Bongo Fury

Posted: **Thu Jul 26, 2007 11:49 am**

Hey you guys are brilliant...these sort of problems are horrible when you're on your own but I feel like I've got a talking Haynes manual sitting on my shoulder!

Mike, I didn't start the engine initially, but just let it turn over on the starter motor in short bursts, without actually starting the engine, so I could watch the camshaft and valve operation and also get all the cam lobes pointing upwards in turn so I could feel the valve operation by pushing down on the spring with a large blunt screwdriver. This also allowed me to check the tappets. Once I was fairly confident that things seemed ok then I started the engine to do the injector checks.

As far as big or little end problems go, I'm hoping that Bumbly is right in that the problem/noise started instantly...there was no build up so I assume whatever the cause it was an instant failure.

My revised plan for today is to remove cam belt cover and check timing marks, adjust tappets, then turn the engine over manually to watch the valve gear operation in more detail, and to see if I can feel anything amiss. I plan to turn the engine over with a 38mm socket on the crank pulley....is there another way to turn the engine over manually which would allow me to watch the cam without a second person?

Beyond this, from your input it seems that a compression test will be the sensible next stage, don't know how to get hold of a diesel compression tester or how to use one...I may phone a local mobile mechanic who is a little familiar with Bongo's and see if he can come and do the test for me without me topping up my mortgage!

It sound like a good idea to drain the oil and checking for nasty bits! I've got little hands and thin arms so with the sump off I can probably reach right through the engine and out of the exhaust! I won't do this just yet though.

Cheers.........Rob

Posted: **Thu Jul 26, 2007 1:06 pm**

...keep us posted, and check/adjust those tappet clearances if you are bored (hmmmm!)

Posted: **Thu Jul 26, 2007 11:20 pm**

Progress Report 2:

OK guys I think I have found out what the problem is! I'm actually almost too embarrassed to post it, but here goes:

When i replaced my cracked cylinder head back in November, I disabled the egr using the bolt in the tube method, but I also decided to 'make sure' by blocking the egr pipe where it meets the inlet manifold. I did this by looking for a suitable object to blank the hole in the curved junction piece where the egr pipe and air intake and inlet manifold all meet up. I found a 20 Euro cents coin in the footwell of the Bongo which fitted perfectly.

Anyway I removed that junction piece today in order to remove the cam belt cover, and guess what? No coin!!!!

I've since stripped the inlet manifold and still no coin, so I'm going to press on and remove the head.....I'm pretty sure I'm going to find the coin in no.1 or 2 pot along with whatever hideous damage has resulted from it's presence.

I've got visions of needing a new block, piston and head..... a new engine realistically so I'm wishing I did buy that crashed Bongo earlier today......it's sold now. It's immaterial really as I couldn't afford it anyway.

I'm feeling more that a little p***ed off now! I was sure that coin couldn't get into the manifold but it seems I was wrong.

Posted: **Fri Jul 27, 2007 12:03 am**

Oh effing bl**dy hell, what a p*sser. Sorry, lesser words wont do. The only cold comfort is that your Bongos reliability sounds like it is no longer questionable. So its a great car, well worth mending, and hopefully your luck will improve. But I'm v sorry to hear the news. Could happen to any of us esp, with the spirit of adventure and experimentation that pervades the Bongo spirit.

Good luck

Mike

Posted: **Fri Jul 27, 2007 12:05 am**

good luck,and hope its not as bad as expected,coin could be trapped between valve,and may have only damaged seating along with valve,i may know were there is a complete engine,but its in the northwest only problem

Posted: **Fri Jul 27, 2007 12:45 pm**

I have repaired engines with similar problems to yours and it is possible to do an amzingly small amount of damage. If the coin sticks upright you are stuffed but often it doesn't. Dont worry about a few small marks on the piston or head - they will take a bit of damage in a lowly tuned engine. The coin will be light and soft so you may get away with valve and seat damage. The coin obviously got stuck in the valve because it dropped onto 3 whilst the compression was low. The coin would then have been squashed into a shape that could fall through, restoring partial compression.

If everything looks OK do a sealing test on the valves by putting solvent in the inlet ports and looking for it leaking past the valves. Sometimes you won't see a bent valve but this will show it up.

