psears

Hello,

So what's the last word on rebuilding/replacing suspect Bosch distributors? I have an '81 SC w/Weber conversion, and the distributor is supposedly re-curved to the '78-'79 specs, since I no longer have a vacuum advance. I get back-firing that seems to come and go however, (I'm changing the CD box next if this doesn't work.) New ones are prohibitively priced. Does'nt ANYONE (MSD, Mallory,..) make a high-quality cheaper replacement? Who do you trust to check it out and rebuild/recurve it? Are any reputable shops doing this anymore?

Thanks!

p.s. is crank-fire worth the money?

Jeff Curtis

IMHO, the Electromotive HPV-1 ignition setup aka "crankfire" is the ticket in my book. I had a 1982 SC with 9.3:1 pistons, webcams, enlarged throttle body, B&B FULL exhaust setup with headers/muffler and the Electromotive setup.

I had all that stuff mentioned done before installing the Electromotive system...that was done well after the other mods. It really "woke up" the car, no lie.

I got a custom pulley with crank trigger and distributor hole blockoff made by a guy out the California that specializes in these conversions for Porsche, nice work - his name is Richard Clewitt.

It sounds like your car, especially with the engine mods (Webers) and I'm sure there's more than you mention, being that you do have Webers installed, could benefit from the HPV-1 setup!

fredseebeck

I just rebuilt my distributor since the mech. advance counterweights were frozen. It is fairly involved disassembling the unit with all the tiny screws and pieces to remove before getting at the guts of the moving parts.
My stock 79 911SC unit had a vacuum retard unit that retards timing off idle and the mech advance then kicks in as revs increase.
If your unit advances properly why change it. Just check that all the mechanisms function properly on the distributor. The only other thing to worry about is whether the shaft bearings are worn allowing the distr. shaft to wobble. This will be evident if you grab the shaft by the rotor and can rock it back and forth.
You need to drop light weight lube oil under the felt pad on top of the shaft underneath the rotor every now and then to keep the counterweights from seizing up. This was the source of my troubles.
Good luck..... <img src="graemlins/roflmao.gif" border="0" alt="[hiha]" />

Toddimus

I just added the oil under the felt pad in my 81SC distributor. Works like a charm. I am still skeptical about the mechanical advance though. When it is at idle, sometimes the timing will retard by about 5-10 degrees, but after a rev it returns to what is should be at idle. Does anyone have an exploded view schematic of the distributor? I'd like to disassemble it and check everything.

Thanks in advance ( no pun intended )

Jdub

Disassemble and clean the distributor. It is not very hard to do, just be careful of the bits a pieces. Make sure to inspect the plastic sheathings that sit on the pins on which your springs will hook. Make sure to get a piece of soft pin metal that you can use to pin the pinion back on to the shaft.

Do a Search at Pelican for more information.

Jw

PS: The early '78 dist. uses a different pitch pinion than later ones, just FYI. Keep this in mind if swapping around (not recommended).