UNEX My truck explosion!

BornFree

BornFree

Came This Far

Doc1 said:
TY, sir. I was a mechanic back in the era when trucks like mine were still common. It has a 240 I-6 and a one barrel carb. The truck does tend to flood slightly or run rich after it's parked and is still warm. My usual SOP is simply to floor it - WOT - when I start it again. Then it will quickly start with no hesitation. As a side note, the old truck doesn't run hot at all.

Just before the muffler explosion, it turned over very sluggishly when I went to start it. Like others here, I thought the timing might've slipped. Remember that after the explosion, it started immediately and easily. This leads me to believe there was an exhaust blockage which caused the fuel-air mixture to collect in the muffler.

Whatever that blockage was still has me baffled.

Best
Doc
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Again you are describing the possible symptoms of a leaking float valve. When you turn off the engine then built up fuel pressure in the fuel line can continue to leak into the engine causing it to flood. Since the engine is not running then it cannot consume the excess fuel.

Do you know why they added the electric fuel cut off solenoids to riding lawn mowers? Because some fuel would flow into the engine after the ignition was shut off, and the engine was spinning down. Then when people would start them again there would be a large explosion that would sometimes damage the exhaust. But it was never good on the ears. The solenoid blocks the main jet the moment the key is turned off.
 
kenny1659

kenny1659

Veteran Member
240 does not have a timing chain but runs gear to gear, so it should not change timing unless the pin that holds the gear on the bottom of the distributor is shearing off. The engine would sound like it was under a load. Inspect the distributor cap for hairline cracks where it could be jumping spark. Sounds like it flooded but if it has never happened before could be a one off. I had one but it would boil water in a heartbeat if it was running rough.
 
Doc1

Doc1

Has No Life - Lives on TB
kenny1659 said:
240 does not have a timing chain but runs gear to gear, so it should not change timing unless the pin that holds the gear on the bottom of the distributor is shearing off. The engine would sound like it was under a load. Inspect the distributor cap for hairline cracks where it could be jumping spark. Sounds like it flooded but if it has never happened before could be a one off. I had one but it would boil water in a heartbeat if it was running rough.
Click to expand...

I was thinking the distributor might've slipped (rotated), not the gears jumping. I didn't even bother checking that after I got it started, as that wouldn't cure itself. We've had over a week of nearly solid rain and thunderstorms, so I haven't been able to deal with it.

BTW, for those who suggested that components may have been wetted, I checked that immediately when I pulled into the parking lot and everything was bone dry. I think I will replace the distributor cap/rotor and plug wires just to be on the safe side. Next project might be rebuilding the carb.

This particular 240 is a honey of an engine. It never runs hot and quietly ticks over like a well oiled sewing machine. I run synthetic oil and a little zinc additive. Over the years I've always had good luck with old Ford I-6s (assuming they were solid when I acquired them).

Best
Doc
 
I

intothatgoodnight

. . .
Doc1 said:
This particular 240 is a honey of an engine. It never runs hot and quietly ticks over like a well oiled sewing machine. I run synthetic oil and a little zinc additive. Over the years I've always had good luck with old Ford I-6s (assuming they were solid when I acquired them).
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The Ford 240-300 straight-six gasoline engine family was widely used in both vehicular and industrial use cases - nearly bulletproof and utterly reliable.

An excellent gasoline engine, on all counts.


intothegoodnight
 
Doc1

Doc1

Has No Life - Lives on TB
I pulled the muffler this afternoon. Here's a pic for those curious. Remember, I did say that it sounded like a 30-06 going off when it exploded.

Best
Doc

PS: I didn't find any obstruction in the muffler or tailpipe.

DSC_0093.JPG
 
S

summer-texan

Contributing Member
had my oil changed on my 03 silverado a week ago. truck ran great. monday my son and i had errands to do in san antonio. rain, traffic made it back to the country here in poteet. truck great. my son is a mechanic. tuesday, i had an errand. round trip about 45 miles. truck ran great.
the computer displayed check oil. hum, oil just touched bottom of dip stick. hum, just had oil changed.
ok, going to go to store to get oil. i started truck and it was missing and popping real bad. i called my son. he got home late. he checked truck.
friggin blown head gasket. WTF. it was running great.
it's now 11pm thursday. he's almost done.
i googled up the cost. this could have cost me $1500 to $2000.
guess he's not that bad of a pain in the ass
 
Doc1

Doc1

Has No Life - Lives on TB
summer-texan said:
had my oil changed on my 03 silverado a week ago. truck ran great. monday my son and i had errands to do in san antonio. rain, traffic made it back to the country here in poteet. truck great. my son is a mechanic. tuesday, i had an errand. round trip about 45 miles. truck ran great.
the computer displayed check oil. hum, oil just touched bottom of dip stick. hum, just had oil changed.
ok, going to go to store to get oil. i started truck and it was missing and popping real bad. i called my son. he got home late. he checked truck.
friggin blown head gasket. WTF. it was running great.
it's now 11pm thursday. he's almost done.
i googled up the cost. this could have cost me $1500 to $2000.
guess he's not that bad of a pain in the ass
Click to expand...
He might not be a pain in the ass, but changing head gaskets surely is! The prep is the biggest PITA. Besides having to virtually disassemble half the engine, the mating surfaces on the block and the head have to be almost surgically clean (to really do it right).

Additionally, when scraping/cleaning, you have to be sure that none of the old gasket pieces fall into any of the various holes in the block. This is a time consuming part of the process that some mechanics tend scrimp on.

You're blessed to have a son who can do that job for you.

Best
Doc
 
kyrsyan

kyrsyan

Has No Life - Lives on TB
summer-texan said:
had my oil changed on my 03 silverado a week ago. truck ran great. monday my son and i had errands to do in san antonio. rain, traffic made it back to the country here in poteet. truck great. my son is a mechanic. tuesday, i had an errand. round trip about 45 miles. truck ran great.
the computer displayed check oil. hum, oil just touched bottom of dip stick. hum, just had oil changed.
ok, going to go to store to get oil. i started truck and it was missing and popping real bad. i called my son. he got home late. he checked truck.
friggin blown head gasket. WTF. it was running great.
it's now 11pm thursday. he's almost done.
i googled up the cost. this could have cost me $1500 to $2000.
guess he's not that bad of a pain in the ass
Click to expand...
No. No. No. That once, way back in the '80s/'90's was more than enough. As were a few other repairs that occurred way back then. (Starter on a caddy, in a parking lot, during a storm, with a bumper jack.) You do some crazy things when you are young and think you are poor. I won't say I had a lot of money, but I have a much better idea of not poor versus poor now.
 
Cag3db1rd

Cag3db1rd

Paranoid Pagan
Doc1 said:
I pulled the muffler this afternoon. Here's a pic for those curious. Remember, I did say that it sounded like a 30-06 going off when it exploded.

Best
Doc

PS: I didn't find any obstruction in the muffler or tailpipe.

View attachment 360763
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Seriously? That's all there is to a muffler? I have never taken one apart b4. Learn something new every day.
 
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