Motor Backfires Thru Exhaust When Trying To Start

[blykins]

You can't put it on TDC and then point the rotor at #1 plug wire. It will be too retarded. Crank a hand-full of advance in it and I bet it will start.

The way I time a brand new engine is this way (adjusted for being a Chevy):

Pull the driver's side valve cover off. Roll the engine over by hand and watch the rocker arms on #1. Roll the engine over until you see the exhaust valve on #1 open then close. At this time the intake valve should be opening as well. Keep rolling the engine over until the intake valve opens, then starts to close. At this time, keep rolling the engine over and be watching the timing pointer and the balancer. When you get to 30° BTDC, stop there and point the rotor at the #1 plug wire on the distributor cap.

I guarantee you that if the engine has spark and fire, then it will start very quickly. Once it starts, set your timing with a timing light.

[Jim Coleman]

Originally Posted by blykins

You can't put it on TDC and then point the rotor at #1 plug wire. It will be too retarded. Crank a hand-full of advance in it and I bet it will start.

The way I time a brand new engine is this way (adjusted for being a Chevy):

Pull the driver's side valve cover off. Roll the engine over by hand and watch the rocker arms on #1. Roll the engine over until you see the exhaust valve on #1 open then close. At this time the intake valve should be opening as well. Keep rolling the engine over until the intake valve opens, then starts to close. At this time, keep rolling the engine over and be watching the timing pointer and the balancer. When you get to 30° BTDC, stop there and point the rotor at the #1 plug wire on the distributor cap.

I guarantee you that if the engine has spark and fire, then it will start very quickly. Once it starts, set your timing with a timing light.

OK, after taking the carb apart and cleaning it finally got it to squirt fuel,
then the connector on the coil on top of the distributor was loose, and I couldn't get it to fire. FINALLY got everything together, and started the process you gave me. My timing indicator only shows a max OF 16 BTDC,
so I guestimated where 30 would be.

Bottom line, it won't start - is backfiring thru the exhaust and now also back firing thru the carb.

Next I'm going to check the valves and see if they're correctly set.

Thanks,

Jim

[Gaz64]

How long has it been since this engine ran?

How old is the fuel?

Gary

[Jim Coleman]

The motor was rebuilt in the 80's.

The fuel came out of the pump at the gas station yesterday.

[Gaz64]

Ok, so the fuel is fresh.
When did the engine run last?
Gary

[patrickt]

Originally Posted by Gaz64

When did the engine run last?

Just prior to the rebuild.

[blykins]

Even if you figure it out, buy another distributor in the near future.

There’s nothing junkier than Procomp. It’s a wonder the rotor even spins on the thing.

If you don’t figure it out, borrow a distributor to try.