MG-Cars.info

Welcome to our Site for MG, Triumph and Austin-Healey Car Information.

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG MGB Technical - Alternator adjusting link

Hi,
I have a 1980 Rubber Bumper roadster(owned from new) & have a query over the link. Some time in the 1980s i had the clutch changed (by a specialist clutch change outfit). In those good old days of long days of work(& this was my daily driver) i simply dropped the car off at the start of the day and picked it up at the end with the job done.Some years later when my car changed its' status to being used solely for pleasure with self maintenance, i noticed that the link was attached to the alternator with a small bolt,large washer & small bolt.(& fitted at an angle (not in line) from the bolt on the engine cover plate to the front of the alternator)Clearly many years before, the clutch change outfit had lost the original fixing bolt/nut etc. and codged it. I am unclear as to whether they lost the link altogether & replaced it with an earlier type.
A different link was used from 1976 on & the parts manuals of Moss,David Manners & MGOC list a number 12G2627. However the picture in David Manners & Moss shows the link as having a dogs leg profile rather than a flat link. (The link delivered using that part number is flat & as a consequence does not line up & rest on the front face of the alternator,but to fit has to rest on the rear of the front face.(The link pivot bolt that attaches to the engine front plate is not long enough (together with nuts & washers to enable a flat link to be set far enough forward which a dog leg profile would have rectified.The alternator,is as originally fitted to the car & i am using a water pump as per original spec.
Has anyone had a similar problem ? Am i right in thinking the link should have a dog's leg? Does anyone have a picture of a link as fitted on a late rubber bumper car?
Apologies for the long ramble.
Cheers
Charles



Charles9

This is the best I can do.

It's from a 1980 B that I owned a couple of years ago, although I don't know how original it is.

It looks fairly flat.

Dave O'Neill 2

Originally there was a flat link 2A497 - straight with a straight slot, with a pillar 2A128 standing it off from the front cover. That seems to have changed to 12H67 which is flat, 'oval' with a straight slot.

The Parts Catalogue for 77 and latter does show what appears to be a cranked link, with no pillar, but the part number Googles to flat, curved with a curved slot as you say.

I can't see a picture on David Manners but if you expand item 41 on Moss, even though the thumbnail looks a bit cranked, it shows the flat oval one, as does everywhere else.

Dave's looks to me like the original i.e. flat, straight with the pillar. I can't see that the water pump changed so the pillar wasn't needed, or that would push the whole alternator back, with implications for the rear mount and the pulley. That being the case, AFAIKS you would need either the pillar, or a cranked link, like the V8 has. It may be that they tried a cranked link for a while, but went back to the flat with the pillar. That's actually more convenient as only a nut needs slackening to pivot the link at the engine end. If it were bolted direct it would be a bolt and nut and you would need a spanner both sides.
paulh4

Thanks both for your observations.It is not absolutely clear on Dave's picture whether it is a pillar (2A128) or a slightly longer version of the screw (SH606111) which would enable a second nut to be inserted immediately behind the adjusting link and thus push the link forward at the engine block end. As far as i can see it looks like a screw similar to the one i removed from my car. (When i removed my alternator earlier this year , as Paul has pointed out,as it was bolted direct i had to use a spanner both sides at the alternator end which is a pig to do! I think the easiest solution, unless i can locate a cranked link is to replace the screw (SH606111) with a pillar!
Cheers
Charles
Charles9

Attached photo shows the adjusting link on my 1980 MGB, which I think is a 12G2627.

The BL microfiche parts list (for MGB - September 1976 on) shows the link as 12G2627.

The link appears to be attached via a 2A128 pillar.

I've just had a look under the bonnet of my 1979 BGT and the link arrangement is the same.

Brian Shaw

Thanks Brian. Your set up is how I think my car came out of the factory.I will put mine back together in the same way.i think however,that you have a screw with a nut behind the link at the engine block end (as per my MG) as the link looks closer to the engine plate than it would with a pillar. (My original hand book shows a nut at both ends of the link facing forward)!
Cheers
Charles
Charles9

"you have a screw with a nut behind the link at the engine block end" i.e. a nut to space the link from the block.

Concur, as the link is behind the ear on the alternator front plate and not in front, as Charles says his is. The pillar allows the link to be in front of the alternator ear, but I'm wondering if the North American multi-belt arrangements required things to be done in this other way, and it was done on all. Doesn't seem likely though as the air-pump belt is further forward. Maybe just cheaper than a pillar.
paulh4

This thread was discussed between 20/01/2018 and 21/01/2018

MG MGB Technical index

This thread is from the archives. Join the live MG MGB Technical BBS now