Doing my first TB/WB refresh on my first 928 (MY '80, 5 sp). The tops of the teeth on both the Crank gear and the Oil Pump gear are both shiny.

The various tutorials on here and elsewhere suggest changing timing gears if they are shiny, even the crank and oil pump gears, but the reasoning is not clear. The "replace" if "shiny" makes sense for the cam gears since they are aluminum and have a special surface anti wear treatment. And, "shiny" indicates the anti wear surface is gone. My problem is both the crank gear and oil gear are steel (or at least my magnet says so).

A second question relates to availability of the crank gear. I see 928 Int'l does not have it on their site and Pelican Parts says it is no longer available. However, Auto Atlanta and 928 Specialists show it is available. Anyone familiar with the background on this?

Joe Romano

 

Hard to avoid shiny. It's worn that you gotta look out for. Is the middle worn compared to the ends?

If they're shot then get good used ones. Some will advise to go with the later sprockets all-round as those use a "better" belt. I think it's the same except with different teeth and not worth the hassle.

 

None available that I could find (I've called around the country, germany, etc). They've apparently been NLA for a decent while.

I've been looking at getting a few custom machined, but as I am out of the country for the next year that has been put to the side for the moment. The tooth pattern is an interesting one.

 

Presumably the early square-tooth crank gear is the one that's NLA? I bought a new HTD crank gear recently. If you need new cam gears, it might be a good time to switch to the high-torque drive gear profile and belt (the teeth with the rounded tops).

Roger had a post the other day saying he had a few sets of the 83-86 16V cam gears in stock, which I believe have the later HTD profile?

 

Thought about changing to the newer style gears and belt, but the cam gears are fine.

 

iirc the early cars all had steel gears.
In that case the shiny parts dont matter.

However it would still be a good idea to upgrade to the HTD (83+) style.

 

Joe if yours has the old type belt I have a good set in the garage their yours if you can use them they came out of mine when I went with the euro top end ! will look in the a.m. e-mail me

 

Steel or not, a sharp edge can develop on the back edge of the crank gear.

Here're a couple worn ones and a new one.

One on the right had about 73,000 miles on it.
Left, hard to say, but could be up to 150K.

(These all happen to be from mid-year cars running newer belt tooth pattern)

 

Landseer,

Thanks for the photo's. MY crank gear pretty much looks like the center one, just w/ shiny tops, but no visible wear.

Now I just need to figure out how to remove the two little circle clips that hold the lower tb cover in place. I have never seen circle clips w/o the little holes for the tool to open them.

Thanks for the help. As a first timer there are lots of little things that are not obvious. For example, the instructions for installing the flywheel lock all say to just undo the clutch slave cylinder and put in the locking tool. Nothing in the PET or any instructions lead you to believe that you can just pull the rod out of the slave cylinder. I probably spent an hour going back and forth here on the list, the online wsm and PET before I decided to just pull the rod out of the cylinder.

 

Do not beleive what you see on some of the web sites - the early crank gear is NLA. Either take SueDen up on his offer, buy a good used one from Mark @ 928 International or upgrade to the round tooth design.

 

Joe the offer still stands ! They came off my car with 35000 miles on it they are like new.