I have an 88 Samurai and just replaced the timing belt and tentioner. It runs great but when the engine passes between 3,000 - 3,500 RPMs there is a vibration coming from the engine. It is not violent but you can feel it through the seat and hear it. It will do this while driving or sitting still so it is not in the drive train. Did I tighten the belt too tight or something? I changed the fan clutch out with another one and that did not do anything. Could it be a
unbalance or damaged fan blade?

To be honest I do not remember before the new timing belt if this vibration was there or not.

Thoughts are appreciated. Thanks

I have an 88 Samurai and just replaced the timing belt and tentioner. It runs great but when the engine passes between 3,000 - 3,500 RPMs there is a vibration coming from the engine. It is not violent but you can feel it through the seat and hear it. It will do this while driving or sitting still so it is not in the drive train. Did I tighten the belt too tight or something? I changed the fan clutch out with another one and that did not do anything. Could it be a
unbalance or damaged fan blade?

To be honest I do not remember before the new timing belt if this vibration was there or not.

Thoughts are appreciated. Thanks

This is a tough one (well, for me) but I'm thinking that maybe the flywheel is loose or the clutch/pressure plate is loose... This is based on a vibration that would be enough to blur your mirrors and would be 'low pitched' - if that make sense... The fan idea was a good one too... Maybe alternator? Hope that helps...

-Eric

I've seen a broken piston skirt (not in a Suzuki) cause an engine vibration
(due to engine unbalance) but it's high speed

Wild

The vibration is enough to blur the mirrors......it runs smooth until you hit 3,000 rpms then it vibrates through to about 3,500.  I guess I can pull the plug on the trans and try to "feel" the flywheel.  But I would think the clutch would preven a flywheel from moving??

Maybe I will pull the fan and see it the vibration continues.  It won't overheat for a short test time.

I truely do not remember this before the timing belt....I think I would have noticed it.

Thanks again for the head scratches.

I truely do not remember this before the timing belt....I think I would have noticed it.

You may have affected something upon the timing belt change.  On my 1st Tracker, the PO didn't tighten the crank pulley bolts well enough and ruined the pulley and crank timing gear.  I'd double check your install.

Start simple, check your motor mounts. does it vibrate too under full acceleration? my vibrated bad and all i had was a broken motor mount. put a jack under the motor, if you see the motor lift you have a broken mount most likely drivers side.

I will check the motor mounts....I did remove the fan belt and crank pully and start the engine.....it still has the vibration.  It vibrates when driving or just in neutral when it passes 3-3.5K rpms.  I checked the flywheel through the bell housing timing hole...looks fine.

I also removed the timing belt cover and started the engine.....nothing running wrong and the belt is not too tight.  I did not remove the crank timing belt gear so I should be OK on the crank end. 

Garry 

Last night I placed a floor jack under the oil pan to give some upward support on the engine.  Started it and ran the rpms up.....still had the vibration around 3,300.  I would think if a motor mount was shot this trick would at least affect the vibration..but it did not.  Any other ideas?

Yeah, here's another idea... Pull all of your spark plugs and check the height of the pistons at the top of their stroke. I'm thinking a possible bent rod? I couldn't tell in your responses but did you observe the flywheel to see if it's staying 'true' when rotating? There's an inspection plate behind the oil pan where you can look at it to see if it's wobbling...

-Eric

Thanks....I will check the stroke of the pistons.  I did pull the inspection plug on the bellhousing and did not observe any wobble in the flywheel.  I hate these kinds of problems!