Timing on Pertronix

[bbonomo]

I’ve searched the forum for a little guidance on this, but thought I’d ask it in a way I can understand...

I’ve had PnizSSI for about two years and it has generally ran well. It suddenly stopped running well (no power under load).

After much troubleshooting of timing, fuel delivery, replacing plugs, etc, I pulled PinzSSI and reinstalled Pertronix. The truck is running well again, but I need to dial in the timing.

I have an inexpensive timing gun, without the ability to set the preferred timing.

I’ve read that I should have the timing ‘advanced’ of TDC. I think I’ve read “4deg”, but have also seen “5 to 10deg.

I just don’t know exactly what that means. With the timing gun should the timing indicator be more towards the drivers side, relative to pointer?

Is it just a couple of mm, like PinzSSI or more like an inch?

Thanks!!

Brett


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[rmel]

Before you give up on the PinzSSI, you may want to take a look
at a couple of possible causes.

First if this is a PinzSSI 1.0 which takes it's power directly from the
bottom Battery, take a look at that voltage just to make sure your
your Battery is good, this could also effect the Pertronix if that is
getting power the same way.

The second thing to look at is the timing disk and photo-diode area.
Make sure you don't have any dust buildup on either -- it's hard to
actually see how clean/dirty the photo-diodes are. Generally
speaking if you have dust on the disk then there's likely dust on the
diodes. That could effect performance messing up Advance and
accurate firing of the coil. The fact that it runs at idle and seems to
have a issue at load (and I bet RMP) , I'd be suspicious of cleanliness.

[bbonomo]

Thanks. I have 2.0. Admittedly, I didn’t check the input voltage, but I think the new regulator/voltage converter is more forgiving than v1.0. I don’t have any reason to believe my voltage was low, but again, I didn’t check. The truck had no problem turning over and idling, just no power.

Also, I followed the instructions that I found on this forum recently and cleaned RFS diode and put a new disc and it didn’t help.

Unfortunately, I’ve given up on SSI until they test and return it.

That leaves me with my original question about timing. Hoping I can dial it in. Although, it’s really running great again. I just want to make sure it’s good and hopefully learn something in the process


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[rmel]

With PinzSSI 2.0 your voltage is likely just fine. It will be
interesting to learn what the problem was once you get
it back.

As far as timing goes, 2MM to 3mm advanced, which
translates into 1.4 degrees/mm should do for both the
PinzSSI and Pertronix. As you know PinSSI provides
advance vs. RPM based on the outer timing slots on
the disk. Pertronix is centrifugal force -- assuming the
springs used dialed in the proper advanced for a Pinz
you'd be all set with a modest amount of static advance.

[ChickenPinz]

Pertronix is centrifugal force -- assuming the
springs used dialed in the proper advanced for a Pinz
you'd be all set with a modest amount of static advance.

My distributor has manifold vacuum supplied to it, and has the Pertronix setup. Is the vacuum advance disconnected in the Pertronix retrofit?

[rmel]

Do you have an external Vacuum diaphragm mounted on the side
of the distributor? Or just a vacuum line connecting to a stock
distributor with a Pertronix conversion. If the former you might have
a modified Pertronix VW distributor, if the later the vacuum to
a stock distributor is only there to pull moisture out and provides
no vacuum advance.

[ChickenPinz]

No diaphragm, so it sounds like stock distributor.

I've not seen other distributors with this setup before. Not on the Bosch 009 distributors, and not on our aircraft distributors either. Clearly one needs to ensure there are no leaks in the distributor as there'd otherwise be a manifold vacuum leak so stock distributors must be sealed tight. A wise thing to keep out dust and dirt -- the kind some other systems seem to be suffering from.

It does strike me as a bit uncommon for a system design. It would tend to increase internal arcing risk at high manifold vacuum levels and require more clearance internally to prevent it. In aircraft, some distributors are explicitly pressurized to prevent issues at high altitude.

thx

[bbonomo]

I just found a spring in the box where I kept my Pertronix. I have a feeling that it should’ve been installed when I replaced PinzSSI with Pertronix last weekend. Where does the spring go?


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[JimmyC]

To set my timing I get it about tdc then fine tune it on a hill by my house. I advance it a little at a time and my speed creeps up. When it quits creeping up with advance I quit advancing. The setting is as little advance as you need to get maximum speed up the hill. I then lug it to see if it pings and retard it a little if it does. Also check to make sure it starts ok. If not I retard it a little. This is what I learned when I was young and working in a shop. In the Pinz it ends up a bit more advanced than the spec and I don’t have to retard for pinging or starting. If weather changes, different fuel, or altitude changes make it ping then retardant a little. If you do it this way you can usually get a bit more power and economy. On my hill I can get 3 km/hr more than stock this way. Not huge but it helps.

[Hotzenplotz]

I just found a spring in the box where I kept my Pertronix. I have a feeling that it should’ve been installed when I replaced PinzSSI with Pertronix last weekend. Where does the spring go?

a single spring is item 15, with dual springs it is 14