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Saturday, 30 September 2017 11:30

Porsche 944 Cam and Balance belt replacement

This is not going to be an article about how to change your cam and balance belt on a Porsche 944 or 968, this subject has been covered elsewhere on the internet and personally, it is one of those jobs where if you have not been trained to do it, are not experienced in doing it, you should not do it.. An apprentice at JMG Porsche is not allowed to change a 944/968 cam or balance belt until they have their basic first two years of training under their belt, after that they are supervised on the first few and on probation for the first 4 years with them being checked... So in short, get a pro to do it, ideally a specialist with in depth knowledge of the 944 and 968 engines.

Over the years I have often been asked how often they should change their cam and balance belt on their 924S, 944 or 968, and my answer is "Every 4 years" and change the water pump, front engine oil seals, belt tensioners and rollers every 8 years!

The following questions and answers are here to explain why I advise what I advise and is actually a cut and paste from a recent answer by myself as a technical advisor to the Porsche Club of Great Britain, as a response to a question on their forum.

To an extent, the same advice applies to any belt, on any car, so a Boxster, Cayman or Cayenne/Macan/Panamera or 911 (996, 997, 981 or even air cooled cars) which as a whole do not have cam belts, but do have auxiliary drive belts which if they fail will at best leave you stranded, but at worst can damage the engine or even the bodywork of the car (belts at high speeds make a mess!)

Other than not having a balance belt, the Porsche 928 advice would be the same advice as for the 924S, 944 and 968 owners. 


What destroys a belt?
From education training and experience
* Entropy (Everything wants to return to its original component materials) - Very slow
* Oxygen (Oxidises the rubber from the outside inwards, forming cracks eventually, which then allow more oxygen deeper into the belt)
* Wear (Accelerated if the tension is too high or too low)
* Incorrect installation
 
Who makes the belts for Porsche?
Over the years I have seen the following belts in Genuine Porsche boxes.
* Dayco
* Gates
* Bosch
* Continental
 
How long can an incorrectly setup or installed belt last?
* As little as a few seconds
* As long as a correctly installed belt
Depends on how incorrectly it has been installed or setup (I have seen many weird things going on in 944 belt covers)
 
What else accelerates belt degradation?
* Contamination from oil
* Contamination from power steering fluid
* Contamination from coolant
* Contamination from dirt/grit
* Contamination from fuel
* Contamination from plastic dressings
* Contamination from sprays such as WD40
* Ionisation of the air in the cam belt cover
 
How soon can a correctly tensioned good quality belt without contamination last?
* Soonest I have seen is 5 years with a missing ionisation cap.
* Soonest I have seen with no visible signs of cause - 6 years
* Oldest belt that I have seen break was 26 years old!!!
 
When would I change the belts on my own 944 fleet?
* Every 5 years without fail and I check inside the cover every year for contamination or issues and always check for leaks every time I drive them.
 
When would I recommend customers change them?
* Every 4 years (as you might not have your belt, oil seals and leaks checked so often as I do)
 
How much damage is caused by not changing them?
* Wrecked cylinder head (Valve contacts and bent/detaching valve heads)
* Wrecked pistons (Valve contact, sometimes with valve heads detaching and bouncing around!)
* Wrecked cylinder block (mushroomed out pistons split the bore)
 
Other advice.
* Change the water pump, tensioners, rollers and front engine oil seals on every second belt change. The water pump can fail through age as well as mileage, as can the seals and tensioners/rollers. Any of these parts can cause the belt to fail.
* Make sure your car has an ionisation cap between the distributor cap and upper front cam belt cover.
This is an important one.
 
When the 944 was designed, it had a hose that ran between the cam belt cover and air box.. This was to bring fresh air through the belt covers, and remove air which had been ionised by the electrical activity within the distributor cap. There was also a plastic cap between the distributor cap and the cam belt cover, to reduce the amount of contamination of the air within the belt cover with air ionised within the distributor cap.
 
