Got my 944 Turbo back, after belts/ water pump...

[coupe]

I could hardly sleep last night, just thinking about getting the car back after the timing belts, water pump, etc, etc...

So I pick up the car and take it for a test drive, this is what I found:
The car has awesome power, but the vibration around 3000 rpm, comes through the engine all the way to the gear shifter and exhaust shaking all my fillings off my teeth.

I am so disapointed, so I take the car back and I take the guy on a test drive, and he tells me that he did it all as per the book, and this is normal, and that the problem is the exhaust system that is leaking, and that I should get a new exhaust system.

The heat shields that protect the engine mounts are all loose and rattling away, banging on anything close by.

Now here is the catch, this guy that did this job, has been working on Porsches for over 10 years. He said that after 1000 kms, when the car goes back, that he will make the final adjustments....

I hope anyone out there can shed some thoughts on all of this.

Thanks

[afx]

It sounds to me like the balance shaft rollers are off. When I put my balance shaft belt on wrong I could feel a vibration start at around 3000 - 3500 RPMs that made the whole car vibrate a whole lot.

[Lawrence Coppari]

Your mechanic did not get the balance shafts lined up properly. I've made the same mistake myself. The vibration occurs around 3K.

[coupe]

Could it be that maybe, he looked at the workshop manual for a different model 951 and made a mistake?> Say, would this also be possible?

[overkill]

I agree boss, check your balance shafts. Rule em out.

[Frank B]

yip

[coupe]

I took the car out again, this evening and the vibration starts at about 3800 and clears at about 4200. This vibration is incredible. I even have more parts vibrating than ever before.

I have also fitted new tyres, Pirellli P 6000, the old tyres were hanging by threads....

[Lawrence Coppari]

See if it does it without the car in motion. Just rev it to that rpm with car stopped. That rules out tires, etc.

[coupe]

Hi Lawrence, I got new tyres. I needed them badly.

I de-clutch the engine while crusing, and it is still there at about 3800 to 4200 rpm. I'm going to see my other 944 mechanic, and let him drive it, and see what he has to say.

[stray15]

balance shaft gets my vote

[944pete]

It's definitely the balance shafts. I did the same thing when I did my belts and it's easy to do the first time you do this job. If your mech has been doing Porsche's for 10 years then he hasn't been paying attention. Each sprocket has marks labeled with a 'U' and an 'O', the upper shaft is lined up on the 'O' and the lower on the 'U'. If you put both on the same mark you get the bone rattling vibration over 3000 rpm. There's a pic in the Haynes manual and I believe there is one on the Clarks-Garage website. Take the pic and the car to him and demand he does it right.

[coupe]

Hello all, the sun finally shines back on my 951, Yahooooooooooo..lol
I got it back today from the performance workshop, and as suspected the balance shaft was out. So, Mr. Udo the workshop manager and owner of a 951 convertible, knows these cars like the palm of his hand, got it all redone and it drives like a dream.

I also got my injectors cleaned by Bosch, they used an ultra sonic method, and re-fitted with new o-rings. I also changed the distributor cap and rotor along with new 8mm performance wires.

Mr. Udo, alighned my exhaust system, so most of the rattle from the heat shields are gone. On the way home, got my a/c gas charged up too.

I feelllllllllllllll goooooooooooooooood.....! Sooooo Gooooood , I gotta youuuuuuuuuu.....

[Frank B]

sweet Coupe..