911SC distributor question - seahawk, please delete this thread. thanks
 

yea I know this isnt the tech section but I know there are a lot of SC owners here and this section seems to be more active...I have spent so many hours looking for this simple answer that im going crazy

Can someone please tell me which vacuum hose NIPPLE off the distributor is the retard and which is advance?

I want to confirm that my hoses have not been on backwards for the almost 20 years i have had the car

the hose (below) on the right (red) has strong vacuum when I increase RPM ---I would assume thats advance....is it on the right nipple?

The hose on the left (blue) has good vacuum at idle....is it on the right nipple?

http://forums.pelicanparts.com/uploa...1691608054.jpg

Post #2 here suggests to me that these hoses are on backwards

http://forums.pelicanparts.com/porsche-911-technical-forum/305604-sc-distributor-vacuum-question.html

As does this

http://forums.pelicanparts.com/porsche-911-technical-forum/616910-82-911sc-distributor-vacuum-line-connection-question.html

And this guy just answered my question so

this can be deleted unless anyone wants to tell me something

http://forums.pelicanparts.com/porsche-911-technical-forum/1144485-1983-ignition-timing-vacuum-hose-question.html#post12063914

Sorry, nothing to add.

It seems to me that reversing those hoses would have a strong negative effect on performance. We'd like to hear how this engine runs once everything has been re-sorted.

I can tell you. --- just tried and I have a new issue

i posted this to my tech forum thread

Something aint right

I switched them around and immediately the idle was way too high

Brought the ide down to 950 and drove about 3 miles. Tach need doesnt come back down. Stops at about 1,500. pulled over and readjusted idle to 950 and drive again. Now needle drops to 0 and car stalls in intersection :-)

my intermittent slight power loss at 2000 RPM is gone (which is what prompted me to start learning about distributor because car always seemed perfect until this spring) though but something is not right now

__________________

on a good note, the car does run different/better. I only drove it around the neighborhood city streets but definitely noticed it gets up to speed quicker and seems to be moving faster for any given RPM compared to how it was.....

Its not a huge difference but I can tell that it is now improved

Pull the dist cap off and make sure your advance mechanism moves smoothly, any play on the shaft? Does your car have any valves inline with the vac lines from the dist?

There is a little pad under the rotor for lubricant for the advance mechanism. I remember my cap was brutally hard to get the clips off for some reason.

No not that I’m aware of.

The idle issue seems to have calmed down and I’ll set timing in a day or two and see what happens

I wouldn't drive it until the vacuum hoses are correct and specs are known.
The 3.0l is an excellent engine but.

Grady Clay aka Early S man (?) with his extensive knowledge of tech literature contributions doesn't seem to appear on the Pelican Search...


My rusty knowledge of CIS is limited and the following could be entirely wrong:
-One hose is definitely a timing advance hose tied to RPM. More speed equals more vac to turn the points plate.

-Vacuum retard balance of the advance mechanism (due to load at any rpm) should come from the intake manifold I would guess. Highest manifold vac is at idle. 18-24 IIRC for a good running engine. I haven't wrenched in a while

-There is divot hole in the throttle plate to allow some air through. There is a manual air bypass screw which must be set correctly. 1.5-2 turns out from seat or something. I don't remember at all. There is a large air hose bypass controlled by solenoid tied to the computer.

-Fuel injector seals and especially the CIS boot have to be changed occasionally to prevent air leaks. There is a VW/Porsche tool for the first. Be careful with this and don't break anything using leverage. They will be like rocks after decades in a hot engine.

-There is the Warm Up Regulator which puts pressure on the the fuel plunger in the CIS system. I think that is heat sensor/electric but could be wrong.


Lubricate everything possible, a dab of marvelous mystery oil in the gas, and start from from scratch would be my WAG.

I have it hooked up right now.

You wouldn’t drive it until it was right? Well, I drove it almost 20 years and 35k miles with it backwards and had no idea so……even if still wrong, probably wouldn’t matter if I drove it one more day

But I’m good now

One other thing to consider, there is also mechanical advance built into the dist assembly, likely should be cleaned and lubed about every 10 years.

