Australian Olympic vs British Seagull AD102
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
Re: Australian Olympic vs British Seagull AD102
Bruce, thanks for providing link to the vid and discussing heights yesterday. I had seen the picture but it did not register fully.
Below are photos I have taken showing the difference in exhaust and drive tube lengths ie Olympic # 103 and # 276 (same) against BS AD 102 standard. The BS tube and drive shafts are the longer.
I wonder if the exhaust tube on your longer Olympic measure the same as the standard 102 exhaust tube? Are you able to compare/measure please?
Thanks & regards,
Spiro
Below are photos I have taken showing the difference in exhaust and drive tube lengths ie Olympic # 103 and # 276 (same) against BS AD 102 standard. The BS tube and drive shafts are the longer.
I wonder if the exhaust tube on your longer Olympic measure the same as the standard 102 exhaust tube? Are you able to compare/measure please?
Thanks & regards,
Spiro
www.vintageoutboardsaustralia.blogspot.com
Re: Australian Olympic vs British Seagull AD102
Agreed Charles, the previous photos were to show there was a difference only. Now a question for you. Have you seen this type of piston ring (Square ends) and ring pin (centrally located in the groove - and extending to the outer perimeter of the piston) arrangement before? What is the gapping procedure?Charles uk wrote:Before you go anywhere near that ring with a file.
Gap it again when it's in the right location, 5 mm above the exhaust port, push it into that position with the skirt of a piston, to ensure squareness.
Measure again.
The previous position was good enough to show that the bore diameters were different.
Here are some more pics. Piston ring and pin arrangments on Olympics # 103 & #276 are the same. I have attempted to drive the pins in further to allow filing of the ring so it sits over the top (per image below) but they wont budge. There is no through hole as such into the internal of the piston, just a solid piece of casting to secure the pin.
Photos the real things lol
Piston from Olympic # 276
Piston from Olympic # 103
Piston internal casting - same on both # 103 & # 276
So we have 4 rings and 4 pins that are identical in every respect.
Clearly, the reason the ring gap must be larger than normal (and possibly still too large due to wear) is because it needs to allow for the centrally pin which is centrally located in the groove. Hence the correct gap may be the sum total of typical gap for 2" piston (in water-cooled engine) and pin diameter.
These outboards were obviously in use, so the piston ring and pin design works. If the rings had sat over the pins and the end sections had broken away, there would be signs of scoring in the cylinder and piston of which there is none.
Although I am certain I have seen this arrangement previously, I am at a loss now to find anything in my files or on the internet that shows and discusses it.
Your comments would be appreciated.
Regards,
Spiro
www.vintageoutboardsaustralia.blogspot.com
- Charles uk
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Re: Australian Olympic vs British Seagull AD102
Ring pin in exactly the same position as a Seagull piston, half in half out of the groove.
Only markings inside the oversize piston A 1 4 smaller ring pin lumps. bare weight 128.4 grams
Seagull new piston bare weight 124.3 grams DINAMIN 766
Other seagull pistons AE 16743, HEPOLITE & a load of numbers
Connect your Olympic piston to a Seagull by putting a single gudgeon pin in both pistons, if both skirts sit level on a surface plate or a very flat surface then the inlet timing is identical if it is, separate them still on the flat surface & compare the transfer side & the exhaust side to compare those timings.
The oversize & the new Seagull pistons have identical port timings within manufacturing tolerances.
I've only seen the hidden pin style on 4 strokes with low height but much deeper rings
I asked about the bridged exhaust as you had caps on both ends of the gudgeon pin I assumed it was a floating pin & you wouldn't want it to fall down the exhaust port.
Only markings inside the oversize piston A 1 4 smaller ring pin lumps. bare weight 128.4 grams
Seagull new piston bare weight 124.3 grams DINAMIN 766
Other seagull pistons AE 16743, HEPOLITE & a load of numbers
Connect your Olympic piston to a Seagull by putting a single gudgeon pin in both pistons, if both skirts sit level on a surface plate or a very flat surface then the inlet timing is identical if it is, separate them still on the flat surface & compare the transfer side & the exhaust side to compare those timings.
The oversize & the new Seagull pistons have identical port timings within manufacturing tolerances.
I've only seen the hidden pin style on 4 strokes with low height but much deeper rings
I asked about the bridged exhaust as you had caps on both ends of the gudgeon pin I assumed it was a floating pin & you wouldn't want it to fall down the exhaust port.
Make it idiot proof and someone will make a better idiot.
