Dizzy re-furb

ian harvey · Aug 22, 2014

It's about time I replaced the distributor drive-belt. I reckon the last one has been on for about 30,00 miles now. My mechanic recommends that the whole distributor be sent for a re-furb with new caps etc. He also says that the plug leads are meant to be swapped every two years, mine have been on for way longer than that and I guess I'm not alone. Should be at least £800 for that lot.

I'm going to take the plunge, though. I'm a bit spooked about the belt so that's got to go and all the other stuff should make the old girl feel friskier, I hope.

These are the kind of things that can easily be forgotten, any opinions on the likely improvement and/or risk of not bothering, does anyone know the recommended lifespan of these items...?

Hacki · Aug 23, 2014

The distributor belt should be checked at least every 20,000 km, if not replaced. If it breaks, it might cause an expensive engine damage.

The plug leads - very expensive, but what a difference when I had mine replaced. After a long track day I felt a significant power loss. The lower plug leads were cooked, sparks all over the place, it was running on six plugs only then. The upper leads were ok, no replacement necessary. Swapping the plug leads every two years is way too often I think.

Dekker · Aug 23, 2014

Hi Ian,

The belts can be supplied from OEM sources. Pro9 in Redditch sell them for £9 including a pin that is often destroyed when disassembling the distributor.
According to my research these often overlooked belts should be replaced at 50k miles or at 5 year intervals, whichever comes first.

CarParts4Less Ltd sell Porsche 964 1988-1994 - BERU ZE751 Ignition HT High Temperature Lead Set which are the same make as those fitted to our cars. In Dec cost me £296.84 incl P&P.
Edit :- £275.40 now on Ebay.
Open the engine lid in the dark, if you see sparks they're duds.

Dizzy caps and rotors will cost about £60, search for Beru items.

ian harvey · Aug 23, 2014

Hacki/Dave,

Thanks for the replies, very helpful.

Ian

Damen · Aug 23, 2014

Hi Ian

Good questions. The ignition side of the engine is often overlooked. Lots of good advice above.

Porsche will now only sell exchange dizzy units and not the belt!! The belt is available elsewhere at very reasonable money. You don't, IMO, need to remove the dizzy but it makes sense to change the belt, rotor arms and caps every 5 years. You don't need new HT leads every two years but every fifth year is a good idea. Make sure you have plenty of time if you're doing the fitting as the bottom set are hard work. If you're not doing it and someone else is make sure they actually do the bottom set - get them to show you the ones they've taken off as proof they've done the job. At the same time I'd recommend you change the plugs but also check the tappet clearances - also more than a five minute job.

In fact, I do plugs every year regardless of mileage (I get my plugs from the Green Spark Plug Company, the best service and the cheapest) and tappets every other year. It's peace of mind and provides a better starting and more efficient running engine.

Damen

Dekker · Aug 24, 2014

Damen, are you saying you can replace the belt without removing the distributor?

The book says you have to but I'm always keen to hear of shortcuts.

Damen · Aug 25, 2014

Sorry for any confusion. The dizzy needs pulling to do the belt but doesn't need pulling apart for a refurb. IMO.

Damen

Laurence Gibbs · Aug 25, 2014

I did my belt when i had my engine out. It's a fiddly job. Hardest part being getting the old pin out, invariably you will destroy the old pin. It is a diy job but you have to be fairly dextrous and resilient. Plug leads are much easier proposition for diy, pretty easy. Though best timed for when a plug change and valve clearance is due(due to removal of the lower exhaust box and cat and covers). The hardest part is likely to be removing and getting them out of the tinware.
Great heads up by Dekker for the leads.
Not sure i would want to change my plugs yearly if doing low miles? There is always a small risk with aluminium heads that you will cross thread a plug. So doing that more regularly would increase your risk, albeit very low? Conversely changing plugs at well over the recommended interval on a higher mileage engine runs the risk of dropping carbon into the combustion chamber. How many miles are you doing between plug changes?

h_____ · Aug 31, 2014

Oooooooo good thread guys - reminds me of preventative maint I need to do.

