Ad0911

After reading many threads about the tensioner, including the current discussion about the pinch clamp tool, I thought I might as well post another thread about my tensioner. It is a sad case of decomposition. Once upon a long ago I bought a PKT thinking I was safe with that. Not realizing I had the heads done so the PKT is extended too much when I fit it. So it is back to the drawing board and try to rebuild the old tensioner. First step is to see if all the parts are there. It appears they are not. I can't find the C-clip that seems to be sitting on the inside of the housing. And perhaps more parts are missing, I don't know yet. Next step will be to see if I can re-aline the discs in the right order and orientation (are they all the same?), carefully following the WSM where I can, but I think the tensioner on my '78 differs from that of the 1982 WSM most of us have in *pdf. I remember something about oil passage ways. There are none in my tensioner housing. So here's the start:

Rob Edwards

You have most of what you need there, all 40 bellville washers are the same. One challenge is that the '78 rubber boot is NLA, Porsche makes a thick rubber band (92810555205) that allows the use of the later/larger boot and clamp, you can see it on the tensioner in the second picture below. However, Greg Brown makes a machined aluminum collar that fits over the end of the tensioner to allow the use of the later/larger boot and clamp, and that's a better solution. Here it is, loosely fitted:




Here's a shot of everything you need for '78, except for the machined collar



You should have 40 bellville washers, their orientation on the piston is shown in the WSM diagram below, 8 sets of 5 washers:

Ad0911

Thanks. I'll have a go at it. I assume these rings have a top side. Can I test this by heating them in hot water and see how the shape themselves convex/concave?

FredR

Ad,

The Belleville washers are all the same- they have a convex surface one side and a concave surface on the other. In the off chance it is not entirely clear, you assemble the washers in packs of 5 all 5 being in the same orientation then when assembling them, you place each pack of 5 on the piston shaft with the first pack concave side to the piston. Subsequent packs of 5 are then placed in the opposite orientation to the previous one until the pack build is complete. Then the assembly should look like the manual picture.

Your components look somewhat grotty, whether they will clean up remains to be seen but they should be bright if they are to be functional I would suggest.

If you want to see how they function make some kind of indexing mark where the last washer sits relative to the con rod. Then put the pack into a pot of boiling water, leave it for a couple of minutes or so and see how much the pack has contracted relative to the indexing mark you made.

You may find it easier to secure a s/h tensioner, that or adopt the PKT you have to suit. Have you mailed Ken for his suggestions for adaption of the PKT you have previously purchased?

Rgds

Fred

DeWolf

I have a 90 model tensioner for sale if it's any good to you. AU$70.00 and whatever the postage is.

Wisconsin Joe

They are curved at room temp. They flatten as they get hotter.

This shortens up the tensioner and allows less tension as the engine expands due to heat.

ROG100

We sell the GB conversion to allow the use of the later rubber boot - way better than the rubber band.

PorKen

He can exchange for a PKT-S which has a larger range.

FredR

I had a feeling you had an option developed for such.

Rgds

Fred

Ad0911

I investigated all the pars and it seems I have them all (including 40 rings and the thick ring) but the ring on the outside of the tensioner # 3 in the WSM picture. This doesn't seem like a very special ring to me. Just flat. Cleaned the parts and found the rubber boot I had in stock. The proper size it seems. It is the same part nr. (928 105 552 02) as is shown in the PET for 1980 (mine is 1978). Fun to see the build year 1977 on the housing. So far so good. I think I can get this together again. This means I have a PKT in spare.

BTW, the spring (left in the picture) apparently does not belong to the tensioner. I think it will end up in the box with forgotten parts. Anybody know where this spring needs to go? Perhaps at the clutch slave cylinder?

FredR

Have you got part No 10 on the diagram?

Ad0911

It is the thick ring. Yes it is there.

FredR

Looks a bit like the spring that goes on the end of the tensioner piston - part of the kit that makes/breaks earth connection for the alarm on the later models but I suspect your MY does not have this feature

Ad0911

Dear Roger. At first I didn't understand the remark of the rubber band. Searching the web I found that the rubber band is used to fit the larger diameter later style boot. The rubber boot I have in stock is the smaller diameter that fits my old tensioner housing. I don't think I need the adapter nor the rubber band.

Rob Edwards

That -02 rubber boot ('convoluted air bellows') should be the correct diameter for your '77 tensioner- the real question is where did you find the -02 rubber boot? They've been NLA for a very long time.