Mrmerlin

the reason i was suggesting to use a slightly lower tension is that the early tensioners seem to have less give.
IE they dont relax as much as the later style tensioners do because the bellvile washers dont have as much dish.

That said putting the tension at the high side of the kemp tool may cause the belt to be come overtensioned when the engine expands to the running condiditon, this would then wear the belt out quickly as well as wear out the gears and possibly damage the oil pump.

I would suggest to replace all the gears in the belt run with the new style rebuild the tensioner, fill it with oil, check the oil pump shaft for visible play, replace all of the cam tower front seals, as well as the oil pump O ring and front main seal , new pivot bolt and bushings and a new belt roller.
This should ensure that your belt drive will be worry free for atleast the next 7 years

Landseer

I've had good luck rebuilding and using the stock tensioners.
Now I even have a spare ready to allow a quick swap, perhaps on the next 928 that rolls my way.

Gordak

I usually order a used oil pump sprocket if its the first time I've done a belt on a car, I dont even look at the original first, I just assume its going to be pretty worn. If It turns out it doesnt need it, I keep in on hand for the next one.

I noticed the official shop manual says go to "8" with the (twist style) tension tool but doesnt really explain that it's the early style tool, and ofcoarse 5 or 5.5 is the tension with the later special tension tool.
One could mistakenly assume early cars need to read "8" on the special tool!! waay too tight.

GregBBRD

Actually, this is only partially correct. By 1982, all of the square tooth cam gears were aluminum and all of the replacement gears, from Porsche were also aluminum. Indeed, the oil pump gears for the square tooth belt cams came in steel, for the 1982 vehicles.

I'm not sure exactly where they changed from steel to aluminum, but I thought it was 1981. Someone on Rennlist will know the answer.

GregBBRD

Now you need to be really careful. I've seen many engines that have had the cam gears changed and ended up with the round tooth design cam gears, while still retaining the square tooth oil pump and crank gear. I've seen both round tooth and square tooth belts on these engines, too.

The wear on the crank gear will probably determine what you do, in regards to changing the other gears. The square tooth cam gear is NLA and you can only buy this gear (new) in the round tooth design. 928 International usually has used square tooth crank gears...although they might not be much better than yours.

GregBBRD

While I do not have, not have I ever used the Kempf tool, this is probably good advice. The factory spec for belt tightness (with the 9201 tool), on your early engine, is 4.5 and the specification for the later design 4 valve engines is 5.0. This is quite a bit less tension.

GregBBRD

5.0 to 5.5 is way too tight. See my post above.

ROG100

Greg,
The change in tooth design happened in 82 when the cam gears went from 928 105 545 04 to 545 10.
The early cam gears are still available and we have them in stock.
Same for the early oil pump gear 928 107 107 04 which like the early cam gears are steel.
Only part NLA is the early crank gear.
Roger

GregBBRD

[QUOTE=ROG100;7863293]Greg,
The change in tooth design happened in 82 when the cam gears went from 928 105 545 04 to 545 10.
The early cam gears are still available and we have them in stock.
Same for the early oil pump gear 928 107 107 04 which like the early cam gears are steel.
Only part NLA is the early crank gear.
Roger[/QUOTE

That makes sense.

Since the steel crank gear would wear twice as much as the steel cam gears, tough to imagine anyone ever needing replacement steel cam gears? If you can't get a decent crank gear, replacing the cam gears seems like it would be futile.

Whenever I get a car with worn gears, I convert everything to the later design round tooth design.

So, since this particular person has an '82, he should have aluminum cam gears, no?

ROG100

Greg,
The change from steel square tooth to Aluminium round tooth happened in 82. This normally related to the production of 83 MY cars which started in August/September 82 after the Summer vacation.
All my pre 83 cars (7) had reusable old design square tooth gears and they stay that way.
Upgrading is very expensive to some users if the original equipment is servicable. If worn then that is another issue especially if the crank gear is worn. However for those financially challenged a good used gear from Mark would be an OK option.
Not all owners can make the upgrade and providing the original equipment is servicable this is an OK option.
Roger

Ethre

Again, thank you all for your input. Lets see if I can get to everything in one post.
(Also, since the car's not infront of me right now, I will try to minimize any assumptions regarding condition of parts)

The belts were changed by the previous owner, and according to the receipts he purchased the tension tool. However, hearing the word "ancient" used to describe the timing belt makes me think something doesn't add up.

The two camshaft gears were changed, but that was ~12 years and 40000(?) miles ago. The parts numbers (if my memory serves me) match the square toothed gears, so all gears should hopefully be the same style(unless there were changes for which I do not have reciepts). That said, the crank gear hasn't been replaced, so this could (and may likely be) worn/damaged/burred.

Could gear wear on a loose belt (if the previous owner hadn't known to retension it) have caused enough damage to the belt to make it appear old? Perhaps this could have been aggravated by initial over-tension (as Greg mentioned)?

Of course, this is all a synthesis of reciepts, telephone talks with mechanic, and memory. Hopefully I should be getting a running car back to tinker with by this weekend.

P.S. I am sure I will get to know you very well Roger.

blown 87

If you are paying a pro wrench to repair this problem, the very last thing you want to do it is tinker with it.

My $0.02

Mrmerlin

it would be nice if your mechanic could shoot some pictures then post them here.
This is a customers car 83 with a broken cams and pulley.
This was one of the dirtiest engines i have ever seen or worked on.
Note the worn aluminum oil pump gear it was a round tooth version

Landseer

How many pro wrenches really are?

How much is a flatbed to Sharpsburg?

Landseer

Or Aurora?