WBX-Unknown

[937carrera]

I'm going to plead ignorance as I haven't seen a late case............ or maybe just plain ignorance.

Thanks for that, curiosity satisfied and knowledge which had been forgotten has been discovered again.

Tonight I have mainly been measuring con rods. I've not finished yet but at this stage I'm getting comfortable that number 3 con rod is not bent

As the small end is wider than the big end I decided to clamp the little ends together in a vice with wooden blocks and a nyrex glove to protect the faces as I don't have an engineering flat block. I then used feeler gauges to measure the gap as 12,3,6, and 9 o'clock, going through each pair in turn and then looking at any variations.It's field engineering by comparison rather than precision engineering but sadly there are limits to my toolbox.

[itchyfeet]

did you have a gudgeon pin in there?

[937carrera]

No, the pins are in the pistons at this point, what are you thinking

[937carrera]

Well, every day brings new surprises

Today I decided to have a quick look at the pistons & barrels, so started at number 1 as you do. Sut up all the equipment to measure the bore, measured it and thought, that can't be right. Double checked and confirmed the reading so thought, well, I had better check the piston. The clearance was about 0.03-0.05mm, depending on which axis was being measured on the barrel, so like new.

Here's the big clue, after removal of the excess carbon, it appears to have oversize Mahle pistons & barrels



You can still see some honing marks on the bore. There is a little piston scuff at the bottom of the barrel, which is more visible than anything else



So it looks like this is a 1933cc DG engine after all, that's got to be worth nearly another whole horsepower

All the bores are measuring 94.51mm

[bigbadbob76]

Worth re-biulding then.
Go on... you know you want to.

[937carrera]

I want to see how yours goes first

[bigbadbob76]

Well.... go on then. Hahahahah...


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[937carrera]

I finished my "measurement" of the conrods. Now it hasn't worked as I hoped, which could be down to my measurement method (quite possibly), conrods are not as straight as I expected them to be (unlikely), or more than one of the rods is bent (possible but not usual).

Twist is the difference between the 3 & 9 o'clock readings, Bend is the difference between 12 and 6 o'clock. The colour coding is just me trying to see if there is a pattern across the different pairs.

I had a mate over yesterday to look at this data. He was of the same opinion as me, data all over the place, the measurement method may not be accurate enough, which leaves me with the likely position that I will need to pay to get these rods checked, and then straightened.

Based on these measurements and the big end bearing wear I do think that rod number 3 is twisted, 2 and 4 seem straight, less sure about number 1

What do you think

[bigbadbob76]

Yaes I agree, data seems to diagree with itself.
surely 1+2 should be the reciprocal of 2+1 etc etc.
I have access to a properly flat table (big chunk of granite ground flat) we use it for checking lapped shaft seals. it really is FLAT.
And a calibrated dial gauge.
If you want to send your con rods and gudgeon pins here I can put them on the table for you.
But what you really want to know is are the big and and the little end parallel in two dimensions and the same distance apart, the sides of the con rods may be out of true while the bores of the bearings are in true.
TBH if you doubt the con rods, replace em. not cheap I know but if you're going for the re-build......
P.S. if you can try the same measurements with a shim between the little ends rather than the cloth you might get better readings.

[itchyfeet]

TBH if you doubt the con rods, replace em. not cheap I know but if you're going for the re-build......
.

This, ^^^^you have the evidence on the bearing, how much is straightening going to cost?
Persnally my time is valuable to me how many hours have you spend on them already?

[937carrera]

Many thanks for the offer BBB, that's a very kind offer from you.

I don't mind spending the time looking at things closely. It's my hobby, I enjoy doing it and allows me to develop greater personal knowledge. The quandary with this engine is why was it available in this condition with no ancillaries or history.

So far we've found out it has what appears to be a rare case design, a good crankshaft, unusual wear on big end journal 3 and oversized, but fairly new oversize pistons & barrels. Much more known than before. The worst thing to do would be to rebuild it without finding out what was wrong with it and allow the original faults to remain. That would be expensive and not provide enjoyment. I might be taking undue care, not only because I want a happy ending, but also because I suspect it has been rebuilt without eliminating all faults before :

I've had bent rods on an engine before, but time constraints mean they've always been sent away. This was an opportunity to see to what extent a DIY approach could work. Jury's out, I suspect it doesn't work, perhaps the manufacture of OE rods is focussed purely on the alignment of the two bearing faces and other dimensions do not matter, but when I have bought aftermarket rods like Carrillo or Pauter they always have much more in the spec. I will try a few more measurements with a different surface protector and see where I end up.

[itchyfeet]

I tried, but not for very long, to think of a witty title.

Picked this up today. History unknown, except it originally came with a van as is. I'm assuming there's been an internal problem and all the ancillaries have been stripped off for a replacement engine.

Do you have any reason to think there was anything wrong with this engine other that your assumption?

lots of people have spare engines and sell them with vans.

just because it has no ancillaries does not mean it was removed because it failed maybe it was removed from a rust bucket and sold, get more money selling ancillaries seperately.

[937carrera]

There was no history with the engine, and it did apparently come with a van a number of years ago.

I made the assumption because I wasn't going to make the contrary assumption that it was good and go through the pain of fitting something in a van that later proved to be no good, especially considering the condition of the exhaust system which looks aged.

You didn't quote this bit from my first post

Personally, I blame this forum for sending me down the road of having spare engines and bits lying around

You made me do it

...and I fancied having a play

[itchyfeet]

More than happy to take the blame for encouraging people to fix WBX

my point is you are looking for the fault that this engine has thats a show stopper and it may not have one, it may just have a few bits that are not A1 but be perfectly good enough to push your camper around.

Don't get me wrong I'm all for DIY methods of measuring and repairing that can be done with simple tools and time.

My take on this is that all the machined surfaces may not all be square to the big and little end and your methods of holding the rods at the little end means any error is amplified, could you hold them at the big end and try putting a gudgeon pin through? need a packer to space them.

[bigbadbob76]

My take on this is that all the machined surfaces may not all be square to the big and little end.

I agree there. I was trying to think through it, does it matter? my brain started to fry thinking in 3 dimensions at once.