Weak spark in Flathead with SBC Distributor

Hi
Ive installed a remanufactured and modified SBC points dizzy in my flathead and its giving a very weak spark and is missing intermittently, sparks so weak my timing light doesnt pick it up at all. i havent touched the points, they are at .008" could be the problem? plugs are NGK B-6L gapped at 30 thou. its running 12v neg ground, the coil is borg warner 27290 2.0ohms and 1.9ohm balast resistor. I have swapped out the condensor without improvement and byp***ed the balast so as to give all 12v to the coil. No change here. checked earths. any other ideas?

 

What are they supposed to be ?
HINT: A lot more than .008".



Look up the spec, set them correctly.

 

Weak spark = bad coil or low Volts or to little dwell

 

Yeah i know, but i just purchased this distributor from a reputable supplier and it has been "bench tested and setup" it SHould be perfect out the box.
Coil and balast were good on original distributor, tried 6 and 12 to the coil, dwell will be wrong if points are wrong but again, distrutor builders setup, dont want to change it untill sure that i need to.

 

I just went through a similar problem last week. ***uming the point gap is correct (it sounds like it isn't so check it again), your coil is bad.

 

.008 seems a bit tight on the point gap. I would try .018-.020 and see if it improves. Better yet contact GMCBubba here on the board and see what he says, he is the resident distributor aficionado.

 

maybe, because its a chevy dist. in a flathead ford??
.008 is way to tight, should be .019

 

Ok thanks guys, ill look at the gap again and set it up but i will be getting bubbas help.

 

Get a points file or use some sand paper to clean the contacts and then set the gap.

 

Good luck finding a dwell meter nowadays. I am still using one I bought in a pawn shop in the 70's. Like others said gap should be much wider. Nice thing about the chevy distributors is you can set points with the motor running if using a dwell meter.

 

New points will wear quite fast at first, so after a few hndred miles now your .008" gap is maybe only .005", believe me try .018"-.020" and report back, everyone makes mistakes .

Dwell meters are sold at most any auto parts stores, yes even to this day.

 

Get yourself some real points/cam lobe lubricant, verify the rotor direction of rotation, and lube the points rubbing block and lightly lube the distributor cam, TR

 

Thanks everybody, so much good info. First things first ill set the points at .019 give em a quick tickle and try again. Thanks bubba, the coil and balast worked with the flaty dizy but as sugested i might try a 1.5 Ohm coil and balast to reduce primary circuit resistance (also being new...). After that, check leads gain, check dwell.

If im going to coil which requires no balast, what resistance should i be looking for? and are there ones designed to run 12v but still work with a coil?

Cheers

 

I think circuit resistance should be about 3ohms.

 

check that the distributor is grounded properly. was the mounting surface freshly painted?

 

Make sure your points are not burned file clean and adjust.
IC66Volkswagen coil 1963to 1969 plus,trucks use IC 64,
IC 712.
These are 12 volt coils,make sure you have good condenser.
Now if you had 12 volt neg and only changed the dist and changed one wire it should work.
Its easer to find 12 volt coil that use 1.5 ohm resister,coil neg side goes to points.

 

Negative ground from battery on the block?