engine

[stuupnorth]

hi all
this must have been asked a few times over the years but here we go again
I have finally got a 1275 midget engine newly rebuilt

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s-l16001.jpg (60.02 KiB) Viewed 2611 times

I'm planning to fit into my 1960 948cc minor
any tips ie gearbox(1098?) clutch ,flywheel am I right in thinking starter will fit(new this year) distributor(25d fitted with electronic ignition) anything else
the car has a maniflow manifold and system already fitted ,it is for the smaller engined minor so will I have to change it ? and I have 1.5 su as well (better with a hif su ?)
I am doing a disc conversion and servo along with engine
any help would be very helpful
cheers Stu

[ampwhu]

Doing the same so interested.

I've got a maniflow system and Hif44

[philthehill]

You will need the 1275cc Midget/Sprite flywheel, driven plate and cover plate.
The 1098cc flywheel will not suit the 1275cc crankshaft as the mountings are different.
You can get the 1275cc flywheel faced off, indexed drilled/tapped for use with the 1098cc clutch cover.

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The Minor clutch linkage can be used with the 1275cc clutch but is a bit heavy and will be either in or out. Pedal pressure can be reduced by altering the leverage of the relay shaft or using one of Declan Burn's special clutch linkages.

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Use the 1275cc clutch release bearing in the 1098cc release arm if using the standard 1275cc clutch assy.
Use the 1098cc gearbox if using anything other than the 948cc flywheel/clutch assy. The inside of the 1098cc/1275cc bell housing is bigger to allow for the larger clutch and also has the cut out for the steering rack.

[stuupnorth]

hi
where would I get the 1275 flywheel modded for the 1098 clutch set up??

[philthehill]

Any half decent engineering company should be able to face off the flywheel and index drill for the 1098cc clutch cover.
You will also need the three clutch cover locating dowels which are available from MOSS Europe.

Alternatively you could purchase a ready modified 1275cc Midget/Sprite flywheel from Peter May Engineering.

[moggiegeek]

Congrats on the rebuild. I've recently rebuilt a 1275
.so far as the clutch/gearbox is concerned I used a 1098 flywheel drilled for the midget 6 bolt crankshaft. I went for an uprated clutch by Drive Torque - expensive but good I'm told. I have a midget gearbox with midget clutch release arm and carbon release bearing. I also opted for a hydraulic clutch.
Like others I've gone for Maniflow 1 5/8 lcb and system and HIF44 on a Maniflow inlet with K+N pancake filter. Head is a modified 12g940 by Minisport with Kent 266 camshaft and crankshaft pulley balance. Rockers standard sintered. It's a Marina engine not an MG so sadly not such a good crankshaft but reground, new bearings all round and bores honed. The engine was balanced.
Because of a stupid machining error destroying one bearing cap I had to go to steel main bearing caps etc courtesy of Peter May Engineering and crankshaft oil seal at the same time.
It has been expensive and taken a long time but some bits I've obtained over the years. I always say it's once in a lifetime experience. Problem is that I haven't installed it yet and am dreaming of a 1380 plus type 9 gearbox.
The car itself had modded suspension, - adjustable Spax, anti roll bar and radius arms as well as brakes to suit - Riley 1.5 front and Wolseley 1500 rears - currently with a servo.
All now waiting for a bit of better weather for installation.

[philthehill]

How you do the job is up to you but I can assure you that you will be much better off with re-faced/indexed drilled 1275cc Midget/Sprite flywheel - or a new flywheel from Peter May Engineering.
Not only has the 1275cc Midget /Sprite flywheel got 6 bolts - it has two locating dowels and a register that keeps the flywheel to the crankshaft.
I have tried various flywheels on the rear end of 1275cc Midget/Sprite crankshafts and the only flywheel that instils me with confidence is a 1275cc Midget/Sprite flywheel with 6 bolts, two dowels and register.
Currently there is a steel flywheel fitted to my Minor which was machined from a steel billet.
If you want to go the whole hog here is a alloy flywheel machined from solid by Manx Racing to suit my 1400cc ' A' Series. Note the register that sits over the rear end of the crankshaft.

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[ampwhu]

sorry for being stupid Phil, but could you explain what you mean by "indexted drilled"?

i'm thinking machined 1275 flywheel to except 1098 clutch?

[ampwhu]

Also is the dowl you mention?

https://www.moss-europe.co.uk/dowel-clu ... soc=143942

do you machine the 1275 flywheel to accept these dowls and then you can fit the 1098 clutch?

