M6 tip-toe tranny - confirm this wiring is correct

[Jacqualine47]

Hi all,

I was researching wiring diagrams and noticed that the M6 tip-toe tranny has 2 wires going to the coil - one is in the terminal that is wired to the dizzy and the other is in the terminal that wires to the ignition-on power. Obviously, the ignition wire is simple to move elsewhere as it just provides power when the car is on. However, the wire from the coil to the dizzy is another case entirely. I think that I have it figured out, but I want to make sure since the old tip-toe trannies are made of voodoo and fairy-dust with a dash of happy weed.

I'm an obsessive planner (and still haven't even taken possession of my project car), so I am already designing my new wiring harness and such (converting to 12-volt, putting in a fuse box, modernizing the brake lights, etc)... but I know NOTHING about that tip-toe transmission or what it does with the input from the Dizzy. Previously, I've always been a chevy girl and decided to start playing with an old mopar for a change of pace (and because I hate chev V6es, but want a classic that gets good MPG) - and all my previous points cars had their ignition systems file-13ed and replaced with an MSD6AL with a magnetic pickup dizzy. My plan had been to use the pertronix kit (part number PNX-1362) to convert the dizzy to magnetic pickup, replace the coil with an ACCEL racing coil (I have a few of them laying around from trades and ebay-trolling), and an MSD6AL (I had a spare that I used to keep in my camaro's trunk 'just in case')...

My ASSUMPTION (and we know what those do...) is that I can tie this into the pickup wire (the black wire from the dizzy that will be connecting to the white wire on the MSD6AL) and the M6 operation will be unaffected. However, I don't really know what that voodoo gearbox does - so I wanted to make sure that this is correct since all the components involved are expensive to replace.

[55 Fargo]

Go to ths website for www.imperialclub.com, as well as yahoos PWHM 1946 to 1948 Chryslers.

These 2 websites havea lot of info on these cars, there mechanicals etc, especially the M5 M6 transmissions.

You really should get on-line and order the shop manual for this car, you can alo get it from Roberts on the East Coast.

The manual is a wealth of info for your car, as well it has the complete wiring diagram you will need for the re-wire job.

On converting to 12 volt, you can use voltage reducers for the gas gauge,wiper motor,heater motor, the radio, is polarity sensitive, not sure what you need to do there.

Usinga GM single wire alt you can easily faba mount, and have the wide belt pulley installed on the alt itself.

You see with the tip-toe trans, the engine needs to idle down to like 450 to 500 rpm, to up shift, it also hasa kick down, to drop to a 3rd gear from 4th on the highway. Tehy are reputed to be great bullet proof trannies, once it is functioning and is well maintianed....Good Luck

[Jim Yergin]

Jacqueline,

I don't know anything about the M6 but I believe the connection to the distributor is designed to interrupt the ignition momentarially to allow the transmission to shift. At least that is how it work's on the overdrive transmission. If that is the case then you may want to check out Blueskies' web site (http://www.50plymouth.com/) . He installed an electronic ignition and had problems with the ignition interrupting set-up for his overdrive.

Jim Yergin

[Frank Elder]

Maybe this one is clearer.

[Jacqualine47]

@Frankie47: Thanks, but that is the one I already have. It still doesn't tell me what the tranny solenoids and governor do with the input from the dizzy pickup wire (IE: the negative coil wire).

I'll check out the imperialclub website and take another look at 50plymouth.com . I'm hoping that the tip-toe tranny just uses the dizzy pickup line to keep track of the motor RPM (I don't see from the wiring diagram how it could interrupt what the dizzy is doing, since it shares a post and doesn't interrupt the line to the dizzy) whereas the overdrive does something else? I'll have to see. The problem is that the wiring diagram I have doesn't tell me what the solenoids actually DO - so figuring out what they use the wire for is beyond me. I imagine that the purpose of the wire is to trip the solenoid when one lets off the gas since that is how one gets the M6 to upshift... but I need to know for sure how it works.

I'm planning on getting a service manual - but I'm not sure if that will help with my current query since service manuals I've had in the past don't usually explain how components work so much as how the components work together. I do have the wiring diagram for the car and for the M6 tranny though - they just give me the layout and color scheme of the wires, which doesn't tell me what the solenoids do.

