Foedoe

In my 67 coronet 440 (318)
Changed my exhaust manifold and doughnut gaskets
When i touched the y pipe to the manifold it sparked!
The battery is grounded to the drivers side head and the block is grounded to the firewall i have some electrical issues like heater and wipers are wacky
What the deal?

440roadrunner

You sure it was an electrical spark, as opposed to "metal to metal"?

Foedoe

Yep ima welder

Greaser

there is no reason to have the battery grounded to the head and the block grounded to the frame. ground the battery to the frame, and the block to the frame. you will have a "bonded" ground and be good.

440roadrunner

Sorry, incorrect. Or at least not "conventional." The first way --battery to block, and jumper to frame--is the way nearly ALL original cars were done. This is because the HEAVY starting current goes to the block--not the frame.

Most 60's and 70's vehicles only had a small jumper, couple of no 10's or so --from the battery to the body for lights and other "small" loads.

If what he had really WAS a spark, and I'm still doubtful, the only explanation is that the ground cable is defective -corroded inside- or just plain a bad connection.

Couple-4 years ago, my old 86 Ranger has a cable with a terminal crimped "inline" in the ground lead. It comes off the battery, goes to the frame via this "inline" crimp, then on to the block. The cable had corroded right there in that "inline" crimp and was no longer grounding. Looked GREAT from outside the plastic insulation!!

Greaser

if the battery is grounded to the head, and the block is grounded to the frame, there is a chance that there is no continuity from the battery to the frame, dirty bolts, gaskets ect.

440roadrunner

I'll put money down. I'll bet you cannot show me ONE ENGINE in good running condition where "a head" is electrically insulated from the block.

Foedoe

Its impossible unless you have like plastic bolts or something haha

Greaser

ok.. so this dude is saying that he has electrical issues, most common problem bad ground. When you connected the Y pipe to the manifold, you were shorting the head to the frame right? yes and it sparked. what causes a spark? A difference in potential. a difference in potential is solved by having a bounded ground. that means that all grounds go to one place. You think your block is spitting sparks, i would put money on it that you have not checked to see what your resistance to ground is from your block to your neg. batt. terminal and or frame. oh by the way, guess what i do for a living.. (hint it involves electricity)

440roadrunner

So you took a whole paragraph to suggest that HE MIGHT HAVE a loose/ bad/ dirty cable.

This still doesn't explain those rare mystery engines with the insulated heads

So let's add this up. He said he has the battery grounded to the ENGINE. Let's assume that the connection is GOOD. Explain to me how "the frame" is magically going to generate electricity and spark from the frame to the block, when the BLOCK IS GROUND

The only thing that makes sense is he might have a bad ground cable/ connection.

Some of the rest of us (hint hint) know a little about juice, too

I was a licensed amateur operator before I left high school in 66

Spent 6 years in the U.S. Navy maintaining GCA RADAR/ TACAN

Worked in and out of electronics most of my life

Worked over 10 years maintaining HVAC, including rooftops operating on 460 3ph, and built some 250hp dehumidifier dry kilns. We even serviced a couple of pieces of mining gear running on 2300 3 ph.

I hate screw compressors

Greaser

I re-read what i said and relize i came off as a dick and i appologize for that. The bit about the heads being "insulated" is not right, i was thinking between dirty bolts, and a gasket there might be some problems for continuity, but i didn't think farther than that.

I have served in the US NAVY for 8 years as an IC and i am still doing so. i specialize in low volatge ie 120Vac to -48Vdc. the wiring in a car is very similar to that of a ship, where you have to use a common that is known good. The common/neutral uses the hull or frame in this case, as a conductor. I have seen many fires on board due to faulty grounds. I have had a car go up in flames due to bad grounds, and i have seen and entire telephone switch go down due to a difference in potential between grounds. A grounding issue can be one of the hardest to identify and find.
"So let's add this up. He said he has the battery grounded to the ENGINE. Let's assume that the connection is GOOD. Explain to me how "the frame" is magically going to generate electricity and spark from the frame to the block, when the BLOCK IS GROUND"
The frame could generate energy by him rubbing against it while working on it or it might not be properly grounded. but if when he "shorted" the exahust manifold to the Y pipe (which probably has a metal hanger on it at some point directly to the frame) and there was a spark, that means there was a difference in potental.

Foedoe

Lets hope my car doesnt go up in flames the head ground is fine but the frame ground is questionable but doesnt look too too bad ill have double check it
Thanks for all the input