Installing the Pertronix MR-183

Try wiring in a 12V bulb instead of the coil, the bulb should flicker if you turn the starter. If it does not turn on at all, either the magnetic sleeve is installed incorrectly, or the Ignitor does not receive 12V via the red wire, or the Ignitor itself is broken.

Good luck,
Adrian

 

The wiring was all correct, it was the magnetic not sitting low enough. Started right up. Thanks!

 

Will this (petronix) stop my car from fowling plugs?

 

Depends on the condition of the carbs, dist cap/rotor, spark plugs and spark wires. It might be a good start to first try NGK BPR EIX spark plugs which are one step hotter than your current plugs before changing the full ignition system.

 

In all honesty, the twin dizzys work great on mine-but this is he one mod I'm just dying to see the results from. Great freaking thread. Has anybody reversed this before-it looks like it would be straightforward?!

 

I'm pretty sure converting a twin dizzy setup to an ignition setup triggered by only one of the two distributors will give you better result in virtually any case. It is nearly impossible to get the advance curve of two distributors in sync over the full RPM range (and this will get worse with the different wear patterns of each distributors advance mechanism over time) and the engine will run much smoother if the two banks are run with exactly the same advance curve.

 

Nobody that's done this has ever wanted to go back!

But nothing is cut or permanently altered in any way. If you really want, you can make it look completely stealthy and the concours judges won't even know (but I preferred upgrading to Flamethrower II coils).

 

That's what I figured.....and, trust me, this car is far from concours!, but it's the old 'if it ain't broke, etc. I'll get the pang in about 2 mos when it's in this warehouse I store it in. And if I do it I'm certain the first think I'll say is why the hell did I wait so long!

 

Late to the party, when you remove the distributor, is the shaft keyed so when you pull it out it only goes back one way? or is it like an American car and the teeth have to be lined up?
Thanks GTJOEY1314

 

It can go in anyway between the gears. You may find you need to rotate it one tooth from the point set up if you are at max adjustment. This happened to me. The pertronix lined up a little more retarded than my points which were at max advance adjustment. I had to pull distributor the. Advance one tooth then put the distributor back to min advance adjust if that makes sense? Google mechanical advance set up.

 

Hi Joey,

You might make this little tool to put you back in the ballpark. Here's a thread from a while back.

Jeff

http://www.ferrarichat.com/forum/308-328/389961-homemade-tool-help-distributor-removal-installation.html

 

I started installing the 9MR-183 kit today on my 75 GT4. I was pleased to note that the instructions I received included reference to both removing the felt piece and the retaining clip that evidently were not previously mentioned. Since my car didn't have either the felt or the R2 points that part didn't matter.

I did find that the plate could be mounted in more than one configuration and used the pictures earlier in the thread to determine which way it should go. (the screw holes used were not the ones originally used by the R1 plate)

I was stuck at the point where the new plate is installed and I need to put the trigger magnet over the lobe. The pressure required to get the magnetic plastic black piece over the lobe was more than I expected. I ended up using a 17mm deep socket to push it on. I have the distributor put back together now, but have not installed or wired it up yet.

 

I have the petronix installed and the car starts, so I didn't screw it up too much. However I am trying to get the timing set and checking it using the two banks of cylinders I find that rotating the distributor with the petronix installed changes either, they are not the same. The bank with the petronix is ~5 degees off the other bank. Does that mean I have the distributor a tooth off? @alhbln is that what you were talking about in your post? (bold below)

 

No, it means the two pick-up are not mounted 135 deg apart -- you need to move one slightly (~2.5 deg) relative to the other.

 

how would I move them relative to each other? I am using the 9MR-183 where they are pre-mounted on the plate by petronix.
The bank with the petronix is set to 7 degrees and the other is around where the "PM" is.

I also noticed something strange, the other bank seems to be less stable under the light. And on the back bank (where the petronix is) the #1 wire won't always light up the light, but number 4 will.

 

Is there no slop at all in the mounting holes to move the pick-ups slightly? Make some marks before loosening anything up to have a reference for where they are now if there is some adjustment possible. If no adjustment is possible, you'll have to get another complete assembly from Petronix as your symptom ("The bank with the petronix is set to 7 degrees and the other is around where the "PM" is") can only be caused by the relationship(s) of the pick-ups not being correct. Another thing to check/confirm is that the physical spacing from the magnetic rotor "prongs" to each pick-up is about the same distance.

 

thanks, dumb question here since I have no experience with points and very little with distributors, but isn't the timing also affected by where the rotors are? i.e. if the rotor isn't pointing to the wire it can't send a signal to the plug at that time. So wouldn't both rotors need to be in sync? I am not 100% positive I put the distributor I added the petronix to back exactly where it was before, it could have been a tooth off.

