Mako 928

A few people got there cam gears re-coated. Is this still a option? And if so where and how much?

Jim R.

I don't think recoating is a viable option unless the gears are 100% flat and true. The cupping of the teeth will just lead to early wear. These gears are just another wear item, and these cars are getting old.........

I would bet that overtightened belts and dry tensioners are more of a factor here than overall miles. But luckily most of us will only have to change them once. Unfortunately it adds a bunch of $$$ to the TB service, but better than a shredded TB from sharp worn gears..........

Jim

AO

A couple of us Michigan boys are running re-coated gears. Big Dave has been running his for over a year now... maybe even two. I'll bet he's got over 10k on them. Not sure how they are wearing for him, but as of the last report which was a year ago, they were doing just fine.

I just finally installed mine. I'll try and keep a log on how they wear.

The original gears had very slight cupping on a few of the teeth before recoating. I didn't do the re-coating myself. MrLexse here on R
list did it for me a couple years back. He used Powerkote's DFL-1. http://www.ceramteck.com/dfl1.htm

I'm not sure on the specifics of how it is applied, except that it needs to be oven cured, so you probably need to have a dedicated oven for stuff like this.

more threads:
https://rennlist.com/forums/928-forum/237536-cam-gears-anodise-material.html

https://rennlist.com/forums/928-forum/219673-melted-cam-gears-pics-not-for-the-squeamish.html

Big Dave

Mine are wearing just fine with over 10k miles (Andrew is correct). Since the re-coating covers the whole gear, not just the teeth, I needed to scuff mine up a bit where the cambolt clamps down. The non-stick surface was allowing the gear to slip against the bolt (stopping at the gear's slot) when I was rotating the engine to set valve timing. This was after I had already logged 6k miles on the re-coated gears but had to replace a head due to a chain tensioner issue.

They're working perfectly now. They weren't cupped at all when I had them -re-coated.

Big Dave

Here's a shot of a re-coated gear vs. a normal used gear:



Here's another example of a gear that's been eroded..this time an oil pump gear:



Once the protective coating is gone, the erosion can happy quickly. It creates edges on the gear teeth, further in from the actual edge of the gear:

Big Dave

These are the gears before I had them re-coated...all shiny, but none were eroded.

I had an extra set laying around that weren't usable, so I had them recoated too, to have a spare set.

ROG100

Hi Dave,
What was the cost saving - new v recoating?
New is $100 + or - a couple of bucks.
Thanks,
Roger

Big Dave

IIRC, Andrew had a set done for about $10 ea. The person that re-coated my first set wanted $5 ea., although he's not doing powdercoating any longer.

It's essentially the same cost as powder-coating. It's just a non-stick material that's being applied.

AO

Yep... I think it was less than $50 for a complete set of gears: crank, oil, and the two cams. That's WAY cheaper than replacements.

Big Dave

Rog...if you have access to a powder-coater...this sounds like a new product line for you.

ROG100

That's what I was thinking and offering a set on an exchange basis.
Looking into it further.

Mako 928

Very good info! Thanks Big Dave and Andrew. I am at this point now and my gears have a shiny surface but are still flat, it looks like this is a very good option for a standard timing belt job. If Roger is interested in doing this it would save alot of searching/sourcing out.
Roger thank you again for sending out those worn cam gears at N/C. If you decide to do this I will gladly send them back to you so you will have a spare set on hand.