RE: IML: 64 Iml HORROR STORY

Jay,

Wow, what a story! Glad everything looks like it’s going to work out OK. Glad you had the fire extinguisher – could have been much worse. But now, let’s explore this a little further.

That “air cleaner” is also referred to as a “flame arrester” (-or”? sp.). Anyway, its OTHER purpose in life is also to (hopefully) contain any fire in case of a backfire during cranking. With no place to go, a fire in the air horn of the carburetor would quickly burn itself out. If the engine were turning even at idle, let’s say 500 rpm, even had there been a backfire, it should have sucked the flames right back down the carburetor as it sucked in a couple of hundred cubic feet per minute, and this could never have happened.

Let’s back up & discuss your mention of the “not running right”, etc – and the “pop”. I suspect maybe the timing chain jumped. That would account for the pop sound (causing a backfire) and if it was bad enough, the pistons could have then started thrusting the fuel charge in the manifold backward into the air cleaner / spark arrester, and thus, causing your Imperial Flambe’. That’s because once the timing is shot to some random place, instead of sucking air in on the “intake stroke”, maybe the intake valves were now all opening on the compression or exhaust stroke – and instead of the hot exhaust gasses rushing down the pipes, they just were thrust backward right up thru the carb, chasing whatever remained of an air / fuel charge in the manifold behind it, and then of course, all bets would have been off (as you found out the hard way).

Also, leaning toward this theory, is your statement about just getting off the freeway when this occurred. In other words, the engine RPMs changed from one pretty constant, exerting a constant tug on the chain in one direction, to suddenly allowing it a little slack (to a good chain, this won’t matter, of course), giving it JUST the impetus it needed to jump or break. A bad timing chain is just offered chances on a silver platter anytime the engine suddenly changes speeds – i.e., sitting at a dead stop and hit the starter; turn off the ignition; or in your case, letting up the gas pedal as you exit the freeway. Granted, it wasn’t much, but it looks like it didn’t take much (to my theory anyway).

So – something to think about as the repairs continue. If it’s that far out of time, I doubt you’ll be able to get it started again without replacing the timing chain and/or gears.

My 2 cents. Let us know how it goes!

--Brooks in Dallas

PS: Dick Benjamin – what do U think?