Starter arcing to header pipe

[wvmarv]

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?

View attachment 1211395 View attachment 1211396

You're drawing at straws unless you actually see the arcing. I have been a mechanic for over 40 years and 12v will not jump that gap. There were plenty of cars built that had gaps that close and closer that never had any problems with arcing. The only way for that to arc would be by physically touching them together. The chattering problem you're hearing is probably the bendix on the starter not mating with the flywheel correctly. The only way to find out is to get under the car and pull the flywheel inspection cover. Then get it to where you can repeat the noise/problem and have someone crank the engine over (pull the coil wire so it won't start) while you lie under the car and see exactly what is going on.

 

[Vanderstel]

Ok, a little more information.

1) When I turn the ignition key and I get the chatter, I can see the fan blade start to move. So I'm guess the starter is turning?

2) If I leave the ignition key in the "on" position, and jump the starter relay with a flat blade screw driver it starts every time.
What does that mean?

 

[dadsbee]

It means your starter relay contacts are toast...

 

[RJRENTON]

It means your starter relay contacts are toast...

YES.....ABSOLUTELY.....Another possibility is the battery is nearing the end of its life....or the solenoid contact in the starter is bad.....check the starter relay first as suggested....
BOB RENTON

 

[steve340]

As above guys have posted you probably have a starter system fault - or you could have a fault in the ignition key itself.

 

[dadsbee]

I just want to know if he actually ever had sparks flying from his header to the + lug on the starter...

 

[moparedtn]

This would be a good one to try to catch on video...

 

[Vanderstel]

I just want to know if he actually ever had sparks flying from his header to the + lug on the starter...

yes

 

[dadsbee]

yes

So what have you done to make that stop?

 

[RJRENTON]

yes

IMO....IF, arcing was occurring, it is highly likely that either the starter connection would have been melted to some degree OR the header tube would have a hole melted thru the pipe or evidence of arc track. Look closely for evidence.....
BOB RENTON

 

[Vanderstel]

IMO....IF, arcing was occurring, it is highly likely that either the starter connection would have been melted to some degree OR the header tube would have a hole melted thru the pipe or evidence of arc track. Look closely for evidence.....
BOB RENTON

I added a ground strap at the starter bolt to the firewall, and there was a rubber boot covering the connector that the arc seemed to be traveling through, it was loose and flopping around, so I took it off. Ok, ok, sounds crazy, but it was there, and now I don't see it.

I've replaced the starter relay. I'm now going to check wiring to the relay, some wires seem worn, cracked etc. My plan is to replace wire harnesses on both sides of the bulkhead, but not right away.

 

[glenns hc]

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.

Agreed