mkg230

Hello to all, I'm new here as well as to classic cars. I have a 72 cutlass 350/350, eldbrock carb, and hei. Yesterday, I completed a tune up on the engine. Now when ever I turn off the key the engine will keep running for a good 5 min.
My question is this: are the firing order different for hei? I have the #1 plug wire pointing to the driverside #1 cylinder. With the following firing order 18436572 going conter-clockwise around the distributor.
Any ideas? I really don't want to set the timing since i have never done it before and it has the hei distributor.

Thanks for your time and information!!!!!!!

Olds64

If you didn't set the timing then you didn't complete the tune-up. I suggest you get a timing light and see where your timing is at. If your car is dieseling that badly then your timing is probably too advanced.

mkg230

Alright so did the 72 cutlass come with hei? If not how do I tell where the timing should be. I've searched the internet and I've found that a 72 cutlass should be at 12btdc and the idle speed 600 rpm.

joe_padavano

Not from the factory. The fact that you have HEI is irrelevant - the timing is set the same. Note that you MAY need to play with the mechanical advance curve inside the HEI, since the factory HEIs come off of smog motors. This will not affect your dieseling problem, however.

Lady72nRob71

Dieseling is also often caused by carbon buildup in the combustion chambers and high engine temps. Is your engine running at 195*F or lower? If so, good.
I assume idle speed is set right?

mkg230

Thanks for all your help. The issue has been resolved!!!

442Harv

To high idle RPMs can also cause this with the timming

Olds64

What did you do to fix the problem?

mkg230

I spoke too soon. At first the timing was off about 3 degrees. She turned off and started just fine for the first day. Now the problem has returned I'm kind of thinking that some how the ingition is still sending power to the coil some how. Does anyone have any wiring diagrams for the ignition?
Thanks

Lady72nRob71

If the car runs smooth and normal when you shut the ignition off, then power to the coil is not being removed.

If the engine runs very rough, knocks, kicks, bucks, and makes icky noises when the key is turned off, then it is dieseling.
Dieseling is usually caused by glowing red-hot carbon on the piston tops or on the cyl head igniting fuel-air mixture still coming in through the carb. The spark plugs will not be igniting the fuel then - only the compression and glowing carbon, hence the term dieseling.

Try switching to high octane gas. If it stops or reduces the dieseling, then that is surely the problem.

Make sure idle speed is at 600-700 and idle mixture is properly set.

Has the car run rich before or burned oil? That would cause fast carbon buildup.
To get rid of it will not be easy. I am not sure if the cleaners at the auto parts stored will help, but mayby Berryman B12 is worth a shot.

JRVintage

Did you check your spark plug gap, .035 is stock. HEI is generaly larger.045