New member, Missing engine, and Used CIS Value?

[Damon in STL]

Hi All,

I just purchased a 1975 911s with a refreshed 3.0 motor (with receipts) running CIS. I'm a long time BMW guy with some previous P-car ownership ('86.5 928 and early 914). The 911 had been sitting for about 6 years and has a couple of issues.

The guy I bought it from never licensed it. Long story short is he bought it after it had been refreshed and had been sitting. He then got transferred out of state and had to sell. To sell it he had it running and had played with the mixture adjustment and idle screw. The car surges at idle.

When I went to pick it up, I had planned on towing it home. It was running fairly well and the owner had just filled it with Techron to help clean out the fuel system. I had brought a buddy with me and the trailer so I decided to drive it the 120 miles home with him following. The car ran fine.

Here are some pics. The first thing was to clean up the hood issue.







The afternoon of purchase......I wasn't wasting any time.








So there are a couple of issues. I have had to do a couple of things to the car for it to pass the state safety inspection. I also went on vacation for a week. The car was running fine but with the surging idle. I did a bit of research and got the mixture and idle sorted fairly well. The surging was at a minimum and the mixture is closer to the rich side. The car ran great for about a week. It has now started to misfire. I'm thinking some of the old fuel/varnish may have broken free and is causing the issue. I will need to investigate further. I have a wideband O2 etc....just have not had time to dive into it yet.

Question:

When I bought the car my plan was to convert it to EFI using MegaSquirt (I have a e30 M3 race car with a turbo M42 engine running MS). As part of the deal a second spare complete CIS system came with the car. What is the value of a complete CIS system? I'd like to sell one system and then either go with the Bitzracing system or build my own.

Damon in STL

[Bob Kontak]

Welcome Damon.

I see three used systems on Ebay in the $600-800 range. Did not look at "sold" CIS units though.

Nice looking car. Take your time blocking the hood before painting. It will pay dividends.

[Bob Kontak]

Originally Posted by Damon in STL

It has now started to misfire.

Do the night time fireworks test for stray sparks.

Pull one plug wire at a time to see if it does not make a difference.

Check injector flow one at a time.

Pull the line off the warm up regulator and make sure the screen filter attached to the WUR is not gunked up.

Make sure your fuel return line to the engine is allowing gas to return.

After these basic "eyeball" tests you need pressure gauges. On the upside, you do have a backup CIS system if you have to snag a few parts.

If you spend time in Jim's link below it will help you start to absorb the CIS functionality.

911 CIS Primer - Index

[timmy2]

If you have a spare CIS why not use it for the EFI conversion and keep the original CIS setup in case you ever want to go back to original?
I did.

[Dave Colangelo]

Nice looking project there. I will throw this out there although if you have made up your mind it may not hold much weight.

Dont convert to EFI, CIS does what it needs to and is not as bad as some of the flack it gets. I have had a stock SC that has been a more or less daily driver for the past 5 years issue free. It needs some tweaks here and again but over all its a very reliable system. If you have a whole spare CIS system then you dont need to worry about parts either. If the engine is running as is I would tune it until you get it to a good point, restore the other things that need attention then go back and start to think about an EFI conversion.

As for CIS value, assuming its all there you could get 500-800 for a full system I would think.

Regards
Dave

[Damon in STL]

Originally Posted by Bob Kontak

Do the night time fireworks test for stray sparks.

Pull one plug wire at a time to see if it does not make a difference.

Check injector flow one at a time.

Pull the line off the warm up regulator and make sure the screen filter attached to the WUR is not gunked up.

Make sure your fuel return line to the engine is allowing gas to return.

After these basic "eyeball" tests you need pressure gauges. On the upside, you do have a backup CIS system if you have to snag a few parts.

If you spend time in Jim's link below it will help you start to absorb the CIS functionality.

911 CIS Primer - Index

Thanks for the tips. I've been to the link and have also done quite a bit of research on the CIS system. I took off the air filter and the air transfer tube across the top to check things out when I adjusted the mixture and idle. There is a possibility I introduced a vacume leak on the back side (doubtful...but worth a check).

