Starter arcing to header pipe

[Vanderstel]

The is a new configuration. I've got a new 318 rebuild and I'm working out the kinks from a new startup last Sat. Things are looking good, but I notice once the engine is warm I'm getting an spark jumping from the starter (new mini from for a 92 Dakota) to the header pipe which is really close, less than a finger width. See attached pictures.

The starter picture shows the connector that is arcing the pipe.

I checked for voltage at this connector with key on and off, none. I'm guessing after the engine and header pipe heats up the clearance closes enough for the spark to jump. When this happens I can't start the car, I just get the relay chatter. Once it cools I'm good to go.

Am I not grounded somewhere? I removed the insulator that came on the starter, it appears to be made of rubber not sure.

Suggestions?

 

[Badvert65]

That boot is usually made of silicone rubber and should withstand the header heat.
jus sayin....

 

[Vanderstel]

The spark was arcing through the boot, it was lightly touching the header pipe, that's why I removed it.

 

[steve340]

You have a block ground problem. Attach a large ground wire between the starter mounts and the chassis.

 

[sam dupont]

 

[Vanderstel]

I'll give it a try

 

[Crackedback]

Before buying or making anything for a ground, try this. Grab a jumper cable and attach it at the transmission case to chassis/battery neg side.

If it stops with the cable connected, get a better ground. Since the starter is mounted to the transmission, ground off the transmission if you don't want to mess with the starter mount bolts. Seen plenty of roasted speedo drive cables over the years with stuff looking for a ground path.

 

[Vanderstel]

Ok, I tried the suggestion about hooking up a jumper cable between the transmission housing and Neg battery. Well, I did that, still I'm getting chatter when I start when warm. Maybe I got a bum starter, it's still under warranty...

 

[451Mopar]

Check that the bolt is tight on the cable.
Unlikely a 12-16 volt system is jumping the gap to the header. To jump an air gap at those low voltages, the conductor would have to be closer than 0.001"
If the connection is loose, might see a spark at the connection?

If it is actually jumping the air gap, I would think a spark plug wire is is trying to find a low resistance ground path. Make sure block is grounded well, and plug wires not sitting on / arcing to the headers.

 

[RJRENTON]

IMO....the terminal has only 12 volts on it and only when cranking, 12 volts will not arc to ground.....it must be touching a grounded component.....unless heat is causing expansion causing the terminal to be grounded
BOB RENTON

 

[LowBikeMike]

Is exhuast installed? If so, could the exhaust be causing the header to flex a bit and hit terminal when engine is trying to torque over during starting event?

 

[steve340]

When the starter cranks it may only be 12 volts but it will be 4 or 5 hundred amps.
It will arc make no mistake. And that amount of current will look for the easiest path to earth.
Put a spanner between the battery terminals if you do not believe me - see what happens! 12 volts cannot arc is bunkum.

 

[RJRENTON]

When the starter cranks it may only be 12 volts but it will be 4 or 5 hundred amps.
It will arc make no mistake. And that amount of current will look for the easiest path to earth.
Put a spanner between the battery terminals if you do not believe me - see what happens! !2 volts cannot arc is bunkum.

I
'm totally aware of the phenomenon of electric arcs......but it depends if, and only if, there is a current path to ground.....its a function of resistance of the current/circuit path.....the higher the resistance the lower the current flow; conversely, the lower the resistance, the more current flow. An 1/8" separation beetwwe the source and ground, might as well be 9 miles...... Good old Ohm's Law applies.....12 volts will not arc to ground unless its originated.....like a "spanner between battery terminals" as you pointed out...but not on its own, the potential is too low.....
BOB RENTON

 

[WileERobby]

When the starter cranks it may only be 12 volts but it will be 4 or 5 hundred amps.
It will arc make no mistake. And that amount of current will look for the easiest path to earth.
Put a spanner between the battery terminals if you do not believe me - see what happens! 12 volts cannot arc is bunkum.

Amperage is current, current does not cause arcing. Voltage is pressure, low pressure = low chance of arc, high pressure=arc. What do you think a coil is for ?

 

[dadsbee]

For once I'm with Bob, there is NO way 12 volts is jumping that gap. Hell I have the cable/starter stud on my '64 less than an 1/8th from the block. If it's actually sparking I'm betting on a plug wire against the exhaust and then jumping to the lug.

 

[steve340]

It is jumping the gap because it is trying to get to earth. Some of the current is getting back to the battery the way it should through the block and earth cables - the rest is trying to find the easiest path back to the battery which in this case is the exhaust.
Read Crackedbacks post.

 

[RemCharger]

What if the header is against the steering box and flexing when the motor is Turing over?
Just spit balling, but I do agree with a connection /ground issue. Make sure the starters tight ,start relay connection / circuits etc.

 

[Vanderstel]

I ran an extra ground strap from the starter bolt to the bulkhead and I replaced the starter relay. Same results, once it get good and hot I get chatter until things cool down and then I'm back to normal. I tried again to see the arcing between the starter lug, and the header pipe but couldn't, so I don't know what's going on.

 

[LowBikeMike]

Have you actually witnessed spark jumping to the header pipe or you thinking the chatter you get from the starter when hot is the spark jumping? Starter issues when hot are a whole different concern and well documented on this site.

 

[sam dupont]

I've seen a battery primary ground wire that was too light cause problems with high compression cars when they are at operating temps.

The jumper cables from the ground terminal to the chassis would most likely cure that issue.