I'm experiencing warm start issues. 468 big block, 10.6:1, Pertronix Ignitor III distributor and Flame Thrower III oil filled coil mounted vertically on the aluminum head. It fires up fast when cold and runs well. I've taken it to 5500 rpm and it seems to perform fine. But after a 5 mile run and 180-190 engine temp, it won't fire. I pulled the plugs and they were wet but not fouled. I've varied initial timing from 6 degrees to 11 degrees and it acts the same regardless. The starter turns pretty close to normal speed when warm so I think the 800 CCA battery and 2/0 wire are sufficient. Distributor resistance to chassis ground is 0.2 ohms. The coil primary resistance is technically within spec: 0.3 ohms cold and 0.4 ohms hot. The Ignitor III requires .3 ohms minimum and I'm close to that min. Loaded voltage test (voltage to coil) is within Pertronix spec: 10-10.35V cold with ignition switch on (spec is 8.0V-11.5V) and 8.8-9.0V cranking (spec is 8.0-9.5V). Measured temp at coil and carb were 140F when engine was 180F. Maybe the coil isn't working when warm? The wet plugs makes me suspect it and I've read enough to suggest warm coil issues. What is the better brand and model coil to use?
Pertronix ignition, why not a...say...a Pertronix coil ? Might the best bet is to give the Pertronix guys a shot at your problem ? They'll have the best questions to ask you, and just possibly, give you back the top answer(s) ! Mike
Yes but unless I want to rewire, it would be to a horizontal position on the intake. Maybe that would work with an oil filled coil, maybe not the best.
Brian: Here's some helpful info: What coil to use with Pertronix III ignitor - Search (bing.com) and Technical - Pertronix III problems solved | The H.A.M.B. (jalopyjournal.com)
I have a Pertronix coil now. and I bet that's what they'd recommend. Just curious if there is a non-Chinese coil that has a good reputation for durability.
Bubba (RIP) always recommended Bosch Blue Coils. They used to be fairly reasonable on Amazon but not so much anymore. Don't know how they would work with a Pertronix ignition.
I’ve had my Pertronix coil mounted horizontal on my intake 11 years. It’s on an aluminum plate suspended from the carb studs and separate stud from a boss on the intake.
Had a similar issue with my 468 c.i. BBC in my Falcon gasser. I mentioned it to a buddy who told me he fixed his by adding a temporary "kill switch" to the ignition. A simple push button that disconnects power to the coil as you begin cranking. Push it in and hold it while you crank the engine, and then release it as the engine is spinning. I figured it was a cheap and easy thing to try, so wired one in temporarily and tried it. My engine fired great when hot by using the kill switch, so I mounted it permanently and used it anytime I had any issues starting it hot.
I guess the idea being that you avoid voltage drop to the ignition while the starter draws a lot of current?
Are you sure it's a ignition issue? Fuel boiling in the carb could give you the problems you describe.
The BERU coil is a good replacement for the Bosch Blue Coil. Mallory Coils & BERU Coil For Sale | The H.A.M.B. (jalopyjournal.com)
Vapor lock was my first thought but I didn't see any evidence of percolation. I have a phenolic spacer on order just in case.
I read that thread on Bosch blue 0012 but I can't seem to find one for a decent price. I guess they are out of production?
I've read that some have experienced ethanol gas vapor lock at 180F. I did measure 160F on the carb feed line but the fuel bowl was only 140F. Just to be safe, I'm throwing a phenolic spacer under the carb and I'll insulate the carb feed line with this: https://www.amazon.com/dp/B07QPZTBXV?ref=ppx_yo2ov_dt_b_product_details&th=1
I’ve had 3/8” phenolic spacers under my dual quads I put on 7 years ago. I had one under the single carb before to fix the heat sinking problem.
They changed the manufacture a few years ago they are now the same as the repro Lucas coils but with a different sticker.
The Jalopy Journal
