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> MPS, Rebuilding the MPS
Ron914
post May 8 2025, 05:06 PM
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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 .
Attached Image
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 .
Attached Image
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 .
Attached Image
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fiacra
post May 13 2025, 01:34 PM
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Ron got that Pertronix from me, and yes it is older. It sat in a box on my shelf for at least 10 years.... If it is a worry for you Ron I'm happy to refund your money and you can simply trash the Pertronix.

I went down the rabbit hole and I think you are correct about the 123 and the smog check. Of course everything depends upon who is doing the inspection. I believe the 123 would fall under the category of performance distributors, and these would require that the company submit it to the CARB for certification that it does not make the car run dirtier than the OE distributor. An exemption would then be issued. I couldn't find any documentation of this having been done.
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Ron914
post May 13 2025, 03:25 PM
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QUOTE(fiacra @ May 13 2025, 02:34 PM) *

Ron got that Pertronix from me, and yes it is older. It sat in a box on my shelf for at least 10 years.... If it is a worry for you Ron I'm happy to refund your money and you can simply trash the Pertronix.

I went down the rabbit hole and I think you are correct about the 123 and the smog check. Of course everything depends upon who is doing the inspection. I believe the 123 would fall under the category of performance distributors, and these would require that the company submit it to the CARB for certification that it does not make the car run dirtier than the OE distributor. An exemption would then be issued. I couldn't find any documentation of this having been done.

