Hot Rods Engine cutting out

Got a Petronix ignition, seems when the car reaches operating temp, it starts cutting out. Bad coil maybe? Any ideas, I'm stumped.

 

What coil did you use? Did this just start after the installation or has it been running fine for a while?

 

Two threads on this one issue/

 

it just started, runs fine when cold, gets worse as it warms up

 

Did this issue ever get resolved. I've just experienced the same issue.

Freshly built 8BA, with one of Bubba's Petronix Distributors and matching coil. It keeps cutting out at anything under 2000rpm. Starts back up instantly but lasts only a few moments. It seems to go ok between 2000 - 4500rpm, but as soon as you drop the revs it shuts down.

Wiring, spark leads and coil have all been checked. Earthing of the Distributor direct, was also done.

Any ideas anyone?

 

maybe its not a ign problem you said fresh build if you have piston to wall to tight with forged pistons they swell when it heats up binding it up you can run fairly tight set up with cast pistons they don't expand as much as forged piston due ive seen guys lock motors up this way when it cools they will fire back up

 

What did Bubba say ? Did you ask him ? ( ***uming its" GMC Bubba" here on the hamb)

 

Thanks, but I can ***ure you the engine spins freely. Tollerances were accurately checked. It's not the issue.

Yes, GMC Bubba. Jim wrote back and stated that whilst he does not have many failures with the Pertronix modules it could be the problem. He asked me to check the voltage at the control module to ensure there was a min of 12v (min of 10v) and that if the issue still persists, he would send me a new module.

I ***ured him there was a min of 12v at the module. The engine was run on the Dyno with an Alternator, to simulate true working conditions, so there was at least 12-13v across at all times.

I also read on a separate forum that the Petronix could be fried by leaving the ignition left on. I can ***ure this did not happen.

<O</OAs a final try we installed a direct wire from a battery to the ballast resistor (bi p***ing the Dyno ignition switch and wiring) and it did the same thing.

<O</OEverything has been eliminated. It all points to the module as the cause.<O</O

 

Check the ohms a.
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Ck the ohms across the small posts on the coil. If reads below 1.4 ohms its drawing to much amperage. Amperage is heat. They may have giving you a .06 coil.

 

get rid of the junktronics as i did and get a hold of dave's small hei..he's on the web...he takes your dist cleans it rebuilds it machines it if need be and builds a hei that fits under your stock cap so it all looks oem...mine cost about $280.00 and comes with a life time warranty....he's a gm as well as a ford master tech and worked with the late Mr. SHELBY....i had a junktronics in my 64' riviera (425) and was having sporadic running issue and someone turned me on to him...well worth the time and money....i had trouble finding the correct resisted wire in my harness and he worked with me until it was solved....would stand by him 1000% my buick starts and runs awesome now !!!!

 

i had a simular problem had me pulling my hair out mine turned out to be the wire going to the coil replaced it and put a 2 prong chrysler ballast resisiter in the wire and hasnt happened since and yes i have pertronix

 

I had a similar problem with a sbc dist. Car would run great, then die. Usually it would start after cooling off, then finally nothing. It took me awhile to find the problem, when I installed the module and fed the wires out the bottom of the dizzy, I had knocked the ground wire loose, that goes to the breaker plate. It was touching enough to run, then when it warmed up it wouldn't. Eventually burned up the module and the coil. New one's been fine for two years now.

 

Thanks for all the suggestions.

Jim (GMC Bubba) responded further. He will send me a replacement module and I'll try that on. I cant ask for more than that. Hats off to the guy for his after sales service.

It's all pointing to the Module, everything else has been eliminated, wiring, earths, voltage & amp checks, with resistor, without resistor, Coil, Spark leads, ignistion switch, fuel etc.

The thing that has us stumped is that it runs perfectly at anything above 2500rpm, but dies at low revs.

I'm picking up the motor next week and will have it in the car and running within the month. I'll update this post further once I get the cause confirmed.