well as i said in my other thread, i have a vibration and nasty sound at 4000rpms. just about everyone said it was my balance shafts. i checked it out and the shafts look to be right on. my question is, on the bottom shaft whould i be able to see the "O" through the circle shaped hole in the metal cover? I know this is a confusing subject because i htink the pre 86 and post 86 models had it switched around. Can i even see if it is lined up right withough taking the sprocket off? i think the O might actually be on the back of the sprocket.

and if that is not my problem what could it be. my car really wont rev above 4000 rpms. not that i really need to very often anyway. but my exhaust seems to be making alot more noise too.

heres my other thread
https://rennlist.com/forums/showthre...hreadid=124981

 

How is the tension on your balance belt? It should be about 1/2" in each direction.

- Julie

 

hmmm mines actually fairly tight. i figured better off tighter than too loose.

 

btw, shoudl the idler for the balance belt actually be touching the belt. mine is just barely resting on it. i realised now that the belt is not flat and that when it rolls along the idler it will vibrate because of the teeth going across the idler. not enough to do this though, i dont think.

 

The belt should not be touching the belt. I leave about 0.5 mm clearance and the balance belt should also be loose compared to the timing belt.

 

You should not be able to see the 'O' throught the circle shaped hole. If you can then your lower shaft is 180 degrees out.

 

+k thanks ill adjust the belt so its not so tight, and ill move that idler.

 

Clarks Garage website has a very good description on the correct setting of the 2 shafts on the early and late models.

 

Brett, Call me now at work...


DAmian

 

Clarks web side and use this diagram to check that the pulleys have been put back on the shafts using the correct key ways.



You can pull the retaining bolts and stick a piece of wire down the keyways to see which way the pulley is mounted.

 

Ok Guys, As some of you know I helped Brett with his belts about two weeks ago, and I can assure you this was not my first set of belts I have ever have done on a 944....As soon as anybody seems to read the word vibration, they right away assume that the balance shafts are out of wack..or missaligned..But I know that we alligned those things perfectly...But my biggest problem with this diagnosis of the problem being his balance shafts, really does not make any sense...I mean if the balance shafts were out of allignment, the 944 engine will vibrate regardless if the car is in nuetral and free revving, or in gear while driving down the road..

On bretts car the vibration only exists when the car is being driven in gear at about 4000K, but once you take the car out of gear and put it in nuetral, then free Rev the engine to dam near redline, and it revs smooth as glass, now why is that...?

If the balance shafts are out of allignment the engine will vibrate period....Not only when its in gear...and not in nuetral....

Somebody please proove me wrong with some logic, not default thinking just because they read vibrations and t-belts done recently...

Thank YOU
DAmian

 

Ok Guys, As some of you know I helped Brett with his belts about two weeks ago, and I can assure you this was not my first set of belts I have ever have done on a 944....As soon as anybody seems to read the word vibration, they right away assume that the balance shafts are out of wack..or missaligned..But I know that we alligned those things perfectly...But my biggest problem with this diagnosis of the problem being his balance shafts, really does not make any sense...I mean if the balance shafts were out of allignment, the 944 engine will vibrate regardless if the car is in nuetral and free revving, or in gear while driving down the road..

On bretts car the vibration only exists when the car is being driven in gear at about 4000K, but once you take the car out of gear and put it in nuetral, then free Rev the engine to dam near redline, and it revs smooth as glass, now why is that...?

If the balance shafts are out of allignment the engine will vibrate period....Not only when its in gear...and not in nuetral....

Somebody please proove me wrong with some logic, not default thinking just because they read vibrations and t-belts done recently...

Thank YOU
DAmian

 

Well, the thing with the balance shafts is they will vibrate exactly the same when the engine is revving freely, as when in gear cruising down the road.
Engine-wise, there is only one thing that changes, load. My engine shakes pretty bad under load, and I believe the problem to be motor mounts, but I don't think that's your issue.

If it only does it in gear, have you determined where the vibration is coming from?

Is it equal in all gears? If so, I'm almost inclined to think it's bearings in the torque tube, or something transmission related perhaps.

I haven't read the other thread, but when did this problem develop? If it developed right after a belt change, that is the first place I would start looking (No offense to anybody who did the work).

 

In the first post on this thread Cass944 asked "on the bottom shaft whould i be able to see the "O" through the circle shaped hole in the metal cover? "
I just answered his question, I wasn't 'default thinking'.

 

Relax you guys, I wasnt being a dick by my last post, but I just dont think its the dam balance shafts...And yeah if the engine balance shafts are not working properly, then the engine will have a vibration regardless of load or not...Right..? And what I wanted to get across by my comment of default thinking was so that people would take the time to maybe think twice before posting, cause of this wierd problem...hmmm Still not sure what it could be...Maybe something broke the same time we did the belts...But then again Brett was also doing other stuff to his car over the past month...Something just seems real odd with this problem..Thank's Guys..


DAmian