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1275 flywheel on an 850
Posted: Wed Dec 08, 2021 3:47 pm
by 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 ?
Re: 1275 flywheel on an 850
Posted: Wed Dec 08, 2021 4:53 pm
by 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.
Re: 1275 flywheel on an 850
Posted: Wed Dec 08, 2021 8:29 pm
by 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.......
Re: 1275 flywheel on an 850
Posted: Thu Dec 09, 2021 8:40 am
by mk1
Both the above are excellent points.
Apart from the comments above, if it looks OK it will be OK.
Re: 1275 flywheel on an 850
Posted: Thu Dec 09, 2021 1:18 pm
by 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
Re: 1275 flywheel on an 850
Posted: Thu Dec 09, 2021 1:25 pm
by mk1
I am clueless on later cars, but weren't pre engaged starter flywheels all Verto type?
Re: 1275 flywheel on an 850
Posted: Thu Dec 09, 2021 2:00 pm
by GraemeC
There was a cross over with the early Metros that had pre-verto flywheels and pre-engaged starter (and ring gear to suit)
Re: 1275 flywheel on an 850
Posted: Thu Dec 09, 2021 2:06 pm
by Alex
I had a Verto flywheel and intertia starter in Betty as factory fitted - the crossover period could be a complete mismash as usual.
Re: 1275 flywheel on an 850
Posted: Thu Dec 09, 2021 2:09 pm
by mk1
As usual, nothing is as straight forward as it first apears.
Re: 1275 flywheel on an 850
Posted: Thu Dec 09, 2021 2:15 pm
by GraemeC
Actually it could've been that way round Alex - you're right.
There was definitely the usual parts bin era.
Re: 1275 flywheel on an 850
Posted: Mon Dec 13, 2021 3:28 pm
by 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...
Re: 1275 flywheel on an 850
Posted: Wed Dec 15, 2021 11:32 am
by woodypup59
I had a feeling the ring gear was different between inertia and pre-engaged starters. The flywheels being the same.
Re: 1275 flywheel on an 850
Posted: Wed Dec 15, 2021 4:05 pm
by 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 !
Re: 1275 flywheel on an 850
Posted: Wed Dec 15, 2021 10:22 pm
by spoon.450
This rings a bell from mid 80’s cars….
Re: 1275 flywheel on an 850
Posted: Thu Dec 16, 2021 10:25 am
by nick@dunsdale
Alex wrote: ↑Wed Dec 15, 2021 4:05 pm
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
Re: 1275 flywheel on an 850
Posted: Thu Dec 16, 2021 12:02 pm
by 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
Re: 1275 flywheel on an 850
Posted: Sat Feb 12, 2022 7:31 am
by 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.