Weird tale

[Alacrity]

For the uninitiated, I am in the trade with my own garage & used to rebuild diesels for a living, so I know a little bit about engines . . .

The Bongo (2,5d 4x4) was used in January during the snow then stood unused until July, when I needed to camp in it at a weekend boat meet. Battery was flat so it sat on trickle for 24hrs, all normal & to be expected. She started instantly & settled down to the normal cold engine fast idle whilst I fiddled with radio settings etc. Then it stopped, just like it had been switched off. Never done that before methinks. On cranking it now sounded really odd, as if the cambelt had snapped with compression on only one cylinder, so that is what I thought had happened. When time permitted into the 'shop she came & off came the cam cover. Strange all OK & turning as it should, so I then wondered if the camshaft had broken. Off came all the gubbins & the cam cover - nope, all turning as it should there & no obvious signs of problems but still whirring away on the starter with compression on one cyl. only. So off came the head & - you've guessed it, all OK in there as well So the head was overhauled valves lapped in etc all in good nick apart from one ex. valve not seating properly, cured by lapping in & loads of coke (black not white powder). All the little pre-combustion chamber caps, as normal, were cracked but most engines I have seen with them are like this after a little time so no cause for concern as far as I was concerned.

Having found absolutely nothing I wasn't at all confident when it was re-assembled but to my surprise & delight it fired up cleanly after only about 10 sec cranking - & it all sounded completely normal.

So work that one out, it now runs better than before (only to be expected with the amount of c##p cleaned out of the ports) & the fuel consumption has finally improved, but I have absolutely no idea what happened to cause the no compression on 3 cyls. Done over a 1000 miles since & all good.

[Bob]

Valve stuck open?

[Velocette]

For the uninitiated, I am in the trade with my own garage & used to rebuild diesels for a living, so I know a little bit about engines . . .

The Bongo (2,5d 4x4) was used in January during the snow then stood unused until July, when I needed to camp in it at a weekend boat meet. Battery was flat so it sat on trickle for 24hrs, all normal & to be expected. She started instantly & settled down to the normal cold engine fast idle whilst I fiddled with radio settings etc. Then it stopped, just like it had been switched off. Never done that before methinks. On cranking it now sounded really odd, as if the cambelt had snapped with compression on only one cylinder, so that is what I thought had happened. When time permitted into the 'shop she came & off came the cam cover. Strange all OK & turning as it should, so I then wondered if the camshaft had broken. Off came all the gubbins & the cam cover - nope, all turning as it should there & no obvious signs of problems but still whirring away on the starter with compression on one cyl. only. So off came the head & - you've guessed it, all OK in there as well So the head was overhauled valves lapped in etc all in good nick apart from one ex. valve not seating properly, cured by lapping in & loads of coke (black not white powder). All the little pre-combustion chamber caps, as normal, were cracked but most engines I have seen with them are like this after a little time so no cause for concern as far as I was concerned.

Having found absolutely nothing I wasn't at all confident when it was re-assembled but to my surprise & delight it fired up cleanly after only about 10 sec cranking - & it all sounded completely normal.

So work that one out, it now runs better than before (only to be expected with the amount of c##p cleaned out of the ports) & the fuel consumption has finally improved, but I have absolutely no idea what happened to cause the no compression on 3 cyls. Done over a 1000 miles since & all good.

The valves that had been open all that time sticking a bit but had eventually fully closed by the time you stripped it?

[mikeonb4c]

Great to have you and your Bongo back and firing in all cylinders Alacrity

[Alacrity]

The valves that had been open all that time sticking a bit but had eventually fully closed by the time you stripped it?

I don't think so. As I say it started up & ran fine for 3 or four minutes, then just suddenly stopped, like it had been turned off then had no compression on three cylinders. I don't believe I will ever get to the bottom of it though, I just thought I would post it up.

Oh & contrary to what I said earlier, fuel consumption is still abysmal managing a measly 20 mpg on a 270 mile round trip with a boat on the back

[clutha]

I'd go for stuck valves too.
I'm a marine engine fitter to trade, (shipyards), and in another life worked in boatyards in Lymington.
A lovely old motorboat with twin Swedish engines was sold to a young man who couldn't afford our winter lay up service which included running the engine with a special preservative oil. (Shell Ensis)
Come spring his engines wouldn't start. They were side valve and through the spark plug hole I could see the exhaust valves stuck open.
I managed to get an allen key in and work away with release oil and WD40 and got them moving and the engine started. Getting the heads off was going to be a nightmare as rust round the studs had jammed them on. Fox wedges wouldn't budge them at all.

[mikeonb4c]

The valves that had been open all that time sticking a bit but had eventually fully closed by the time you stripped it?

I don't think so. As I say it started up & ran fine for 3 or four minutes, then just suddenly stopped, like it had been turned off then had no compression on three cylinders. I don't believe I will ever get to the bottom of it though, I just thought I would post it up.

Oh & contrary to what I said earlier, fuel consumption is still abysmal managing a measly 20 mpg on a 270 mile round trip with a boat on the back

Shame about the mpg, although I guess a heavy boat would drag most car mpg figures down? I recently got 31 mpg put of my 2wd on a motorway run that included over an hour in standing traffic and some short local travelling at the end. I was impressed. What mpg are you getting on the open road without a big load behind?

[Alacrity]

Only a light boat . . .