That drop in idle speed could also be caused by your auxiliary air regulator acting up.

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OK, this probably doesn't apply and I'm a mechanical idiot and don't know anything about 911 dizzys...

But when I had similar problems in my 356 I discovered that dad's prior mechanic used a VW 009 distributer intstead of one with the proper advance curve for the 356C engine (a VW 050 is fine, meant for the alcohol powered bugs).

So... I have to ask.... do you have the right distributer in there? With correct points/condensers/etc ?

Wouldn't you normally confirm the advance by revving the engine while you used a timing light?

Yea I have the original distributor

And yes you confirm advance is working with timing light

But can confirm vacuum is ok at the hoses by unplugging and using a finger at the hose opening.

As stated above, I confirmed mine were installed backwards by the prior owner

https://forums.pelicanparts.com/porsche-911-technical-forum/1144485-1983-ignition-timing-vacuum-hose-question-2.html#post12064425

I’m all set now. Just need to check my timing this weekend and put this behind me.

Unfortunately I’ve experienced almost 20 years with my 911 not accelerating as optimally as it should. I’ve never driven another air cooled 911 so I had no point of reference and there was no obvious issue. I only discovered the hoses were backwards when I started diagnosing a power loss under light load at 2k RPM. Power loss is gone now. I believe a combination of the distributor mechanical advance needing lubrication and not having the vacuum advance properly connected to assist with low load advance was causing my power loss at 2k RPM. If that power loss had not happened, I would still not realize the hoses were backwards and I would be ignorantly believing my 911 performance was normal.

A good learning experience and if you have a late SC with 2 vacuum hoses at the distributor, it is best to check they are connected properly

Two different people.

Early S Man died a couple years before Grady.

Major faux pas there. Shameful of me. They were true legends outside the tech forums as well.
They should be go-to stickys.

(Cat missing. Email inaccessible. Computer acting funky. Got frustrated. Made the mistake of shvodkas. That's no good at all.)

FWIW a MityVac hand pump comes in handy for manually checking vacuum operations.

Find a good shop that knows air-cooled 911s, you're not qualified to be working on your car. I don't say this to insult you, people's talents lie in many different areas. Yours do not lie in mechanical things.

Wayne started this website in order to encourage everyone to work on their own Porsches so that he could sell more parts directly to customers but the results have been untold numbers of butchered and ruined cars in the 20+ years I've been here. Determining which diaphragm in a vacuum unit move the distributor in which direction is about as complicated as a steak knife. You simply remove the distributor cap and apply vacuum to each nipple and see which way it moves the plate in relation to the direction that the rotor turns. If any of the last sentence confuses you, move away from the car and take it somewhere. Driving around with vacuum advance/retard hoses on backwards could have a very negative effect on timing and cause overheating, among other things. Ignition timing on any engine is important, on an air-cooled engine, it can be life or death.

ok bub. Thanks you are so helpful


BTW I dont have a good shop within 300 miles of me. NOBODY here knows these cars. There is one shop here that everyone will say is THE shop to go to. Having left my car there for the last 2 months and seeing the results tells me they do not.

Im not in LA like you...or somewhere in california

I also figured out the problem immediately and just needed 1 simple question answered, which was answered

Not all of us have a way to create a vacuum on the spot.

AS I said, I didnt create the problem. The problem was created by the prior owner and there was no way or reason for me to be aware of it until now as the car ran fine for almost 20 years ive had it.

You might not mean to insult me - you didnt - but rather just confirmed your an arrogant dick with a bad attitude. If that sentence confuses, well, ask around

"I don't say this to insult you, people's talents lie in many different areas. Yours do not lie in mechanical things."

Huh? Go eff yourself dude. Your an A hole and have absolutely no clue about my talents regarding "mechanical things"

Adios

We are only here to help (some more diplomatic than others). Speeder gave good advice and it was taken personally and responded to in the wrong way. Wow. That'll teach anyone trying to help. You got it all figured out big man. Maybe next time he won't say anything at all.

Right now it 'feels' like it's running better but overheats or knocks in the future as mentioned. Then what..
Suggest you research further and get advice from the tech side.