I've already thoroughly researched the 12v conversion, so no problems there. I'm going with a three wire 105amp OEM GM alternator instead of an aftermarket one-wire though - one wire alts have a lot of issues since they sense the battery charge rather than the main junction's amperage draw (and I can get the 105 amp three wire out of a junkyard for 15 dollars rather than pay over a hundred for a similar new-in-the-box one... and I actually like having the idiot light to tell me if the alt isn't charging). I have a schematic for a solid-state 6v regulator, wiring schematics for the car, instructions on how to refurbish the radio to be negative ground (and in the meantime replace the capacitors and add an aux-in... plus wire it through an amplifier so that it can run four 4-ohm speakers with no distortion or lack of amps), heater motor will be replaced with a 12v unit from a 90s van (they are the same size amazingly enough - I got that info from 50plymouth.com ), a source for a wide pulley for the new alt, a list of 6v->12v bulb part numbers, a source for a universal alternator mount that makes it a bolt-on (actually from a tractor-supply store funnily enough), and a source for a 50amp rated voltage reducer (NOT a regulator, so no good for low-draw or sensitive stuff like a radio) for the wiper motor (which I probably won't need, since the wipers are likely going to be vacuum operated)... All I have to do is finish my design for a new wiring harness and find a source for a two post key switch rated for the kind of amperage that I'll be needing to put through it - the original would probably work, but I don't want to trust it 'just in case.' If I can't find an appropriate switch, I'll just use the original in conjunction with a heavy duty relay (the kind designed for remote battery kills) so that it doesn't have to be a conduit for the amps. The gas gauge will go through the 6v solid state regulator along with the clock and radio, and the ammeter will not be hooked up because I don't feel that it could handle the amperage I'd have to ask of it. I may re-purpose it - but it'll probably not be hooked up at all. I also found the part number from advance auto to get a 12v starter solenoid for 15 bucks (that took a lot of detective-work - it was starting to look like the cheapest one was going to be more like fifty dollars), and I plan to use a second 6v regulator to make sure that the solenoids on the M6 as well as on the carb (kick-down switch and anti-stall control, hooked to the M6 solenoid and governor via the brown and yellow wires respectively) only get a six-volt supply.

So the only questions I really have on the whole mess are that one wire, what the tranny does with it, and whether the M6 governor is polarity sensitive (I'm pretty sure that solenoids won't be polarity sensitive).

I mentioned that I'm OCD about planning, right? LOL

Edited September 6, 2009 by Jacqualine47

[PatS....]

If you have a 47, you do NOT have an M6, you have an M5. There are some differences in the two and the wiring is different. M6 came out in 49 second series cars.

There is a Yahoo group for the 46-48 Chryslers called Postwar Heavy Metal, they may be more informed about the M5. Also the Imperial Club has some info online.

http://autos.groups.yahoo.com/group/46-48Chryslers/

The power runs from the coil for the transmission...even on a 12 volt car the coil is 6 volts (ballast resistor reduces the voltage to 6 for the ignition system) so there shouldn't be a need to have a separate regulator.

The systen doesn't "keep track" of the engine RPM, it just won't operate properly if the rpm is much over 450. There is an interuptor switch to cut the power to the ignition momentarily so the tranmsission can shift.

Don't think modern computers...think primitive mechanical...these transmissions are really very simple once you wrap your head around them. It only took me 30+ yrs!

Edited September 6, 2009 by PatS....

[Jacqualine47]

Okay, I'll check the other websites.

The car in question is a 48, but supposedly the motor and transmission are out of an early 50s vehicle.

I'm just trying to understand how a wire going to the negative post on the coil can cut the ignition when it doesn't interrupt or otherwise impede the wire from the dizzy to the same post... does it do something to cancel out the signal from the dizzy? Its starting to sound like I'll have to keep the original ignition system until I rip that transmission out and put in a five-speed.

I'm not using the original coil or ballast resistor - I'll be using an aftermarket coil manufactured by Accel... so it will be 12v and the reducer will be needed - also, I'll have to relocate the ignition power feed anyway, as the wire from the MSD to the coil won't be constantly hot with the ignition switch turned on like the original wire was.

[Jim Yergin]

Jacqueline,

My understanding is that the wire to the ignition grounds the circuit thereby interrupting the ignition.

Jim Yergin

[Jacqualine47]

EDIT: Thanks Jim, you posted while I was reading the info on the website, and I didn't hit refresh before posting... so thank you so much! That was just the info I was looking for - the how rather than the what

So the solenoid shorts out the ignition coil for a second (EEEK!) - just grounds it out for a split second so that it misses a little bit...

So the answer is that to do this in a manner that won't fry an electronic ignition, I just need to setup a relay to turn off the IGN-on feed to the MSD box whenever ground is applied to it, and hook that to the solinoid... YAY! Simple answer. MSD shuts off the engine just long enough for the tranny to do its thing, then turns back on.

I'm just in disbelief that they intentionally short out the ignition system for a second... that just seems wrong to me LOL.

Edited September 6, 2009 by Jacqualine47

[Dodgeb4ya]

It's the interupter switch on the transmission that for a split second grounds out the ignition circuit to relieve torque on the input shaft so the trans will be able to downshift. The shift rail piston moving back causes a ball on the interupter switch to be depressed and this grounds the ignition circuit. The blue wire goes to the single wire interupter switch.

Bob