Brian Wilson

Hey peeps,

If you haven't tensioned your belts lately, I would highly suggest you do so. My car was running great, until the head gasket blew. When I got everything apart, I noticed that the belts were mighty loose! Don't take a chance, go ahead and replace them or retension them. Mine were brand new, but had loosened off quite a bit.

Tabor

Just so everyone knows, belts should be retensioned 1,500 miles after their initial install, then 15,000 miles after that. Then they should be replaced 15,000 miles later.

So:
0 - Install
1,500 - Retenstion
16,500 - Retension
31,500 - Install
Rinse, Repeat

Dan in Pasadena

I never knew about the re-tensioning after 1500 miles thing. Had mine changed, went along happily until Tabor mentioned this a while ago. Coincidentally, I called my wrench today...again, he said no need to re-tension, he does that at 15K service!! I'm feeling mightly uncomfortable. The car is a daily driver and I've put on 9000 miles since the bel was changed. I need a new shop. Anyone know one in the L.A. area?
How hard is it to do myself....really! I can't afford to screw this job up.

Danno

Takes about 15-minutes to check and retension the timing and balance-shaft belts.

adrial

Dan, you have an '87 so you have the auto-tensioner for the timing belt.
That one's just a question of losening and retightening a bolt or two.

The balance belt has to be set manually...but its tension should be about 1/2 that of the timing belt.

Make sure the engine's cold before you tension the belts...

crushingday

Don't shoot me for this one guys ..I have not replaced or adjusted my belts in my 87 944S for .....65K miles...yes thats right 65K!.
I think I can hear the thing ticking. I am putting it off until I find a 968 engine to install. I hope she makes it.

tecart

on the 1986 turbo is thier a way to tension the cam/timing and balance sheft belt without the factory gage tool? my belts are being done and we dont got that tool, my belts have about 10,000 miles on them, what do you recommend beside paying porsche again to do it? CAN MY MECHANIC DO IT? HE HAS LOTS OF TOOLS NOT THE PORSCHE ONE THOUGH. THANKS

Brian Wilson

tecart,

Ask around, but I would go with someone who has the Porsche tool. Porsche is smart and made their vehicles so that they had to be serviced by them. Don't underestimate them, take it to the dealer if you have to.

Martin

Some mechanics over tighten new belts figuring they will stretch to the correct specs, some other cars are set up by that method, however I consider it bad practise as it puts undue strain on water pump bearings.
There are other tensioning devices available than the factory tool, or measure the deflection pushing against it with a spring (to a measured compression)like I do (that is how we set up door drive belts in elevators).
If you have an "S" model then you also have a cam chain to worry about, the intake cam is driven via a chain from the exhaust cam, if the tensioner pads let go you will be looking for a new head.
If in any doubt pay the money and get it done properly.

Dan in Pasadena

Adrial, Thanks for the response.

I have no clue how to do the tensioning and I am nervous about doing it wrong. But I will if I can find a tech article worth a damn....maybe from Skip? I thought I heard you have to use Lok-tite (what kind?, where?)

I knew the '87 has an auto-tensioner, but I've heard it isn't to be relied upon? Good info? or incorrect?

The balance belt is "1/2" the tension of the timing belt, you say? Measured how? By the way deflection by hand feels? Or is there a gauge? Sorry to be such a ninny on this one.

Tom Pultz

The term "auto tensioner" is a misnomer... it's actually a manual process to set the tension using a preloaded spring in the tensioner. It does NOT adjust the tension dynamically like the one in the 968. On my '90 S2 it works great... but I always double check the tension it applies, which is right about 3.7 on the factory gauge.
Not true. The correct tension for the newest, 18mm wide 04 belt is 3.5 +/- 0.5 units. So, the cam and balance belts have roughly the same tension.
With the expensive dial indicator gauge.

As for how often you change the belts, a little common sense is needed. If you drive your car very hard and run it on the track a lot, you would probably want to be a bit more conservative and change the belts every 30K. On the other hand, most people should easily get 40-45K, provided they are retensioned every 15K and are not contaminated with engine fluids.

My belts have about 40K and they still look new, but I plan to change them before the 1st track day this Spring.

johnr

how hard is to to change belts and rollers by yourself? Can you set the tension relativly and drive it to a shop for tensionong?

Danno

The manuals says something like "inspect belts and replace if necessary". Yeah right, like you can really tell if belt needs replacing. It can look perfectly brand-new just 1 mile from snapping. Well, besides the obvious stuff like rips, tears and missing teetch.

adrial

"Not true. The correct tension for the newest, 18mm wide 04 belt is 3.5 +/- 0.5 units. So, the cam and balance belts have roughly the same tension." said Tom

Thanks for correcting me. I can't remeber who told me that...oh well.

thanks again,
Adrial

P.S. Dan, there's a group of guys that rents out the expensive tool...I think Skip tried it with little success (couldn't get his hands on the tool)..I'd look into that more...wish I had before I put down $500 to do the belts then $150 to tension...rip rip rip rip off...

Brian Wilson

Johnr,
Belts and rollers aren't that hard to do if you have a little time. I am about halfway through the project right now, awaiting parts in the mail.

As for the tensioner, Pelican Parts has it for rent on their webpage. I haven't called for a price, because my mechanic will do it for cheap.