Get it right my friend, and then go out and enjoy the experience.

He did not give good advice and he knows nothing about my "talent with mechanical things".

If he knew me, which he wont and dont, he would know I am actually quite good with mechanical things. He assumed I was not. He is rude and arrogant.

He loves to go around picking people's posts apart and and pointing out why he thinks the person is wrong, or an idiot or whatever. I've been here a long time...im not blind. Go look at his other post from a few minutes ago on the Robbie Robertson thread going out of his way to criticize someone's use of the word "starstruck"

Give me a break John

My car doesn't knock and has never come close to overheating and if does, ill deal with it using my talents and looking for assistance if need be

His intention was not to help. If you cant figure that out, then oh well

As I said multiple times above, I am all set. The problem is fixed. So why did he take the time to write such a long post accusing me of having no mechanical talent? Figure it out

Have I ever spent more than 30 seconds learning how a distributor works? No. Not until yesterday, ill admit that but I can guarantee that when I am done with it, I will be an expert in distributors and on to the next mechanical problem that life throws at me daily

Have a nice day :-)

No good deed goes unpunished with some people. The guy is an absolute idiot on something as simple as a vacuum advance unit on a distributor, thinks that he should be working on his own Porsche and lashes out at someone knowledgeable trying to help.

Fk the OP but for anyone else reading this who might be miles from a decent shop, the internet and some simple tools available online will solve a lot of questions. Everyone should have a simple vacuum pump if working on anything that uses vacuum to control engine functions. You don't need a Snap-on pump, (though they are great), any Chinese one from Amazon works fine. They are cheap.

There is no way to determine whether a vacuum unit of any kind is functioning without applying vacuum to it. Unless you can suck a golf ball through a garden hose, you need a pump to test them. Diaphragms go bad in the 40 years since 911SCs were made. You also have no idea whether a two-hose diaphragm is all retard or advance without the pump...sometimes both hoses are advance but work in stages. I'm speaking generically of vacuum units, not specifically Porsche. Hundreds of distributors used vacuum units over the decades.

Making sure that an old distributor is working correctly and the movements or plates are moving freely is essential to proper ignition timing and keeping engine temps where they need to be. If this stuff is over your head, bring it to someone.

lashes out? yea ok.

because i am not a distributor expert yet I shouldn't be working on my porsche?

Seahawk, if you see this please delete this thread. Thankyou

“Please don’t move,” then “please delete.” This guy is a fking riot. :)

On a different note, I have seen these vac lines swapped backwards before, not sure if it is in a book somewhere illustrated wrong. I was told by somebody who is well respected on this form that it does not matter but I totally disagree we were discussing a 930 ignition, I didn't bother to get into it with him. The more you learn about your own car the better off you will be, when I can't service it I will sell it.

While we are all having a happy debate about vacuum lines I thought I'd ad my handy helpful hint.

A few times I've suspected something vac' line related, so I've snipped about 10mm off the ends of (some of) the lines and reconnected them. And the problem has gone away Problem is they bounce around, vibrations etc, and stretch at the ends. 10mm snipped off they still have enough length but a nice tight connection.

Yep, the ends get to be like an old wizard’s sleeve.

A search would be for Early_S_Man

Legend, yes.

Mr. Walker could likely tune this engine in ten minutes, if he kept his eyes closed. But it can be done by many of us. Except that mixture should really be set with a sniffer in the exhaust pipe. And fuel pressures are important, which requires another gadget. But ignition timing and advance can totally be done with a good timing light. My '78 SC has an '83 motor in it, and this motor does well at about seven degrees of advance beyond factory spec. Some of these engines can do that, and others can't. Many mechanics like to advance timing until the engine starts to knock/ping, and then back the timing off a couple of degrees. The pinging will be most apparent in fifth gear at 2000 rpm or so. Pretty easy to hear. Pinging is really bad. Pinging will not happen at factory ignition timing spec unless something is really wrong. But as I say, some of these engines will also not ping when timing is a bit advanced, and they will perform better there.

At any rate, congratulations on finding and fixing this problem.