SD restoration
Moderators: John@sos, charlesp, Charles uk, RickUK, Petergalileo
- Charles uk
- Posts: 4971
- Joined: Wed Feb 27, 2008 4:38 pm
- Location: Maidenhead Berks UK
Re: SD restoration
Try Simply Seagulls in NZ they're on the links page.
Make it idiot proof and someone will make a better idiot.
Re: SD restoration
We need a thumbs up icon! Thanks Charles, will pursue.
Re: SD restoration
I've got some more done over the last week. The cylinder has been degreased and given 2 coats of black gloss, with a rub down in between. It will harden off for a couple of days before spending a couple of days next to the log burner to fully harden off. I've also assembled the replacement crankcase half.
I realised that the old piston rings were solid, but I applied a little heat and they popped off really easily. I cleaned up the ring grooves and the new (old ex WD stock, thanks Jan) are in. The piston was stamped with "JN" Anybody know the background to that?
Couldnt resist popping the block onto the crankcase for a little look see
Next job is to build up the powerhead and then set to work on the tank. Won't be long now...
I realised that the old piston rings were solid, but I applied a little heat and they popped off really easily. I cleaned up the ring grooves and the new (old ex WD stock, thanks Jan) are in. The piston was stamped with "JN" Anybody know the background to that?
Couldnt resist popping the block onto the crankcase for a little look see

Next job is to build up the powerhead and then set to work on the tank. Won't be long now...
Re: SD restoration
I missed something.... you have replaced crankcase with tiller mount? One half or both?
Re: SD restoration
I obtained a SD half crankcase from Jan, as well as a package of other parts.
- Charles uk
- Posts: 4971
- Joined: Wed Feb 27, 2008 4:38 pm
- Location: Maidenhead Berks UK
Re: SD restoration
Crankcases are made in pairs, i.e. 2 matching halves.
Try fitting the crankshaft into the new crankcase bits your intending to use, bolt both sides together, do all the bolts fit easily & will the crank rotate without pinching, now check the face that the crankcase fits against, is there a step where the 2 faces fit together & do the cylinder bolts fit in the holes.
If you get a perfect fit go out & buy a lottery ticket.
Seagull only ever supplied crankcases as a complete unit never just one half.
Try fitting the crankshaft into the new crankcase bits your intending to use, bolt both sides together, do all the bolts fit easily & will the crank rotate without pinching, now check the face that the crankcase fits against, is there a step where the 2 faces fit together & do the cylinder bolts fit in the holes.
If you get a perfect fit go out & buy a lottery ticket.
Seagull only ever supplied crankcases as a complete unit never just one half.
Make it idiot proof and someone will make a better idiot.
Re: SD restoration
Well, the crankcase bolts fit easily, and the crank rotates with no bother at all. After a closer look there is a slight step between the crankcase halves which I did not see last night as I only loosely assembled. The cylinder goes on ok, but is a little tight when the location spigot on the cylinder joins the crankcase.
"Oh dear" springs to mind. And it was all going so well
Further investigation required I think.
"Oh dear" springs to mind. And it was all going so well

Further investigation required I think.
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- Posts: 2838
- Joined: Thu Aug 07, 2008 8:42 pm
- Location: Surrey
Re: SD restoration
Do you have any access to a milling machine?
I would take the con rod off, bolt up the crankcase with the crank in position,
Make sure it spins freely, pop it in the mill and level up the mating surface.
If you do not have a milling machine, then pop down the local machine shop and cross their palms with beer tokens.
It should only take them a few minutes.
Worst case pop round and I will do it for you.
H-A
I would take the con rod off, bolt up the crankcase with the crank in position,
Make sure it spins freely, pop it in the mill and level up the mating surface.
If you do not have a milling machine, then pop down the local machine shop and cross their palms with beer tokens.
It should only take them a few minutes.
Worst case pop round and I will do it for you.

H-A
Re: SD restoration
Just had a detailed look at the crank cases. Crank rotation is good and all the crankcase bolts fit smoothly through both halves of the crankcase. When bolted up there is a small step about 5 thou across the gasket face, this photo makes it look worse than it actually is. The cylinder spigot is also just catching, but a little fettling will sort that out though.
H-A I do have access to a milling machine, so I may well go that way to clean up the gasket face.
Another question: Should I use a good joint sealant like hylomar each side of the cylinder gasket?
H-A I do have access to a milling machine, so I may well go that way to clean up the gasket face.
Another question: Should I use a good joint sealant like hylomar each side of the cylinder gasket?
Re: SD restoration
As I can see on the photo the combination of two different crankcases looks ugly aside of the problems with the line boring.
I've searched in the shed and I think this is the upper crankcase to match your lower crankcase I sended you.
I was stupid to send you only the lower part of the crankcase
I'll solve this mistake.
For gasket sealant I prefer the old style sealant you can apply with a brush. It looks more original than the Hylomar.
Jan
I've searched in the shed and I think this is the upper crankcase to match your lower crankcase I sended you.
I was stupid to send you only the lower part of the crankcase

For gasket sealant I prefer the old style sealant you can apply with a brush. It looks more original than the Hylomar.
Jan
Re: SD restoration
Thats very kind of you Jan. Many thanks. Now I must get that stuck woodruff key out!
Re: SD restoration
That's very reputable Jan! I'm impressed.
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- Posts: 2838
- Joined: Thu Aug 07, 2008 8:42 pm
- Location: Surrey
Re: SD restoration
Jan to the rescue again.
When shall we have an SD rally?
Are there any good venues in Nottingham/Derby?
Might be a little far to come from Holland.
Jan are you coming to Hayling Island ?
H-A

When shall we have an SD rally?
Are there any good venues in Nottingham/Derby?
Might be a little far to come from Holland.
Jan are you coming to Hayling Island ?
H-A
Re: SD restoration
I'm still waiting for the Hayling Island Marathon date
LR is ready, a box full of used SD parts is ready to build a 'Salt Water SD' and I'm looking for a trailer or lightweight dinghy I can carry on the roofrack.
Jan

LR is ready, a box full of used SD parts is ready to build a 'Salt Water SD' and I'm looking for a trailer or lightweight dinghy I can carry on the roofrack.
Jan
Re: SD restoration
A SD rally, there is an idea.. I do know some good venues including parking and a slipway!