Point / condensor substitute?

I found these two pick-ups (looks magnetic) inside Distributor 1 off a 77 308 GTB. The two pick ups drive the two banks coils. Can someone who has seen these point me to a description so I know how they work and how to set static timing?

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Well, that is a Pertronix Ignitor II. Still don't know how to static time it yet.

 

Set motor to TDC #1 compression
Install distributor with rotor on #1 cylinder
Connect wires to coils (red to + black to -)
If it fires, fine tune timing. Distributor with Pertronix installed sets timing for both banks
If it doesn't fire, swap wires to coils

Instruction manual here
https://cdn.shopify.com/s/files/1/0247/6913/4628/files/9MR-183.pdf

 

By rotating the distributor housing . What Dockboy wrote to set it up, but it would be a case of selecting the best single distributor housing position for both bank 1-4 and bank 5-8 for the final fine adjustment -- i.e., if you set the bank 1-4 idle timing to where you want, and the bank 5-8 is way off, then you have to muck with moving the pickups relative to each other.

 

It was running before so my guess is the 2 pick ups are set up 90 degrees from each other, or very close to it and I have not mucked with them. I had to remove Dizzy 1 to change the seals so now I have to static time bank 1. Then bank 2 will be OK.

 

Probably be OK if working well before, but you may have to do a little "sharing" between the two settings as things are rarely perfect. It's 135 deg physical from each other for the pickups = 45 deg electrical of dist rotation (because of the 4 magnetic poles 90 deg apart) = 90 deg of crankshaft rotation between the coil firing signals.

 

I have installed this set up many times on 308s. Like stated above, just get the distributor set close on number one and use a timing light to set the timing you want after it starts. It should work fine.

 

Steve, what is a good crank setting to static time bank 1 if there is only one set of point? TDC or something else?

 

TDC is usually close enough to get it running so that you can then make the final idle timing adjustment with the timing light, or you can set the flywheel to the static idle timing that you desire. To get ticky-tack about it, you would set the flywheel to the idle timing that you want for cyl #1 when the thing triggering the bank 1-4 coil (whether a point or a magnetic pick-up) is firing the 1-4 bank coil. The factory procedure of using the rotor end pointing at the red mark on the distributor rim is also really just a "close enough to get it running" thing, and doesn't account for the fact that, when the rotor end is pointing at the red mark, the thing triggering the bank 1-4 coil may not be exactly perfectly positioned for firing the 1-4 bank coil (although it should be if the distributor was assembled perfectly).

 

I just did this on my GT4 with the dual sensor Pertronics installed in the 1-4 distributor and the TDC was a little rough to get started. I had much more success installing both distributors at the +6 degree mark as recommended in the WSM for the stock points system.


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Thank you. +6 degrees is what I wanted to know.

I am also trying to understand why it won't rev past 5,000 rpm. That may not be related, however.

 

@kiwiokie, By the way, that is 6 degrees BEFORE TDC, correct?

 

Yes sorry was referring to 6 BTDC mark on the flywheel.


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I go with two possible suspects initially:

1. A fuel delivery problem (weak pump, kinked line, blocked inlet screen, faulty US version fuel pressure sensing cutoff valve, blocked/restricted fuel filter, etc.). You should be able to do a fuel delivery test by disconnecting the fuel supply line from the fuel pump at the 5/6 carb inlet and make a measurement of X volume delivered in Y seconds with the pump running to see if the flow rate of X/Y (at zero pressure) is reasonable compared to the "capacity" spec in the 308GT4 WSM on page C13.

2. The Pertronix pick-ups are not in the right place (relative to the rotor end), and the 1-4 rotor end becomes so unoverlapped from the contacts in the 1-4 dist cap that is misfires. Using the wider tip QV dist rotors 124288 can help this situation. On the 5-8 bank, even though it has no pick-ups inside, you still need the rotor end to point at the notch in the rim of the dist housing when the crankshaft is at/near PM5-8.

Good Hunting!

 

Cliffs notes version of a long story. Our Lamborghini LM002 (long story, not my fault) has a fragile distributor drive piece and allows the rotor to get out of '"ALIGNMENT" with the internal workings. In other words its pointing in the wrong direction. This is on a 2 contact rotor in a 12 cylinder cap. When it goes out, over a certain RPM it just looses a bank. No misfires, nothing. As said, it might have a lack of proper phasing of the rotor to the reluctor.

The small divot in the OD of the distributor housing indicates the firing point with the points installed. At TDC or a few before, wherever you want the timing it should line up with the middle of the rotor and the point of the reluctor should be right at the pickup.

 

@Steve Magnusson, I found that the fuel pump capacity is 1.04 L per minute, whereas the specification in the GT4 WSM calls for 100 L/hour (1.67L per minute). 1.04L seems too low against the spec, don't you think?

The thing does have an after-market fuel pump. Which pumps are now available for this old car to meet the spec?

 

Does seem lowish. If it's still got the US version fuel pressure sensing cutoff valve in the plumbing, you might try remeasuring with that out of the equation, and a blockage/restriction is still possible.

Try some searches on Pierburg, Hardi, and/or Facet for prior threads/recommendations. I know the Facet fits well, but it's a bit high on pressure and kind of noisy. I'd try to use a rotary vane type pump (like the stock one) rather than a diaphragm type pump - JMO.

 

Hmm, the thing has a new-ish Hardi 18812 pump which is supposed to pump out 100-130 L/Hr, and is also self-regulating for fuel consumption. The test I conducted had the fuel delivery line disconnected from the carbs and inserted into a container so it should have put out maximum flow rate. It does not seem like it.

 

Only if everything else in the system is OK -- no blocked inlet strainer, no kinks, no blocked fuel filter, etc.

Does the fuel system plumbing look like the one shown here on pages 6&7:

https://www.dropbox.com/s/bp5gpggs2d4z5il/MUM_308Gtbna%2077%20addendum.pdf?dl=0

or has it been modified to the more simple "euro" configuration?

 

No it does not look like that. It is a bit simpler so I think the EU configuration.

Secondly, I happened to have a set of QV rotors and I swapped them in, and I was able to get the car to rev to 6,000 RPM + so it was the ignition system that was holding it back.

Third, I set the static timing at 1-4 TDC, pointing the rotor to Cyl 1 position right over the dot, and the car will fire but runs poorly at idle. Putting a timing light on Cyl1 trigger shows no paint marks (I made those on the flywheel) at all. I am at the conclusion that the Pertronix trigger is off.

What is the procedure to get it back to correct positions, or should I just experiment with mounting the distributor one spline off?

 

Well, moving the 1-4 distributor one spline did it. I was able to rotate the dizzy to get the paint mark to show under the timing light. And I was able to rev past 6,000 RPM. Time to balance the carbs.

 

Now that you've got it running at the 7 deg BTDC idle timing at 1000 RPM, you can always set the flywheel to the 7 deg BTDC mark and see where the dist rotor end is now relative to the notch. If it's way, way off, you'd need to move the pick-ups in the distributor housing (make some sharpie marks to know where they were).

Using some numbers given in the injected model WSMs, and doing some handwaving math , says the absolute minimum fuel delivery to get the 3L engine to the 7700 RPM redline is about 70 L/hr = you'll have to keep chewing on that issue to get the fuel delivery up IMO.

 

I've installed 3 sets of Pertronix in 308's and never had to move the pickup modules

 

I think I will get a red facet pump