PorschesNeverDie

Hi guys

My 1983 Porsche 944 had its timing and balance shaft belt replaced by a local mechanic/friend. I knew that these cars are finicky about the tension on these belts so I told him about the 90° and 180° thing. He replaced the belts and the car runs just as great as it did before apart from a whining sound almost like a little supercharger. Does this mean that the belts are over tightened?
If anyone could tell me if this is normal or not that would be great. Just to clarify I do not mind the noise at all I'm just concerned about the damage it might do.
Videolink of the noise:
Kind regards
Fellow Porsche enthusiasts

tempest411

I believe that noise is from the balance shaft belt being a bit tighter than it should.

mytrplseven

Did he replace the rollers and idlers when he did the belts? Regardless, it's probably the balance belt too tight. When the mechs work on these and they see what they assume is an excessively slack balance belt they snug it up, regardless of the 180 degree twist.

PorschesNeverDie

Thanks for replying, it is greatly appreciated.

I bought a kit online and that is what he installed. He mentioned that something was missing from the kit. The kit included "Cam & balance belt + cam & bal Tensioners" 4 parts in total.
Should I ask him to recheck the tension on the balance belt or will it loosen by itself over time? Or is it perhaps the tensioner being tightened counter-clockwise whilst it should be clockwise?

Thanks in advance

Dan Martinic

Cold engine:



Warm engine:

1933beer

The belt will loosen a bit over time. You are supposed to recheck belt tension after so many miles. I do it after 1 year but I only put 1 to 3 k a year now. When I first got my car the belts were too tight and I readjusted the BS belt. I like how Van does it. Look for utube video 951 water pump change. He has several videos on 944s. I have changed my belts twice and will do it the third time this summer. I will watch his video again.

mazdaverx7

I agree that the balance shaft belt is too tight. It will not stretch enough to quiet the noise. The belt should be tensioned properly.

pfarah7

If I may add to this conversation...

I just completed the major service which included TB &BB that I purchased from a popular online source; Gates and Contitech were the manufacturers, respectively. Having performed this job several times, the belts went on without a hitch and were properly tensioned using the Arnnworx Tension Tool. The engine instantly produced the infamous whine that I couldn't get rid of, even when adjusting the tension to the loose end of the acceptable range. After discussing this issue with the local Independent P-shop, they recommended that I replace both belts with Genuine Porsche belts (not cheap). So... Long story short, the Porsche belts completely eliminated the whine. I did notice that the teeth on the Contitech BB have a dimple (Porsche's did not) which may have contributed to the noise issue.

MAGK944

+1 Ive been saying this for years, Porsche commission a variety of manufacturers to produce their belts, they’ve likely used both Conti and Gates as OEM suppliers. Thing is Porsche branded belts are produced by Conti or Gates to Porsche standards and specifications which may not be the case if you buy a Conti or Gates (“OEM”) branded belt. This applies to any part, OEM doesn’t mean it is produced to the same spec as Porsche intended, it just means it was made by the same supplier.

As for using the 90/180 degree method of tensioning, I know very experienced mechs use that method and be spot on but if you don’t do a lot of these and don’t have a “feel” for it, relying on the twist method isn’t recommended, use the tool ftw.

Tom M'Guinn

For those who missed it, I wrote an entire article on this for in the May '18 Panorama ("Tensions Run High"). The punch line, after lots of testing and effort, was that only the factory tool and the Arnnworx tool achieved the factory spec on a reliable, consistent basis. (The Krikit is a placebo, others didn't fit, etc.) I'm confident that those who are getting away with setting the belts by "feel" are really just just proving that these motors won't blow up on the spot if the tension isn't exactly within the factory ranges. I'm not saying there isn't some belt savant somewhere who can do it consistently, but I'm highly confident that the vast majority of people who use the twist method are not reliably and consistently within spec. I've done the job dozens of times, and for the article I even set a belt to 2.7 on the factory tool to calibrate my thumb in an effort to get it right by "feel." The difference between in spec and out of spec is mighty tough to sense by feel. Even with a side-by-side reference like that, I got it in spec "maybe" half of the time. (I tried over and over and over....). That said, I was rarely "that" far off, so I imagine people who are very familiar with how it should feel are getting "close enough" for the motor to run happily ever after. Everyone gets to make their own choice, but for me "close enough" isn't.

pfarah7

Funny but I typically use the twist method with good results; never fell out of range (ok most times...).

Dan Martinic

When I first bought my car, I had a mechanic change the belts: self-tensioner for timing belt, his personal experience for balance belt.

Five years later, I decided to do the job myself. The TB still looked good but the BB was so floppy, I could almost pull it off just like that. I hadn't noticed anything odd while driving.

I suppose non-self tensioned earlier 944 TBs could be sensitive, but in my experience, BB tension is a non-crucial area in terms of potential issues: it's just the whine thing. You got a wide range of loose to play with

Tom M'Guinn

If by "within range" you mean your car runs fine and has never had an issue, then happy motoring to you! If you mean it's within the factory spec range, then I'd say it's somewhat self-evident that most twisters can't be sure of that. Without the tool, you can't confirm you're right. And, realistically, if you had the tool you'd be using it...

Tom M'Guinn

If the balance shaft belt comes off, it can get caught up in the timing belt and wipe it out. Just say'n.

I tested the factory spring-tensioners as well in my article and they consistently under-tensioned the timing belt (relative to the "used" belt spec, and even more so relative to the "new" belt spec). Also, the "new" belt spec is significantly tighter than the "used" belt spec and the factory mount has no way to adjust for that.

Dan Martinic

Hmm.. last year while doing some work I had to remove the TB from the cam sprocket and I am happy to say that prior to doing so, it seemed tensioned correctly--and It's been about five years and many, many miles since I "auto-tensioned" it. Not only that, but I kept the belt--it looks so new still. I think we underestimate the longevity of these belts.

I remember taking off the tensioner, cleaning and freeing it up well with WD40. I get that it's meant more for the "used" spec, but that's why there's the official instruction to re-tension shortly after installing, which I did, after about a few thousand miles loosening and tightening the tensioner again. I'm going to guess it's better than going by hand feel, though I'm sure using a proper tool is best, for those who have invested in that.

BTW I am curious how do you use the tool with the self-tensioner? I suppose you set it up and kinda force the tensioner tighter then lock it down somehow quick?