MSD SC rotor mod

[wolds]

All,

I've read all the threads on this subject and thought I'd take a stab at it. I have ordered two non-resistor rotors which I should have tomorrow, but on the outside chance they are of the resistor type and with idle time on my hands I though I'd take a used rotor and see what I could come up with. The plan is to vacate the rotor of its contactor, fill the void with JB weld till it's even with the projected tip and then fabricate a single piece of replacable brass to be held to the rotor body with a small machine screw. So this is the progress so far. Warren

[wwest]

Why not just bypass the resistor? Or even use one of a higher wattage?

[wolds]

That's how this all started. I went at the epoxy potting material with a ball burr on my dremel and never saw a resistor. After I got the material cleared out I didn't see any way to bridge the two contact points with a suitable piece of material. I also like the idea that I'll be fashoning the contact out of a single piece of 1/16" brass and will be able to change it when it wears out. Like I said, I'm hoping that what I recieve tommorrow will be the non-resistor type of rotor. I can see where as more of us switch over to the MSD CDI we will be needing a supply of rotors. Warren

[LEAKYSEALS951]

oreilly rotor- no hoping involved!

[wolds]

Tried that, no joy. Warren

[LEAKYSEALS951]

really? what happened? Mine worked. Just curious... (actually don't tell me- I dont want to jinx myself!)
Ron

[wolds]

If you have your local FLAPS run that number it comes up as a resistor type rotor. I ordered two rotors yesterday through amazon manufactured by Standard. The picture shows non-resistor type, hopefully that's what I'll recieve tomorrow. What I'm doing here is just a "plan B". Warren

[john walker's workshop]

napa. echlin brand.

[The cap'n]

"Standard" parts would be second rate if only they were better. They're, in general, cheap junk. I've personally witnessed total meltdown of their caps and rotors in less than 50 miles.

The Cap'n

[wolds]

I've already gone down that road checking with Napa as a result of reading previous threads on the subject. That PN refers to the resistor type rotor, it's what is depicted in their catalogue. I think somewhere along the way they have changed their manufacturing specs. Warren

[LEAKYSEALS951]

I hope your part works tomorrow. I ran down the same road with NAPA myself. I was in oreilly not 6 months ago and they entered "1978 911 sc" and it came up with three rotors, a resistored rotor (the one they recommended)and two resistorless (one of which was NLA and the other was this exact part #. The computer actually had pics of the part numbered rotors and you could see the resistorless feature on top. I ordered that # and got exactly what was pictured. I hope they haven't d/c'd that one as well... I might just go by there out of curiosity and check.
Good luck
R

[wolds]

I'm thinking that someone should market the non- resistor type. As time passes there will be more of us going the aftermarket CDI route and a demand for this part. My Permatune gave up the ghost on the way back from Hershey last month. I've been running on a borrowed Bosch while I gather parts for the upgrade. I've got an MSD Streetfire CDI and Blaster high vibration coil to install. Warren

[K Sykes]

Don't cut off the tip or the center and solder some copper wire between the two, and bed it in some epoxy. I did that when I was running MSD and it worked fine. I'll see if I can find mine and send a pic.

[wolds]

As you can see from the picture above I've already done that (no harm no foul) it was a used rotor anyway. We'll see what arrives in the mail tomorrow. Also, I spoke with a associate at O'reilly auto parts, he has a BWD D-703 and a Masterpro 2-3114 rotor that may work. Otherwise, I'll continue with my little project. If all else fails I'll try the bridge wire approach bedded in epoxy. If I take the bridge approach I'll share some pictures. Thanks for the help. Warren

[wolds]

So I received my rotors from Amazon today and am happy to report that they are the non resistor type. The box says Intermotor PN GB330. made in Mexico for what it's worth. Once I get the MSD Streetfire installed I'll post some before and after waveforms of the Bosch vs MSD for future reference. Warren

[wolds]

Here's a picture of new rotor and box. Warren

[garrett490]

Sorry but what's the advantage of doing this? Lower cost parts, better performance??


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[wolds]

This all started when my permatune went south and I was in need of a replacement. I purchased an MSD Streetfire CDI and Blaster coil as a replacement. The stock resistor rotor is not up to the task of pushing 45Kvdc to the cap so you need a non-resistor rotor. My attempt to modify a resistor style rotor to non-resistor became a mute point when I recieved my non-resistor rotors in the mail last friday. Warren

[T77911S]

i have been using stock rotors with MSD for over 10 yrs and no problems. i have also put in 2 MSD's, one with points and one on my 930, never had any tach issues that i hear about.

[Bob Kontak]

Originally Posted by T77911S

i have been using stock rotors with MSD for over 10 yrs and no problems.

MSD installed maybe eight years ago. Stock rotor.

Only think I notice is a build up of a gray crust on the cap contact points after 500 miles. I dremel or lightly scrape the stuff off and the car runs smoother.

I don't remember this with the Permatune(s) but it has been a while.

Not sure what it is from or if normal. There must be something amiss as the issue would surface in the forums.