Early 911 Distributor Experts - Need Some Help

[t6dpilot]

OK, I have another question about my bitsa engine. As many of you know, I have a cutout issue at about 5,800 revs and am working to diagnose the problem. I have decided to go back to square one with respect to the ignition electrics and replace the dizzy cap, rotor, plug wires, and points to see if that helps. I have a new cap and went to fit it on yesterday and it does not fit. I noticed that there is a small notch on my existing cap and not one on the new one. So..... I went to look up to see if the 72/73 cap is different and it is not, but I did notice that there is a note to file a notch in the cap for 65-68 cars.

Hhhmmmm... That got me to thinking, maybe I have a SWB dizzy. Probably from a 67 S since those are the heads that are installed on my engine. Just a guess, though since I don't know if there was a difference between the normal cars and S cars. I did not get the P/N on the dizzy yesterday, but looked at it some time ago and found it hard to read all the numbers (backwards and upside down).

My questions are thus:

1. Can someone help me with the cap notch issue? How to do it and is it likely that I have an early dizzy based on my description?
2. Can you use a SWB dizzy on a 2.0L engine with 2.2 P&C and 67S heads (S crank and cams)?
3. Will that dizzy handle the 7300 RPM of a 2.2S?

I will try to look up the number again this afternoon because I am sure most of you will want to know that information. Thanks for any help that can be given.

[Grady Clay]

Scott,

You might set the engine to TDC #1, pull the distributor and take it to someone with a distributor machine. That will let you see what the actual advance curve is. You can clean, re-lube, install new points, etc. It also lets you run in the distributor before you reinstall it.

Do you have a rev-limiting rotor? What rpm is marked on it? If so you might try a standard rotor and see if your mis goes away. There is an inexpensive VW rotor that fits.

I hope all is well with you.

Best,
Grady

[304065]

Scott,

Here's all ye need know about SWB distributors.

http://forums.pelicanparts.com/showthread.php?threadid=252299

Back after that long read? OK, the easiest way to tell if you have an SWB distributor is to look at the body, they are black-painted cast iron. A '69S should have an aluminum bodied distributor with a yellow-cad-plated distributor clamp. If it's a normal the nomenclature plate should be black and white. If it's an "S," yellow. Whoops, now the price of distributors just went up again.

The reason you need a half-moon shaped cutout in the SWB cap is so it will clear the white plastic circular insulator where the bolt carrying the points connection passes through the distributor body. In the later cars, there was a plastic insulator that replaced this, so the half-moon shape went away. It was replaced by a distributor clip that sticks up a couple of mm from the distributor body, and this fits into a square-shaped notch in the new light brown cap.

Can you use an SWB distributor on an LWB S? Yes, but it's clearly "wrong" to anyone who knows what they are looking at. Also, the SWB distributor uses an older style of points that relies on a spring to carry the points current to the distributor body. There is a paper insulator to prevent the points from grounding out on the distributor body and a very precise assembly sequence that must be followed when replacing the points, all of this noted in my thread above. The LWB distributor uses modern points with a wire to the plastic insulator, with the result that they can be removed and serviced a hell of a lot easier, without even removing the distributor. So I would recommend that you track down a correct 006 or 007 distributor.

Here's the other problem: you need the correct advance curve. MOST cast-iron distributors are worn out and end up giving like 45 degrees of advance because the pivots and springs are sloppy. If I had a '69S with the wrong distributor I would buy a brand-new Bosch, have a machine shop cut off the cast-in clamp and turn the shaft down to the correct size for a 2,0 motor (smaller than the 2,7 for which the new distributor is offered), blank the vacuum advance port and have the curve set for an "S" with modern gas. Many of the pro shops who post on Pelican can do this for you. It's not cheap but it's very, very important to do correctly.

In the alternative, if you find a core 006 or 007, have it overhauled with new springs, teflon rubbing plate, new bushings, etc., and have the curve precisely set to "S" specifications.

Hope this helps! Check Warren's Distributor Lube thread for more excellent information.

[t6dpilot]

Thanks for the responses guys.

Grady, hello and hope things are well with you. Everything good here except I am wiped out after finally getting my "Auto Spa" up and running - working 12+ hours, 7 days. Good advice on the distributor pull, I think I will do that this winter. On the rotor, I have the correct one installed and tried another new one for an S and had the same result, so it is not that.

John, wow - great information. I am not familiar with the SWB distributors, but now that you described it to me, I definitively do not have one. Mine has an Al core and is not black. What I do have is a small raised square piece in the casting that fits into the distributor cap that acts as a "key" to make sure the cap is installed correctly. The cap I have new does not have that notch in. I'll bet it is the wrong cap, when I thought it was correct. It came with a parts cache when we bought a 73S. I just assumed it was for a LWB and did not cross ref. P/N's. Could it be possible that I have some other distributor in there? I am really curious now and am going to get the numbers after work. Thanks for your help and detailed information.

[Restorer72]

Hi Scott, I have a 2.2s and I am experiencing the same problem. My car goes great but cuts out at 5800rpm. Im looking for solutions. Im wondering if you've found a soloution to your problem or a cause?
Regards
Jason

[t6dpilot]

Jason,
Interesting that you are experiencing the exact same problem. I have checked fuel flow, fuel pressure, float settings, main jets (135) and all are within spec. On the ignition side, I have checked the CDI box, replaced the distributor cap and rotor, plug wires, and checked timing, which was within spec. Points are next to be replaced, although my current set are fine, and a new coil - it is good to have a spare anyway. I am still experiencing the same problem, but the car seems to run just a little bit smoother/stronger now. A valve adjust is on the list and I will probably pull a plug or two to check condition. Beyond that, I am baffled. I have had suggested to me that the tach is not reading correctly, but I am very confident that the tach is accurate. I will check it as well, though.

Sorry, so far no solutions, but if you PM me your contact info, I will keep you informed. I would suggest that you check all the I did and give the car a good tune up to set a baseline for the ignition system. That way you can potentially eliminate the ignition as being the culprit. Good luck.

[304065]

There is a MFI pump failure mode that causes cut-out around 5K. However, I would investigate the ignition first.

[t6dpilot]

John, thanks for that regarding the MFI. Unfortunately, or fortunately depending on how you look at it, I have Webers installed.