so it dun do any damage if a FU occurs

run it thru the gears to check for vibration

take note of Rd speed, rpm,gear etc

C ifn all wheels run n tru

jist a process of elimination

jist my view from the armchair on D udderside of D world

LOL

cya

§wishy

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Forget the dampener cause you could remove it and at idle its not going to show you anything.Unless you have damaged the dampner its ok with no more mileage than you have on it.If the virbration started when the engine was changed then it could be in the clutch or flywheel.You can remove the pressure plate to flywheel bolts and slide the pressure plate back enough to clear the flywheel.start it and see if its still running rough at idle.And for as virbrating on a pull it could be drive line problems. If its air ride get the ride height set to what factory say and not by what looks good.This is very critical.Let me tell you this a virbration in most cases is very hard to find and as for as we being able to tell you what it is we can only guess.

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glenn akers

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I think you got some great ideas to work with, I still question the dampener if this has been this way since the eng was installed who says it wasn't a faulty item!

I too agree with Swishy get that thing in the air and run it in place then add or remove items drive shafts , clutch , intermediate shaft. see if it changes.

what caused the loss of 6 injectors? is this a eup eng. do you have a cam failing?

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First of all, I appreciate all the input. These vibration issues are always a real pain in the arse. I had thought of the clutch/flywheel being out of balance. I think the original flywheel was used, ive never had to replace the clutch since i bought the truck used. Maybe something happened when they took the flywheel/clutch out to put on the new motor.

I'll re check the ride height...ive had it be off slightly before.

As far as the injectors..3 were bad, 3 were marginal. I had all 6 Delphi injectors replaced with Bosch. It is an EUP eng. I've had the #1 EUP replaced about 1.5 years ago. I do get an occasional #1 EUP trouble code. I use a Mack shop (not a Mack dealer). They had also suggested going to the dealer and have them re-flash the computer as this can "wake up" the engine abit. They don't suggest that this will solve the vibration problem though.

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The field test engines I followed would normally breakin between 50K and 100K miles. But usually after 50K everything looked "normal". To be on the safe side I would drop a few bearings and take a look. Perhaps the crankshaft was not ground correctly. An incorrect grind would not cause the vibration but a bent crank could cause the vibration AND bearing wear.

Ken

PRR Country and Charter member of the "Mack Pack"

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With engine vibrations the first thing I do is remove the belts, inspect the front balancer for oil or damage. If everything looks ok I'll unbolt the clutch pressure plate and see if the vibration disappears. Be sure to mark the position of the clutch pressure plate to flywheel. If the vibration disappears try bolting the clutch back up 180 degrees from the original position. If unbolting the clutch does not help then there could be an internal issue with the engine.

The higher lead/contamination from the oil sample could be from the engine vibration. Get that figured out and the oil samples may start looking normal.

To be clear, did the engine vibration start when the reman engine was installed or when the front mount broke? If the front balancer was hit in any way, shape or form I would not trust it.

For the driveline vibration, with an air ride suspension make sure the ride height is at spec. Driveline angles that are off will cause some serious problems like taking out a transmission synchronizer. If not an air ride system make sure the correct torque arms are installed, slip yokes on drivelines are in phase. With carrier bearings, we have had fewer problems with the "vented" than the solid type. The solid type seemed to have more vibration issues.

Good luck

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There was a slight vibration when the reman was installed. It was really bad when the front mount broke. After that was replaced it settled back down a bit to where it was when installed. But it seems to have been getting progressively worse over the last few weeks. I wonder if the shock of the motor falling onto the cross member when the mount broke had damaged the balancer. there was a pretty good 'bang' when it failed.

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when you remove the balancer clean and then install a dial indicator on the front of the block then set the dial on the crank shaft check end play then rotate the eng 360 degrees and check for run out,if present crank is most likely bent.( install a board or such to hold the clutch pedal down, this will give a more accurate reading while rotating the eng. by holding the crank against the thrust brgs.) if this checks out reinstall the balancer and then check it for excessive run out both radial and lateral.

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There was a slight vibration when the reman was installed. It was really bad when the front mount broke. After that was replaced it settled back down a bit to where it was when installed. But it seems to have been getting progressively worse over the last few weeks. I wonder if the shock of the motor falling onto the cross member when the mount broke had damaged the balancer. there was a pretty good 'bang' when it failed.

When this happened was the balancer hit in any way? Inside of that balancer is an inertia ring surrounded by oil. The ring is a tight tolerance to the outer section so any type of damage could prevent free movement of the inertia ring. The inertia ring counter acts any frequencies created by the engine. I'm not sure but I think the front balancers for higher h.p. engines are different than other engines, could possibly be the incorrect one as well.

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