Distributor Belts

[John Reay]

What is the consensus of opinion on changing the distributor belt on a 993?

There is nothing in the service manual suggesting/advising when to change the belt so was wondering when other 993 owners have changed them and at what sort of cost.

My own 993 is coming upto 8yrs old and has 46.5k on the clock.

John

[verysideways]

My C4S was still going strong at 83k miles, and i believe the current owner has recently seen 96k miles, and with no sign of a problem on the dizzy belt.

I replaced the caps and rotors at about 74k miles, but even that wasn't strictly necessary, simply for my peace of mind.

My current C2 is just over 50k miles and is an October 93 car (very early!) and no belt problem yet (touch wood).

VS

[clubsport]

not a big problem for 993...it was more of a concern for early 964 cars where the belts could effectively perish.
This was overcome with a venting tube modification on later 964 that was standard on 993.

[nel]

In the Porsche parts manual (PET) the body of the double head dizzy is shown as a single part number, with no possibility of buying the internal components separately. I.e. they don't sell the dizzy linking belt (if in fact it is still done with a belt on the 993) as a spare part.

This implies to me that it doesn't need replacing. Note that the service manual stipulates checking of operation of ignition circuits 1 & 2 every 20,000 km. If they found a problem with one of the circuits they'd just replace the whole dizzy I suspect (at great expense compared to the price of a £5 toothed belt were that to be the problem!).

In conclusion, don't worry about it until your mechanic says he's got to replace the dizzy or you notice a sudden drop in power output.

[pfecteau]

Hi,

I've got a '96 993 and I just read about this last night in Panorama (the PCA monthly) in the technical section. They said that the 964, and 993, and all racing variants of the era with dual ignition, use a belt to drive the second distributor off the first. The spark creates ozone, and ozone eats away the rubber over time. Hence the "fix" for 964 is a ventilation kit (mentioned by previous contributor) that is standard on later 964s, and all 993s. The article went on to say that if the belt broke, the car keeps running on the primary distributor (may be a little rough or lose power a bit). The slave distributor arcs away continuously on one of the 6 cylinders. The response of the driver, typically, is to try the loud pedal. Meanwhile, the cylinder that is arcing away trys, and succeeds, at 'welding' the piston to the cylinder or the head, and poof! you need a new engine. Apparently happens so fast you don't hear it coming.

Having read that I thought I'd see about replacing my belt every 10 years. I wonder now how much the entire double dizzy costs....

Paul

[John Reay]

Thanks guys,

Was aware of the 964 belt problem due to lack of ventilation tube and also no significant reported problems on the 993.

Just wanted to get a feel from others on this as I tend to adopt the preventative maintenance policy.

Wasn't aware that you couldn't buy the belt. Get the impression from the Rennlisters that changing the belt at 50k to 60k is 'advisable' and it costs approx $200 to do the job.

John

[iguana]

nel said:

In the Porsche parts manual (PET) the body of the double head dizzy is shown as a single part number, with no possibility of buying the internal components separately. I.e. they don't sell the dizzy linking belt (if in fact it is still done with a belt on the 993) as a spare part. This implies to me that it doesn't need replacing.

Ah but Porsche don't stipulate a tensioner blade replacement on a 944S2 or cam teeth checks on a 968 either.....

As said before, 993 belt not known for snapping like 964 (also a complete sealed unit from Porsche) but it has occasionally been know to happen.

Porsche offical snapped belt fix= new dizzy- not cheap, but because of the daft new dizzy replacement cost (actually think prices have come down now compared to what they were) some specialists have got a toothed belt supplier for pence & have designed a tool to replace the belt for an hour or so's labour charge.

[John Reay]

Iguana,

Who are the suppliers that have found belts and change them?

Thanks

John

[iguana]

John Reay said:

Iguana, Who are the suppliers that have found belts and change them? Thanks John

Autofarm used to change 964 belts, dunno if they have done the same for 993.

[nel]

This thread is making me glad that my porker only has a single ignition system, given the potential consequences of belt failure .

However, the issue of replacing entire units rather than replacing the faulty component within them is a major consumerism wind-up. To the manufacturers it no doubt represents a good saving in parts inventory management and better margins on parts replacement, but it pisses me right off. I recently replaced a £1k electro-hydraulic pump unit that basically needed a new £10 shaft seal.

[clubsport]

nel said:

This thread is making me glad that my porker only has a single ignition system, given the potential consequences of belt failure . However, the issue of replacing entire units rather than replacing the faulty component within them is a major consumerism wind-up. To the manufacturers it no doubt represents a good saving in parts inventory management and better margins on parts replacement, but it pisses me right off. I recently replaced a £1k electro-hydraulic pump unit that basically needed a new £10 shaft seal.

The serious tuners tend to go "twin plug" on 993TT in their quest for real power...it's not that bad really

[nel]

clubsport said:

The serious tuners tend to go "twin plug" on 993TT in their quest for real power...it's not that bad really

Yep - seem to recall reading that Ruf go up twin plug ignition on the 993tt. Incidentally, if anyone is interested here is a recent Ruf price list that a french buddy received for 993 turbo R conversions (in Euros) :

993 Turbo R
Price List

1. Engine conversion Turbo R from a 993 Turbo € 19,000
including an oilcooler

2. Engine conversion to Turbo R from a 993 Carrera 2+4 (3,6 l) € 40,500

a. Turbo transmission necessary € 6,500
b. Rear spoiler from Turbo € 4,500

3. Taller 6th Gear for topspeed up to 200 MPH € 3,000

4. Sportsuspension € 3,600

5. CTR 2 Integrated Rollcage € 9,900
including all the necessary upholstery work

6. CTR 2 Front spoiler and rear bumper € 4,800
with chrome tailpipes

7. Ruf-Instruments € 1,300

8. 18“- Ruf wheels (8.5“ + 10“ width) € 2,600

9. 19“- CTR 2 forged Magnesium wheels (8,5x19, 10x19) € 10,600
and tires (245/35 ZR 19, 285/30 ZR 19)

10. CTR 2 Shift lever € 420

11. Front shock tower brace in aluminium € 300

not include VAT.
Pfaffenhausen, February, 2004

[pfecteau]

iguana said:

John Reay said: Iguana, Who are the suppliers that have found belts and change them? Thanks John Autofarm used to change 964 belts, dunno if they have done the same for 993.

I just googled "porsche 993 distributor belt" and got several links to distributor belt 'distributors'. Check out this one, John:
www.type-911.co.uk/gp_serviceitems.htm

It has a nice DIY diagram and instructions (scroll down to appropriate section and click on information), and just your luck, located in England!

[Ian964]

Most decent independents will be able to change the dist belt on a 964 or 993 for around £100 - it's quite a common juob (esp. on 964s!).