TR4/4A Ground strap, ammeter

[dexstruh]

Would not having an engine timing-chain-housing-to-chassis ground strap cause the Ammeter to peg fully positive (and head up the supply wire)?

Trying to trace a (positive) ground issue.

 

[Geo Hahn]

Off hand I do not see how it would. You might get some strange things going on while cranking the starter but once the engine is running (and presumably getting a ground from somewhere) I would think the ammeter would be unaffected.

My guess is that you're looking for a big bad short. Does the battery cable get hot? Mine did:

But it was fine once the cable melted though.

 

[TexasKnucklehead]

That wire had some current running through it.

Regardless of positive or negative ground, your complete electrical system needs to be "earthed" to the same electrical point (ground). The generator ground needs to be the same as the regulator ground. With your battery disconnected, you should be able to use an ohm meter to be certain the generator frame and the regulator earth have close to 0 ohms. Depending on the accuracy of your meter, you may find some resistance there, but it should be no more than a few ohms.

 

[dexstruh]

Well, you were right. We didn't have your problem (yikes!), but here's what happened:

The wooden dash was removed, so when the gauge was tight the U-bracket that holds the Ammeter in place was touching the fasteners for the two heavy-gauge wires. It only reared up as an issue when the gauge cluster was installed, and subsequently shorted out to the body.

Solution was to make a U-bracket that was the same depth as the Oil gauge. Oh! And make a new wire from the starter solenoid to the ammeter...