A sad tale

[Ian67912]

As you are all probably aware the heater is not the 912's best feature. I bought an electic heater to supplement mine. It arrived the day that I was due to do a 500 mile round trip. I'd try it out, what's the worst that could happen, it'll only blow a fuse. WRONG!! It blew the dynamo up.
Anyway to cut a long story short I had to leave the car at a garage and get the train home, 150 miles. I collected the car two weeks later complete with replacment dynamo and regulator.Total bill was about £250, which I did not think was too bad, but I suppose I could have bought a nice warm coat instead.
When I got home the engine was covered in a very fine oily film. Due to the timing case oil seal leaking, probably due to re-adjusted fan belt. So, any tips on replacing the seal, can it be done in situ or does the engine have to come out?
Cheers Ian.

[C. Clark]

Ian,
I'm sure I'm showing my ignorance but what's a "dynamo"? Ah maybe the generator...
Chas.

[Ian67912]

It sure is Chas, but it wasn't "Generating" very much by the time the new electric heater had finished with it.
Cheers Ian.

[jac912]

Ian...I've often wondered why the great P Engineers didn't use an electric heater. Did you wire it direct to the battery or with someting else...and what was the current draw?
Jim in chilly New England.

[Green 912]

Sorry about your generator. Yes the pulley seal can be replaced with the motor in. You will have to remove the pulley tin and the big tin as well. Remove the pulley and carefully pluck the seal out. There is a very nice seal installer that has a bolt that threads into the pulley bolt hole and then has a plate that presses the seal in. You can still press in a new seal without the kit. You can use a seal press disk and the pulley bolt to press it in.
Before you start to replace the seal clean the pulley with Brake Klean (or the UK version) and run the motor to see exactly where it is coming from. It is common for the pulley to leak oil through the KEYWAY. It will come out from under the pulley bolt and show on the front of the pulley. If that is the case remove the bolt clean everything with solvent and put a thick bead of RVT sealant on the shoulder of the pulley bolt and torque it up.

Porsche didn’t use electric heat because it is very inefficient. You would need a BIG generator and much HP would spend making little heat when there is a gob of waste heat being dumped from the motor already. You would be converting gas into heat (combustion) and then into motive force. Much energy is lost as the motive force is converted into electrical energy. The electrical energy would then have to be converted into heat with yet even more energy loss. You loose energy at each step and you started with heat in the first place. The trick is getting the heat into the driver’s compartment. Most low or no heat problems stem from the flapper boxes and the heater valves not being adjusted well as it can be a bear to get all 4 cables right.

[Green 912]

Forgot to add.

Check the belt tension. If it is too tight it will eventually damage the generator and it could damage the pulley end crank bearing as well. If it is too tight then an old stiff pulley seal might leak where a newer one might not.