will a magneto over heat my rod?

i have a 427 ford fe with a magneto in my 34,its been rebuilt.but it over heats on short drives,its got wire leads and have the rite gap on the plugs.and today it just lost all spark.so if the magneto it not doing what it should will this cause the over heating?

help!!
thanks steve

 

First step with any electrical issue like this is to make sure all your wires are plenty big, and connected tightly. Make sure your engine grounds are good, remove any paint between a ground wire and it's connection. Many people have chased ignition issues only to find a thicker block to body ground wire, or removing the paint on either end of the ground wire, will solve your issue.

 

all that is done,i can only put it all down to the mag.it has a big fan and radiator,was going to try a dizzy

 

whats been rebuilt the engine or mag? whats the timing set at?

 

Pretty much the only way an ignition issue is going to cause overheating is either a very weak spark or retarded timing ~ neither of which should be a problem with a Magneto.

 

A buddy has a mag in his Cad powered 40 coupe. It is so sensitive that if it is off a hair it will kick back and blow the starter drive out.

 

motor and mag where rebuilt.but could it be that the mag is playing up,as now its got no spark?think i mite put an Pertronix Ignitor Ignition in and see

 

timing is good

 

Is the Magneto Internal Coil or External Coil?

 

The mag will not over heat your rod. Improper tune, not enough coolent or cooling capacity, lean carbs and any number of things will over heat your rod but the magneto itself will not over heat your rod.

Here is what the magneto does, it supplys spark to the spark plugs. If it is misfireing or not firing at all then you are just running raw fuel through the cylinder unburnt fuel will not cause your engine to run hot. Now improper timming can cause your engine to overheat but that is not the fault of the magneto that is the fault of the tunner.

 

Did it overheat before you put in the mag?
Is the mag itself getting to hot to touch?

 

A lot of mags that were in race cars will have the advance locked. That may be why MJ40s buddy has kick backs. Timing is on the ragged edge for starting but not to bad for driving. If yours is locked out and you are timing at idle for initial advance, that may be all you ever get. In which case your retarded on the hiway. That's the only thing I can think of a Mag will do to cause overheating. Just rebuilt? Head gaskets in right side up? sealed good? 427 has a big bore and combustion gasses will sure heat the water if they get there.

 

This is important and correct - could be your problem!!!

 

How have you doublechecked the timming.
if you dont have enough advance it will overheat.

Try adding advance a little at the time by turning the magneto, and see if it helps.
if it does you need to double check you timmingmarks and maybe the magneto advancecurve.



Another thing it could be check the thermostat, it could be mounted wrong or stuck closed.
I ussally drill a small hole in the thermostat so air gets out and all the water gets'in Another cause of overheating, is not enough water.

 

A stock 34 radiator won't cool an FE. I got my first 34 radiator from a friend that stepped up to a Walker to cool his FE powered 34.

 

Your first post stated no magneto spark, check the contact nub in underside of the cap. 3/4 years back my '54 235 begin to run raggedly at random times before quitting
on a main street at the Goodguy's in Puyallup. Can't tell you the number of street rodders who slowed asked if I was having problems? When I replied yes, they responded with "Good Luck" and drove on... A young guy walking down the sidewalk with early bike mag experience pried the nub out of my spare cap and replaced the one was just gone. Joe Hunt has replacements. I now carry a spare cap complete with wires for simple trade-out. Hope this helps...