 

I am pretty sure there is no way to adjust them, the pickups are screwed to a plate, you can see a closeup at https://static.summitracing.com/global/images/prod/xlarge/pnx-9mr-183_xl.jpg

 

Steve's right, you have to move the plate to get the trigger points exactly 135 degrees apart. 2.5 degrees is a tiny amount so slight differences in the height or proximity to the magnet can cause that. I would loosen the nuts and push them together or apart while tightening them (depending on whether the second trigger is lagging or leading- respectively.) Files the holes a little bigger if needed.

For the synchronisation of the "slave" distributor, I would take off its cap, put a spare plug onto that coil's HT lead, put the timing light onto that plug and point it at the slave distributor. The flashes will indicate where the rotor should point so mark one of the flash positions on the distributor and then adjust so that the marked position lines up with the rotor and the output on the cap.

 

No, it can cause a misfire, or a crossfire, if the dist rotor isn't properly aligned to the dist cap, but it has no effect on the timing. The "slave" dist rotor does need to be aligned reasonably well to its cap, too. One thing that can make the rotor-to-cap alignment less fussy is to use the 124288 QV rotor that has the wider end width (the middle one in this photo):

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124288 308QV rotor:
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As Derek suggested, my guess would that be there would be some clearance in the mounting holes of the pick-ups so that loosening the nuts would allow the pick-ups to be moved a little (or the advanced class would be to enlarge the mounting holes to allow more movement if they are too tight), but you seem uncomfortable messing with this so asking your supplier to recheck, or replace, the assembly may be your best course of action. It is a little tricky as you want to change the angle between the two pick-ups, but keep the pick-up-to-magnetic rotor spacing the same. (However, your report that one pick-up's timing seems less stable could indicate it's spacing isn't correct now.)

 

I called Petronix and they said I needed to make sure the slave distributor was set to 0, but when I asked what exactly that meant they offered to email me some documentation. It never came so I emailed them and they again said to set it to 0, but again failed to follow up with what that meant or how to do it.

@derekw suggested that "For the synchronisation of the "slave" distributor, I would take off its cap, put a spare plug onto that coil's HT lead, put the timing light onto that plug and point it at the slave distributor. The flashes will indicate where the rotor should point so mark one of the flash positions on the distributor and then adjust so that the marked position lines up with the rotor and the output on the cap." I am afraid I didn't quite follow that.

Can I just set the timing using one of the spark plug wires from the master and lock the master down and then use of of the wires from the slave and twist the slave distributor until it matches what I had on the master?

 

Hi again,

No, normally in the slave distributor you have the points or sensor mounted in the right position relative to the posts on its cap. Now the sparks are triggered from the master so you lose the physical connection between points and cap posts.

My suggestion above is the simplest way I can think of-/ hopefully someone else smarter than me can think of something. I’ll try to be clearer:

First do the timing in the master bank as normal. Then mark on the slave body where the four plug lead posts line up. Remove the cap, pull the HT lead off the slave coil and connect a plug wire and spare plug to the coil. Put the plug on something metal so it is earthed. Put a timing light on that plug wire. Run the engine and see where the rotor points when the timing light flashes. Rotate the slave distributor so that the rotor is pointing just past the post position at low rpms (as the spark advances with higher rpms it will come earlier and earlier on the rotors travel.)

This assumes the rotor position is close as you said the engine is running. If it doesn’t work you need to put the crank to cylinder No.1 TDC compression stroke and make sure the rotor is pointing towards No. 1 post. As suggested, use the wider rotor. Hope this helps.

 

@derekw you are still talking about rotating the entire distributor, rather than moving the rotor a tooth to make the alignment, correct?

Not having a spare plug, the second method of getting cylinder #1 to TDC may be the easier method.

 

Yes, loosen the nut and rotate the distributor body.

 

I wanted to give a report. I marked where the slave distributor was set and then tried rotating it while watching the timing light. Rotating the slave did not change the timing at all, it was still a few degrees off measured on the slave bank than what I read on the master bank. Since the car seemed to be working ok, I decided to just try driving it with the two banks a few degrees off. What a huge improvement. Car runs better hesitates less, and pulls to redline with an intoxicating sound. So not sure it is exactly right, but it is way better and I am happy for now.

I should note that previously while I was trying to set the primary bank timing I had noticed that the timing light did not work on cylinder 1. Turns out the plug extensions were falling apart and that one was grounding out. So I have replaced them, which helped a lot. Also I set the master timing to be a few degrees advanced vs. the 7 degrees that was factory recommended for the U.S. since I know the European models had about 16 degrees.