1992 Jaguar XJ40 SuperTurboDiesel

[biturbo228]

Thanks man! That's more like it. I've had another look and it's $41 rather than £41 so that's a little more affordable.

A little more searching has brought up a part number of JLM1240 which brings up a listing you can buy from JLR classic car parts in lots of 5. It's different to the BAU2043 which is the part number I'm after, but at £1.2 it's worth a pop!

Will be in touch if it doesn't fit!

[biturbo228]

It passed! Nowt but a wiper blade which I forgot to change.

Chappy didn't quite know what to make of it when I arrived, but rather liked it after the test drive to do the brakes

Of course, it popped a boost hose on the way home again and an indicator bulb went out, but it was very polite of it to do that after the MoT

[75swb]

Excellent news! And very good of it to behave when required

[biturbo228]

Yeah I'm hoping it feels pampered enough now to behave not that it was particularly obstinate before TBH, was quite reliable until the heater hose blew (and even then if I'd been with the car when it did I expect it would have been fine).

[Ralph.Wrecked.It]

Very cool bit of kit that! love it!

[biturbo228]

Took the Jag to get a wheel alignment ahead of taking it over to the new place. Highlighted that the steering rack bushes are shot and the rack can slide side-to-side. You can make up little spacers which were fitted to police-spec ones to take the play out, which will have to do for now. Did manage to get this photo of its first excursion into the wild though



Unfortunately, the trip over East has highlighted some more issues. First off there's a lot of noise from the rear end. Possibly poly-related but I really should triple-check there's oil in the diff

There's also a rather nasty thrumming noise that starts up from a smidge over 50mph. Feels propshafty. I've thought of a way of checking the front guibo alignment, but I do remember thinking there was more play than I'd like in the centre bearing. Like the seating surface for the ID was a smidge too small so it could move aroudn slightly. I'm suspecting this would allow the prop to whip ever so slightly, which might build up to a noticeable wobble around 50-ish.

Bit late notice to be sorting stuff like this, but there's a chance it could be fixed in time for mapping on the 5th

If anyone can think of a way of testing that which doesn't involve me getting under the car to have a look while someone else runs it up to speed I'm all ears!

[glenanderson]

You could do what someone did with my lorry to access the centre bearing without going underneath; hack a hole in the floor…

Probably not the best option. 🤣

[kevins]

can you paint mark the centre bearing joint, take it for a drive and take a look to see if it has been moving?

[giuliettaevo]

To check alignement on the first part of the propshaft i take out the bolts from the front donut and then use 3 longer bolts to sandwich the donut between both flanges. That way it's hard mounted and should point straight to the middle of the middle bearing.

[biturbo228]

I'm all for access holes to be fair! Chopped one in the boot so I can do the diff oil without having to navigate around the rear subframe mount.

Tested it by solid-mounting the guibo like you mentioned giuliettaevo and this is what I found!



That's about 6mm of runout at the centre-bearing end, which I'm going to hazard a guess and say is far too much. Took it off, cleaned up the mounting faces on the guibo and refit it and there was no change.

Need to check which bit in particular is off, but I'm fairly confident it'll be the guibo mount on the new prop. Did a little bit of trig and 6mm of movement at the centre bearing is 0.337deg out at the guibo. That translates to the mating surface with the shaft of the prop being 0.447mm out.

Currently wondering whether I can get it close enough myself. I'm thinking spend some time pinning down which side is 'low', carefully grind off all the weld apart from the 'high' side, very carefully tap it up just under half a mm, tack that in place and then test it again. Rinse and repeat until I can get the runout down to an acceptable level (whatever that might be).

I would take it back to the prop place to fettle but I don't think they'll get it back in time for mapping!

Edit: Found this thread over on the H.A.M.B and this table of marine propshaft tolerances by length, both of which suggest an upper limit of around 0.25mm runout for a metre(ish) long shaft. So 24 times the tolerance. No wonder it feels horrendous!

[westbay]

"I would take it back to the prop place to fettle but I don't think they'll get it back in time for mapping!"

Assuming you paid for the work they should fix it ...

If you fiddle with it , and still cannot correct, you will probably have to pay again !


Frustrating either way ...

