vwmann1

does anyone know where I can get mine rebuilt? a new one from Porsche is like 1,500......

MB968

What isn't it doing? Is it an electrical issue, or hydraulic. Are you getting power at the electrical connector. If so, is the solenoid valve activating. If not you'd need to replace the solenoid valve. I doubt that the electrical part is made by Porsche, probably Bosch or the like.

If it is hydraulic, it just may need to be cleaned or rebuilt. I'm not intimately familiar with the unit, just the concept of how it works. But, buildup of "silt" in hydraulic cylinders can cause them to stick. This can be a common industrial issue for tight fitting "seal-less" piston cylinders, such as in servo valves. If the unit is a seal type piston/cylinder, the seals could be worn out, and may just need to be replaced. A good hydraulics shop may be able to look at the hydraulic portion of the unit, and get it functional for you. Also, I think some of the parts of the unit like the check valve are sold separately if you find they are the issue.

Assuming the unit is getting power, and that isn't the issue, I'd try calling all of the known 968 places like Lindsey Racing, or Paragon, etc. to see if they can recommend someone.

mhariush

Hey vwmann.

You can change just the plastic chains. But you can also get it for cheaper than 1500... I bought a brand new genuine tensioner for my 16V S and I'm sure it's the same part, for 500. The pads run like 100+ or so.

http://www.paragon-products.com/Cams...9.kit-rail.htm

Here's the changing procedure:

https://rennlist.com/forums/968-foru...oner-pads.html

vwmann1

Thanks for the replies. nothing is wrong with it except being 20+ years old! im in the middle of a rebuild and im looking into this thats all. I will check the solenoid for resistance and go from there.

mhariush

You should change the pads, they get brittle with age, and when they break, so does the engine. You don't need a new tensioner, but the pads are a cheap insurance.

Arominus

The 968 tensioner is different than the s/s2 unit due to the variocam action.

mhariush

It was listed under the 968 page.

Here's one that says it's for the 968. And it's cheaper...

http://www.paragon-products.com/Prod...5%2E201%2ERail

Arominus

The pads are the same, but the tensioner itself is different.

FRporscheman

I've never heard of anyone rebuilding the tensioner. They're actually very reliable; I have 200k one one, and 250k on another.

The solenoids do occasionally fail, though. And I don't think you can buy it separately! You just keep using the one you have, hoping it won't fail.

I'd say just leave it be (but change the o-rings, pads, chain, etc).

Jfrahm

I have a cam chain tensioner which at 160K miles makes a weird 'braaap' noise, I bought a low mile replacement but have not changed it yet. It seems to be noisy when it operates. There is a thread or two about it. Another user had the same issue and finally replaced the tensioner to cure it.

I do not think the pads are the same between 16V 944 (and 32v 928) and the 968.

FRporscheman

I agree, the pads are unique to the 968. Here's the 968 pad:
http://www.paragon-products.com/Cams...5.201.rail.htm

Here's the 944 S2 pad
http://www.paragon-products.com/Cams...5.049.rail.htm

I think the part number for the 968 pad is 944 105 509 00

I've heard that sound on someone's car, it happened when the variocam actuated. Unplugging the VC solenoid stopped the noise, so we concluded it was the solenoid. Coulda been wrong tho!

Looking at PET, it seems you can order the solenoid separately. Part number is 944 605 123 00.

Jfrahm

It's not the solenoid. Tried that. It does go away with the variocam unit unplugged. It's not the check valve , chain, pads, etc.

Another lister with the issue traced it to the tensioner itself. Worn out and rattling when it actuates? Who knows.