1275 flywheel on an 850

[woodypup59]

We're gradually assembling the 850 short engine but will need a flywhel for it.

We have 1275 one which will fit (we think).

Will that be too light or too heavy ?

[gs.davies]

Depends - if the crank has the usual sized tail (from about 64 to end of production) then yes. Early 850's had an 1 3/8 tail which only accept the early flywheel.

[bwaminispeed]

Also, some 1275s in Austin Americas and 1300s had extra metal around the outside diameter, these are very heavy, and, would make acceleration rather glatial on an 850.......

[mk1]

Both the above are excellent points.

Apart from the comments above, if it looks OK it will be OK.

[nick@dunsdale]

A late 1275 with a pre-engage starter would be a different flywheel i would imagine
Happy to be corrected as not 100%
Just that pre-engage flywheels are generally different

[mk1]

I am clueless on later cars, but weren't pre engaged starter flywheels all Verto type?

[GraemeC]

There was a cross over with the early Metros that had pre-verto flywheels and pre-engaged starter (and ring gear to suit)

[Alex]

I had a Verto flywheel and intertia starter in Betty as factory fitted - the crossover period could be a complete mismash as usual.

[mk1]

As usual, nothing is as straight forward as it first apears.

[GraemeC]

Actually it could've been that way round Alex - you're right.
There was definitely the usual parts bin era.

[Alex]

I've seen them both ways round - built an engine & 'box for a friend and it was a pre-engaged pre-Verto.
Made a horrible noise when cranking with the expected inertia starter...

[woodypup59]

I had a feeling the ring gear was different between inertia and pre-engaged starters. The flywheels being the same.

[Alex]

It is - there's a different tooth profile and tooth count.
...but it's one of those parts you don't rigorously check until you realise you ought to !

[spoon.450]

This rings a bell from mid 80’s cars….

[nick@dunsdale]

It is - there's a different tooth profile and tooth count.
...but it's one of those parts you don't rigorously check until you realise you ought to !

It is usually easy to tell which ring gear is which

As one has parallel teeth and one has a tapered leading edge teeth

[Alex]

You don't know what you don't know until you find out you don't know it...

I can now identify a ring gear at a dozen paces

[Dan Tweed grey]

Well i have done the other way round, fitted a flywheel from a 1983 850 to my 1275 as it was much lighter.