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MG Midget and Sprite Technical - Bell Housing Noise

The Sprite has developed a rattle in the bell housing. It is similar to the noise first gear makes but happens in all gears. It is not constant though, it only starts after about 1/2 mile and then sort of pulses i.e. last for about a second, stops and then starts again. VERY ominously it stops when I press the clutch. I will drop the gearbox oil and see if there is any debris there but it looks like the front gear box bearing is on its way out. Anyone got any ideas.

Jan T
J Targosz

Clutch thrust release bearing? Is it a carbon one Jan?
Jeremy MkIII

Does sound a bit like a front bearing or cluster shaft issue--they both give the same symptoms
Standing still in neutral, engine running---With the clutch depressed, if it rumbles in the box when the clutch is released,then quiet again with the pedal depressed again it'll be a bearing in the box for sure.

I feel your pain, the flywheel in my trusty VW decided to come apart yesterday, you aught to hear that---sounds like someone trying to break out of the bellhousing with a jackhammer at idle---silly thing is it still drives perfectly which it'll have to do till the new flywheel gets here
William Revit

Willy,
is it one of those very clever VW dual-mass type?
Nigel Atkins

Was Nigel, now it's two separate pieces of metal trying to bash each other to death
new flywheel arrived late today, it's a tricky looking jigger with screws and plates and stuff everywhere
I tossed up between genuine, Luk and Sachs, Went for the Sachs in the finish, it read up better with a planetary gear set in it to soften the jerks--I must admit I've never chopped a genuine one up to have a look-see ,but will when this one comes out, I think the genuine one just has opposing spring loading---we'll see--I'll put some piccys up if you want when it's all apart, won't be for a little while though as there's concrete boxing blocking the door of the surgery for another week or two---bad timing on my part
willy
William Revit

Willy,
thanks be interesting to see.

Thank gawd the wife's car isn't sophisticated or overheavy enough for the lightly made main components from a certain European country to need such a DMF.
Nigel Atkins

Dual mass (or variable mass) flywheel is brilliant.
In concept.
In execution - not so much.
It would work great except for cost cutting. Bloody accountants.
Sunday rant. My wireless has blown up so I can't have a rage at Radio 4.
As you were...
Greybeard

'Rage at Radio 4' that's an oxymoron surely Grey?
Jeremy MkIII

Grey,
Shula's leaving, good riddance, but the Ed Reardon (repeat) show is always worth a listen, stellar cast of actors with individually decades of top grade comedy performances so they can really make the written interplay work. As always, poor Elgar.

Catch up on BBC Sounds on your preferred platform. 😁
Nigel Atkins

I have now identified the noise as coming from the gearbox. Putting my stethoscope on the filler plug confirmed this. I will now have to remove and dismantle the gearbox. I have an engine hoist but it raises via a long screw rather than hydraulics. This isn't a problem and actually gives better control. What I don't have though is one of the attachments to tilt the engine. Last time I removed the engine it was a real struggle with my wife working the hoist whilst I juggled the tail of the box out of the tunnel. A friend tells me he used to remove the engine from his midget, in the street, outside his mother's house by taking off the front panel and radiator surround. Can I do this my simply removing bolts. I have a heritage shell with perfect paint work and no way want to break spot welds or take an angle grinder to body seams. I do have some paint and am prepared to touch up the inevitable chip.
Regarding the potential gearbox rebuild I have seen kits for sale on ebay. The prices do vary. The most expensive appears to be from Heathrow Transmissions. They state they only sell top quality KSM bearings. I have always maintained that if a bearing is hard to get at then only fit the best. Can anyone advise on the best bearings to use.

Cheers

Jan T
J Targosz

Jan,
regarding careful extraction of the engine/ gearbox unit, which I have often done unaided. The thing that I find works best is to position a trolley jack under the rear of the gearbox, orientated in line with the car. I then gently lift the engine and roll the car back enough to get the tail of the gearbox out from the tranny tunnel. It can then be lowered slightly so the bellhousing clears the underside of the battery tray, and the engine then raised whilst the jack wheels allow it to roll smoothly forwards, tilt and clear the slam panel. The lifting point on the engine needs to be forward of its centre of gravity; somewhere near being over the front rocker box bolt is about right.
GuyW

Heathrow Transmissions are a reliable firm. Other gearbox specialists are Hardy Engineering. Peter May also supplies uprated heavy duty bearings and layshafts.
Its worth replacing every bearing in the gearbox especially the layshaft as the needle rollers are subject to relatively high wear.
Other causes of the noise could be a worn spigot bearing in the crankshaft, allowing the gearbox input shaft to move.
The front panel on a spridget is bolted on, there are no welds to remove. It is easier if this is removed as the engine does not need to come out at such a steep angle but removing the panel and radiator can be quite fiddly.
I had an engine hoist like yours and I agree is easier to use than the hydraulic one. Without the front panel you may be able to remove the engine using the standard lifting hooks.
Bob Beaumont

Guy I owe you a drink. Positioned the chain on the hoist with 2 links to the front and 5 to the rear. As I lifted the engine the tail of the gear box dropped and all I had to do was push the car backwards with my knee as I raised the hoist. Job done in 5 mins.

I have also dismantled the gear box and the front bearing is toast. The rear is not much better. I was able to loosen the large nuts holding the bearings on their shafts really easilly which suggests a poor quality previous rebuild. Also I was able to remove the bearings by gripping the outer race in a vice and tapping the end of the shaft with a copper mallet (the one for the wire wheels). I thought I would have needed a decent quality puller. I wonder if poor quality bearings have been fitted.