Re: Australian Olympic vs British Seagull AD102
Could be from a Villiers Midget or any number of other engines as that profile was not uncommon.Charles uk wrote:Ring pin in exactly the same position as a Seagull piston, half in half out of the groove.
I'm all Olympic'd out for the moment lol. Will leave it till the weekend.Charles uk wrote:Connect your Olympic piston to a Seagull by putting a single gudgeon pin in both pistons, if both skirts sit level on a surface plate or a very flat surface then the inlet timing is identical if it is, separate them still on the flat surface & compare the transfer side & the exhaust side to compare those timings.
The oversize & the new Seagull pistons have identical port timings within manufacturing tolerances.
Makes sense.Charles uk wrote:I've only seen the hidden pin style on 4 strokes with low height but much deeper rings
Appreciate the concern lol.Charles uk wrote:I asked about the bridged exhaust as you had caps on both ends of the gudgeon pin I assumed it was a floating pin & you wouldn't want it to fall down the exhaust port.
As for ring gap sizes, what is typical for an unused Seagull 102?
Searching the net, I found this guide by a ring manufacturer, Wiesco I think it was.
A rule of thumb for ring end gap measurement is to use the bore size in inches x .005”. In the example here, a KTM150, the bore is 56mm (56 divided by 25.4 = 2.2047”). If you multiply 2.2047” x .005”, the result is .011”. This would be the minimum installed ring end gap. A typical high measurement for the piston ring end gap would be the bore in inches x .007” (2.2047 x .007” = .015”). These calculations are a general guideline, and your OEM service manual will also provide further detail.
How does that stack up?
Also, what are your thoughts to gapping the rings on the Olympic. I am thinking it should be the sum of ring pin diameter plus the standard Seagull gap. Does this sound about right to you?
Thanks & regards,
www.vintageoutboardsaustralia.blogspot.com
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Re: Australian Olympic vs British Seagull AD102
Having some problems in locating what parts were returned from Steve.........I found this though.
The Clamps are bright plated.....
BnC[/color][/b]
The Clamps are bright plated.....
BnC[/color][/b]
A chicken is one egg's way of becoming others
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Re: Australian Olympic vs British Seagull AD102
This was a mission to find and extract from under a heap of heavy and sharp projections commonly found on Old Dears......it was outside under a woodworking bench....protected from weather but not dust and critters....found an early Evinrude 5524 that was just waiting for a head gasket as well (12 years and counting).
Number 304
Seagull bracket.
Early gearbox.....no cav plate.
I can not find any previous pics of this one? No idea!
I will pull it apart on the weekend so as to have another box of Old Dear Fragmentation.
BnC[/color][/b]
Number 304
Seagull bracket.
Early gearbox.....no cav plate.
I can not find any previous pics of this one? No idea!
I will pull it apart on the weekend so as to have another box of Old Dear Fragmentation.
BnC[/color][/b]
A chicken is one egg's way of becoming others
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Re: Australian Olympic vs British Seagull AD102
OK another One.....the black and blinged up one.......
It is 386.
Interesting that the stamping is different and on the starboard side as compared to 304 on the port side.
Add to the mix S.
Regards
BnC[/color][/b]
It is 386.
Interesting that the stamping is different and on the starboard side as compared to 304 on the port side.
Add to the mix S.
Regards
BnC[/color][/b]
A chicken is one egg's way of becoming others
Re: Australian Olympic vs British Seagull AD102
Hello B, thanks for sharing. More useful information indeed.
Sorry also for the delayed response!
Looks like you have them breeding over there again lol.
A few observations from your vid also:
1. Your blinged unit is fitted with a raked SD style propeller, which is not original. Also, the dimples on the tank end, I have not seen another Olympic like that. Edit: Via the Search facility I found previous comments, tank not original, modified fire extinguisher lol.
2. The image of your short and long Olympics together, interesting to note that both have pump housings with cavitation plate. Both are therefore more recent builds, like your Tiller.
3. Images of Tiller in your kitchen further confirm it is without serial / build number.
4. One of your fuel tanks shows black paint over green. This gives me hope that the tank on # 103 will be same, thus allowing me to color match locally.
Bruce, look also here; viewtopic.php?f=17&t=5305&p=44733&hilit=olympic#p44733 You will see your Olympic # 447 with Seagull Conrod. Piston looks to have same rings as those pictured above, hence is likely to have the centrally located round stop pin as well.
