Ignition ground circuts

[waynep712]

I have been reading the various articles on ignition systems and wonder if anybody have ever thought of the path of the spark to complete the circuit .

across the spark plugs and through the heads, to the intake manifold and then through the hold down clamp....

i was thinking , wondering if anybody had drilled and tapped the bottom of the distributer housing and added a pair of wire to ground the back of each head to the housing to complete the circuit......

perhaps this is also what causes dist gear failures. with many housings with o rings sealing the block oil galley there might only be ground through the cam drive gear...

this type of failure has been seen on many cars usually at the U joints where the engine is not properly grounded to the body... i have even seen dodge vans with the throttle balls burned away when the ground cable to the front of the block was loose...

this is just a though... but as every one knows the ignition system will not work if the distributer is out of the motor with out a ground wire to the housing...

[84Dave]

With the MSD billet, mag pickup distributor I use in Chev V-8's, it's a 2-wire coming off the mag pickup and the ground required is back at the MSD ignition box. I did have a perplexing problem on a Chev V-8....... one time. The [4] plugs on one bank fired intermittingly. I used a lot of sealer on the block end threads of the ARP head studs. That, and the particular head gasket used, apparently partially isolated the heads from the block. I then used short lengths of #8 wire to ground the heads to the block at the rear of both heads. Then the block grounded to the tube chassis with a short length of #10 wire. The problem disappeared immediately and never returned. Since then, I always ground the heads to the block. Whether aluminum or cast-iron. Dave

[BlackCat13]

About 15 years ago I had a wierd problem, and have been using an auxillary ground wire from distributor to block ever since, on my own engines.
Other people think it is unnecessary, so the "customer is always right".

I do ground my heads to the frame/chassis with battery cables with eyelets on each end.