I blank the EGR by removing the gasket and scribing around it onto a thin sheet of aluminium. I then cut this out (without the big hole, obviously) and bolt it in place. It acts as a gasket and blank and has two bolts through it so it cant budge.

Posted: **Fri Jul 27, 2007 3:41 pm**

Thanks for the replies again. Well the head is off now so:

Progres Report 3:

Oh dear! The coin is in a million pieces, spread between pots 1 & 2 (possibly even a tiny bit in 3)! I'm not sure that there are enough pieces to make a complete coin which is a bit worrying. How did this happen?Surely it means that the coin must have been in more than 1 piece before getting into the inlet manifold. This figures because I'm sure that it couldn't have passed through the hole on the 'elbow' joint in 1 piece. So was it a combination of heat, vibration and pressure which broke the coin allowing it to move from it's original position?

Anyway, as I said, the coin is in lots of parts so i'm worried that some small fragments may have found their way between the piston and the bore and are now riding on the rings, although there are no scores or scratches on the bores. I have to say that it almost looks like I could clean it all up and put it back together, but I'm probably being way over optimistic.

My thinking is that if you guys say I need a couple of new pistons and a cylinder head....then it's probably as economical to get an exchange engine which i can't afford just now, so I might as well do what I can with this one and hope for the best...the worst that can happen is that I will still need a new engine, and i'll have wasted a couple of days! Oh, and I suppose I'll have to fit a new head gasket and bolts so there's the cost of them too.

So what would be the best way of cleaning the piston heads and valve area?.....I would think to hoover up what I can and give them a light wire brushing but what do I know!?!

Smartmonkey, what sort of solvent would I use to check the valve sealing....would petrol be ok? Also, do you think It'd still be worthwhile taking the head to a specialist to get it all checked out?

Anyway here are photo's of the damage......what do you think?

Piston 1

Piston 2

Piston 3

Piston 4

Valves 1

Valves 2

Valves 3

Valves 4

Head

Block

Well that's it for now...any further help/advice would be gratefully received and thanks again for your help/moral support to date.

Rob

PS: Must remember to have a word with Gordon, tell him not to get into Euro currency....their coins are shite!

Posted: **Fri Jul 27, 2007 3:47 pm**

I would try and smear grease on the bores and turn the crank (if you can)
then if any parts of the dirty foreign money is there it would hopefully stick to the grease.

I think you should put it back together and try it.

I for one am glad I didn't try that egr thing.

Posted: **Fri Jul 27, 2007 4:04 pm**

Petrol is fine to check the valves - its just a way of doing it without removing more than you have to (paint thinners etc - water has too high a surface tension though).

Some of those marks are pretty deep but like you say, nothing to lose. If you can smooth off the worst of it (difficult with the pistons in the bores) it will help keep the hotspots to a minimum. You have a lot of stress points there so I would drive a little cautiously and keep it below 3500 just to give everything an easy time. Try grinding any slightly damaged valves back in. Any really bent ones will have to be replaced.

I assume the coin went into one pot and then got fired back into the inlet as shrapnel and hence into the next pot on the inlet stroke.

If you don't develop any cracks it should run fine afterwards (with the valves reground). If you can get access to an air line a good squirt of air will help remove the debri. Failing that get some wd40 or similar squirted in the gap between piston and cylinder, anything with a bit of pressure to blow it out.

Really hard lines and I can sympathise with how gutted you must be due to the circumstances. I hope it fires straight back up and runs like before (quite likely with good valve sealing).

Posted: **Fri Jul 27, 2007 4:12 pm**

i`ve had worse casting`s than that
i`ve bought new in some of the russian bike engines
still ran fine
as you say what have you got to lose

only one i would seriously check is on valve 2 upper right valve seating
may have to have that one recut
and piston 2 again about 2 o clock is it chinked or bits of the coin
file it smooth if the rings are ok should work
that seems to be the one that`s taken the brunt of it
whack some petrol in the head see if it leaks

wire brush em bit of polishing would`nt hurt
with autosol not pledge

Posted: **Fri Jul 27, 2007 4:52 pm**

I agree with westonwarrior re the grease, and clogger re the valves in number 2 cylinder.
Apart from that, you may well have got away with it - stick it all back together and try it. Don't thrash it straight away - give it a chance to prove there is no serious damage.
Good luck.

