Cam chain tensioner Pad photos

[zooklm1]

Over the past couple weeks I replaced the cam chain and tensioner pads as a PpPreventative maintenance item. My car is a 94 Cabriolet that has 79,350 miles and no records of the chain/pads having been replaced. The maintenance records I received were not comprehensive and dated back for 10 years.
Overall, the pads showed slight wear/grooves, mostly on the top pad. There was no visible cam tooth damage/wear and no cracking in the pads. They are brittle, though because the lower pad broke when I was removing it. The chain looked really good, as well but I replaced it, too.
I hope this info and pictures helps a member.
Lee

[Latitude48]

Thanks for the pictures, etc.

I replaced the hydraulic cam chain adjuster in my S2 at about 52,000 miles (the top pad was pretty grooved) and again at 142,000 miles. My S2 has about 155,000 miles now and I think it would be prudent to, like you, proactively replace the cam chain. The chain adjuster doesn't need replacement again, but I do have a new set of Porsche upper and lower guides I will install.

A genuine Porsche cam timing chain is only about $42, so that seems like the one to get.

Since I have new hardware and seals for the cam cover, I think I'll get it stripped and painted. Quite a few years ago I had it powder coated and that hasn't really held up that well as there are bubbles in places. I recall reading that powder coating these magnesium covers isn't recommended.

I may also get the aluminum cam gear cover set from Rennbay since mine look pretty sad, but don't appear to be failing with heavy corrosion like some magnesium covers apparently have.

Any tips or tricks you learned would be appreciated.

[zooklm1]

A couple issues I ran into. First, I tried taking the valve cover off and had the hex socket on the bolt adjacent to the cam gear cover strip out. This is a bolt that is external to the seal area and had a bit of corrosion. If I had taken the cam gear and cover off first, I could have applied PB blaster and not stripped out the head. I didn’t and ended up cutting the bolt head off to take off the cover. The second issue was that someone in the past (probably while changing the camshaft seal) severely damaged the inside cover and cobbled together a repair using aluminum rod they threaded and epoxy to glue the rod to the cover. It looked like the bolts that held on the outside cover had seized and the inside cover boss had sheared off while trying to loosen the bolt. The other boss looked like it had started to fail because there was some cracking. I bought a new cover set. One other thing, pay attention to cam holddown brackets location and orientation. Initial I put a couple in upside down (correct original location) and the cam would not turn. Send me a note if you have any questions.
Lee

[stitch2k1]

S1 and S2 owners rarely pull the cams, but if you beat on your car (as you should, it's a Porsche) you should be changing it and upgrading to the IWIS Racing chain, which is what I used. Noticeably beefier links, I would trust it to last a long time, and it was a $5 difference.

[zooklm1]

I also used the IWIS Racing Chain, given the minimal difference in price.

[Latitude48]

S1 and S2 owners rarely pull the cams, but if you beat on your car (as you should, it's a Porsche) you should be changing it and upgrading to the IWIS Racing chain, which is what I used. Noticeably beefier links, I would trust it to last a long time, and it was a $5 difference.

Did you take any comparison pictures of OEM vs IWIS chains? Please expain what you mean by beefier? The sides of the chain are thicker?

I purchased a chain from Porsche. The original has lasted 155K miles and 35 years, so a new one will far outlive me.

[stitch2k1]

Did you take any comparison pictures of OEM vs IWIS chains? Please expain what you mean by beefier? The sides of the chain are thicker?

Yes, the components in it I would say are about 10-15% larger, and side by side with my original chain the stretch was noticeable, the intake cam was definitely out by a degree or maybe even two.

[Latitude48]

Did you take any comparison pictures of OEM vs IWIS chains? Please expain what you mean by beefier? The sides of the chain are thicker?

Yes, the components in it I would say are about 10-15% larger, and side by side with my original chain the stretch was noticeable, the intake cam was definitely out by a degree or maybe even two.

What is the mechanism that allows a chain to "stretch?" The links are rigid, so is it wear where the links attach, or something else?

[Tom]

Did you take any comparison pictures of OEM vs IWIS chains? Please expain what you mean by beefier? The sides of the chain are thicker?

Yes, the components in it I would say are about 10-15% larger, and side by side with my original chain the stretch was noticeable, the intake cam was definitely out by a degree or maybe even two.

What is the mechanism that allows a chain to "stretch?" The links are rigid, so is it wear where the links attach, or something else?

I discovered chain 'stretch' on my old 450SL -- the timing shifts over time as a result. Here's a good article on the subject. The TLDR version is that material wears off the pins and the holes they sit in -- if that's say 10 thousands per pin/hole, that's nearly a mm for every 2 links...

https://interflon.com/us/news/3-causes- ... prevent-it

[stitch2k1]

What is the mechanism that allows a chain to "stretch?" The links are rigid, so is it wear where the links attach, or something else?

Fatigue will cause metal to stretch

if that's say 10 thousands per pin/hole, that's nearly a mm for every 2 links...

Also this. M116 and M117 also break chains a lot on top of that.