Cheers

Hugh

ian harvey · Sep 17, 2014

As mentioned above, it would be wise to change the plug leads at this time. OPC Leeds are quoting £59.30 each plus VAT which is impressively expensive!

Does anyone know of a good alternative for sensible money, please?

Ian.

Steve Brookes · Sep 17, 2014

£292 + VAT for a set from Type 911

http://www.type911shop.co.uk/shop/article_658/964--Ignition-Lead-Set.html?sessid=cMdXK7RT4lRq39XN2FSseAbqpGo5nhWFuHXuJlCPActrXszZFQpXjyRMJxjTcmSx&shop_param=cid%3D1902%26aid%3D658%26

I've had these put on mine (note that I didn't do the job myself as there's a lot of stripping down the engine bay needed to put them on).

ian harvey · Sep 17, 2014

Steve

That's more like it. If you didn't fancy the job yourself then nor do I. Did you notice any improvement?

Ian

Dekker · Sep 17, 2014

http://www.ebay.co.uk/itm/PORSCHE-911-3-6-CARRERA-4-BERU-ZE751-Ignition-HT-High-Temperature-Lead-Set-/400615540901?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5d468c08a5

£275.40 incl VAT and delivery

Steve Brookes · Sep 18, 2014

ORIGINAL: ian harvey

Steve

That's more like it. If you didn't fancy the job yourself then nor do I. Did you notice any improvement?

Ian

Yes but I had the distributor rebuilt at the same time. Prior to the dizzy rebuild and replacing the wires I had regular stalling (car would cut out when off the throttle) and there was a noticeable power loss at the top end (most likely the ECU retarding the timing to compensate for a bad hall sensor in the distributor). The car has been brilliant ever since.

As regards fitting, Unit 11 did mine at the same time as a full service which meant that the exhaust, etc were already off so they only charged me an extra hour labour to strip off the old wires and put on the new.

Hacki · Sep 18, 2014

ORIGINAL: Steve Brookes

there was a noticeable power loss at the top end

That´s exactly what happens when the ignition leads (normally the bottom ones) have said goodbye. Feels like 30 - 40 horses less.

Laurence Gibbs · Sep 18, 2014

Some excellent bedtime reading follows

http://edelweiss.smugmug.com/Cars/Porsche-Technical-Stuff/Beru-Ignition-Cables/14867824_K5kCMk/1109407752_LNgPStP#!i=1252201572&k=Wp64Wtn

great info. Some other useful stuff on the site too.

Laurence Gibbs · Sep 18, 2014

the crimp tools a bit rich. I am thinking a M7 metrinch ring spanner split in half and rounded off and used in channel lock pliers would crimp the outer end no probs[

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ian harvey · Oct 17, 2014

I've now had the dizzy belt, caps, rotor arms and all plug-leads changed. The old belt looked like new (after more than 12 years!), the caps and rotor arms were visibly warn (I guess they've been on since new, 64,000 miles) and the leads looked ok.

Whatever, there is a marked improvement with the car: it starts more easily and runs way better. It pulls cleanly at lower revs, noticeably so, but at high revs it really flies, it feels very crisp and fast! I've been on my favourite roads and was arriving at corners much faster than I've been used to.

If you think your car is due similar work, it will be well worth it!

ChrisW · Oct 18, 2014

Refreshed suspension has a similar effect --- it only (?) keeps the tyres on the road [

]

So when somebody tells you that their RS keeps firing them at the scenery ---

ian harvey · Oct 18, 2014

Chris,

I'm sure you're right. Apart from occasional geo checks and the odd replacement part, my suspension has essentially remained unchanged for many years. It always receives a clean bill of health when inspected but is probably not performing as well as it once did although it's still pretty good, no untoward noises or odd behaviour.

The ride does not seem as harsh as it once did which may indicate that it's lost it's edge.

Going for the KW3 ('Ring set-up) has crossed my mind, storing the original for safe-keeping. This would suit my road usage but I'd hate to lose the current/correct track set-up.

Ian