Bill51sdr

Not hard, just time consuming. I got it down to 5 hours once, everything went smoothly and no WYAIT's along the way.

Big Dave

Stig...just use John Pirtle's excellent write-up:

http://members.rennlist.com/pirtle/tbelt.html

Mongo

I was just looking at them. I have the workshop manual on CD too and it doesn't tell about all this other stuff you have to remove...

Mongo

Hey Bill I forgot to ask you when you came over if you have P9201 tension tool or not. I'm thinking of watching my mechanic do it and giving him a hand. Kinda pricey, but I'm sure well worth the learning experience in the end. Then I"ll buy the tool after that and try it myself with Pirtle's tips and the shop manual CD.

mark kibort

piece of cake! just change the belt. no need to go crazy. if you need a water pump, it will be making noise or leaking. Ive had more bad luck out of changing perfectly good pumps than with leaving the old pump in there.

mk

Mongo

me thinks this will be fun! But is 10,000 miles on a belt and 4 years of age really make it worth changing ASAP due to a faulty tensioner light???

Big Dave

(I had to change my belt earlier than usual because the pump started leaking)

Big Dave

I think the consensus is (if a consensus is possible here) that belts should be changed every 45K or 4 years. There are stories of belts lasting longer, but there are also stories of belts not lasting longer.

MGW-Fla

I thought it was check the belt tension at 15k & replace it at 30k??

Big Dave

After a new belt installation:
Check tension at 1,500 miles
Check again at 15,000 miles
Check again at 30,000 miles
Replace again at 45,000 miles (subject to the 4 year limit)

Bill51sdr

No I don't have that tool, I ain't rich! The Kempf tool works just fine. There are a lot of shortcuts and methods you learn when you've done a few T-belts. It's not really that difficult Andy, and I think it is something you should tackle yourself if you decide to change the belt. I'd be happy to help out.

dr bob

Two things to stir into the discussion:

In one of the Sharktoberfest tech sessions on the timing belt, 928 guru Gregg Brown of Precision Motorwerks in Anaheim made a good observation: With all the belt parts in new condition, 60k is a very safe change interval. He then went on to list all the things that need to be in "new condition", and that includes pretty much everything the belt touches. Particular attention was put on the cam sprockets, where the anodizing gets worn if the belt is dirty, too tight, or gets stretched. So decide how long you want to wait based on how good/complete a change was done last time.

Belt change intervals are usually pegged to miles driven, but can be much more accurately described with a product of total engine revolutions and speed (as RPM). If you are a typical American driver, your --average-- speed is not very high. We did the 'tour' to Devek in San Francisco a year or so ago, and decided to reset the dash computer before we left. 5 Minutes from the house, jumped on the freeway and headed north, 65-70 MPH. Stopped for coffee an hour or so later, a rest stop an hour after that, etc. Got caught up in some construction detours, took a few turns off the freeway to get to my brother's house in San Jose, drove on to Devek in evening traffic. Average speed while driving? A little better than 30 MPH.(!!!) So even on "freeway" trips, it seems that I just don't seem to average anything close to the speed limit.

So how much of that wasn't in top gear? Maybe that's the bigger question? Airplanes use a recording tach to base their maintenance schedules. My tach doesn't record, so I have to guess a bit. Comes down to how your use pattern and total engine revs compare with what the factory was thinking when they decided that 60k is the 'right' number. Drive the car gard in lower gears? 60K might be dangerous. Or maybe that 60k recommendation already includes a big factor for driving the car harder, in lower gears. We have no good way to know.

---------

A couple years ago, I was driving a sghort distance from home, and got the dreaded T-B warning. Pulled off the freeway, car was still running fine, etc, so I cruised gently the last mile to the house. Pulled the cover, looked perfect. Bought a tensioninig tool, checked the tension, and it was just at the bottom of the window. Adjusted it back to the middle of the window, no issues since. It was a very small adjustment, by the way. Topped up the oil in the tensioner (it was dry...), that was probably the root cause of the belt fluttering/light coming on.

My rambling thoughts, HTH!

rob rossitto

FWIW, had a similar issue on mine - 12k mi. after a "pro" belt job, I discovered the tensioner was totally dry... although it ran fine w/just an occasional "belt tension" light that was easily reset - knowing what I know now (from the rennlist gang) I was just VERY lucky...

ps - that engine oil thing is total nonsense - our tensioners are a seperate item... be careful!! my "pro" told me the tensioner lt was an electrical issue... they probably don't want to have to fix it under warrenty/rather have it blow up and blame it on you/PO/etc... might want to find another wrench...

catflab

Anyone know if I can follow JP's guide to change the TB on a 1985 Euro 928?

Anything I should watch out for?

UKKid35

Lack of oil in the tensioner increases belt tension when the engine reaches operating temperature, there is a possibility that the lack of oil may reduce damping making low tension warnings occur, but I'm not convinced.

Checking belt tension in itself is of little benefit, as many of us can attest, you have to check the whole belt mechanism including rollers, sprockets, tensioner oil and seal, bushings etc. If any one component fails then the belt will either fail immediately or long before the recommended change interval, and almost certainly without any warning.

Just to clarify: if the belt has skipped a tooth, it hasn't. What has really happened is that the tooth (or probably several teeth) is no longer there, the belt is now seconds from total failure.