It's not a problem fiacra ,
I don't want any money back . Everything with this car is a learning experience for me . I will just be extra diligent when outside of the car tuning it . If I was to eventually pass a smog test I could then install the 123 but would have to remove it every two years or find a guy as everyone tells me that looks the other way . Hopefully Jay Leno's law passes and I won't have to worry about the smog check any more . I know there is a lot of controversy about that law . I could also buy a newer version of the Pertronix if I wanted to but I would rather put that money into a 123 but first order is to get my car sorted out and pass the smog test .I want to drive my car to my first WCR in June .
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Posts in this topic
Ron914   MPS   May 8 2025, 05:06 PM
Superhawk996   There you have it, now you know why it was a leake...   May 8 2025, 06:36 PM
Ron914   There you have it, now you know why it was a leak...   May 8 2025, 06:58 PM
MDTerp   There you have it, now you know why it was a leak...   May 8 2025, 08:17 PM
Ron914   Well all done . I must say it was easier than I th...   May 8 2025, 08:30 PM
JeffBowlsby   Another documented case of a completely fractured ...   May 8 2025, 10:15 PM
emerygt350   Way to go. I mean you are disassembling the most ...   May 9 2025, 06:57 AM
rjames   Crazy that it could hold vacuum at all!   May 9 2025, 10:01 AM
Superhawk996   Crazy that it could hold vacuum at all! Mine...   May 9 2025, 01:24 PM
Ron914   Well I was optimistic that my car was going to run...   May 9 2025, 05:37 PM
emerygt350   You can pull the wires one at a time till you find...   May 9 2025, 06:09 PM
Superhawk996   This is going to be a tough love post. When you ...   May 9 2025, 07:26 PM
Ron914   This is going to be a tough love post. When you...   May 12 2025, 03:17 PM
Superhawk996   I’m going to post this over here This is anoth...   May 9 2025, 07:53 PM
rjames   What Hawk said. And you just rebuilt your MPS, so...   May 9 2025, 08:17 PM
Ron914   Thank you Superhawk and emery ,You are correct in...   May 9 2025, 08:27 PM
emerygt350   Once it is all back together, remember that inner ...   May 10 2025, 04:22 AM
emerygt350   Don't worry about TDC, the distributor only go...   May 12 2025, 05:50 PM
Ron914   Don't worry about TDC, the distributor only g...   May 12 2025, 06:57 PM
fiacra   If only I didn't live in California I would b...   May 12 2025, 08:03 PM
Ron914   If only I didn't live in California I would ...   May 12 2025, 09:46 PM
Superhawk996   First on the to do list MPS is leaking down too ...   May 12 2025, 06:57 PM
Ron914   First on the to do list MPS is leaking down too...   May 12 2025, 09:44 PM
Superhawk996   Aren’t other guys in CA running 123’s? Regard...   May 12 2025, 07:00 PM
Superhawk996   Also with respect to the dizzy vs timing Yes - s...   May 12 2025, 07:19 PM
Ron914   As far as putting a 123 in my California car I was...   May 12 2025, 09:11 PM
Superhawk996   I would open the MPS back up. I can post time lap...   May 13 2025, 08:37 AM
Ron914   I would open the MPS back up. I can post time la...   May 13 2025, 10:19 AM
emerygt350   I agree with hawk. The first time I rebuilt mine ...   May 13 2025, 10:02 AM
fiacra   Ron got that Pertronix from me, and yes it is olde...   May 13 2025, 01:34 PM
Ron914   Ron got that Pertronix from me, and yes it is old...   May 13 2025, 03:25 PM
fiacra   If I was to eventually pass a smog test I could t...   May 13 2025, 07:00 PM
Superhawk996   Remote stater switch is about $15 and pricele...   May 13 2025, 01:35 PM
Superhawk996   Z0n2aTFRMiI?si=W8rg02X2Kwp4r_54 I cut this off at...   May 13 2025, 02:40 PM
rjames   There is an art (and likely some luck) in getting ...   May 13 2025, 03:00 PM
Ron914   There is an art (and likely some luck) in getting...   May 13 2025, 03:10 PM
SVG223   Good luck with this, my MPS is leaking too, watchi...   May 13 2025, 04:18 PM
Ron914   [quote name='SVG223' post='3205335...   May 13 2025, 09:01 PM
JeffBowlsby   Just a heads up, there are other places the MPS ca...   May 13 2025, 06:18 PM
JeffBowlsby   dbl dbl.   May 13 2025, 06:18 PM
Ron914   Well I opened my MPS and found that the order in w...   May 14 2025, 07:57 AM
ChrisFoley   I switched from a round o-ring to square in my kit...   May 14 2025, 10:45 AM
Ron914   I switched from a round o-ring to square in my ki...   May 14 2025, 12:07 PM
emerygt350   I think that is exactly what I did the first time ...   May 14 2025, 11:54 AM
Ron914   I think that is exactly what I did the first time...   May 14 2025, 12:08 PM
Ron914   I think that is exactly what I did the first time...   May 14 2025, 04:36 PM
emerygt350   I think that is exactly what I did the first tim...   May 14 2025, 04:48 PM
emerygt350   Although no leak is best. That leak is pretty slow...   May 14 2025, 12:29 PM
Superhawk996   Get rid of the adapters Go straight from vacuum ...   May 14 2025, 01:41 PM
Ron914   Get rid of the adapters Go straight from vacuum...   May 14 2025, 04:32 PM
Superhawk996   [quote name='Superhawk996' post='3205480' date='M...   May 14 2025, 05:58 PM
rjames   [quote name='Superhawk996' post='3205480' date='...   May 14 2025, 06:20 PM
Ron914   [quote name='Superhawk996' post='3205480' date='...   May 15 2025, 12:29 PM
SVG223   Mine takes 45 seconds to leak from 10 in/hg to 5 i...   May 14 2025, 03:12 PM
emerygt350   Mine takes 45 seconds to leak from 10 in/hg to 5 ...   May 14 2025, 04:18 PM
ChrisFoley   Problem with the old square o-ring is that it will...   May 15 2025, 08:57 AM
Ron914   Problem with the old square o-ring is that it wil...   May 18 2025, 01:41 PM
Superhawk996   :trophy: you’re getting there!   May 18 2025, 02:17 PM
rjames   No need to crack it open again to adjust if you ha...   May 18 2025, 03:12 PM
Ron914   Well after putting the old square O ring back in ...   May 24 2025, 08:40 AM
rjames   Put the ecu knob back in the middle and adjust onl...   May 24 2025, 09:16 AM
Ron914   Put the ecu knob back in the middle and adjust on...   May 24 2025, 10:27 AM
rjames   Put the ecu knob back in the middle and adjust o...   May 27 2025, 06:30 PM
Superhawk996   I need to add that I must set my timing still , ...   May 28 2025, 05:36 AM
Ron914   I need to add that I must set my timing still ,...   May 29 2025, 06:25 PM
JeffBowlsby   Of those three pairs of wires, one is grounds for ...   May 24 2025, 10:49 AM
Ron914   Of those three pairs of wires, 1 iz grounds did t...   May 24 2025, 11:09 AM
Superhawk996   Those grounds are mighty crispy and corroded and a...   May 28 2025, 05:31 AM
Superhawk996   My bad Ron I completely forgot you were running P...   May 30 2025, 04:15 AM


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