911 sc dizzy vacuum advance part number

[scott.k]

hello,
I think my dizzy vacuum advance is fried, the porsche shop that i took my car to a while ago said it was, and at smog the guy said it wasnt advancing properly. But it might be the rotor spring or something else, and I would like to check those out first.

1) what should I check first?

2) can anyone tell me what the 911 sc dizzy vacuum advance part number is?
if its NLA, then if people could tell me what other parts might work in place of it. there are lots of new advances for VW dizzys and other cars that look identical and seem like they would work.

thanks
scott

[scott.k]

here are some part numbers that seem like they might work

Bosch 07217

Bosch 07065

basically a bunch of bosch ones that have a 7 as the first digit, a 1-3 as the second digit and then some more after that.

would any of these fit? there are a ton of new ones on ebay
thanks

[jason2guy]

i think the 80 is just advance- no retard. one that will fit is one from a six cylinder engine running a stock bosch dist. i would try one from an older 911. if thats not avail go to pick ur part and get one from a 6 cylinder running a stock bosch dist. good luck

EDIT- your unit is a retard/advance. you could buy a brand new unit for the -89 930, itll fit and work fine

i had the same issue. i got a unit at pickurpart from a mercedes 280e and with some delicate repositioning of one of the
hose connections it works great

[Pazuzu]

Bosch HEI - Holdenpaedia

Any vac advance will bolt up, but you need the right throw and spring level for it to work properly. Pull yours, find the 3 digit info on the arm based on that link, and start researching from there.

When you find a source tell me, because mine is goobered as well

[jason2guy]

actually ANY vac advance will NOT bolt up. they are all different, and im just speaking of the actual fitment to the dist body. example- a vac advance made for a 4 or 8 cyl distributor wont fit on a 6cyl dist.
i learned the hard way. what sucks is bosch discontinued our unit but continues to make the units for much less desireable cars

[Pazuzu]

Let me rephrase that.

Any vac advance unit that looks generally like the one that is on there will bolt up and work. The housing was standard across a wide range of cars and engines. The thing of interest is how far and how hard the advance arm moves, not the model number. If you can get a unit from a different car that has the same throw and "springy-ness" as stock, then it will act the same.

[tyro]

My vac advance was just rusted/frozen. Took the dizzy apart courtesy of a thread on this list, and took a lot of time to make sure it worked.

If the pod holds vacuum, you're probably good. It should move the internals with a little bit of vacuum applied, doesn't take much.

My distributor part number is 0 237 301 007. Car is an '80 RoW.

[jason2guy]

the right part is bosch 07180 or 1-237-122-763
bosch has 2 different #'s

[brads911sc]

or you can send it to Barry Hershon for a re-curve / Vacuum delete and it will feel like you put carbs on your car... Just sayin. I have spent ALOT of money on my car and by the far the one with the most bang for the buck was the dizzy recurve with Vacuum Advance delete... this would be true for any 80-83 SC which had a advance curve for efficiency not performance.

[Pazuzu]

Originally Posted by brads911sc

or you can send it to Barry Hershon for a re-curve / Vacuum delete and it will feel like you put carbs on your car... Just sayin. I have spent ALOT of money on my car and by the far the one with the most bang for the buck was the dizzy recurve with Vacuum Advance delete... this would be true for any 80-83 SC which had a advance curve for efficiency not performance.

What kind of turn around did you have for that? I'm stuck at work and can't call Barry right now, so I figured I'd ask you. My engines coming out this weekend for a 3 week overhaul, it's the only chance I'd have...

[brads911sc]

took him less than 3 weeks... incl shipping. It was fairly fast. I think he had it less than a week.

[scott.k]

Ok, thanks. i will try to test out my vacuum advance unit and see if i can fix it. if not, maybe recurving my dizzy and scrapping the vacuum unit would be the best way to go.

recurving is just different weights and springs?

thanks
scott

[brads911sc]

yes. he will also clean it and replace any broken/work out parts. blast the outside, use all new screws and hardware. money well spent since these are usually neglected.

[scott.k]

i bought an msd 6530 a while ago that ive been using on the stock ignition curve thus far, so I guess this is a good time (with my vacuum advance currently not working) to stop being lazy and lock out the dizzy and set up a curve for about 92 octane on the msd. this can actually be a performance upgrade rather than a problem

[arbita1]

Originally Posted by scott.k

i bought an msd 6530 a while ago that ive been using on the stock ignition curve thus far, so I guess this is a good time (with my vacuum advance currently not working) to stop being lazy and lock out the dizzy and set up a curve for about 92 octane on the msd. this can actually be a performance upgrade rather than a problem

I might be in the same boat. Did you get any idea on what this costs?

