Before there was BHKZ: SWB engine electrics

[304065]

[304065]

Warren:

How right you are about becoming an expert at removing the advance plate circlip! It only took me 90 minutes this time. I used a safety pin with the keeper bent at 90 degrees to the pin, so I could have a sharp, spring-steel point to jam between the edge of the shaft and the washer and the circlip, and then used an eyeglass screwdriver to pry the other end of the clip out and up!

I am almost thinking of drilling and tapping a very small hole into the end of the distributor shaft, to mount a screw and teflon washer to retain the plate, and make assembly/dissassembly easier!

Anyway, the reason for my re-working was to install a teflon shaft plate surface and to REMOVE the metal washers I installed on top of the advance weights. The order is, shaft plate, sliding surface, phenolic washers, weights, then a pair of hairsprings to retain the weights. The additional washers aren't illustrated in the exploded view, and I was concerned they were binding the advance.

More test data soon. . . I only got it fired up and the plugs cleared out before I ran out of time.

[304065]

OK, so part of the problem I was having was getting correct advance at idle. With the distributor rotor pointing to the notch in the distributor body at #1 TDC, the rotor pointed roughly to the 5:00 position if 12:00 is the front of the car. This made it impossible to rotate the distributor clockwise sufficiently to get the correct advance. With the distributor turned as far as it would go clockwise, the bottom of the body would hit the stud for the clamp right by the oiling cup.

After thinking about it for a minute, I realized that I could remove the distributor and index the rotor and the distributor body counter-clockwise by one tooth of the distributor gear. This made the rotor point closer to the 4:00 position. But the rotor still pointed to the #1 notch in the body. This allowed me to rotate the body a greater number of degrees before the body hit the clamp. Started the engine and I was acually able to dial in RETARD at idle. Now, the spec is TDC at idle, so I got that dialed in, and ended up with about 38 degrees total advance at 6000 rpm. Pretty darn close.

NEVER trust that the PO has installed things the right way. Higher temperatures and probably engine damage from detonation were no doubt caused by the distributor being one notch off and too far advanced.

Except that I managed to strip the distributor clamp! Doh! A new one is on the way.

There is a new problem. The engine likes to idle around 1500. I think it could be the carb adjustment. When I shut it off after idling at 800, there is a slight pause, then a 12-gauge sounding backfire from the exhaust. The fun never ends. . . but you gotta. . .

Keep the SWB faith!*

*with credit to the late Harry Pellow.

[mjshira]

i learned this with the 2.5 and a couple rings later...

[304065]

What? Did you loosen up the clamp and crank the advance?

Don't make me get Tyson to tell me what happened!

[mjshira]

you can ask him.

It was a very ahh sophmore like mistake. had the timing off and couldn't get it "right". followed all instructions, still was not perfect. Later found that a couple rings had paid the price for my lack of knowledge... you live an learn. some of us are better off with motronic :-D

[Jefpl8]

Great thread. I am trying to time a 68 right now and this is great help. Can someone tell me what the little knob or attachment is at the bottom of the dist?

[304065]

That's the oil cup. You rotate the knob and it exposes the oiling hole. Fill the cup till it overflows, any motor oil will do. Turn the cup to cover the hole. While you are at it remove the rotor and soak the felt with oil. Don't get any oil on the points.

Do you have a CDI in your 68 or are you still using Kettering ignition?

[Jefpl8]

Thanks for the oil cup information.

My car is a 1968 911T (VIN 11835354) with a Type 901/14 engine. The PO poorly installed a Delta Mark Ten B, removed all the emission control equipment (air pump, vacuum lines, throttle compensator), and replaced the OE distributor with a 0.231.121.006. The odd thing about the Mark Ten is that all the original equipment like the ballast resistor, relay, and coil were left in place and the Mark Ten was switched was into inductive mode. I really do not understand what the advantage of installing it was.

Well, here in Wisconsin, I have to pass emissions just once for collector’s plates. When I took the car in, it spit out triple the HC limit but very low CO emissions – a “lean miss”. I started out by changing the air filter and plugs, but balked when I started to look into the rest of the ignition system. The lack of support, documentation, and long term reliability of the existing setup worried me.

So here is what I did. Installed a MSD-6420 ignition control and MSD-8207 Blaster SS coil (brand S was having a sale). The MSD box now picks up the rev limit since the rotor no longer has a rev limiter built in. The distributor got new cap, rotor, and new Pertronix Ignitor (PN 1866) points replacement. The MSD box and voltage regulator are installed on the fender wall (the fuel pump was already moved by the PO to the smugglers box). The coil is installed on the tinware where the air pump lines passed through. The install went well and the motor starts nicely. Timing is solid at idle. I also performed an oil change and retuned the carbs. I am just waiting for some help to verify the timing at various RPM and for the snow to clear

My question to the assembled SWB braintrust is:
1) Is the 0.231.121.006 distributor OK for use on what is effectively a Type 901/06 motor?
2) Does anyone have the timing curve for this distributor?

Thanks - Here is a picture taken at Road America this last fall – not bad for $7800, eh?

[304065]

Jeff, great car! Thanks for joining the thread.

All of the advance curves are found in volume III of up-fixen der Porsche and in the factory workshop manuals. Unfortunately I will be away from a scanner for a while, but hopefully someone else can post the curve. It is very similar to the 159 distributor in terms of the shape of the curve (unlike the 002 "S" distributor") but I believe the later distributors have less total advance.

[Grady Clay]

Jeff,

A very hardy WELCOME to the Forum.

You have a great looking 911, congratulations.