As always, i would love to be able to search your sheds for parts lol. You have a gold mine over there my friend!
Regards,
S
Sorry also for the delayed response!
Looks like you have them breeding over there again lol.
A few observations from your vid also:
1. Your blinged unit is fitted with a raked SD style propeller, which is not original. Also, the dimples on the tank end, I have not seen another Olympic like that. Edit: Via the Search facility I found previous comments, tank not original, modified fire extinguisher lol.
2. The image of your short and long Olympics together, interesting to note that both have pump housings with cavitation plate. Both are therefore more recent builds, like your Tiller.
3. Images of Tiller in your kitchen further confirm it is without serial / build number.
4. One of your fuel tanks shows black paint over green. This gives me hope that the tank on # 103 will be same, thus allowing me to color match locally.
Bruce, look also here; viewtopic.php?f=17&t=5305&p=44733&hilit=olympic#p44733 You will see your Olympic # 447 with Seagull Conrod. Piston looks to have same rings as those pictured above, hence is likely to have the centrally located round stop pin as well.
As always, i would love to be able to search your sheds for parts lol. You have a gold mine over there my friend!
Regards,
S
Last edited by AusAnzani on Fri Mar 22, 2019 2:29 am, edited 2 times in total.
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Re: Australian Olympic vs British Seagull AD102
Sorry - deleted duplication
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- Charles uk
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Re: Australian Olympic vs British Seagull AD102
I don't have pictures of a Montessa but from memory the tank has 4 dimples on each end like some plastic bottles.
do you have a pic of tank?
do you have a pic of tank?
Make it idiot proof and someone will make a better idiot.
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Re: Australian Olympic vs British Seagull AD102
Charles uk wrote:I don't have pictures of a Montessa but from memory the tank has 4 dimples on each end like some plastic bottles.
do you have a pic of tank?
The tank with the dimples is or was a small fire extinguisher. The cap and the up-threads are original.
Dimples are one end only and the release valve hole has been welded over on the other end.
I have a spare tank to change it out later.
BnS
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Re: Australian Olympic vs British Seagull AD102
Thanks for that link S!
I have added those pics that Steve sent me below. They should be here I think.
BnC
[/color][/b]
I have added those pics that Steve sent me below. They should be here I think.
BnC
[/color][/b]
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Re: Australian Olympic vs British Seagull AD102
Still no feedback as to your piston ring pins S?
Not really expecting any confirming as legit, as I said in our last call, the pin you have X 4 should be machined back within the land.
Why did Charles indicate above that your pics and initial Q, that your pins were 1/2 of the groove? Obviously not the case.
I will pull apart another one (mentioned earlier) this weekend to check if there are yet X 6 of them.
Music and Beers so Cheers for now
BnC
Not really expecting any confirming as legit, as I said in our last call, the pin you have X 4 should be machined back within the land.
Why did Charles indicate above that your pics and initial Q, that your pins were 1/2 of the groove? Obviously not the case.
I will pull apart another one (mentioned earlier) this weekend to check if there are yet X 6 of them.
Music and Beers so Cheers for now
BnC
A chicken is one egg's way of becoming others
- Collector Inspector
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- Joined: Sun Jun 29, 2008 4:32 am
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Re: Australian Olympic vs British Seagull AD102
6 x 6 S!
304 has the same ring pins.
Con-rod as yours. Ugly but very sturdy.
Piston skirt is 2.2525"
Piston pin height = to BS.
Exhaust tube is exactly 15".
Exhaust port has a bridge.
BS style drive shaft. Fits over 0.37" square section.
Whitworth fasteners inc coarse threads.
They spared no cost saving measures with these. Hardware shop stock items.
Crankcase and cylinder were silver frosted.
Gearbox/WP housing as well.
Cheers
BnC[/b][/color]
304 has the same ring pins.
Con-rod as yours. Ugly but very sturdy.
Piston skirt is 2.2525"
Piston pin height = to BS.
Exhaust tube is exactly 15".
Exhaust port has a bridge.
BS style drive shaft. Fits over 0.37" square section.
Whitworth fasteners inc coarse threads.
They spared no cost saving measures with these. Hardware shop stock items.
Crankcase and cylinder were silver frosted.
Gearbox/WP housing as well.
Cheers
BnC[/b][/color]
A chicken is one egg's way of becoming others
- Charles uk
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Re: Australian Olympic vs British Seagull AD102
Any manufacturers mark/logo inside piston? Bruce.
Make it idiot proof and someone will make a better idiot.