Dutch 928 fan

Thanks Garth. It still amazes me how quickly the people on this forum have the exact info at hand! Many thanks to all. I now know what to do.

Dutch 928 fan

Hi I am back again. Got my new correct thicker pivot bolt. I put it all on, but there seems to be too much play? Hopefully the rim of the pivot bolt did not catch the rear plastic liner when i turned it in...
I will check tomorrow. But I assume you guys can tell me this is too much play on the pivot bolt/arm before I unbolt it again.
TB does line up perfect though.

GlenL

You are missing a thick washer that goes on the threads of the bolt.

Dutch 928 fan

No, I have the thick washer on. But what I found strange is that the smooth part of the bolt is considerably longer than the bore of the pivot arm.

tom-in-tempe

Leo, not sure if this will help but here is a pic of my 86 Euro after partial reassembly about 4 moths ago. Didn't have any issues with the tensioner bolting back up.

Dutch 928 fan

Thanks Tom. That looks like the fit I expected. I will double check my set up.
Perhaps the bolt is too long? Although I understood that the hole for the bolt goes well into the block.
Anyway, as long as it aligns well and I have sufficient thread I assume a thin washer at the end does not hurt.
Especially considering I drove thousands of miles with the PO's bolt that was too thin which he made up for with insulation tape....

ROG100

Leo,
Check the part numbers.
S2 M28/21 -----
Bolt - 928 105 570 03
Two pivot bushes - 928 105 613 04
Idler roller - 928 105 571 02
Washer - 928 105 572 00

Be aware that parts were different for M28/22 engines.

Dutch 928 fan

Yep. Thanks Roger. I got those numbers, apart form the plastic bushes. Are these bushes really different? If so they must be a couple of millimeters thick at the rim?
The porsche dealer had them for 30 euro each...while the rest of the parts like thembolt was just pennies...
Otherwise it must be something else. I will go into my garage now and report back.
I have the m28/21 engine.

ROG100

Leo,
Yes a big difference between the thin plastic bushes you have and the correct phenolic bushes that you need.
We sell for $23 each so 30 Euros each is not that bad - swallow hard and buy them and you will be good to go.
Roger

Parts get very tricky between late 83 M28/11&12, 84 M28/21&22 and 85/86 M28/21&22.
Generally if the parts fit an 85/86 M28/21&22 they fit the 84 M28/21.
84 M28/22 is a bit of a crap shoot.

Dutch 928 fan

Ok! I was already starting to think like a true PO...like putting some rings in between at the engine end as the new bolt is longer anyway...
But I will order parts tomorrow and wait some more days before putting it all back together properly.
Thanks for the advice and keeping me on track to correct the mess the PO made. ;-)

Dutch 928 fan

Thanks Roger. Also for keeping me on the straight path and do it right. Unlike the PO...

I just double checked and took the rollers off.
I did fit it together properly. It is just that there is too much play between the bushes and the bolt and thick washer. So I will have to order the correct thicker bushes then.

Just to show you how the PO solved this with a metal washer and a home made plastic washer. (First picture)

And the difference in bolt lengths and smooth part of the bolt. Just for peoples future reference when they search this thread. (Second picture)

Mrmerlin

Ummm your still going to have a problem I think you need a bolt with a shorter shank
OR a newer Idler roller arm.
NOTE the new bushings will not take up the difference in shank length

Lizard928

Tom in Tempe,

Never use the contitech belt. Get a Gates, or factory timing belt......

ROG100

Leo,
Lets back track a little. In your first post you say the tensioner arm is 928.105.540.03. That tensioner arm was fitted to the M28/11&12 engines and in theory not your engine. Mr. Merlin is always right so we need to figure out if the tensioner arm is original or was changed by the PO.
In theory your engine should have tensioner arm 928 105 540 05.

What parts are correct (and not a grey area) for your car ----
928 105 570 03 Bearing pin - used from 82 to 86
928 105 571 02 Roller - used from 83 to 86
928 105 572 00 Washer - used from 78 to 95

Ambiguous parts (according to PET) are the bushes or the tensioner arm itself.

We need to re-consider the roller as this was specific to the engine number.
It is possible that a solution with roller 928 105 571 00 and bushes 999 924 003 40 along with your tensioner arm may fit.

Your VIN does not work in the Porsche system so can you reconfirm it is correct please? Also let me have your engine number as well? Actual number not the M28 definition.

worf928

+1 what Sean and Roger write above: You've still got a mishmash of parts.

Based upon your latest picture, if indeed the dimple in the carrier is centered over the rod of the tensioner and the carrier is flush against the big washer (which should be against the idler roller) then your tensioner and carrier arm are correct for each other (if not for the engine.) So, getting just the carrier that matches the new pivot bolt is not going to work; it will just make the problem worse.

Follow Roger's advice: get the part numbers from your parts and engine number and go from there.