camshaft/KEY/sprocket

Bill A · 11-12-2005, 09:17 AM

Has anyone ever heard of the camshaft key-slot wearing out to the point that the dealer service advisor would say don't get it very hard. My dealer replaced the t-belts 8,000 miles ago, and now I have this issue. I believe the tect. did the work wrong by replacing the belts by removing the cam sprocket.
Anyone else hear of such of problem?

Britwrench · 11-12-2005, 10:42 AM

I have seen the cam sprocket key loose when someone attempted to tighten the cam bolt incorrectly. To replace the cam belt the cam sprocket does not need to be removed.

You need to define what exactly is happening and the current fault. What does your invoice actually state?

Bill A · 11-12-2005, 04:13 PM

I will get back to you sunday with more.
Thank you Bill

Bill A · 11-14-2005, 07:21 AM

Hey Britwrench,
To answer the question what does the service invoice say? " The end cap of cam shaft keyway has worn into the cam distributer rotor and became lose. Replace end cap and cam seal, Tighten, Its ok now but it will need a new cam ".
More info you may need;
Appox. 8,000 miles ago all the belts were replaced, and the 2,000 mile check was done per warranty requirement.
I have always taken my car for service to this dealer. Unfornatuly the Tect. who worked on it has retired. He was great! Now a new Tect. has worked on my car. I took my car in to have the T-belts replaced and to have a aftermarket alarm removed because it was killing my battery in a few short days. I picked up my car and started to drive away and the shifter started to vibrate alot at appox. 2200-2500 rpms. I turned around and the service advisor and the tect. test drove it. They said "that a rubber part had worn out and not worry it can be replaced at the 2,000 mile check of the belts". Ok so I drive away again and listen to the engine for awhile, I then turned on my stereo and it did not work. I got home and called my service advisor and told him about the stereo. Remember the alarm item?. Well he said that "his guys are not stereo people and to take it somewhere else". I looked at my car for awhile and was able to find the problem. The tect. had cut the end off the wire to the amp. I installed a new end part and secured it the power supply and it worked.
Now comes the 2,000 mile check up of the belts. I called for the appointment and remined them of the shifter part that also needed to be replaced. All went well and I drove away again, What happened next leads me to belive that the tect. working on my car is not to bright. I shift to 2nd. gear and the shift knob comes off in my hand... at this point I dont want this guy near my car. I get home look at it and install it myself.
So anyway, 8,000 miles go by ( 6,000 after the belt check ) I hear a noise in the engine. I was short distance away from the dealer so I drove there and dropped it off. 2 weeks later and no calls from the dealer I called them. " Your car will be ready to pick up today". So the service advisor says "I have good news and bad news" thats when I hear the bad news about the cam/key problem. I said whats my options? He said "$5,000 for a new head or sell it" At this time to hear $5000 was a major shock to me. It still runs well. My advisor even spoke of other places to take it, that he trusted, even saying "that the guys there were not quailtfied to work on this type car". I don't want to sell my car but after a coment like that I don't see a reason to keep it, mostly because the nearest mech. would be about 200 miles away.
I have come to belive the tect. removed the cam sprocket to do the belt service and with the new belt under tenison tried to reset the cam sprocket causeing the damage to the cam shaft.
So do you think that could have caused the damage or just good old bad luck?
Thanks for your time and any ideas you may have.
Bill 86 turbo

rudidelange · 11-16-2005, 05:52 AM

The cam is very hard metal and it would be difficult to damage. I would guess that it would be easier to damage the sprocket.
It would be about impossible to reset the sprocket with the belt tensioned and with the key in place - unless force was used.
I would remove the belt, the sprocket and look at the so called damage to the cam. I am sure that an engineering shop would be able to re-cut (slightly) enlarge the groove on the cam that holds the key and also then to cut the groove in the cam. A larger key will have to be made from appropriate hard metal to fit the larger groove in the cam and the sprocket.
Selling the vehicle is a no-no and 5000 for a new head is also rediculous. If there is any damage I am sure that a good engineer / fitter / turner would be able to do the repairs.
Get another mechanic
Good luck

Bill A · 11-16-2005, 06:49 AM

Thank you for your reply.. Yes I agree very much with what you said, however do you think the work can be done with the cam still in the car?.
Also I do think the mech. did force the sprocket onto the cam shaft causing the damage. My service advisor without trying to get himself into a pickle I belive, is trying to tell me something without realy coming out and saying it. The more research I do may help somehow prove this to be the case. Thanks again for any and all useful infomation you or anyone else may have.
Bill 944T

rudidelange · 11-18-2005, 02:46 AM

No, Machine cannot be done with the cam in the car.

