M211 Ignition?

[Willie]

52 GMC M211 302 six. This is just like any other ignition right Looks a bit different. I was told it was so it could be water proof. Any ways I have no spark. It has been sitting a few years. Need some help on finding some books with the sechmatics and the power points. Any help is much apericated. Thanks []

 

[n1bnc]

Good Morning,

The ignition is exactly the same in principle. The only difference, besides the 24V, is that the wires from the distributor to the plugs are shielded. It still has points on the inside and the various capacitors and resisters involved. You can do the rest of the diagnosing with a volt ohm meter. I worked through my distributor issues with one and all you have to do is make sure voltage is where it is supposed to be and in my case I checked the coil with an ohm meter and where it should have read somewhere in the realm of a couple of ohms was "open". A new coil was then purchased from Sam Winer in Akron and the truck fired right up. I was annoyed initially because "it's never the coil" being preached, but I measured another coil and found my argument to be true. take one of the plugs out (use a VERY deep 13/16's socket) and reattach it to the cable (after making sure the shield is not shorted to the center conductor) and watch the plug spark, it does not need to be held to the chassis because it is already grounded. When I did this, I had my wife operate the starter and sure enough I now had spark and the truck was trying to catch!

For a schematic, look for the TM 9-8024. They are often on Ebay. You could also draw out the schematic visually as there are so few components.

Above all have fun, and when it annoys you, walk away and review the facts later.

Another tech tip, on vehicles this old, check all the plugs for crud. My Unimog in its finest tuning runs a little bit rich, my 302 does as well, although I am still working out the details...

 

[Willie]

Thanks for the help :yeah: Where is the best place to get parts to these? I don't the local store is going to have these. Need a coil and rotor, or a whole tune up kit work work also.

 

[n1bnc]

Try Sam Winer in Akron Ohio or Memphis equipment in Chambersburg, PA and ask for Mark. I was just there on Monday, which is why it took so long to reply.

 

[williamh]

i have gotton my parts form napa/carquest ... it will be several days before i can get the numbers for the points / coil ...but you should be able to take the parts down to them and they can match them up .

 

[Tony]

M-211 ignition

h1bnc--- in reading your post you stated "open" this phrase is not familiar to me..pls explain

thanks

Tony

 

[G744]

"open" when using an Ohmmeter means infinate resistance, or no pointer movement. No continuity. No flow of current. An open circuit.

dg

 

[JasonS]

The best thing you can do is convert to a civiliian style distributor. Get a disty from an early chevy six. You can also convert to a pertronix electronic ignition. I used the 1167 pertronix in my m35 but the gmc is the same internally. You will need to keep the original ballast resistor and use a pertronix 3ohm coil (40511). The 1167 can be gotten in 24V for $40 more but I used a 7812 linear regulator to supply power to the module (red wire). The coil current is switched between the black wire of the pertronix and ground so the regulator only has to supply a small current. You will have to remove the points adjustment cam and drill and tap a new hole for the pertronix mounting screw. Works great but if I could convet to a civilian disty I would in a heartbeat...

 

[n1bnc]

I was thinking about the civvy dristrbutor myself and the thought came up about vacuum advance. Does the civvy one have it and if so how did you supply the vacuum.

Was there a noticeable performance change with the pertronix?

My current issue seems to be spark related on my truck now. I have a bit of backfiring through the carb on hard acceleration and I have a hard time getting up a hill without forcing a down shift and sit for the long ride. My points, plugs, coil, cap, rotor, condenser are new along with fresh gas,carb and fuel pump, and the weights move just fine. So I am at a loss here.

I have only been able to time the engine by ear as I do not have a method of getting the timing light to work with the waterproof system. I wouldn't mind hanging on to the current system, but i could easily be talked out of it. The wires alone at memphis are about $200 for the set.

I also need to move the M135 to its new home this winter and i would be happiest if it did under it's own power.

 

[MVtrucker]

Do a compression test. Might have some burnt or non-seating valves.

 

[JasonS]

The lines to the military disty are for the governor. Neither the civy nor military 302s had vacuum advance; it wasn't used in the big trucks. It would be of limited value in a large truck since you seldom are at light load.

You can stay 24V regardless of whether our not you keep the points. The key is to limit points/pertronix current. The stock system uses a 1.5ohm coil and a 1.5ohm ballast resistor. The coil can be transferred to the civvy disty but you will need a new 1.5ohm ballast resistor.

The pertronix will not likely give you much better spark than new points. However, it will last indefinately. I would rather spend money on the pertronix once than points every year. It is below zero here and the truck starts fine (daily driver). You can also modify a later model hei from a 250/292 chevy but it will not run on 24V.

I second the compression test. You could also have a lean misfire under load. You can use a standard timing light: You will need one civvy ignition wire and one civvy spark plug. Trim off 1/4" of insulation and stuff the wire into the disty cap. Then connect your inductive pickup and the timing light to ONE 12V battery.

 

[Tony]

M211 ignition

Hi guys, I understand the open part of a circuit, what I don't understand is " " could someone explain this to me.

Tony

 

[G744]

Open?

Already described above.

dg