MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

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 MGA - 1800 transplant, which clutch?

I am just now getting around to finishing my 1800 engine transplant. However, I can't remember exactly what the clutch setup should be. Is it, MGA pressure plate and MGB clutch disk?

Please advise,
Thanks,
Danny
Danny T

Danny,

It is not clear what you are doing. Are you fitting an 1800 MGB engine with your MGA gearbox? Is it a 3 main bearing MGB engine.
The normal procedure is to use the complete MGB diaphragm clutch. Are you using a 3 dowel MGB flywheel? If you use an MGB clutch with an MGA gearbox you have to fit an MGB gearbox front cover.
All this is explained on Barney's site.

http://www.mgaguru.com

Mick
Mick Anderson

Hi Mick,

I'm installing an early, (1967), 5 main 1800 engine and using the original MGA transmission.

DT
Danny

Danny,

Generally the MGA pressure plate is not up to the challenge of the extra BHP.

So people often fit the MGB pressure plate, but retain the MGA 10 spline friction plate.

If you do this, then you need the MGB clutch fork and thrust bearing.
To use these, you must first change the front gearbox plate to an early MGB one. Not that hard, even if your MGA gearbox is still in the car.

I got all the parts from here.
http://www.mgbreakers.com/MGB.html#Transmission
but MGB MKi clutch forks are a sought after item and hard to get.

Hope this helps.
Cheers <MARK>
Mark Hester

Danny,

I also got my clutch fork and gbx front cover from MGbreakers. price was very fair.

The advantage of the B or Sherpa van covers (the Sherpa one is even stronger than the B one, but needs more pressure to release) is that they are stronger and cheaper than the A ones. You need to use the correct friction plate to fit the gearbox input shaft, but this is nothing special, and if you take the old one to your local parts supplier, they will be able to match it (not a unique item to the MGA that one!)

Remember to make sure that the step in the end of the layshaft is in the right position or the cover will not seat (basically, dont move anything when you remove the old cover, and replace immediately with the B one. It is very important to centre the new cover on the front of the gearbox. Make sure that you do this according to the manual, otherwise it WILL leak. Make sure that the new cover has a clean and flat mating surface. A new oil seal and gasket is compulsory!

You also need to either change the flywheel to a B one, or have the locating pins moved in the A flywheel to match the locating pin locations on the B cover. In both cases I would strongly recommend having the flywheel lightened. This transforms the responsiveness of the car without any idling penalties. The engine becomes much freer to rev. The clutch does become much sharper, so you will find that any other drivers will immediately stall the car on take-off, but you will get used to it very quickly indeed.
dominic clancy

Oh,

This is a Must or you will destroy your MGA gearbox.

You need the adapter spigot. Moss part STN71X

http://www.moss-europe.co.uk/MossUK/ProductList.aspx?SubSubCategoryID=MGA_UMGA-120

Expensive for what it is.

The MGA input shaft is reduced at the end where as the MGB on is not.... Thus you MUST fit this. regardless of what clutch you go for or you will destroy your MGA gearbox eventually.

Cheers <MARK>
PS don't lighten the flywheel too much or you will affect the idling.





Mark Hester

Mark

How much is too much off of the flywheel? I will be doing this with a 5 main in my 58 eventually but plan to use the B transmission that came with the engine.

Thanks

Larry
Larry Hallanger

Larry,

If you check out the MGB technical BBS and search there you will know doubt find the answer.
Don't get too carried away though.
I'd rather not say how brave we got, plus can't remember...

I slip the rear MGA gearbox half onto a late 4 hole layshaft MGB MK I gearbox (1966 or 67).
Then you get a stronger gearbox, plus all the clutch bit and slightly better ratios...

only takes about an hour...

If you have the early sliding tail shaft then you need to change that though.

Cheers <MARK>
Mark Hester

I took my flywheel down to approx 16lbs/7.5 kilo's, you can go lower but as suggested you could affect the idle and stalling. Standard weight of the inertia type flywheel varies between 20 and 22 lbs ( I had a choice of 2 and they were diferent weights) You'll need a special backplate available from Hi-Gear Engineering if you use the 'A' transmission


Terry
Terry Drinkwater

Sometimes the MGB pressure plate will impact the transmission bellhousing near the starter. Make sure to check for this before fitting the setup in the car and grind away material if needed.
Mark

This thread was discussed between 16/05/2006 and 17/05/2006

MG MGA index

This thread is from the archive. The Live MG MGA BBS is active now.