I could then use the mechanical clutch (1098) with a 1275 engine fitted.

[philthehill]

Index drilled means that the required holes are all drilled/sett at the required degrees therefore spaced correctly for the clutch cover.

The dowels (Pt No: 1G2984) in your link are the correct ones.

The 1275cc flywheel is faced off (as per my picture above), then the flywheel is indexed drilled for both the clutch cover dowels and the clutch cover securing bolts.

You will need the 1098cc clutch cover and dowels to accompany the 1275cc flywheel to the machine shop so as they have they can determine the required specification.

Phil

[IslipMinor]

Why make it so complicated? It's standard 1275 Midget engine, why not just use a standard Midget 1275 flywheel and the standard Midget 1275 6.5" diaphragm clutch. It works very well in standard form!! That's what we have with our 1380, apart from an uprated driven/centre plate. It's heavy enough to encourage good discipline at the lights, i.e. select neutral, but otherwise very easy to use.

[philthehill]

Richard
I totally agree with you and have mentioned/advised using the standard flywheel/clutch assy with modified linkage above - but the questions have been asked.

The OP does not appear to have a 1275cc Midget flywheel. The 1275cc Midget flywheel even S/H is not cheap and not readily available so I would advise that all options should be explored.
Here is a 1275cc MG Midget flywheel for sale - not cheap and they are never are.

https://www.ebay.co.uk/itm/MG-MIDGET-12 ... Swi5FdTvcD

Phil

[ampwhu]

Thanks phil. I think the penny has dropped. I already have the 1275 flywheel. I need to find a 1098 clutch cover. The only one I have is on the car.

[ampwhu]

Why make it so complicated? It's standard 1275 Midget engine, why not just use a standard Midget 1275 flywheel and the standard Midget 1275 6.5" diaphragm clutch. It works very well in standard form!! That's what we have with our 1380, apart from an uprated driven/centre plate. It's heavy enough to encourage good discipline at the lights, i.e. select neutral, but otherwise very easy to use.

Would this work with the 1098 ribbed box and 1098 clutch arm?

[philthehill]

Ampwhu.
Thank you for clarifying that you do have the 1275cc Midget flywheel.
In that case just keep it simple 'as per Richard above' and obtain a 1275cc Midget driven plate, pressure plate and 1275cc Midget carbon thrust..
Here is all you need:-
https://www.ebay.co.uk/itm/MG-Midget-12 ... xyTjNSe4PW

If you modify the relay shaft as per the drawing above the pedal pressure will not be much more than that of a standard Minor clutch pedal pressure

Phil

[ampwhu]

Phil, I already have the following to hand

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1275 clutch.JPG (81.48 KiB) Viewed 2291 times

whilst were on the subject, this is a picture of one of the bores of the 1275 block. Would you say this looks like it has a sleeve fitted? It measures 70.6mm or there about. That's standard bore size for a mg midget is it not?

1275 bore.JPG (86.27 KiB) Viewed 2291 times

i'm thinking new rings and a cylinder hone should be enough. there is no ridge at the top or bottom.

[philthehill]

Looks as if you are all ready and good to go.

I would clean up the driving face of the flywheel and see how deep those scores in the driving face are.

I would replace the centre/driven plate. Fit the 1275cc carbon thrust if using the 1098cc gearbox/release lever.

The block certainly looks as if it has been sleeved. Absolutely no problem with sleeves/liners being fitted.

A light hone is all that is required if all the bores are good as that.

70.61mm is the standard bore size of the 1275cc Midget/Sprite engine.

[ampwhu]

so I use the 1098 fork with a 3 piece 1275 clutch then. Think i'll buy a new clutch for piece of mind. I could put the flywheel on my lathe at work and give it a light skim.

[philthehill]

A light skim is all that is required.
But - to keep the pressure plate loading the same you need to skim across the full raised rear face of the flywheel. It is no good just skimming the rubbing face inside of the dowels/bolts.
To do the job properly you will need to remove the three dowels. This can be done easily by drilling a small hole right through the dowel and flywheel. Then drill a slightly larger hole through the back of the flywheel only - using the small hole as a pilot. Then with a punch knock the dowel out.
Replace the dowels - link above.
Make sure that when setting up the flywheel in the lathe - use a dial gauge to make sure that the new rubbing face is true to the old rubbing face.
Phil

[ampwhu]

that's sounds like the right way there to do it.