engine vibration (idle and high rev)

KyleKoehler · 10-12-2007, 10:21 AM

I just purchased a 91 Samurai with a 93 1.6L tracker engine. Engine was installed professionally using a Petroworks mounting kit.

Only problem I am having is a vibration in the engine. It is there at idle and becomes a loud droning vibration at high rpms to the point that it is VERY loud. Car has new tires and is newly aligned. If I put the car in neutral while going 40mph or so the vibration/droning is still there ONLY if I keep the engine rev'd to the same speed (i.e. it goes away if the car is still doing 40 but the engine goes back to idling while still going 40). So I don't think it is in the transmission, tires, bearing, etc.

The engine idles great (except for shake) and starts super.

To give a better glimpse into the problem... if the license plates aren't tied down I get a loud tin rattle from them that scared me the first time I heard it and didn't know what it was.

I have read on this forum about distributer issues in the manuals about firing sequence being wrong and manuals not correct. Could this be the problem. If the plugs are wired in the wrong order could this be the issue or would the engine run more poorly than I am experiencing (really the only problem is the shake).

Again the motor was just installed 500 miles ago and the mounts look good and tight. The shake can be felt at idle but gets loud and "droning" at high engine revs (feel and hear it most right before shifting or when I am going 55-60 in 5th gear).

What do you think and try not to be too technical for me!!!

Kyle

Max · 10-12-2007, 10:36 AM

If it was the firing order off, you wouldn't see "55-60" mph, IMO.

Did they install SOLID (vice OE soft) engine and transmission mounts?

Have you checked the timing?

You may have a "vibe" flywheel or driveshaft issue there as well. An improperly set-up pinion angle (trans to differential interface) as a result of installing the new drive line components could whip things into a frenzy (but don't account for the rough idle).

Did it run this bad as a result of the new engine install? If so...I'd march the vehicle right back to them to sort out the poor performance issues.

KyleKoehler · 10-12-2007, 10:52 AM

I did not contract the engine install. It was done by the previous owner.

Perhaps I can find out who did it and talk with them.

The engine mounts have large 3-4" diameter green urethane engine mounts (is that good or bad?).

I have not had the timing checked. I have been working at taking care of many little small issues on the car and getting down to just this one issue (it needed brake and tail pipe issues).

On the "pinion angle" issue... wouldn't the fact that I still feel it when engine is rev'd but car is in nuetral rule that out (again I am not technical in this area... so I am guessing).

Thanks,
Kyle

Max · 10-12-2007, 11:20 AM

See below...

Quote:

Originally Posted by KyleKoehler

I did not contract the engine install. It was done by the previous owner.

Perhaps I can find out who did it and talk with them.

The engine mounts have large 3-4" diameter green urethane engine mounts (is that good or bad?). I don't believe those are stock, nor supple like OEM mounts, which WILL lead to engine vibration transmitted throughout the vehicle.

I have not had the timing checked. I have been working at taking care of many little small issues on the car and getting down to just this one issue (it needed brake and tail pipe issues).

On the "pinion angle" issue... wouldn't the fact that I still feel it when engine is rev'd but car is in nuetral rule that out (again I am not technical in this area... so I am guessing). Good point. Which leads me to believe that the clutch / flywheel assembly could be out of balance, but given the urethane mount info...you'll feel ALL of the even the slightest driveline vibes now.

Thanks,
Kyle

KyleKoehler · 10-12-2007, 11:44 AM

I guess I assumed that the mounts came with the petroworks adaptor kit (the steel and urethane that make up the mount are brand spanking new looking).

SO I guess my question is... has anyone out there used the petroworks conversion kit that includes motor mounts... or is my assumption wrong that these mounts came with the conversion kit???

Max · 10-12-2007, 12:38 PM

Give em' a call...

Petroworks Off-Road Products Inc.Home of Suzuki Samurai Parts and Services

KyleKoehler · 10-24-2007, 07:23 PM

Had a mechanic look at the car today and he's pretty sure the "droning" at high RPMs is coming from the fan clutch on the radiator cooling fan.

I tried removing it by loosing the four nuts that hold it to one of the engine pullies. With the nuts off I couldn't budge the thing.

Is this on a shaft that has to be pulled or is it just bound up a little and needs to be "janked" with some force?

Do I have to remove the radiator to get it off or does it (if loose) slip over the four studs that the nuts tightened onto?

Any help here?

Kyle

Ronzuki · 10-24-2007, 09:06 PM

fix one thing at a time. get rid of the vibes by ditching the poly motor mounts. they cause problems everwhere they're used. tcases on samis, motor mounts on jeeps. heard this complaint many times by jeep guys putting in 1" motor mount lifts that have poly bushings...too stiff and not enough give. they end up going back to stock mounts with a 1" spacer under the mount. not familiar w/ the petroworks (or any) 1.6 install kits, so I don't know if you can even use an OE rubber mount.

After that, then see if the droning is still there. if it is, ditch the fan clutch and go with an electric fan....if the fan clutch is truly the cause.