OA Parts

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Collector Inspector
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OA Parts

Post by Collector Inspector »

This a last try for me and OA262 before getting into some serious internal modifications that can never be reversed once done.

This means that 262 will never be "proper" within... ever.

I have a standard piston for a 50mm bore and a cylinder that is 0.020" oversize.

I would like either a standard cylinder OR an oversize piston.

OR

Some other way of sorting out with hard parts either way.

If anyone can help PM me please.

Funds exchanged as per usual.

Regards

BnC
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Horsley-Anarak
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Re: OA Parts

Post by Horsley-Anarak »

Charles is your best option Bruce, he will have all the information of what is available on the Marston Register spares list. There should be lots of spare pistons as cylinders fail most.
Not sure what the standard bore size was, replacement cylinders are very rare and expensive. I would think making a new piston would be the best option, and match it to your cylinder bore.
Get it going and I will race you for pink slips.

https://www.youtube.com/watch?v=jPA8ySSR40Y&t=3s

H-A

P.S. Hope that was not too childish for you Keith P !
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Charles uk
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Re: OA Parts

Post by Charles uk »

Can you post a picture of the crown of your Marston piston & the diameter of the wrist pin, as I've never heard mention of over size pistons & cylinders.

I've worked on more than 25 Marstons of all flavours & provided tech support for many of owners on the register & just wonder if someones tried fitting a piston from something else when reassembling .
Make it idiot proof and someone will make a better idiot.
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Re: OA Parts

Post by Collector Inspector »

Yes I can Charles.

Piston is 49.70mm diameter

Pin is well worn 9.49mm to 9.47mm



20082020390.jpg
20082020387.jpg

I feel more than happy now the old dear may get sorted in this regard.

Cheers

BnC
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Re: OA Parts

Post by Collector Inspector »

Horsley-Anarak wrote: Wed Aug 19, 2020 5:28 pm Get it going and I will race you for pink slips.

https://www.youtube.com/watch?v=jPA8ySSR40Y&t=3s

H-A!
I like that (pink slips :lol: ) but my aim is not to go fast but just 6 hours in one day down and back the Donnelly River.

That is both ways and still running at the end of the day. The return trip will be somewhat lighter depending on beers consumed per hour aye.

Then retired finally on display in the lounge room.

Not many of these have the chance of being worn out in one hemisphere and brought back to some operation in the other.

Kind of 8)

BnC
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Charles uk
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Re: OA Parts

Post by Charles uk »

Well that's a standard early OA Piston.

I've lent my bore micrometer to a mate, I'll get it back & measure the bore.
Make it idiot proof and someone will make a better idiot.
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Re: OA Parts

Post by Collector Inspector »

Thank you Charles

My bore is 50.66mm by the way.

Remember back so many years ago we had a chat about there being a crankcase gasket between halves?

This is the reason for that.


20082020391.jpg
Diameter to big.

Thank you for the help in this.

Regards

BnC
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JERSEYMAN
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Re: OA Parts

Post by JERSEYMAN »

I’ll have a look, I’ve got a couple of spare pistons, slightly different from each other, I’ll measure them up. I’ve also got several cracked barrels which I’ll measure out of interest as I’ve never really taken any notice, when I strip an OA I tent to clean up the bore and piston, pop the rings in the bore, if worn I replace the rings, get the ring gap correct then reassemble. It’s never occurred to me to measure everything up if all looks well.
I’ll get back to you with the piston measurements.
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JERSEYMAN
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Re: OA Parts

Post by JERSEYMAN »

Here are some sizes it pretty much any piston will fit any barrel
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JERSEYMAN
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Re: OA Parts

Post by JERSEYMAN »

And more
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Re: OA Parts

Post by Collector Inspector »

Thanks for this.

Pics and details not often seen like this which is extremely helpful for everybody.

My barrel 50.65mm is obviously the problem.

Hepolite 14465!

Nice to know that my friend.

Regards

Very 8)

BnC
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JERSEYMAN
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Re: OA Parts

Post by JERSEYMAN »

Maybe re-sleeve the cylinder?
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Charles uk
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Re: OA Parts

Post by Charles uk »

It might be cheaper & less scary to have a custom piston made.
Make it idiot proof and someone will make a better idiot.
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JERSEYMAN
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Re: OA Parts

Post by JERSEYMAN »

Charles, you’re probably right there, a piston would be cheaper and much safer.
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Re: OA Parts

Post by Collector Inspector »

By the sounds of this I have missed the boat in regards obtaining a barrel ?

Yeh I left the old dear too many years I am convinced.

Getting a piston made as a once off is not cheap in Australia. I estimate about $700.00 for one.

Then the barrel base does not fit into the cases properly....

NUTS!

BnC
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