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MG MGB Technical - New BGT owner....

Hello People
Newby BGT owner here, formally italian and german 'classic' owner, finally succombed to the lure of British rust.

Could anyone shed some light on a couple of issues for me please...

* is a GHD3/ chassis plated car on an F plate a mk1? If so is there any issues regarding running gear that differ significantly from later models (assuming there is some original gear left on it!)?

* on trying to start the vehicle for the 1st time the starter spins but doesnt engage with the flywheel, the clutch pedal is lazy on return aswell. Are these related?

Cheers for your time, sorry if the Q's seem a bit obv but am without Haynes or owners doc at mo so a little in the dark.

Graham
Graham

GHD3 is a MkI of 62 to 67, irrespective of the number plate. I don't know about issues as such, but there are certainly a lot of detail (and some not so detaile) differences with later cars. Anders Ditlev Clausager's 'Original MGB' contains a huge amount of detail on the changes over the years.

A MkI would originally have had an inertia starter where the pinion is flung up a spiral gear into engagement with the flywheel to turn the engine. It isn't uncommon for these to stick and either not engage, or engage and then fail to disengage meaning the starter won't turn at all and you have to rock it back and fore in 4th the release it. Remove the starter, clean the spiral gear, and *lightly* lubricate it with a drop of light oil, and turn the pinion up and down the shaft by hand to get it working. But if the car is new to you anything could be wrong with it.

Nothing to do with the clutch pedal, which could simply be the return spring on the pedal missing, or problems with the hydraulic system. And again if the car is new to you anything could be wrong with the hydraulics or clutch itself.
Paul Hunt 2

Hi Graham, welcome to the B world! Hope you enjoy the stay.
Regarding the spec, I'd get a catalogue from Moss as a cheap route to all your exploded parts diagrams (also on their website). That will ensure you have the right part numbers to hand when you need to order bits, wherever you go to get them. First items I'd look to identify, and others will be able to suggest more:
Engine number
Axle (salisbury or banjo?)
Carbs (they get swapped about
Dizzy (because you'll want to pull it out to get to the starter)
If you can post pics to a website and put the link here you'll get quick IDs.
It's also well worth taking a moment to register on this BBS as it gives you access to the archives which have to be about the most complete B resource on the planet.
Steve Postins

Graham,

One of the biggest differences is the gearbox. A mk1 car should have a 3 syncro box (not in first). Quite common for the 2nd gear synchro to play up. All cars from 68 on had a stronger 4 sync box. Also if you don't have overdrive then a 3 sync OD box is very expensive (I know, I just bought one!), whereas the 4 sync ones are cheap, but more difficult to fit (they are wider and need a different engine back plate).

Iain
67 BGT
www.mymgb.co.uk
I D Cameron

Thanks for the useful info guys.

Still waiting for amazon to deliver the haynes before attacking the starter motor - call me a wus.

Regarding the removal of the dizzy to get access to the starter - I have two oil pipes coming off the block right above the dizzy leading to a cooler situated in front of the rad... this isnt standard is it?

Engine seems to be a replacement gold in colour stamped with 48G739.... with C AD beneth. Anyone shed any light on that?

Gearbox has OD (whether that works or not is anyones guess) no idea how many syncs though. Same can be said for the axle....

once again thanks
all the best
Graham
Graham

Graham

Here is a pdf manual if you want to have a look at the dizzy before the haynes arrvies. Same one as some people sell on ebay.

http://octarine.mywowbb.com/forum28/

Steve
Steve99

Graham,

48 engine number are factory replacement gold seal engines (hence the colour). So not the original engine, and could be anything up to 30 odd years old! Doesn't really matter, and it's much better than finding the engine from a marina or sherpa van under there!!

For the gearbox it is easy to identify. If the bellhousing has a hole right behind the starter motor the it is a 3 sync. If not then it is a 4 sync. Normally they have different types of starter motor, so worth confirming that it is a 3 sync as expected before buying parts for starter motor if needed.

Oil cooler was option from new, so could well be original or may have been fitted with replacement engine.

Iain

I D Cameron

Graham,

Another thing to be aware of is that it may be a +ve earth car. Many have been converted, but if you look at the battery and see which terminal is connected to the body then you will know.

Iain
I D Cameron

Distributor is a fiddle, you may have to remove the cap to get it out, and that is a fiddle in itself with the oil cooler pipes as they are. When replacing points I always remove the distributor as it is not easy adjusting them in-situ, but then I have made myself a bench rig where I can spin the distributor, check the dwell, and make any further adjustments in comfort. Since I started checking gap with dwell rather than feeler gauge - which is non-invasive and hence preferable, as well as showing up other problems that a feeler gap wouldn't, much like setting timing dynamically is better than statically - I haven't had to readjust points on either the roadster or the V8 between the normal replacement intervals.