Britwrench · 08:45 PM

Ok, let's try and work through this one issue at a time. It might have been better to seperate each problem.

1. The cam problem

The only way the rotor drive gets loose is if the bolt wasn't tightened or tightened incorrectly. I still don't understand how it was noticed, on a belt re-tension there is no need to remove the distributor cap: so how was the looseness detected? There is way more to this story, both the "before" and "after"

If the cam is worn then you need a new cam. Used cams are available and reasonably easy to change. I'm sure George at 944ecology would have one. I do not understand why a cylinder head would be required.

My thoughts are that you are taking the car to a Porsche dealer...and they are hinting they are not interested in working on cars that are out of warranty and more than a few years old.

This is very common for many makes of cars..."well, sir, I see your car's warranty is expiring, our sales department has some new models you might be interested in" is the attitude today.

2. Alarm

The stereo/alarm problem is a two-way situation. Who installed the alarm? Are they still in business? Is the alarm manufacturer still in business and the wiring diagram for YOUR car available? If not then it's is both expensive and time consuming to remove aftermarket alarms.
The tech made a mistake, it happens and the dealership should have solved the problem for you. To go one step back, the service advisor should have explained that the shop does not work on non-Porsche installed parts (if that is what it was).

3. Vibration

That should have be diagnosed and reported to you. There are many reasons for vibration, from collapsed engine mounts to worn clutches to balance shaft belt pulleys being incorrectly aligned. Diagnosis takes time and we charge the time it takes to find the cause. The dealership should have given you a written report.

I have no clear idea of what actually happened, it may go back some time to a previous repair. It can be fixed, but you need to find a trusted local Porsche experienced shop. If there is not one within reasonable distance and you are not in a position to work on it yourself, it's time to decide if you can keep the car or not. Owning an older Porsche (and 944s are old) means that the owner has to have both knowledge and understanding of their own car.

PM me if you have more information or need further advice

Bill A · 11-19-2005, 08:21 AM

#1 cam problem; The loose part of the problem was noticed when driving back from getting a hair cut. At a stop light at idle, the engine compartment all of a sudden started to have a metal tapping sound. My first though was oil pressure and looked at the gauge, it was ok (psi I dont recall, but looked normal). Water temp. had not changed, no smoke ect. Thats when I took the chance and drove it to the dealer a short distance away and dropped it off. When I dropped off the car the advisor had his guys take it into the shop and said with a stearn voice "Not to Rev the engine" and just park it. He had listen to it and I believe he knew what it was. He used to race 944turbos and is quite knowledgeable.
#1a; New head? No, I was told the head had to be removed to replace the cam. How true I dont know.
#1b; Yes it is a dealer. I also think it has changed ownership and maybe why the mech. that was there has left. The place used to be more friendly and now is somehow cold feeling. Although the service advisor has been great to me for many years.
#2; The alarm was on the car when I bought it. It was an aftermarket unit and looked easy enough to remove and could have done it myself. However I dont try to do much of any work on it myself for the simple reason I dont want to screw anything up. I have left it to the pros. Once the alarm was removed the battery has not died. At the same location that the alarm got power the stereo amp got power. The tect. cut the end off of a 6 gauge wire and just left it there with no end on it. It lead to the amp installed in the back portion of the car. The stereo and amp are of course aftermarket and were installed at a shop by the car owner before me. I was not told anything about the dealership now wanting to work on my car for any reasons whatsoever, and did not ever expect I would.
#3; Vibration; I was the person who noticed the very bad vibration when I picked up the car after paying nearly $1500.00 to have the belts, water pump, alarm issue, new battery ect. and drove down the street. I turned around right away and had the service advisor get in and drive it. He took the mech. with him and returned soon. They said it was rubber part of somekind at the shifter that needed to be replaced and can be done at the 2000 mile reinspection and not to worry. You said in your note, Balance shaft belts, that belt was also to be replaced at the same time. This begs the question, was it realy the so called shifter part or a balance shaft belt problem? The vibration was only at a rpm range of appox. 2200 to 2600 rpms and then would go away.
The written reports I get have been very vague and only to point of small amount of useful infomation.