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MG Midget and Sprite Technical - 1098 Engine - MG v Minor ?

Hi All

Just come over from the Magnette pages

I have a friend who tells me the engine in her 1098 midget is knackered.

Seems these engines are few and far between but there are moggie minor engines around.

My question is what is the difference between the 2 engines? Compression ratio etc?

Is this the best option to go for?

What about 1275 engine - easier swap?

I think all the items bolted to the engine are in good condition.

Thanks
Gobby

Gobby

depends exactly what type 1098 she has; the early ones were same as Minor, later ones with 10CC prefix had bigger big ends so are stronger, and are Spridget-specific.
David Smith

Gobby,
The 1275cc engine, IMHO, is undoubtedly the better option, however, for originality's sake, the 1098cc might be preferred. A good 1275cc can cost a few quid though. I have a friend who has put a moggy 1000 engine in his MkII and it is gutless. He is planning to put the head, off his original engine, onto the Moggy one as the compression ratio is higher, apparently. I am certain that there are folks on this BBS who can add to this.
Neil (K series)

reconditioning the current engine not an option?
1098's are lovely and not that down on power compared to a 1275

the advantage is that you know what is done and only have done what is needed
Onno Könemann

Keep a real close eye on all the classifieds - including the ones from the club pages - MASC especially. I saw one advertised recently, but, sorry, can't for the life of me remember where .......
rachmacb


Thanks Guys - appreciate your help

Yes - I think best bet is to rebuild the original - like you say Onno at least you know what your getting

I will find out the engine number- all I know is its an early Mk2 1966

Cheers
Gobby
Gobby

Should be the 10CC engine prefix and as such has the 2" main bearing crank (same as all the 'big block' engines). Rebuild the existing engine as it is NOT the same as the Minor.

You will find the 1098 engine good and with the strong crank, just as tuneable as the 1275 unit. To enhance the driving pleasure, I would do a couple of mods... fit the Swiftune SW5-07 camshaft and get the head mildly gas flowed (not too much though), perhaps a tubular exhaust manifold.....

She'll love the new life her Spridget will have...

Mark.
M T Boldry

AIUI the Midget 1098 has a better cylinder head and slightly wider overlap / higher lift cam in order to increase torque.

CC is the better block, as noted earlier.

When I moved from 1098 to 1275 I was a little disappointed; the 1275 seemed flatter / less turned. I got the impression that the 1098 cam on cam around 3K; there was no such feeling with the 1275 (which was quicker, but did not feel so).

For originality, why not build your 1098 (assuming CC) with +60 pistons for a little more capacity?

A
Anthony Cutler

Be careful over boring to +60 thou, it makes the gap between 1 and 2 and 3 and 4 very small. I blew my head gasket last week between 3 and 4 and mine is only +40 thou. There was also evidence on the gasket of it leaking between 1 and 2. But as every one is saying, rebuild the 1098. If it's a 10CC engine it will have the better 12G295 head which has slightly larger inlet valves and better combustion chambers.

Bernie.
b higginson

Nobody has mentioned the head yet

The spridget should have a 12g295 head which was also used on the 998 cooper and is a much better head than the 12g202s which are fitted to minors...

1098 minor engines are dirt cheap, so unless its going to be thrashed to within an inch of its life I would go for a minor engine with the spridget head ;)
Matt 67&68 mk4 sprite

however the 12G202 head is teh more reliable one and if flowed properly can flow almost as much as a well modded 12940 (1275 head)
And the 295 ha s a much bigger chamber and thiner deck so can't easly be skimmed back to a sensible CR
Onno Könemann

As Onno correctly mentions, the 202 head give far better results when modified correctly.....

http://www.calverst.com/cc110f.htm

See Small Bore...

Mark
M T Boldry

If its of interest, I might be willing to sell the engine from my MkII Midget. The unit in question is a 10CC version, fully rebuilt in 1984 which has covered about 23,000 fairly gentle miles since. When being rebuilt it was fully balanced, crank, flywheel etc, and the crank was nitrided also. Its a very smooth unit uses no oil and runs extremely well.

If sold it will come less all ancillaries, including both inlet and exhaust manifolds, dynamo etc.

Should this be of interest, please let me know should you be interested.

Dennis Wharf
DR Wharf

This thread was discussed between 23/04/2010 and 26/04/2010

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