welding vs electrics in a 911

[advtracing]

Guys i have a euro 76s with cis , i will be welding in a strut brace etc... soon and need to know other than disconnecting the battery totally , is there any other electrics that could get damaged during a mig welding session on the body?

[wildcat077]

I did some welding repairs on both my rear sway bar mounts ... just disconnected the battery first and suffered no ill issues !

Cheers !
Phil

[jeffs9146]

MSD recomends disconecting the CDI units + and - wire before welding on the car!!!

The point is that if you have an MSD you should "disconect it"!

[Chuck.H]

While disconnecting the battery isn't a bad idea, I don't think the muffler shops do this and they weld on virtually every car that comes in.

One tip though, put the ground clamp as close to your weld as possible, so the electric current has a very short path that doesn't include any electronics.

Hope this helps,
Chuck.H
'89 TurboLookTarga, 327k miles

[Tom '74 911]

Originally Posted by Chuck.H

While disconnecting the battery isn't a bad idea, I don't think the muffler shops do this and they weld on virtually every car that comes in.

That's a very good point. When I weld on my car, I remove the battery and MSD box (or now the 964 ECU Brain) from the car completely. My thought is that it's only a few extra minutes of work to be safe nothing's harmed. Probably overkill but. . . my garage isn't a 1hr. muffler place. (nothing against 1hr. muffler places. . . )

[Don Ivey]

I had my rear sway bar mount rewelded, the battery was not disconnected, and soon after the ECU died. Coincidence? I don't like coincidences.

Don Ivey
'87 Carrera

[dshepp806]

Although my 89 is outside of the OP's year,..I will say that I'm up for WEVO rear sway bar mounts reall soon,....my conversation with the P-wrench was to make sure that battery was disconnected and MOST IMPORTANTLY: the DME connector was disconnected....P-Wrench stated that it would be disconnected as well......they already knew!!!! My kinda' guys!

No doubt he'll (welder) be throwing some major "sheeit" to ground...... ALWAYS: better safe than sorry.

BEST!

Doyle

[lupin..the..3rd]

I had Wevo rear sway bar mounts welded in, both left and right, to my '87 Carrera. A beefy 240v Miller welding machine was used. Nothing was disconnected before hand, not the battery, nor anything else. None of my electronics suffered any ill effects. Not the DME, nor the MP3 stereo, nor the G2X GPS track computer, nor anything else for that matter.

I've had numerous other cars where welding work was performed, on the exhaust and elsewhere, and nothing was ever disconnected. I never experienced any electronic component failures or any other ill effects.

Remember, electricity is lazy, it takes the shortest possible path to ground. From your welding tip, to the ground clamp, is maybe a few inches? The battery and ECU are 10+ feet away. I find it hard to believe that welding on the body would cause electrical problems with anything in the car.

Remember, there are divers who do underwater welding in highly conductive salt sea water. They don't get electrocuted, because the electricity takes the shortest path - the few inches from the welding tip to the ground clamp. The current has no need to go through the diver's body or anything else for that matter, it simply takes a very short direct path to ground.

[dshepp806]

I'll rephrase: " I will not have my DME nor battery see ANY of the spurious voltages from a welding process, regardless of any distance parameters from ignition source,....i.e.: disconnect battery and DME connector, please Sir.

I would completely agree, as to "path of least resistance" proposition. One can, sometimes, assume the physical "nearby" areas are "electrically,... obviously,...evident of THIS path",..when, in fact, that's not the case,..due to whatever reasons that would ALTER the proposition (electrically-speaking).....ground continuities, in example.

I simply wouldn't take the chance on my 89 w/o battery disconnected (quick-disconnect-on-the-car) and a few screws to get the DME connector dropped......NOW, I'm tweaked a bit for "isolation" of the event to(rather, "from") my electronics......be it abnormal or normal....."abnormal, being (probably) a condition whereby the grounding integrity within the car may be compromised for various reasons,..and "paths" change a bit.....

To each, his own,...for sure.

Yeap,..those electrons are a bit "lazy" (it would seem),.....but to predict their paths could easily be assumptive,.....I try to never make any such potentially bothersome endeavors when I can eliminate the probability so easily. Statistically, you're on, bro'.

BEST!

Doyle