Second service (suspension, head gasket and underbody)

[Driver+Passengers]

Good luck with getting it done Matt. I admire your energy and positive approach. At the end of this you should have a good working machine whose innards you'll know inside out. The AFT is always a concern on ageing Bongos. Mine has been fixed 3 times, hopefully ok now after two expensive new motors.

Some might say hasty or misguided.

[Driver+Passengers]

Another milestone achieved.

[Driver+Passengers]

My photography skills are not great, but I took some photos when the head came off.

Top of the gasket




Bottom of the gasket




Head surface




Block Surface

[Driver+Passengers]

My options are:

- clean the head and block and refit with a new gasket
- strip the head and get it skimmed
- strip the head and get a cold pressure test and skim
- strip the head and get a hot pressure test and skim
- buy a bare head casting and build it
- buy a fully built head


There are a couple of marks in particular on the block/gasket that suggest water has been sitting where it shouldn't. There are so many variables, cost vs time options, eventualities, etc in what I do next. I've been mulling over this while cracking rusty nuts under the van, and shearing the odd bolt.


Lets just say that it is combustion gas getting into the coolant. If a new gasket doesn't fix it, then it's either a warped head or a cracked head. Either way that means stripping it. I don't know if it has been skimmed in the past and at that point if I was taking it off again, I'd be likely to opt for a new bare casting. Great fun! If there is in fact nothing wrong with the head and I can get the mating surfaces meticulously clean, follow the correct torquing order as I did to remove the head, then I can see little harm in refitting the existing head as-is, though I might be wrong. The time/effort/risk/cost involved in stripping the head for a skim, test or whatever are such that I'd rather do it in order to transfer to a new head, particularly as my hunch is that the head is fine. I'd rather not strip the head if I don't have to and so I'm leaning towards refitting the current head as-is and then monitor the situation as I have been doing.

[rita]

Hi,

If you clean the head thoroughly then run a straight edge over it,you should see if it is warped or not.

If need be you can also shine a light behind the straight edge to help with inspection.

[Driver+Passengers]

Hi,

If you clean the head thoroughly then run a straight edge over it,you should see if it is warped or not.

If need be you can also shine a light behind the straight edge to help with inspection.

The problem is that I don't know if I can trust the straight edge(s) I've got. I think you can put them next to each other and then flip one round or something. Still got some crap on the surfaces so I'll check properly once I've cleaned up head and block.

[peterrc]

Hi,

If you clean the head thoroughly then run a straight edge over it,you should see if it is warped or not.

If need be you can also shine a light behind the straight edge to help with inspection.

A defenite must before you make a decision.
Lay your straight edge on a piece of paper and draw a line down it on the paper. Move the straight edge to give a mirror image placed as close to the original line as possoble. Draw another line they should be parallel.
Peter

[briwy]

Matt

If you're checking the head do the top of the block as well. It's pretty unlikely to be bad but worth checking.
Once you have your straight edge sorted you ideally need some feeler gauges to check any gaps. I don't know what the allowable is but I'm sure someone will.
Good luck with it.

[Driver+Passengers]

I never knew that the spare wheel did that! I've never had it off before! Nice to find after all that's gone wrong!

I've got all the holes in the top of the block plugged with lint free tissue, so I'm ready to pop in back and scrape the guff off the block mating surface.

In this picture...


...you can see a patch between the left bore and the far-top bolt hole. Two orange waterways either side with a whitey brown patch within the semi-circle (what is that?). That feels rough to run your finger over. There's a corresponding patch on the gasket that's carrying more corrosion than most other parts. I'll try and get decent lighting to take a couple of close-ups. I'll take the opportunity to degrease block to some extent.

I've been borrowing tools from various folk. I have a 26mm 12-sided ring spanner that will go onto the lower ball-joint nut (just, it's tight) but rounded with bodyweight behind it, so I stopped and will have to rethink that one. I won't risk rounding the other one too. Considered shimming the socket with a coke can...

All droplinks and anti-roll bar bush brackets came off without to much hassle. Had to saw off the off-side front droplink and the off-side front bush bracket was particularly corroded. The lower off-side rear bush bracket bolt has sheared. I have a centre point punched in the centre of the back of the bolt and a nibble drilled into it but I need a lesson in drilling metal, please.

The rear diff has had a stiff brush down and a coat of fertan. I've got last night's Chinese takeaway foil trays layed out with various baths for small parts. Under the bonnet has received a wipe down on pretty much every surface with ACF-50. It was perhaps not as clean as it could have been - I never got the pressure washer into the garage or anything! Hopefully it's not going to look too smeary in the light of day.

Now, I'm sure there was another bolt I'd snapped. I'll go check and report back.

[Driver+Passengers]

Lots of little bits of different jobs done this evening. I started a bit of underbody protection, cleaned crap off the mating surface of the block, prep'ed the front end for putting back together (above the bumber, that is!), checked all mating surfaces for flatness and a couple of other bits and bobs.

Flatness:
- Block <0.02mm
- Inlet manifold <0.02mm
- Head - mostly <0.02mm, 0.02 in places and I think I snuck a 0.03 under a corner, once. I'll measure again once I've cleaned it up a little.
- Exhaust - taking flat as middle two ports, left and right sides are out by: top bolt holes 0.25/0.1, ports 0.4/0.25, bottom bolt holes 0.45/0.35

OK, a few questions and photos... firstly, what's that brown stuff?





Secondly, this doesn't look like it's going straight back on, does it??!









Thirdly, how do I drill this out? What's it made of? What kind of bits do I need to use? What diameter do I start with and at what speed? I could barely make a mark on this thing!!



And finally, not a problem in itself but I did spend 45 minutes doing this when I could have been doing something else. It is a black and shiny as it looks!

[peterrc]

Hi Matt, put me down for the broken stud. I will try and get over some time this morning and will bring all the necessary with me.
Comments on the rest I will leave to the experts.
Peter

[Driver+Passengers]

Thanks, Peter.

PS. I have just remembered where the third sheared bolt was - front bumper stay.

[briwy]

Do the dips in the head correspond with the dips in the block?

[Driver+Passengers]

Do the dips in the head correspond with the dips in the block?

There are no measurable dips in the block. The thinnest feeler I have is 0.02mm.

[Northern Bongolow]

looks like your egr is stuck open, this will give you all the oil into the inlet side/valves when the engine is started from cold. or your oil is too thick. or your turbo oil seals are leaking. is it using oil ??.
i have a full set of inlet valves spare (under the bed) if you need them matt, but check the seats first.