[scott.k]

Originally Posted by arbita1

I might be in the same boat. Did you get any idea on what this costs?

I actually bought the 6530 and high vibration coil a year ago from jegs on a combo christmas sale, and i think it was get the coil free and i got free shipping too, or something like that. so i think I was just paying for the 6530. anyways, ive been using it as just a normal CDI and have only set up the rev limiter feateure, but now that I need to do something about my distributor (the vac advance isnt working) its a good time for me to lock out the dizzy and set up the MSD.

Anyways, to answer your question, I think I bought it for about $350 with the high vibration coil shipped.

I also wanted to add that ive been reading up a lot about the locked dizzy's, and their hugely popular in the drag scene (american muscle). they love locked dizzys because its smoother and can get you more power when drag racing. Downsides are crappy low RPM driveability, high idle, terrible gas milage, and inability to start the car, especially when already warmed up. this is why msd and other companies made their retard curve units, really as a solution to these problems. hence the fact that the MSD "retards" the timing, not advances, and the msd unit i have also has the option to wire in a temporary push switch that allows you to spin the starter motor with the ignition essentially "off", to allow your starter motor to get the engine spinning.

I also read up on a guy who did something that I love, I really think its an awesome idea, and I will either do this or just straight up lock it out.

actually, forget it, ill just copy it from the mopar forum i found it in
"I put real light springs in my cars that are just strong enough to pull the centrifigal weights back when the motor shuts off. At idle they are at full advance. This eliminates the hard starting being talked about. "

Super light springs would allow you to do the same thing that the msd temporary push switch does (start the car) so maybe ill just lock it out and then make a retard map on the MSD

lots of other cool features on the MSD too.

btw, if anyone has locked their porsche dizzy before, please let me know, because the only reference I have for doing this is reading up on american car threads, im sure the dizzys are all similar, but im not positive.

[scott.k]

to be honest, it seems like their are a lot of ways to "lock out" the dizzy, and im going for the easiest and least permanent one, and based on the quote i took from the mopar forum, maybe just removing the weights would work?

[scott.k]

Hello,
Im thinking of an idea that I am taking from sigurd
first off, does anyone have a map or numbers that tell me when the vacuum advance kicks in to advance the dizzy timing? is it all the way through the rpm range? Does it contribute to max advance?, or does it just help it get to max advance faster?

2nd question:
with my vacuum advance gone, could I turn the dizzy (advance it)/(compensate for the broken vacuum) to get it back to factory spec? I dont care it it is too advanced at some spots, just if I could get the timing back to where it should be at the points where it would suffer the most from the loss of vacuum advance? (the parts the will be too advanced,if any, i can retard with my MSD ignition control)

I know this is confusing as heck, probably due to may lack of knowledge, but if anyone had a graph/ an answer to my first question, I could probably figure out the second question.

heres the thread, look at the first post (thread topic)
and the second post
MSD6AL-2 Locked distributor

thanks a lot for the help
-scott

[scott.k]

anyone? where in the rpm range and how much does the vacuum advance kick in?

thanks
scott

[psalt]

Scott,

The vacuum advance has little or no effect at idle. It is designed to add 5-10 degrees of timing at part throttle cruise. It is most active at around a 50-60 mph cruise when there is around 18 inches of vacuum.

Vacuum advance has no effect on measured performance. It is a load based system, light load it adds advance, full load, no added advance. You cannot compensate for it by increasing the static setting, you will have too much advance under WOT and it will ping like crazy.

If you drive your car 100,000 miles a year and fuel economy is your goal, buy a good used distributor, retard the timing to 3 BTDC, set the mixture to 55 duty cycle, run it on 87 octane, and put on a set of steelies with 165 tires at 45 psi, this will give you the lowest cost per mile.

Your Mopar description makes no sense to me. A locked distributor on a drag race car is a reliability issue, not a performance adder. The reason MSD makes electric retards is to get the motor to start, it will kick back if locked at 38 BTDC. There is little or no benefit to recurving a stock distributor with a stock lambda CIS, unless you are replacing a worn out distributor. The small runner motor cannot handle more than a few extra degrees of timing and bumping the static to 7 or 9 and running premium is about all you can hope for.