Balance shaft Bearings???

Weldin · 10-18-2000, 04:00 PM

Has anyone had to replace theirs? Ive got an anoying whine coming from the front of my engine, and I think ive finally traced it to the balance shafts. The car has 123K...are there any oiling problems with these? Any similar experiences?

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Porsche 951 Fanatic · 10-18-2000, 04:17 PM

might be the water pump my dads did that before going out...

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PORSCHE-THE BEST!!!!

cyclemike · 10-18-2000, 04:20 PM

Have you checked the tension of your balance shaft belt? It will make a whinning noise if the belt is too tight. I know this from experience.

Weldin · 10-18-2000, 04:24 PM

Yes I just replaced the timing & balance shafts & tension them with a krikit per the instrucitons on this site, and changed the waterpump!....it made the same noise before all of this also...

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rwsams · 10-18-2000, 04:44 PM

I just replaced the balance shaft belt using the Krikit to tension. I think the 30 lb setting is too tight. It sure would be cool if someone would reference the Krikit against the factory tool, wouldn't it?
I'd be happy to send somebody the Krikit tool if they would do a reference chart against the factory tool.

Weldin · 10-18-2000, 04:48 PM

Thats a great idea -- ive thought of that also...I assume thats what blazak (or whatever) did...altough I thought the 28 lbs seemed OK....you should have seen how tight they both where before I replaced them! way too tight, and im wondering if that didnt damage the balance shaft bearings....? or just the milage...

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3sonfather · 10-18-2000, 05:36 PM

Bet on overtightness regarding the whining noise - just loosen slightly and see if it goes away. The Kriket sounds like a great thing if we can calibrate it against the factory tool as mentioned in the prior. If anyone has this luxury, please post the results. Also, it might be a good sanity check to twist the belt to check tightness. I know a old mechanic who adjusts the belts by feel and rotates the belts to near 90 degrees on the long exposed portion of the belt. Again, this 'feel' was gained through experience.

Lawrence Coppari · 10-19-2000, 01:09 PM

Sometimes the whinning noise comes from the idler pulleys. If you buy one of the inexpensive stethoscopes that has a rod on it, you can place the rod (probe) on each bearing while the thing is running. It is very easy to isolate the culprit doing it that way.

Lawrence Coppari · 10-19-2000, 02:11 PM

Last time I had my belts adjusted it came back with the whirring sound. It went away. Methinks the belt was a little too tight. Think I'll do the belts from now on.

Weldin · 10-19-2000, 04:42 PM

I got a hold of a mechanics stehescope & started poking around....ive come to the conclusion the front bushing(bearing) on the upper balance shaft is making the noise....Im going to remove the balance belt this weekend to see if it goes away...if it does BINGO - after that I'll try to adjust it out, worst case would be a new bushing and/or balance shaft...while im thinking of it...are there any long term ill effects of removing the shafts all together? Ive heard racers do this for the power....I really dont mind the vibration....any experiences?? I'll post later if/when I figure it out. Thanks!

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Weldin · 10-21-2000, 12:58 PM

Hey guys -- I "think" I got it figured out. I took the car apart today & removed the balance shaft belt altogether. before doing so I put my stethescope to each of the rollers. THe idler had a little noise. The tensioner A BUNCH of noise...I kind of over looked it because it didnt make any noise by hand & was a plastic one so I knew it wasnt original. Anyway, after removing the belt & rollers & starting it -- ta da - no whine!!! So i'm just going to replace all of the rollers & im 95% sure that will fix the problem. I think the sound must have been migrating thru th eblock & belt to the shaft on top...i hope anyway. The rollers are much easier to get at than the balance shaft....I'll post again after I replace the rollers...

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bitsnpcs · 11-26-2001, 09:56 AM

I have had the same whirring noise eversince replacement as well. I noticed after inspection of the new Idler that the shaft it mounts on is somewhat undersized. I took some pvc material and forced it over the threads and then mounted the idler over it. On starting the sound had virtually dissapeared. I think the noise is more of the vibration of the idler in the shaft itself and the PVc material dampened the sound. Not sure how long it will last (heat) etc..

88_944 · 88_944's Garage

Quote:

Originally posted by cyclemike
Have you checked the tension of your balance shaft belt? It will make a whinning noise if the belt is too tight. I know this from experience.

Yes, this will reduce the balance shaft whinnig sound alittle but from my experience i had to change my balance shaft seales and I take off the front top and bottom balance shaft housing. When I put back the seals and housing, the sound was gone. I think it's the line up of the balance shafts.