Hello dear friendly experts,
I had a strange event today: took her for a short 3 mile trip to the next town and back to my village...parked her...turned off the engine... got out to open the gate and - after at least 5 seconds there was a bang from the direction of the exhaust. I'm not really sure if this really was a backfire or someone in the neighborhood did e.g. a shock shot (against grape plundering birds) or something else.
Of course, maybe the engine might run a little lean, because there is a little 'puffing' from the exhaust going downhill.
On the other hand, the exhaust pipe is black inside, but this is only a very thin coating: wiped it out with a cleanex and really not worth mentioning.
Did one of you ever had a backfire some seconds after the engine was stopped??
greetings
dr. trinkmann
strange bang from the backside
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dr. trinkmann
- Sergeant
- Posts: 68
- Joined: October 12th, 2016, 5:58 pm
- Location: Germany, Bavaria, Ufr.
Re: strange bang from the backside
That is very possible, it would be running rich if it was puffing out the exhaust and this is the perfect scenario for a backfire. Delayed backfires are rare but they do happen. They are caused by a small leak somewhere in the exhaust somewhere close to the engine and when the engine is shut down oxygen migrates into the hot pipe and if things are just the right ratio and temperature it will light off. The usual spot for a leak on these is the manifold but I have seen a lot of them that leak at the first joint, the flange where the manifold meets the pipe.
1964 M151A1
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone
1984 M1008
1967 M416
04/1952 M100
12/1952 M100- Departed
AN/TSQ-114A Trailblazer- Gone
Re: strange bang from the backside
I would also check the ignition timing. If the timing is off a little bit, it will still run ok but you will get that downhill puffing you mentioned.
Horst
1972 USMC M151A2 w/ROPS (ex Barstow) and M416
1962 M201 and trailer
1966 GTO,1982 E350 Skoolie, 1987 SJ413, 1987 911
Gone: 2xM35A2c, Unimog 404S, Hanomag AL28, DKW Munga
1972 USMC M151A2 w/ROPS (ex Barstow) and M416
1962 M201 and trailer
1966 GTO,1982 E350 Skoolie, 1987 SJ413, 1987 911
Gone: 2xM35A2c, Unimog 404S, Hanomag AL28, DKW Munga
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dr. trinkmann
- Sergeant
- Posts: 68
- Joined: October 12th, 2016, 5:58 pm
- Location: Germany, Bavaria, Ufr.
Re: strange bang from the backside
The powerpack came out last year for painting the engine compartment.
Thereby a new manifold to exhaust-pipe gasket was installed.
I checked that gasket today - backside with a mirror, too - but i couldn't find any black traces for a blowing gasket. So thumbs up for this...
I thought a popping or backfireing exhaust means the engine might run a bit to lean?
Will check timing and points or change to solid state (Swiss) when back from holiday...
Nevertheless there's a good chance that the loud bang i heard just seconds after stopping the engine came from a propane cannon in the Vineyards nearby. The local vintners didn't use them (to scare away the birds stealing the grapes) over the last 20 years, but this year there a three of them banging around again.
Thereby a new manifold to exhaust-pipe gasket was installed.
I checked that gasket today - backside with a mirror, too - but i couldn't find any black traces for a blowing gasket. So thumbs up for this...
I thought a popping or backfireing exhaust means the engine might run a bit to lean?
Will check timing and points or change to solid state (Swiss) when back from holiday...
Nevertheless there's a good chance that the loud bang i heard just seconds after stopping the engine came from a propane cannon in the Vineyards nearby. The local vintners didn't use them (to scare away the birds stealing the grapes) over the last 20 years, but this year there a three of them banging around again.