Posted: **Fri Jul 27, 2007 4:59 pm**

Thanks guys....I'm feeling a little better now!

As for cleaning up, is it ok to lightly wire brush the piston tops and the valve area, with a vacuum hose in close proximity to suck up the debris? I can turn the crank to get the pistons to the top of the bore. Then do the WD40 bit around the piston edges then turn the crank to watch if anything comes up?

Clogger, do you mean polish the piston tops with Autosol, or the valve area as well? (Isn't that taking 'pimping up' a bit far?????

)
btw piston 2 mark is bits of coin not a chink I don't think, and i'll have a closer look at that no. 2 valve seating.

And to check the valves, I'll do the petrol bit....if the valves seal ok does that mean it's unnecessary to get them checked further? I can turn the cam shaft which is still fitted and watch the valve stems through the inlet manifold holes, would I be able to see if they were bent?

Also, I know I've got to get new head gasket and bolts, but do you think I can get away with the old inlet and exhaust manifold gaskets? I replaced all the gaskets with the head last November so they're not very old, and look ok.

Oh, and what about the cam belt.........it's only a year old, but it has been removed and refitted twice. Alright, stupid question I know..........I'm going to replace it! And the tensioner spring. I'm not going to replace the tensioner though.

Sorry to fire loads of questions. I don't really feel confident about removing valves and grinding in etc so I'd prefer to keep it all intact if I can. If I don't get good sealing, then I'll take it to a specialist to remove the valves, check and regrind in. Does that sound like a fair plan?

Cheers..........Rob

Posted: **Fri Jul 27, 2007 5:03 pm**

I'm with Clogger on this one, go for it - nothing to lose.

Posted: **Fri Jul 27, 2007 5:06 pm**

If you clean up the top of the pistons try and leave about 3mm 1/8th of an inch all round the edge untouched then it will still be 'sealed' to the cylinder.

Posted: **Fri Jul 27, 2007 5:12 pm**

RobnKathryn wrote: As for cleaning up, is it ok to lightly wire brush the piston tops and the valve area, with a vacuum hose in close proximity to suck up the debris? I can turn the crank to get the pistons to the top of the bore. Then do the WD40 bit around the piston edges then turn the crank to watch if anything comes up?

Your better to use grease than WD40 - the bits stick better.

Clogger, do you mean polish the piston tops with Autosol, or the valve area as well? (Isn't that taking 'pimping up' a bit far????? )
btw piston 2 mark is bits of coin not a chink I don't think, and i'll have a closer look at that no. 2 valve seating.

It looks like the areas of the head round the valves in number 2 cylinder are all dented, especially the top right valve in your photo - just make sure the valve isn't hitting it. It shouldn't overheat as it's an inlet valve.

And to check the valves, I'll do the petrol bit....if the valves seal ok does that mean it's unnecessary to get them checked further? I can turn the cam shaft which is still fitted and watch the valve stems through the inlet manifold holes, would I be able to see if they were bent?

Probably not, unless they're very bad. Bent valves will have damaged the valve guides and the petrol will leak through.

Also, I know I've got to get new head gasket and bolts, but do you think I can get away with the old inlet and exhaust manifold gaskets? I replaced all the gaskets with the head last November so they're not very old, and look ok.

Yes

Oh, and what about the cam belt.........it's only a year old, but it has been removed and refitted twice. Alright, stupid question I know..........I'm going to replace it! And the tensioner spring. I'm not going to replace the tensioner though.

It should be OK but I'd replace the lot just for peace of mind.

Sorry to fire loads of questions. I don't really feel confident about removing valves and grinding in etc so I'd prefer to keep it all intact if I can. If I don't get good sealing, then I'll take it to a specialist to remove the valves, check and regrind in. Does that sound like a fair plan?

If you're not confident, it's the best plan - they're easy to do but you will probably need a valve spring compressor to do it.

Cheers..........Rob

Bongo Fury

Dropped valve, slipped cam belt, or injector problem?

Valves

Pistons