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MG Midget and Sprite Technical - Gear Box Paint Colour

My gearbox is in pieces awaiting arrival of an overhaul kit from Heathrow Transmissions, the one including the syncro rings. I have given everything a good clean including the casings which on my car were black. I don't think this is original since paint washed off with thinners. I have aersols of engine green, black and silver. I am not overly concerned with originality but since I probably already have the correct paint what was the original colour on a 1966 Sprite?

Jan T
J Targosz

IIRC mine wasn't painted, it was just the bare aluminium.
Jeremy MkIII

I think it's bare aluminium as standard.
Bill Bretherton

The earlier smooth case boxes were painted the same as the engine. The later ribbed boxes were often plain ally. Certainly the 3 I have had never been painted.
Years ago I did have a RWA midget and that had black paint splashed over it around the bellhousing to match the black engine!!
Bob Beaumont

I'm at the same stage as Jan - waiting for my rebuild kit from Heathrow, it was due between Monday and today but no sight of it yet - has yours arrived Jan?

I have just had my gearbox on the bench and begun to clean it before opening it up. It's painted black, which I thought was authentic for later 1275 boxes but I can't find anything about black gearboxes in my copy of Terry Horler's book.

However, what I have found is traces of gold paint beneath the black. Does this mean it's been through a factory re-build at some stage and been sold as a 'Gold Seal' unit as engines once were?

Colin
C Mee

Yes there were gold seal gearboxes. I bought one for a RWA Midget back in 1977 from University Motors in Epsom. I had acquired the Midget, which was then only 4 years old, rather cheaply as it had a noisy first gear as the PO had rather ruined it. Apparently all the internals were brand new components, it was just the casings that were recycled.
I used the Midget as a daily driver for 3 years as it came with a factory hardtop.
Bob Beaumont

I once had a recon gearbox (1275) and it had been given a light coat of black paint, presumably to make it look better. Can't remember which supplier I used, as it was a long time ago (20+ years).

Jon
Jonathan Severn

My Heathrow Transmissions refurb kit arrived on Thursday so I'm hoping to get cracking this week.

The kit includes the following: DIY overhaul kit contains the following:

1X FRONT MAIN BEARING
1X REAR MAIN BEARING (with shim)
1X TIP MAINSHAFT BEARING
1X LAYSHAFT
2X LAYBEARINGS
1X REAR OIL SEAL.
3X SYNCHRO/BAULK RINGS
1X FULL GASKET SET

I'll have to wait until the box is dismantled before I can confirm the state of the gears and selector forks but are there any other consumable/wearing parts that I'm likely to need in addition to what's included in the kit?

Colin
C Mee

Colin, was first gear noisy?
Bill Bretherton

Bill, I don't know!

It's a 1275 box that I acquired via Ebay. Turned over by hand all gears select and I don't hear any odd sounds. I've no idea of how many miles it's done but I discovered the other day that it's a Gold Seal unit so I hope there won't be too much wear for me to find.

Silly novice question: Will a 'noisy' 1st gear be obvious once it's out and on the bench?
C Mee

Colin, I'm no expert but the first gear cog should have decent teeth with no pitting or obvious chewed up edges, Same for the gear it meshes with on the laygear (the straight cut one) and same for the reverse idler. I replaced first gear, reverse idler and laygear but these parts are normally expensive and only need changing if badly worn. I presume you'll post pictures when the box is stripped.
Bill Bretherton

Colin, are you planning on doing anything about the input shaft regarding oil sealing?
GuyW

Thanks Bill. I'm hoping that, with it being a Gold Seal unit, the gears won't be too worn. If Bob's correct, most of the internals were replaced with new when the box was refurbished.

Guy, I wasn't intending to do anything non-standard. The inside of the bell-housing is clean with no signs of leakage round the input shaft. It doesn't appear to have been cleaned up specially for selling. However, none of the parts diagrams I have show any kind of lip seal or similar where the input shaft passes through the front cover so how is that made oil-tight?
C Mee

Its a scroll seal, same as the crank. There is a modification that involves machining the input shaft cover and fitting a lip seal. I have one I bought ready to fit on my gearbox next time I have it out.
GuyW

Colin,

Apart from the obvious chipping and damage as Bill describes to 1st gear, the other wear items will be the little 'teeth' on each cog. They should have a distinct profil, if they are rounded off or irregular then there is more risk of jumping out of gear. 2nd gear is the favourite for this! The other wearpoint is the end of the third motion shaftwhere the needle roller goes. It can become pitted and damaged.This would then wear the needle roller in double quick time allowing the input shaft to float about. Sadly the only solution is a new shaft
Again pictures will help to identify any nasties!

Bob
Bob Beaumont

Guy, Bob, thanks for your comments, they're really helpful.

To avoid hijacking Jan's thread further I've started a new one on Gearbox Refurbishment: http://mg-cars.org.uk/cgi-bin/or17?runprog=mgbbs&mode=thread&access=&subject=97&source=T&thread=20221003103128103047

Colin
C Mee

This thread was discussed between 23/09/2022 and 03/10/2022

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.