Ignition wiring help please.

K

keeeef

Member
Hi

I am converting my 36 pickup from 6v pos ground to 12v neg ground. I have fitted the distributor coil converter, new coil, solenoid etc and wired as shown in diagarm below but dosen't want to start? Kept the 6v starter and its spinning ok. Can anyone spot an obvious mistake before I go troubleshooting!

Thanks
Keith
 

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Please clarify, it cranks but won't fire, or won't crank at all?

Do you have 12V at the + on the coil with the ign on?

Are the points clean and gapped right and grounding effectively?

Mart.
 
Hi Mart

Cranking fine.

It was running on the old 6v sytem a couple of weeks back so assume points ok.

Got 12v on the + and - at the coil with ignition switched on.

Keith
 
keeeef said:
Hi Mart

Got 12v on the + and - at the coil with ignition switched on.

Keith
Click to expand...

Do you have voltage at the coil while cranking? Depending on your switch and how its wired, you might have 12 volts to the coil with the ignition switch on, but not when the starter is engaged.

Tom
 
Keith, check as 47 says above, that the 12v is still there when cranking, also check that the - side of the coil goes intermittently to earth as the points open and close.

Mart.
 
Thanks guys will check it out tomorrow.

I did squash the coil a bit forcing it in to a home made bracket and wonder if I may have killed it!!
 
keeeef said:
Hi Mart

Cranking fine.

It was running on the old 6v sytem a couple of weeks back so assume points ok.

Got 12v on the + and - at the coil with ignition switched on.

Keith
Click to expand...

Unless you have a coil with internal resistance you should not have 12 volts to the coil.
 
Does your switch have 3 or 4 terminals the center one is the power one if 4 terminal.
Also you need a 1.5 OHM resister and a 12 volt coil.
There is a resister under dash .5 ohm not needed.
Run wire from switch to resister then to pos coil terminal.
 
Ed Pitts has a nice picture of the ignition circuit. You should have a #12 wire from the column drop switch directly to the resistor/coil. Nothing to fail.
As you stated, you might have damaged your coil. Condensors can fail also.
 
She's alive!! Thanks all for the help.

Turned out to be the 'pig tail' spring under the coil adapter needed stretching out to make good contact.

However I don't have any resistor in the circuit to the coil, should I fit one?

This is my first flathead V8 and I am still finding my way so any advice is much appreciated. I shipped the truck over from Illinois to the UK in Feb and it arrived with 2 batteries fitted, one 6V powering the ignition and a 12V wired just to the starter!! (see pics below). The wiring was a real mess so I took the whole lot out and started again with a Haywire Pro-T harness, 1 wire Alternator, Flamethrower coil, 12v solenoid etc. but I don't have the resistor.
 

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Keef, Those pictures are great! Ya gotta frame them and keep them for future reference... :D

It took a real genius to build: From one side, the batteries hide most of the wiring, and from the other side, the batteries are invisible 'cause you're mesmerized by the maze of wiring!
 
Wonder if it was an old farm truck ( judging by the creative use of a license plate as a patch )
 

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Was anybody hurt??..............OLD..........BILL
Yes I was going the say check the adapter plate, I/we have seen some good ones, and some not so good. .... your going in the right direction .... and have fun
 
Just a note, you got a 94 carb on there with a manifold originaly ment for a 97. There appears to be some kind of vacuum take of plate twix the carb and manifold, so this is a make sure note. That type of manifold has a hole in the top under the carb, this is an exhaust heat riser hole. When a 94 is used on these manifolds that heat hole can burn the power valve in the carb. If there's a hole there it needs to be blocked. I've had success with a thin stainless plate, sandwiched between to carb base gaskets, with no heat hole, as a hole blocker. The top of the manifold is quite thin and I feel not enough meat to tap an plug.
Of course that plate thing on yours, could already be doing the blocking job.
Martin.
 
Thanks BillM, I have the 40011 and if I had bothered to read the instructions in the box it would have confirmed no resistor required!!

Scooder, thanks for pointing that out, I would never have known that and will check it out this weekend.

Below are a couple of pics of the engine bay without the double batteries and spaghetti wiring!!
 

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LOOOOOOKING GOOOOOD ,, yes much better..... BUT ...you need a flex line (hose) between the fuel pump and the pickup line, as the engine and the frame/cab move different from each other, and I say again looking good. .... OLD.....BILL
 
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