Engine Grounding???

BlackRocket · 03-21-2008, 03:43 AM

I am assemblying a track car with very few wires; starter, electric fan, electric fuel pump, alternator, an MSD box, and a few gauges.

Everything was running fine, then after deciding to ground the engine block to the frame we began having problems...

First there were spark fron under the lower side of the crank pully to the lower frame crossmember about 1/4 " away?

We looked for any leftover wires, but only found the deactivated anti-skid wires and removed them. We cranked the engine again and then there was an electrical fire from the same area??? (No wiring is present there!)

Can't figure out what is going on??? (Should the engine have a grounding strap attached to it?)

With the battery cut-off switch in the off position killing power to everything, there is a small burst of power when I turn on the IGN switch since there is an associated light then it goes out. This may be the MSD box with stored power?

Any clues or ideas would be appreciated.

Thanks!

Richard454 · 03-27-2008, 03:21 PM

If you are using solid motor mounts- grounding shouldn't be an issue.

If not- the engine SHOULD be grounded-starter sees the negative side of the battery through the block-as does the alternator.

Richard

BlackRocket · 03-28-2008, 11:47 PM

After hours of cutting out my wiring and direct wiring the starter I found the problem....

The starter mount needed sanding to ground out.....

Richard454 · 03-29-2008, 10:25 PM

Lesson learned...Not that I have EVER done anything like that... well maybe my wiper motor in a C2 that is a PITA to pull out...or that rubber isolator that BMW's use on alternators to keep vibration down...

I now get out my meter and check continuity from motor/starter/alternator to ground or negative term of the battery...Usually saves me from rewiring/unbolting and pulling out what hair I have left....

Richard

BlackRocket · 03-31-2008, 01:25 AM

Yeah, I'm no electrician, but I can use an Ohm meter to check for continuity and it all checked good.

This one nearly drove me and a buddy crazy since we had a direct wire to the starter....

Well, everything works as advertised now after buying new NAPA starter for no reason....