[kevins]

If I understand correctly you are saying if you rigidly mount the in and out side of the guibo and turn the gearbox output shaft you get 6mm of movement at the centre bearing 18" or so further back?

Is this problem due to the guibo holes not being concentric to the output shaft or the mounting faces not being perpendicular to the output shaft?

If it is the later I cant see it being a problem, the guibos are designed to take up to a couple of degrees of misalignment, If you want to eliminate this surely some shims between the guibo and the flange would get it completely true.

one thought is about the guibo joint, I assume it is the type with a centre bearing, this is in place and in good condition?

[biturbo228]

Thanks folks.

Yes kevins that's exactly what I was getting. It was the mounting faces not being perpendicular to the output shaft. Runout at the gearbox end was barely perceptible. Normally guibos are pretty good at taking up misalignment, but from what I gather these BMW ones don't tolerate it much at all. I'd thought about shimming, but it is one of those props with a centre bearing and that would throw off the alignment of that to the yokes (and that bearing is newly fitted).

I've taken it back to the prop place, and after a bit of explaining they got what I was wittering on about. Popped it back in the balancer using the pin for the centre bearing, clocked the yoke a little, welded it back up and rebalanced it. I've retested it with the same solid mounting setup and we're down to 1.5mm of runout, which translates to about 0.16mm of height difference at the yokes, which should be shimmable if there's still issues.

Here's where I think the error came in. This is what the yoke looks like:



It looks like the outer, proud section is a machined datum surface for mounting, but it's actually just machined for clearance. The mounting surface is the inner shoulder, and with some feeler gauges I measured a little over a 0.5mm variation in the heights of the outer proud section. If it was chucked up using these then it'd throw out the rest of the prop.

It could well be that this wasn't the issue, and that when the centre bearing was swapped out for a 35mm one it wasn't rebalanced. Either way they've gone over it and think it's good! Free of charge as well, which is great.

I did also find that the guibo was fitted in the wrong orientation:



Those arrows are supposed to point towards the mounting lugs. I don't think this would have caused the issue as I hadn't touched the guibo prior to this and it had driven down from Newcastle just fine!

I'd love to have tested it on the road again, but this happened!



Coolant isn't supposed to be that colour!

Bit of research suggests this is probably the gasket in the oil-to-water cooler. If this goes then the higher pressure of the oil system pumps the engine oil into the coolant system, pressurising that so the cap relieves. Luckily I caught it quite quickly so I don't think it ran the engine dry.

With all the postal strikes I wasn't sure a gasket would arrive before mapping so I rang up the nearest BMW dealer. Can get one in later this afternoon, and for a very reasonable price! Perhaps I should try dealers more often...

[kevins]

Probably means they sell loads of them!

[biturbo228]

Aug 26, 2022 10:25:07 GMT kevins said:

Probably means they sell loads of them!

Haha that had occurred to me!

There were some chunks of what looked like ossified rubber seal that came out when I flushed the coolant so I reckon that's it. There's a nice film of oil emulsion coating the whole coolant system now which is brilliant. Going to have a try at getting it with some dishwasher powder when the new seal's fitted!

[felix2566]

Just finished reading this, what a mammoth effort. Fair play for sticking with it and persevering with the project. What a brilliant engine to choose, I love them!

Look forward to reading the rest of the story!

[reliantscimitar]

hi there

I have used "elbow grease" diluted 1:1 to clean out contaminated cooling systems. It works really well.

Cheers - mike

[giuliettaevo]

I was told that a dishwasher tab would also work wonders.

[Tamber]

If you're going to use dishwasher soap, you're probably best off with the plain old powder. It's easier to get into the cooling system, and disperses itself better than the big solid tabs.

You will likely have to take several passes at it, and even then you'll probably still find little blobs of oil surfacing months later. Oil cooler failures make a real mess! (And another point to "if they have the gasket in stock, this probably happens a lot" )

You may also find yourself having to replace coolant hoses, too, if the contamination was bad enough. They go all horrible and mushy...

[vitesseefi]

Aug 26, 2022 10:25:07 GMT kevins said:

Probably means they sell loads of them!

They do. They are good at leaking to the outside world too.

Nick