Our ’68 coupes are 10 numbers apart! They must have been built the same day.

not bad for $7800

I paid $6709.25 + 3% Colorado tax – ordered new from PAG. HeHe.
I'll be glad to help with anything you need.

I too have some collecting to do. When I changed things over the years I mostly kept the original stuff – but not perfectly. At least it is original engine, transmission and paint with absolutely no rust.

It is resting quietly for my son to graduate from college and we start rejuvenation – it doesn’t need restoration.


I’ll post the advance curves tomorrow but with some searching they are in some archive. Pelican (and others) search function is masterable with some work. I wish someone would post a good set of instructions.

I’ll speculate your miss is a plug connector or other in the HV side of the ignition or something as simple as an idle jet. Here in Colorado all it takes is a normal, good running 911 and it will pass the exceeding liberal emissions standards with flying colors.

Best,
Grady
gradyclay@hotmail.com

[Early_S_Man]

Jeff,

That is a great looking '68!

Here is a thread with schematic, circuit description, installation, and troubleshooting information on the Delta Mark 10B ignition ...

68 911 electric...please help!!!

[cassidyp]

Jeff, that is a great car. Pay you $8K for it right now! Ha ! Ha! As usual the pics and information contained in the thread will be invaluable to countless Porsche fans now and in the future. My thanks to all

[Grady Clay]

Here is the curve for Bosch 0 231 121 006.

"
"
© Dr. Ing. h.c. F. Porsche A.G.

Best,
Grady

[Jefpl8]

Wow, Thanks everyone for the great welcome. I am very excited to own such a great car and relish the time I spend twirling the iron on it and driving it. There is no denying the beauty of this design. In fact just being around the car inspired a friend to realize his dream of Porsche ownership. He and I subsequently road tripped to Pennsylvania for his purchase of a beautiful black/black 1982 911SC.

Regarding timing advance, Thanks for the timing curve. I also found a reference that the 0.231.121.006 and 0.231.159.001 were both used thru 1967 (Up-Fixin 5/71). That same article seems to indicate that this disributor should use cap 1.235.522.109 and rotor 1.234.332.159. This does not match what the PO had on the distributor (cap 1.235.522.109 and rotor 1.234.332.159). The car seems to run well and I don't need a rev limiting since the fancy dancy MSD box should take care of that. Any thoughts on this topic?

Grady – I amazed to hear your car is so close in VIN. I feel like I’ve found a long lost 10th cousin once removed! I am glad to hear that a well tuned 911 should pass emissions. That means there is a light at the end of the tunnel.

Thanks again for the advice and compliments, see you on the road.

[cassidyp]

Jeff,

I guess that is a no huh? Glad to have a new member. Where did you go in Pa for friend's SC?

Patrick Cassidy

[304065]

Jeff,

As long as the cap fits tightly and doesn't rotate you should be fine. See picture above of the old cap, you can clearly see the half-moon shaped notch that is designed to clear the plastic insulator for the points. You can either grind a notch in a new orange cap or grind down the plastic insulator so it will clear. I chose the second route because I replaced the insulator.

Re the rev-limiting rotor, I haven't detected any differences in the advance curve. It is actually easier to set the advance with a VW style non-rev-limiting rotor because you can clearly see the middle of the contact point.

The MSD rev limiter is a lot more accurate than the rotor. In that same old issue of Upfixen, there's an article that talks about using an electronic rev limiter instead of the expensive ($29 back then, which is a fortune today) Bosch rotor. Plus the standard deviation of the rotor's cut-in point is probably 500 rpm, and the resistor in the rotor may burn out. So I would say VW rotor is OK.

How did you set up the tach drive? Are you using the MSD tachometer output?

[Jefpl8]

Thanks for the info everybody.

The cap and rotor fit well enough. The cap did not need to be notched as the points insulator was removed when I installed the Ignitor. The strain relief has lots of clearance to the cap. Is the cap and rotor I am using from VW?

Regarding the rev limiter, I agree the MSD should do a better job than a rotor. MSD claims that the box is accurate to 1% of RPM. I also purchased a couple of extra “pills” so now I can limit in 200 increments between 6k and 7k. For what it’s worth. I did have to buy a tach adaptor from MSD (p/n 8920) for the tach to work, but it runs nice now, no erratic behavior.

I have a new question: After looking through old Up-Fixing’s I saw an article for Grose Jets for webers. There is also a thread on Pelican on these:

High performance gross jets

If anyone in the braintrust wants to post their input on if these items on this old thread, my ears are open.

Patrick, the car came from Forty Fort, just north of Wilkes-Barre. We drove in from the west and came through the Appalachians. Beautiful in the fall colors. Tough drive doing it nonstop from Milwaukee to Forty Fort and back. I was wiped after that.

Grady, Thanks for the curve.
http://forums.pelicanparts.com/showthread.php?s=&threadid=94950&highlight=grose+AND+jet

[304065]

Well, I found an original electrical panel from a '67 SWB which had the ballast resistor and a filter cap on board.

You can clearly see the wirewound resistor. I hooked a meter up briefly and it showed 1.3 ohms across the resistor from terminal 15 to 16. Not certain that's accurate, however. I need to scuff the oxidation off the brass terminals on the orginal wires to check it properly.

The cap value I'm certain of, 7.65uf.

This will be restored to concours standards and kept ready to be swapped to the car for Kettering-ignition at shows.

[Mycar]

Don`t mean to butt in here, but here`s the ignition system on my 1968 2.0s. Pretty original I think, except for the coil which is a recent edition. What colour would the coil have been originaly? I still have a blue one.



Regards, Mike.