1275, Backplates and gearboxes

[moggiegeek]

Have finally built up 1275 currently with an ESM backplate and modified 1098 flywheel, uprated clutch which for a while for running in I will pair with existing 1098 gearbox in the car.
For the future to match it with an MG 1275 box I assume I will need an MG 1275 backplate but can continue to use the modified clutch and flywheel above?
As an aside I used Peter May Engineering for steel main bearing caps, new high tensile bolts crankshaft oil seal and full balancing. I hadn't intended to go this deep but was obliged to do so by a previous firm destroying the main bearing cap by machining too much from it.

[philthehill]

The ESM modified rear engine plate can be used with the 1275cc Midget gearbox. No need to buy a new or S/H 1275cc Midget rear engine plate.

Did you replace all three main bearing caps or just the centre main cap?

[moggiegeek]

I went with all three caps. They use MEV components. Shame it wasn't on an mg block but ...I The crankshaft seal involves matching the crankshaft scroll and they say it has a very extended life on a road car. However on the forum people are pretty critical of the aftermarket kits.
So it's all now assembled. Stage 3 minisport 12G940, Kent 266 cam maniflow exhaust and inlet. Vernier Duplex. Hif44. Probably overkill is the KAD oil pump
Question now is what needle would be best match?

[philthehill]

Thank you for the reply re the main bearing caps.

Regarding the rear crankshaft seal.

There are seal kits and seal kits !!!

Those seal kits that rely on the lip of the seal running on the outer face of the flywheel mounting flange are not to be recommended.
For example:-
One oil seal kit for the 1275cc Midget requires the use of a spacer between the flywheel and crankshaft which lifts the flywheel off the register which can allow the flywheel to come loose with serious consequences.

The MED rear seal kit which is a much better deal :- https://www.med-engineering.co.uk/engin ... n-seal-kit

See also the MED video (3.52 min onwards) which includes the fitment of the rear seal kit:-
https://www.youtube.com/watch?v=9sxy1pU ... Q23OoE_cNO

[moggiegeek]

Yes it's the MED kit fitted. No spacers involved.
Do you have a recommendation for a needle with the engine as built above?

[philthehill]

No not really as the only way to determine the needle required is to put it on a rolling road or undertake extensive road testing.

[moggiegeek]

Starting point would be handy!

[Banned User]

Starting point would be handy!

What if someone recommended a AAA and you melted a piston?

There’s a piece of software that you can download that will give you a rough starting point. https://www.winsu.co.uk/

[les]

I’ve found a chart that suggest, If you’ve got twin carbs, an option for a tuned 1275 S mini is BG needles and blue springs, so maybe you’d want to start there.

[Chipper]

A standard MG Metro (with HIF 44) used a BDL or BFY needle.

[Banned User]

A standard MG Metro (with HIF 44) used a BDL or BFY needle.

But he doesn’t have a standard MG Metro engine...

[moggiegeek]

I will read the Vizard Bible and consult the needle chart.
I don't think in the end it's that wild a creation. It's got the 266 which people mention in the same breath as the MG metro cam and the head is not dissimilar but slightly larger valves and more flow work, shaped valve guides etc. Compression ratio is standard. K+N filter and better manifolds. It's a 1275 with +10 rebore and balanced statically and dynamically. Rocker gear is standard sintered.
I did fit 30% uprated clutch.
Obviously I take responsibility for what needles I choose but I really value the opinions/expertise here.