docmirror

In my limited, unprofessional, and ad-hoc opinion the two cam gears will not wear at the same rate. The left cam gear will generally wear faster than the right due to torque load, and I can see(slightly) from the pic some silver on the left gear, as well as what looks like a fairly sharp ridge starting. Of course, this is just one person's opinion, and shouldn't be taken as anything more than blather.

go...

Wisconsin Joe

My understanding is that "Too much" is through the coating and into the metal. Once the metal is affected, the gears are done.

And gears are readily available. Roger has new gears for both the 16v & 32v motors. Steel oil pump gears too.

hwyengr

There is zero rush on swapping to the Porken since you just had the stock tensioner rebuilt. You should be good AT LEAST until your next belt change. Wasn't your shop 928-board approved? They saw the parts going back together, so it's gotta be good enough for a while, right?

If I could impart one piece of advice, from experience, address problems on this car as they come. You've got a backup car, so it can sit for a while while you're fixing. Most of these parts are far too expensive to replace while they still have service life in them.

Crumpler

Thanks Joe.
That's good, I will look into it. I don't know why I remember Roger doing a limited run of cam gears.... Maybe I took too many blows to my head

hwyengr

The gears came back from the dead at Porsche. Roger did make a run while they were still NLA.

ROG100

Also remember that all the new gears are made of a much HARDER alloy and that the surface is also now hard anodized. These were redesigned by Porsche to overcome the problem of cam wear seen on the older softer gears with the spray on coating.
New gears are not cheap but probably the last ones you will ever buy.

The oil pump & crank gears are steel so unless the belt is way over-tightened they should see no wear at all.

V2Rocket

What is stopping you all from re-plating/anodizing these parts if they really are aluminum?

The Forgotten On

The alloy gets worn away to the point that you will still have a divot in the cam gears after you coat them.

If you can put the gears on a flat surface and see light coming through on the other side, they are toast.

V2Rocket

Wonder if you can just swap a 944 crank and cam gear set onto the 928 crank?
All steel, and the cam gears use the same mounting parts.

944 stuff has fewer teeth than 928 (22/44 vs 24/48) but if you swap the pair then it shouldn't matter.

What's the diameter of the 928 crankshaft where the crank belt gear goes?


....or...
Drill out the center of these, cut a key slot, and make sure the 3-pointed propeller thing fits.
Steel, 48 teeth, same belt pitch and belt width as the 928.

Proven production parts, available by the millions.

http://www.ebay.com/itm/1995-1999-MI...xWOCkS&vxp=mtr

skpyle

Greg BBRD: Thanks for the look, I appreciate your advice. I had forgotten about the crank gear. Makes sense that the gears wear as a set, and should be replaced as a set.
To my knowledge, this is the third timing belt on this car: Orignal from 1986, replacement in 1998, replacement a month ago.
I am trying to avoid being one of those vehicles 'that are not going to make it another 40,000 miles." However, I also need to step back and not spend money where not needed.
And...trying to avoid Godzilla.
I will keep an eye on the gears through the next belt change and go from there.



James Bailey: Yeah...reality check. I am getting a bit ahead of myself. The Red Witch is fine and has just been given a clean bill of health. I need to enjoy and take advantage of that.
AC is taken care of. I have sent Roger another grand for parts. I wonder if he takes direct deposit...?



docmirror: Thanks for the advice. I will get a closer look this weekend and evaluate from there.



Wisconsin Joe: Yeah, to my knowledge as well, once the metal starts to wear, the gear is done. Good to know they are still available, though.



hwyengr: Very true, it is all in good nick. The Red Witch was worked on by a Porsche 928 trained mechanic, so I trust him. The report I got back from him was that all the gears looked fine.

I have been trying to ride a fine line about the shop that worked on the Red Witch. I thought it was a very good experience. Granted, the Red Witch wasn't ready on time, but there was a good reason for that. I believe they did good, thorough work and was priced accordingly. I don't think I was gouged. However, I see an undercurrent on this forum against shops. Many have had a bad experience having their 928 worked on at a shop. I did not, and am very pleased about that. So, I have been hesitant to bring it up much to turn it into fodder about how do I know the shop did the job correctly, etc...

You bring up a very good point: address problems as they come. Don't go looking for more issues. I am a 'curious george' with machinery. It fascinates me. So, I REALLY enjoy the mechanics of a vehicle, and the 928 is special in that respect. So, I am already looking at everything.
Thanks for the reality check.

Good to know Porsche brought the gears back from the dead.



ROG100: Very good to know that the new gears, while more expensive, are better made. I will look into a set as required down the road.



V2Rocket: To my knowledge, recoating has to be done before there is wear to the parent metal. Otherwise, you have coated worn metal.



The Forgotten On: Yep



V2Rocket: Good question, that I have no clue about.



Thanks, gentlemen!

Seth K. Pyle

Imo000

You can recoat them even if some but not too much of the metal is worn. The new Porsche gears are very nice, installed a pair a few months ago but they are anything but cheap.

skpyle

That is very good to know. I wasn't sure if it was an all-or-nothing thing for the wear. I have read several posts from Rennlister's who have recoated their gears for very reasonable money.
Yeah, I have not seen a price, but figured the new Porsche gears would be heart stoppingly expensive.


Thanks!

Seth K. Pyle

Ducman82

button up, drive it. maybe collect new/better gears and parts for later.

skpyle

Ducman82: Yep, that's what I am thinking. I have years to go before I worry about this again. I'll worry in 4 years or so.

For now, drive the wheels off of it.

Thanks!

Seth K. Pyle

Wisconsin Joe

Define "heart-stoppingly".

32v are about $400 each. 16v are about $250 each. I learned this because a "certain British gentleman" sent me the 32v gears for my 85 euro (16v motor).

For the record, the mistake was discovered at dinner time on a Friday, an e-mail was sent out around 7PM. I had an apologetic reply by Saturday morning, the correct gears were in the mail first thing Monday.
Nobody is perfect, and the real test of customer service is how mistakes are handled (and I felt this was handled very well).