Well some of you guys that have been active over the last year and a half know that I taint no professional mechanic, I couldn’t make a living at it because I get to hung up in the little teeny tiny details. But that said, I’ve been twisting wrenches in some fashion for most of my 65years and conceder myself a half way decent mechanic. At least I have a pretty good grasp of automobile physics in most cases. Now that I’ve twisted my arm patting myself on the back, I want to talk about something that happened today that I don’t, understand!
I’m approaching about 3,000 miles since I’ve done all my mechanical restoring and rebuilding chores and she’s been running just peachy keen. Starts first time over hot or cold, she hasn’t missed a lick in all those 3k miles, until today.
So it was such a beautiful day today, forecast to be 65°, 15° over the average for this time of the year, not a cloud in the sky and the whole weekend was supposed like that. I decided to reach way out and just do some motoring today and was about 75miles from home just cruising along nice and smooth not slowing down, nor speeding up and all of a sudden there came a VERY loud bang from under the hood. A single backfire through the carb, it was so strong that even though I’ve got the stock spark arrester fitted with a paper filter on the carb that the hood actually bulged up when she blew. A half block later when I got the nerve up to step on the gas to see if it was still running everything was just “Peachy Keen” again. There was a big empty parking lot in the next block that I swung into. By now I’m trying to recall the proper use of the fire extinguisher from my training that I had to have every year for 27years at the last job. With that loud of a bang I thought for sure that it had blown the arrestor clean off the carb and was probably ablazing under the bonnet.
I whipped open the hood and not’a, nothing wrong, the air cleaner was just fine not loose no burn marks, no fuel running out onto the exhaust, everything looked and sounded just fine.
The 75 mile jaunt on the back side of my trip was uneventful. Just that one single big bang and then all is well again. So I’ve been trying for the life of me to figure out what could have caused it but keep coming up empty. Rechecked the timing and took a read on the plugs when I got back home and she’s spot on the factory specs right where she’s been for the last 3,000 miles. Took a look under the distributor cap and everything looks is working fine under there also, nothing to loose or to tight.
I did a valve job back then also with every thing fresh, new valves, guides and hard seats and adjusted hot, dead nuts at .007” & 014”.
So I’m out of ideas as to the why! Any more suggestions?
Denny Graham
Sandwich, IL