Jan T
J Targosz

That's good to hear, Jan.
The addition of the trolley jack is because as you lift and therefore tilt the engine, the rear of the gearbox drags forwards on the floor. The trolley jack just makes it a smoother operation. I lift using a Weston Differential chain hoist off a steel RSJ that I added for the purpose when I built my garage, 30 years ago. So, like you, I am lifting from a fixed position and need to be able to push the car back to clear the engine.

I once helped a mate with the same task only he used a mobile engine hoist on a wheeled frame that you then pulled back to clear the car. I really didn't like it! By comparison, with the heavy engine swinging about, high enough to clear everything, it felt really unstable, top heavy and risky.
GuyW

Nigel
Woke up to rain this morning so thought today would be VW day, Dragged him indoors and pulled the box out.
The flywheel was really sloppy/loose and i could move it round probably 20mm back and forth easy by hand-clunk,clunk, can't move the new one at all--Luckily the 2nd half of the flywheel hadn't gone round too far and could still get at the bolts to get it off, unlike how transit vans go round and cover the heads of the bolts meaning the gas has to come out to cut new access holes. Inner CV joints were a bit tired so treated him to a pair of new drive shafts while it was apart. Finished him off just before lunch and wifey took it to town shopping this afternoon which is a 200klm round trip and all is good again---
Here's a couple of pics of the new/old flywheels showing the obvious higher quality of the new one over the tinny looking original--and a pic of how far the boltholes had moved
I want to get the old one pulled apart to have a look inside but it looks like a major undertaking, don't know if i can be bothered, next wet day maybe
Cheers
willy






William Revit

Willy,
thanks.

120 miles round trip just to go shopping no wonder your VW hasn't fell apart sooner, a typical shopping trip in the UK would be a lot, lot, lot shorter and lot more stressful on the vehicle, and driver.

20 mm (25/32" or 51/64" in archaic imperialist) sounds a lot of 'play'.

And just look at the ancient German engineering 'excellence', to a non-engineer like me it looks like bits bolted together found at the back of a shed and an excess of fixings to use the box up. I'm sure there's lot of precision to bolting on another heavy lump of metal.

A great heavy lump of metal to make up for over stressing the light metal and plastic bits in front of it. Late 20th century engineering applied to your beloved later 19th century technology, it must be a joy for you to see.

And interesting for me to see, thank you, I thought there might be dobs of weld on the VW original as a modified 'improvement', or bits chisel out. Or a bolted on modification to bolt on to the bit already bolted on. 😄
Nigel Atkins

one interesting little feature of the original flywheel was that it had been balanced by spotwelding weights on the back face of it but strangely it looks like almost identical weights almost opposite each other--bit weird
The new one only had a couple of tiny drill holes for balance out on the outer edge----I'm going to have to chop the thing up---desperate to see what's in it
willy


William Revit

Blimey I thought I was joking about blobs of weld as weights, now I'm surprised they're not bolted on. All very low tech stuff.

Yeah lets have those bits apart, you might find springs, more bolts and hi-tech bits of concrete in the middle.
Nigel Atkins

Nigel; -It got the better of me and I just had to see what was inside
first pic, drilled the rivets out of the steel mounting plate and removed it- didn't learn much there
pic 2 drilled out the outer row of rivets and removed the outer ring assembly





William Revit

Flipped the outer piece over for a look and nothing there really except another spring steel plate the same as the other side and also a cast iron ring pressed into the outside ring, just for extra mass I guess

next pic, back to the main flywheel , there's a floating plate (with the drilled out rivets)- It's got what looks like a 'plastic' lining around it where the screwdriver is---doesn't look like it'll come apart much more than this--i want to know more--





William Revit

The main bit that's left is welded around the outside-

so into it with a cutoff wheel and there it is--
The 'plastic' lining is paper thin and falling apart and also the springs that are supposed to control the thing have collapsed and don't even touch the dick on the plate





William Revit

There's about 8mm clearance from the end of the spring

-and the other spring is worse, hiding in it's hole

no wonder it rattled and vibrated-----
Nice ring gear though- was





William Revit

Thanks for that Willy. Interesting, springs not quite as I expected, although I'd expect VW to say the spring gap is a piece of complex calculated quality engineering. Looks like something from a vehicle of the 1910s except for the VAG fantastic-plastic.

Surely thick lumps of heavy metal have used forever with the ancient ICE technology to overcome engineering and manufacturing compromises, nice to see traditions aren't lost. 😁

Any experience with VW dampers that are not leaking but misting, until they leak?
Nigel Atkins

Yep.--I expect the springs were originally way longer and under compression but have collapsed with time-

I've seen heaps of VW shocks, well gas shocks in general with a slightly damp look around the seals, it doesn't seem to effect them but eventually they must run out of gas and revert to being ordinary oil shockers.
Our old racer had monroe coilovers and the guys from howe recomended if we were having leak issues to run the shocks upside down so that the oil lubed the seals--that worked ok but a bit difficult to do on a std. VW
also ,we had Ford F250 trucks here as ambulances for quite a while and they were fitted with monster Bilstein gas shocks--they must have had heaps of pressure in them new to help the ride quality but when they lost their gas the ambulances would get too jiggly cruising along and yet the shockers were working ok but just lost their pressure----I know the gas is only supposed to keep control of the oil temp. but these ambo's needed it for comfort as well-and you could really feel the difference from gassed up or not

willy
William Revit

Thanks. I'll not soil this thread with anymore VW failings.
Nigel Atkins

This thread was discussed between 12/09/2022 and 28/09/2022

MG Midget and Sprite Technical index

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