Saving Old Seagulls

I owed a swap debt for an Australian Commando Outboard from years ago.

I repaid the outstanding $s with providing two spare Olympics to the Creditor so that he could build one out of the two and return what was left to me .....of course.

SO

Speaking with him today some interesting turn up that raises more questions than answers that our British Bretheren have been after for ages.

See the pics in that:

The piston is 102 measured and compared. Standard.

The con-rod is how you see it.

The crank is totally different.

The cases are totally different

This particular power head has been apart before and while being of good compression going back together............there is no conclusive as to the rod and piston were original or something that "Worked" as a repair at some time.

The second power head has not been apart and will be back to me with other left over bits later. I will investigate that when available.

My 1952 complete motor (See post for Tiller) may be pulled down if it gives trouble. I know that it is completely original everywhere but stays in one operational kit for now.

The con-rod while saying Seagull 1.........................is odd in lettering maybe?

AH well......................any news is always good news for us aye.
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Is the block a standard 102?

Indeed I do.

My activity is elsewhere

Trying to work out if this is worth transporting 850 miles. I think it is cute and same model as my hippy van:
It would make a good display stand for motors, anyway back to Olympic.

What does it say on the crown of the piston?

Charles uk wrote:What does it say on the crown of the piston?

STD
OD15

When compared to any other Gull Piston there are no measurement differences.

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As Adele would say "rumour has it" that the cylinders Seagull supplied for the Olympics were intentionally produced oversize to prevent customers like Olympic interfering in Seagull's spares sales with their inventory.

Though the same person also said that any cylinders that didn't clean up when machined to a bore of 56.871 mm were taken out 10, 15 or 20 thou. more & matched with oversize pistons & rings as a method to lower Seagull's scrap cylinder percentage & sold on to people like Olympic & Montessa

The 1 Olympic piston I have is a 20 thou oversize.

Are the main bearing journals in your pics Bruce? heat shrunk sleeves or the way the crankshaft was machined from new, as I'm sure I would have noticed the big holes on the one my piston was stolen from.

I know nothing about the Olympic years Bruce, I've only ever seen 2 of them, 1 in Melbourne & 1 in NZ with a dead cylinder, from where I got my piston.

Just trying to establish how much Seagull DNA they contain.

Do all of your's have the giant main bearing journals?

Could you compare one of your Olympic cylinders with your Seagull 102s to see which is the closest match, core plugs, transfer size, transfer bridge, exhaust bridge, casting numbers & thread types?

Bruce
i've just had a look through some of your old photos and vids of olympics.
As Charles was pointing out, there seems to be a lot of DNA from a seagull in these motors.
I was looking at your pics and noticed an olympic with what looks like a seagull 102 cylinder with the brass core plugs and low inlet carb stub.
Whereas your other pic of another olympic has (again what seems to be) a later style seagull 102 cylinder with NO core plug fitted ,BUT with a more centrally mounted carb stub?
There might be some truth in that BS were trying to minimise "wasteage" in cylinders that didn't quite come up to specs, hence boring out to 20 thou oversize would start to make a bit of sense.
I'm still a bit stumpped with the size of the crank journals though! (they're hoooooge compared to a seagull)

Have you got any pics of a cylinder so we can compare any external differences between the 2?
I might be able to help with some pics of "older" seagull 102 cylinders if you get stuck. (it was more the transfer port area i was talking to Charles the other day)

Strange old bird, but interesting never the less

jon

When I get the unused parts back and when I investigate the 1947 one I will get back to this.

Please read the post from the start...........I can not just ask all of these questions remotely.

All will be laid bare when I can.

Hugo may be persuaded to pull the barrel off his in the meantime aye?

"Tilla" remains intact.

Pics of Tilla
Castings........

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