The one thing I'm curious about (haven't really looked for info yet) is how the CIS adjusts for more aggressive cams. I have Web 258/246 cams.

Originally Posted by timmy2

If you have a spare CIS why not use it for the EFI conversion and keep the original CIS setup in case you ever want to go back to original?
I did.

That is the plan. Once I have the engine up and running on MS it is unlikely I will ever go back. So, just checking on the value of the spare CIS.

[Damon in STL]

I pulled the dist. cap last night and cleaned the contacts....car ran better. I then checked the timing and the static setting is about 10 degrees BTDC?

Hard to see and a bit blurred....


My engine is said to be a 1980 3.0

Hmm....


So, where is the next place to verify?

I then spent a bit of time trying to find the timing settings for my engine. It was an exercise in confusion. Not knowing for sure what engine I have....makes it a bit difficult to determine what the setting should be....but, I think I found the correct info!

So, I then loosen the distributor....and find I can only advance it! More confusion.

I decided to sleep on it.

Bingo....the distributor must be stuck in an advanced position!

I'll fiddle with it tonight.

Damon in STL

[javadog]

The value of a CIS system is dependent upon which one it is, if it is complete, and its condition. The '78/'79 US systems and the ROW versions are probably worth more. You'll have to identify what you have before you can get anywhere with this question. If it were my car, I'd keep it.

Identifying the engine will take some detective work. If you have no serial number, because of a replacement case, you probably won't have en engine type number, either. At that point, you need to identify the engine through documenting the differences that existed between the various versions. I'd start with the CIS components, as most of those have identfying numbers on them.

The distributor advance mechanism is probably not working, due to lack of maintenance. You'll need to fix that, then figure out which engine you have before setting the timing. Slight differences exist in how that is done.

JR

[Damon in STL]

Thanks for the info.

One other piece of info I should have included...rotating the distributor clockwise advances the timing. I read where some distributors rotate one directions and others rotate in the opposite direction depending on which engine. Does this help define which engine it is?

The other thing I noticed is my #1 on the distributor cap is is closest to the #1 plug. Some images/pics I saw last night had it on the opposite side of the distributor cap.

Damon in STL

[javadog]

When Porsche introduced the 911SC in 1978, it featured a distributor that rotated backwards to all 911 distributors up to that point. So, you basically have everything up to that point rotating one way and everything after that point rotating the other. So, it won't help to differentiate between the versions of the 911SC. Looking at what little I can see of your distributor, it doesn't appear to be from a '76/'77 Carrera 3.0, which was the other 3.0 engine made by Porsche in that era. It used the smaller distirbutor shared with the 2.7 engines.

Like I said, start with the obvious stuff. Does it have a cat, or a pre-muffler? Two way cat, or three way cat? Does it have an O2 sensor? What are the Bosch numbers for the WUR, fuel distributor, etc?

JR

[timmy2]

Ideally your timing will be spot on with the adjustment bolt somewhere in the middle of the adjustment range. Your distributor may have been installed one tooth out.
When installing the dizzy the rotor should line up with the notch in the housing for cylinder 1 at TDC for cylinder 1 and the bolt should drop in to the adjustment slot with motion available in either direction.

[Damon in STL]

Originally Posted by timmy2

Your distributor may have been installed one tooth out.

This was my initial thought. Does anyone know how many degrees of rotation on the crank pulley this would cause?

In general...I like getting to the root cause.

Damon in STL

[Damon in STL]

New info: The engine is a '80-'83 3.0 SC motor. It also has the wrong distributor on it. My static timing is a bit off and the distributor is hitting the stop (about 5 degrees advanced). I need to go back and check but the 4000 rpm setting appeared to be close to the 25 degree setting. The springs work freely.

What was really confusing was that the #1 wire in the cap is facing towards the #1 plug. All the pics I could find showing where the #1 wire is are on the opposite side of the cap!

I'm now thinking about using MS for both fuel AND timing.........

Damon in STL