In about 1988, Porsche eventually go to the bottom of why so many 944s suffered with hydrolocked engines following driving through deep puddles or crossing a river/ford crossing... It turned out that as soon as water was sprayed around the front crank pulley, or the pulley entered water, the water would go into the belt cover and the balance belt would throw this water directly at the vent port which had the hose to the air box.. Once the air box contained a certain amount of water, or you turned a corner, the water would flow through the airflow meter, and get sucked into the engine... Nasty.
 
Porsche then issued a TSB to say that all Porsche models should have this hose where fitted (important) and a blanking plug fitted (Not so important, I leave them open for ventilation on the advice of my mentor at Porsche).
 
The problem with this deleted hose, is that without it, it is even more critical to have the ionisation cap installed. They are cheap and available.
 
That is all :)

Monday, 30 April 2012 13:38

924, 944 and 968 Servicing and repairs

924, 944 and 968 Servicing tailored to your requirements

With its roots stretching back to the original 924 in the mid 1970's which evolved into the 924 Turbo, Carrera GT and 924 S, the 944 was released in 1982, featuring the new 2.5 Litre engine with a complicated belt arrangement requiring specialist attention. Later a Turbo model was introduced, 16 valve variants and capacities of 2.7 and 3.0 Litre also evolved. Eventually in 1992 the model was replaced with the 968, featuring variocam variable cam timing and a new body design. Each model of 924, 944 and 968 requires its own attention to detail only available from an experienced specialist. If looked after correctly, there is no reason why this model should not last forever and provide the same driving experience as they did when new.

At JMG Porsche we are familiar and equipped to deal with with both the earliest 924, 944 through to the last 968. This includes the 924, 924 Turbo, 924S, 944, 944S, 944S2, 944 Turbo, 968 and 968 Club Sport. We are even experienced with the more unusual 924 Carrera GT, 944 Turbo Cup, 968 Turbo S and 968 Turbo RS.

Selecting the correct service for your Porsche can often be a confusing task for those who do not deal with it every day, more so if you only cover few miles per year, so we tend to recommend that when you need servicing ask us for our advice, we will be more than happy to ask you a few questions and reply with the ideal service for your Porsche.  If on the other hand you are sure which service you would like performing from the factory schedule, we are also more than happy to do so.

As part of the service your car will be inspected beyond the usual items listed by Porsche to be inspected. Should we find any problems, we will try to call you so it is important to make sure you are available by telephone and if you are unable to answer our call, to call us back as soon as possible so we can discuss the issues and if need be, so you can authorise any additional repairs.

We are probably more experienced at maintaining, repairing and modifying these models than anyone else in the UK and possibly the world. Our chief technician and managing director, Jon Mitchell is also the author of books on the subject and the technical advisor to the Porsche 944 registry of the official Porsche Club of Great Britain. Beyond this we have experience of building some of the most powerful 924, 944 and 968 turbo and non turbo Porsche in the UK and possibly the world. In short, we probably know more about these models than Porsche do!

 

Minor service - £199.20*

Major service  - £329.20*

Brake fluid replacement - £59.10

Including all parts and labour

 

Repairs at a reasonable hourly rate of only £79.95 per hour for cars over ten years old

 

Porsche Models over ten years old are considered as classic cars and as such in our ongoing commitment to keeping older Porsche cars on the road, we discount their hourly rate to what you see above.

* Servicing includes all parts and labour except for the cost of additional fluids which are only specified to be topped up in the factory service schedule, such as screen wash, or for additional parts or labour not usually required to complete the service, due to corrosion or other damage.

All prices are plus VAT at the standard UK rate.

 

Interesting service and repair information for the Porsche 924, 944 and 968 models.

Service interval - Even though the service book specifies six monthly and yearly services. We would strongly recommend that all Porsche models are serviced at least yearly or every 10,000 miles if more than 10,000 miles are covered per year to avoid expensive repairs and to potentially catch issues early, where they may be less expensive to repair.

