MPS, Rebuilding the MPS Options

[Ron914]

Hello to all who have helped me with this project . @emerygt350 ,@TJB/914, @Superhawk996 , @ChrisFoley , @rjames , @MDTerp
I am in the middle of rebuilding my MPS and have a couple of comments and questions .
First when I opened up the unit I found the most difficult job was removing the rivets holding the two halves together.
When I removed the retainer plate to take out the old diaphragm it was in two pieces .

I needed to take two measurements since I was replacing the stop screw , I needed to measure the the stop screw protrusion into the housing . The instruction sheet sent to me by a member had the measurements he must have made when rebuilding his MPS . His stop screw protrusion was 1.97mm and mine only measured 1.72mm.
His inner/outer screw assembly depth in the old diaphragm measured 6.51mm .
Here's one of my questions ?
when I measured mine I got two measurements depth to inner/outer screw assembly was 4.03
and depth to the washer outside the inner/outer screw assembly was 5.46mm.
Again there is a difference and since mine was never accessed before (epoxy over screw was not disturbed) is the difference in measurements ok and which measurement should I use I will try to attach a photo or two to help with my question.
this one .

I have not touched either of these measurements yet and awaiting any help/comments.
I think it's this one to the washer on diaphragm .

[emerygt350]

Don't worry about TDC, the distributor only goes in one way, it has an offset on the shaft. You can put it in wrong and clamp it down so hard it will spin but don't do that.

I would go back to the pertronix for the moment.

Did you double check your trigger points connections?

If you can get it back to where it was when you tried running it, that would be great.

[Ron914]

Don't worry about TDC, the distributor only goes in one way, it has an offset on the shaft. You can put it in wrong and clamp it down so hard it will spin but don't do that.

I would go back to the pertronix for the moment.

Did you double check your trigger points connections?

If you can get it back to where it was when you tried running it, that would be great.

Hi ,
yes I rang out the wires from the trigger points plug to the ECU plug and I have continuity on all three ( I must not have had the probe inserted correctly (I added resistance values for the individual wires for both the MPS and the trigger points .
Also checked the resistance of the CHT wire without that added resistor in circuit and it was
000.2 ohms.

I will reinstall the Pertronix back and follow up here on this post .

What about the bad bushings in my distributor you mentioned ? Can I purchase parts and replace them or do I need to look for a new distributor . If only I didn't live in California I would buy a 123 .

[fiacra]

If only I didn't live in California I would buy a 123 .

I'm not aware of any reason you can't run a 123 on your car here in California. If you are thinking it is because of the smog check, I don't think that's the case. You can correct me if you're aware of some part of the regulations that I'm not remembering. In any case, I wouldn't try switching out to the 123 until you have solved your current issue.

I don't have much to add to the advice your received so far from people with more experience than me, but do be sure to carefully check your distributor cap for a hidden crack. I couldn't tell from the picture if there was any streaking on the cap. There is some wear around the rim of the distributor cap that I can see in your picture (at 12 o'clock in the pic) that makes me a bit suspicious that the cap was moving around.

[Ron914]

If only I didn't live in California I would buy a 123 .

I'm not aware of any reason you can't run a 123 on your car here in California. If you are thinking it is because of the smog check, I don't think that's the case. You can correct me if you're aware of some part of the regulations that I'm not remembering. In any case, I wouldn't try switching out to the 123 until you have solved your current issue.

I don't have much to add to the advice your received so far from people with more experience than me, but do be sure to carefully check your distributor cap for a hidden crack. I couldn't tell from the picture if there was any streaking on the cap. There is some wear around the rim of the distributor cap that I can see in your picture (at 12 o'clock in the pic) that makes me a bit suspicious that the cap was moving around.

The cap is brand new that wear was on the cap when I took it out of the box ,I assumed it was cleaned up during assembly that way . It was securely snapped into place .