When reinstalling the distributor be careful not to over-tighten the long bolt in the clamp-plate which goes round the distributor body, this can distort the base of the distributor which causes it to jump out when you are driving along, at which point it is scrap. When reinstalling the distributor shaft can only engage with the drive dog in the block in one position, the drive slot and tongue are slightly offset to one side even though it doesn't look like it at first glance. Make sure the distributor is fully pushed into the clamp plate when the plate is tightened down to the block, only then is the drive properly engaged.

48G739 is a Gold Seal (factory reconditioned) replacement for the 18GB high compression unit used between October 64 and November 67 and as such may well be the correct replacement for your car, if its chassis number is between 47112 and 138360. If so that is interesting as my 73 also has a correct Gold Seal replacement for its year, which makes me think the replacement happened in its early-ish life, either that or the owner was very picky about what he replaced it with.

OD can be checked by driving along in 3rd or 4th at a steady speed and flicking the manual switch on and off allowing 2 or 3 seconds between each movement. If the revs go up and down with the switch it is working. This is easier to spot at higher revs. Once you have established it *is* working do the same test in 2nd gear, and the revs should *not* change. This is very important, if someone has fiddled with the interlock switch on the gearbox to allow OD to work in lower gears it may well be engaged in reverse as well. If you reverse with OD engaged you will destroy the OD! The interlock switch is designed such that OD can ever be engaged in 3rd and 4th (UK cars) and never in 1st, 2nd or reverse, regardless of the position of the manual switch.
Paul Hunt 2

Hi Graham

I, too, should like to welcome to the wonderful world of MGs.

My first suggestion to you is to join the MG Owners Club and get to know your local MGOC affiliated Club. That way you will meet a multitude of like-minded people who have a vast wealth of knowledge across the spectrum of MG ownership who are only too willing to help a fellow MG owner, and their help comes free of charge. After all we, likely, will have experience of most, if not all, of the problems you are, or will, experience during your MG ownership.

Secondly, get hold of a copy of the MGOC Parts Catalogue CD for the MGB & MGB GT 1962 to 1980. Your local MGOC Area Secretary should have a copy or you can get a copy from the MGOC direct. Download it onto your computer and it will be a mine of information on parts, prices and where the parts fit!

As Steve P from Oxfordshire says, you might also like to ask Moss Europe for a copy of their MGB Catalogue. The exploded diagrams in the catalogue will prove invaluable in the months and years ahead and you will find that you will save an awful amount of time by spending a few hours 'acclimatising' yourself with the layout of the MGB/GT.

Paul Hunt quite rightly recommended Clausager's Original MGB book. This is unquestionably 'The Bible' for MGB owners and will also prove to be very important when determining which Part Number of an item is relevant to your particular vehicle.

The only other source of reference I can recommend is a copy of the original factory Parts Catalogue, reproductions of which are also available from MGOC. Like the exploded diagrams in the Moss catalogue, this book will save you hours of frustration in finding a part, part number or simply finding where a particular part goes.

With all that said, you are in for many hours of fun with your new 'toy' and also many hours of heartaches. But remember, you can always rely on your fellow MG owners to help you.

And don't forget - the time honoured tradition that ALL MG owners flash their headlights at other MGs, a tradition that the MGF/TF brigade seem to have ignored!

Remember to look at www.mgownersclub.co.uk, www.moss-europe.co.uk and I cannot forget www.cornwallmgowners.co.uk where there are many links to other sites of interest to MG owners.

Safe MG motoring.

Robert
Area Secretary Cornwall MG Owners Club

R Lynex

Once again thanks guys

Just to let you know of the progress on trying to start her up....

Seems I do have an inertia engaged starter, it also seems like its near impossible to remove without the heartache of moving the oil cooler pipework and filter.

On inspection, whilst pulled out of housing, there seems to be some damage to the cogs on the barrel of the sm. Some rounding all over but significant sheering approx 1/4 from end nearest sm body. Anyone experienced this? The barrel does move, not easily, so will grease and reassemble with crossed fingers.

cheers
Graham
Graham

I'd recommend light oil, not grease on the spiral gear, and only just enough to get free movement after working the pinion up and down to distribute it, and only that after thorough cleaning. It used to be said *never* lubricate that spiral gear as it holds dust which *causes* the problem, but I have found too clean is just as bad.
Paul Hunt 2

Good news she's turning over yippee.

Now for the fuel and sparkers.....
Graham

This thread was discussed between 24/10/2006 and 29/10/2006

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