Engine failures - Not as common as you would expect, we at JMG Porsche have never had to replace one of these engines due to wear, however we have had to replace many due to insufficient servicing and maintenance, but there are still worthwhile ways of avoiding unexpected large engine rebuild costs. One of which is proper servicing by a real Porsche specialist, which may not need cost as much as you think. There are also some ways to avoid unexpected bills by following some of our other advice bellow.

Brake fluid - Did you realise this should be changed every two years? Not doing this can cause problems with expensive parts within your car, such as the ABS pump or any part of the brake hydraulics due to water contamination as the brake fluid actually sucks moisture out of the air (hydroscopic), so even if the car is not used, the brake fluid must be changed every two years!

Water Pump - Often thought of as a part which fails with age, mileage and quite suddenly, leaving you stranded, our expert technicians are used to inspecting these during services, and so may spot tell tale signs of failure long before they become an issue, so saving you from the indignity of being broken down at the side of the road. A 944 and 968 Waterpump is also part of the cambelt drive mechanism, so it failing can cause serious damage to the cylinder head and engine as a whole.

RMS - Rear main seal - Something else you might see horror stories on the internet about, these used to be a real problem and Porsche re designed the part several times to arrive at the current design which is the only one we at JMG Porsche use. Like an IMS Bearing replacement, this is best performed during a clutch change, however on tiptronic models or on cars not needing a clutch, they can be changed at any time.

Transmission services - Not clearly noted by Porsche for when the transmission should be serviced and this vital expensive part of your car should not be overlooked. Just like your engine, the transmission is filled with oil/transmission fluid, which over time degrades. Not only this, but not many realise that many Porsche transmissions also contain a filter, which becomes clogged over time and can starve your transmission of lubrication, causing expensive repairs. We recommend all Porsche transmissions are serviced every 4 years or 40,000 miles, whichever comes soonest.

Diagnosis - Long has gone where cars had limited electrical equipment and a wiring diagram could be found in a manual from Halfords. Now the Porsche models have multiple separate computer systems, which all talk via networks, and many sensors to feed those computers with information about the world around it all tied together with many hidden wiring looms of thousands of wires and connectors. This can mean that in the event of your Porsche suffering an electrical issue, it is important that a Porsche specialist auto electrician is available, as we have at JMG Porsche. It is also important to understand that sometimes, finding the fault will not be as simple as plugging in a computer.

Drive Belt - Many of you may have had cars where a drive belt, timing belt or cam belt needs to be changed at a regular interval. Your Porsche model has a belt which should be changed every 4 years. Failure to do so can cause instant overheating, loss of power steering and damage to the engine very suddenly. We recommend you have this changed at least every 4 years.

Cam and Balance belt - The 924S, 944 (ALL) and 968 (ALL) have a cam belt and balance belt, which has to be set to a very precise tension and run across various pulleys, tensioners and rollers to function correctly, if these are not maintained with a new cam belt and balance belt every 4 years, and a new waterpump, tensioners and rollers (as well as front engine oil seals) every 8 years, the consequences can be catastrophic to say the least.

Brakes - The Porsche 944S2, 944 Turbo and all 968 models are fitted with Brembo callipers, which overtime suffer from corrosion build up which can cause the pads to stick and bind up within the callipers or even make it difficult to fit new pads. When this happens the calipers require a service rebuild of the slider plate mechanism, which needs to be performed by a specialist with the right experience, techniques and tools to make the repair more than a very temporary one.

Heavy clutch? - A heavy feeling clutch which is stiff to use is not normal on a Porsche and often a sign that the clutch has almost worn out. Ignoring this can cause further damage, such as to the dual mass flywheel and clutch fork.

Alarm system - At JMG Porsche we are experts of all Porsche security systems and have reverse engineered all the various control units. This not only means we can program new alarm control units and keys to your car, just as the main dealer can, but in some cases we can repair your old alarm control unit and keys, or in some cases recover your old keys to be used on the new alarm control unit, which is a service unique to JMG.

Alarm system causes - In most cases the cause of alarm control unit failure is water damage, we can perform modifications to your Porsche model to help mitigate the chances of this happening to your Porsche.