replacing 803 engine & Gearbox with 948 or 1098

[rogerowen]

I am considering changing the engine and gearbox of a '56 series 2 to (ideally a 1098), or 948. Apart from oil leaks the 803 engine is pretty OK, but the gearbox is totally shot (syncromesh). I understand rebuilt exchange 803 gearboxes are unavailable and having the existing box rebuilt could be very expensive.

Can anyone give me a list of all the other mechanical/body modifications that will need to be undertaken for this upgrade?

Thanks.

[Neil MG]

Apparently the 948 is a direct bolt on using the 803 rear housing. No changes necessary and much better ratios! I have one waiting ready for my Series II, but the original just keeps on going...

[bmcecosse]

Neil is talking about fitting a 948 gearbox - which can be fitted with the rear part of your 803 gearbox to retain the pudding stirrer gearlever. Obviously you can then fit a 948 or 1098 engine to that gearbox. Using a complete 948 or 1098 gearbox will involve mods to the floor and purchase of a gearbox cover. With an engine change you will certainly want to change the rear axle ratio too - and the speedo to keep the readings correct.

[Neil MG]

Thanks Roy!

Now I see it "...changing the engine AND gearbox..." I saw "...the 803 engine is pretty OK..." and immediately thought "if it were my car" and lowest cost option...

[rogerowen]

Thanks very much for the info, can I ask another question please? Is the gear lever position for the 948 and the 1048 the same? And, if I managed to get a suitable gearbox cover, would I have any other problems with fitting a 948 or 1098 engine and gearbox combo, i.e. can I use the 803 flywheel, prop shaft? Also, can I re-use the old 803 ancillaries ( SU carb, dynamo, starter motor, etc. ) Sorry, big list! Many thanks.

[bmcecosse]

Gear change on 948 and 1098 same place. Prop shaft will be fine - but use the correct flywheel for the engine. Starter and dynamo - yes, SU carb from 803 is far too small and the manifold is horrible..... Use HS2 and manifold from a 1098 - or even better - the HS4 and manifold from a Mini for a few extra horses.

[rogerowen]

That's brilliant, thank you so much!

[chickenjohn]

If you need a 948 gearbox, I have one for sale that was allegedly re-built by the previous owner. Has been kept in my shed since and is no good to me as I have 1098 CC cars.

Make me an offer!

[dellerie]

so an 803 tailshaft fits the 948 box? direct fit? isn't the 948 a remote gear change?

[mike.perry]

That is the idea, it makes the 948 box look like an 803 box and keeps the car looking original whilst giving you a decent set of ratios.

[dellerie]

looked at this today and i can't see how it would work



the tailshaft is from a series 2 box. the gold one is a 948 box. surely the gearstick position makes it not possible?

[Neil MG]

But that's the whole point, to keep the Series II gear lever position...

[dellerie]

but would the gear change work? it would obviously be in the wrong position, so i can't see how it would connect.

[bmcecosse]

It will be in the 803 position! With the long pudding stirrer gearlever. Is that not what you want??

[dellerie]

yes, of course. but wouldn't the remote connect by a series of longer rods? with the gear stick in a different position, how would that work?

[Neil MG]

It's no longer remote!

[bmcecosse]

You are not going to use the remote! You unbolt the complete rear section from the 948 and throw it away - and then you bolt on the rear section of the old 803 box......... Simples !

[dellerie]

ok, it wasn't explained at the start.

[brucek]

Better to compare the bellhousing end of the 803 box with the 948 box - they are practically the same casting - it's just that the 948 box has better ratios and the remote extension arrangement for a shorter gear lever. When you see the two together, then you will see how similar they are without the remote gearlever extension. Look at where the 803 gear leaver enters the car in comparison with where the gear lever is on a 948/1000. It may look odd for now but LOTS of people have done this and it DOES work

[rogerowen]

This is getting interesting! Have I stirred up a Hornets Nest? The way I see it - you replace the 948 gearbox back section with the original 803 back section (i.e. no remote), and the original 803 long gear-stick connects with the 948 internals. this way the gearbox tunnel of the 803 car does not have to be changed to a 948 one.