Distributor help needed

[jbs3]

I have an unmodified 81sc. While replacing my blown airbox, i have been doing a lot of neglected maintenance. One discovery is that the Vacuum Can (2 way actuation, both advance and retard) on my distributor is totally shot. The activator arm is frozen and will not move in either direction. Applying vacuum to either of the nipples does nothing. The retard side of it seems to be clogged full of rust and the nipple is loose in the hole. I don’t believe it can be salvaged.

Given that the correct VC is NLA and the cheapest used one i can find is like $600, is there an acceptable alternative. I live in a state where there are no emission requirements for my car and have read that the RETARD FUNCTION on the device is primarily for meeting emission requirements.

Can i use some other model of Vacuum Advance or is there another solution to replace it altogether.

[icarp]

I think this is the finest option for air cooled 911 engines

https://123ignitionusa.com/porsche-911-bt-tune-3-0-sc-works-with-hkz-6-pin-bluetooth-programmable/

Ian

[arbita1]

While the above option looks interesting. When I rebuilt my engine I found a similar problem with my distributor. There is a rebuild kit which worked for me. The vacuum pod was not working because the arm inside the distributor was seized. I was able to get the vacuum advance working but not the retard. You don’t need the retard anyway. Maybe give that a shot before spending the money.

[jbs3]

Thanks guys. Arbita1 where did you get the rebuild kit?

[eastbay]

Someone posted awhile back that Vertex had the vacuum units, same as Mercedes

[dreichman]

Another option may be having it rebuilt professionally. Parts Classic rebuilds them for a reasonable price and their turnaround is pretty quick.

[911obgyn]

They have parts for the distributor too if you want to tackle that job.

[AndrewCologne]

Originally Posted by jbs3

I have an unmodified 81sc. While replacing my blown airbox, i have been doing a lot of neglected maintenance. One discovery is that the Vacuum Can (2 way actuation, both advance and retard) on my distributor is totally shot. The activator arm is frozen and will not move in either direction. Applying vacuum to either of the nipples does nothing. The retard side of it seems to be clogged full of rust and the nipple is loose in the hole. I don’t believe it can be salvaged.

Given that the correct VC is NLA and the cheapest used one i can find is like $600, is there an acceptable alternative. I live in a state where there are no emission requirements for my car and have read that the RETARD FUNCTION on the device is primarily for meeting emission requirements.

Can i use some other model of Vacuum Advance or is there another solution to replace it altogether.

Hi jbs3,

look here – especialy at point 6:
https://nineelevenheaven-wordpress-com.translate.goog/wartung-des-verteilers/?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=de&_x_tr_pto=wapp
(Google translated)
There its described how to loosen the sticked plates where the lever/arm of the vacuum unit is attached to.
If all bushings etc. are ok without any rdial or axial play then in most cases a simple deep maintenance of the dizzy as described in the link is enough and the ticket to success.

[arbita1]

Originally Posted by jbs3

Thanks guys. Arbita1 where did you get the rebuild kit?

I thought I got it on EBay but I don’t see it there anymore and google search only comes up with PartsKlassic.

It looks like the vacuum pods are now available again too. They were no where to be found a few years ago when I rebuilt mine.

[jbs3]

Thank you to everyone who’s offered suggestions. Just to clear up some apparent confusion, My problem is with a completely frozen/not working vacuum canister on the side of the distributor. I have disassembled the actual distributor and cleaned and lubricated everything. It is actually in very good shape and is not the cause of my vacuum advance issues.
When i looked to find a replacement vacuum canister it showed as no NLA. So i was asking the experts what my options were.

[sigchuck]

I am far from knowledgeable about distributors, but I do have an 83 US-spec SC with dual port vacuum can and have spent countless hours reading Pelican threads (have also stayed at a Holiday Inn).

My understanding is that the retard function is emissions related and that disconnecting it has no effect on performance and will cause the car to run slightly cooler at idle (my further understanding is that it only retards at or near idle).

I disconnected mine and plugged the line coming from the throttle body and the port on the distributor a couple of years ago for the heck of it and have noticed no ill effects, so maybe you can rebuild yours with the advance only can? I was referred previously to Aaron Burnham for this type of work by Supertech. I can't find his number, but I think Supertech could probably give it to you. PK is an awesome business, but in my experience they're generally too busy to talk hypotheticals with customers and trouble shoot - more just a "no we don't have that and we only rebuild to factory spec" (not a knock - I'm sure they're hit up with multiple random questions and what-ifs on a daily basis).

The only potential downside I could see would be it's no longer factory correct and it may hurt on inspection depending on how strict Florida is. I don't think it would impact performance though.

[Matt at Pelican Parts]

I have been digging to see if we can get just the vacuum diaphragm but unfortunately I'm not having much luck. I do see there is a rebuilt unit with a core charge available here:
https://www.pelicanparts.com/More_Info/930602021FXOEM.htm?pn=930-602-021-FX-OEM&bt=Y&fs=0&SVSVSI=796

It seems on some aftermarket distributors they actually delete the vacuum advance/retrard
There's a thread with some decent info on it

[AndrewCologne]

There are many BOSCH compatible dual port vacuum units of those years listed on ebay etc.
What you could do is search for an offer and check there the named BOSCH part number. Do a search in the internet how its part number specific behaviour at the given vacuum values is.
Compare that vacuum curve with the original BOSCH one and if ok, ... try.