Can I reuse my piston on my 102?(pictures attached)

[pat777]

Thanks Collector Inspector. When I'm ordering parts again I'll look into the availability of the older type piston. I'd imagine we will be trying out the current piston for curiosity sake anyway. I'm hoping you're not proven right. My Dad was born in the war so unfortunately it's very much a case of "waste not, want not" when it comes to purchasing new parts. I'm already in enough trouble for ordering new copper gaskets for the centuries that we have taken apart,when we could have reused the old ones if we annealed them.

I'm still under the impression that once the piston rings are pressing against the cylinder bore okay, that what's going on below that is going to have a negligible effect on the running and performance of the outboard. Unless somebody can give me some more information on the subject to discount my theory. (After all I am a pure novice when it comes to seagulls) I'm not trying to wind anyone up, and I do appreciate all the advise I'm getting here and all opinions are welcome in my topics. I mean it's not a shiny new outboard and if the compression is a little low compared to when it was first made it's not going to be the end of the world. After all we are just chugging up and down the canal, but at the same time if it is found to be unreliable when starting and running then we'll have to get the replacement piston.

Thanks for the advice, much appreciated.

Cheers Pat

[headdownarseup]

my offer still stands PAT.
if you need a replacement piston, i've got one here but you'll need new rings to go with it!
CI is right. do the job properly the first time. dont muck about with it. you'll thank me later
regards jon

[pat777]

Thanks Jon, I'll have a chat with my Dad and see what he wants to do. I'll be ordering parts from John in sos soon, so I'll see if he has one suitable. I have some spare piston rings as I ordered an extra couple of sets with the last order, which should hopefully be delivered this week sometime.

I ordered the new 1940's ex dutch army piston rings from John. Has anybody used them? I presume they must be good quality, otherwise John wouldn't be selling them. They apparently have a preservative on them, which I presume I should just wipe off with a cloth. Anyway it will be a while before we get around to looking at the 102 as the two centuries that are taken apart have to be tackled first.

Thanks Pat

[headdownarseup]

as far as i am aware pat, the piston rings were made by british seagull for the army as a "joblot" of spares that might have been needed in the field during battle conditions. the preservative should just wipe off with a bit of petrol or similar.
let me know if you need the piston though.

jon

[Charles uk]

The preservative is horrible very sticky stuff, but works better than anything you can buy now, soak in petrol & wipe several times.

I think these rings are better quality than the current version.

[pat777]

Thanks Jon and Charles. Perhaps I should buy a few more sets, they are good value at £5 per set of two and when they're gone they're gone. John is apparently down to his last "few" sets (March 2013). I bought four sets the other day so there can't be too many left. Good to hear that they are better quality than the current production. Lets hope we don't break too many getting them in the bore. Easy and slow!

[Hugz]

I'm sure that piston will work fine until...... The fatigued metal is near the gudgeon pin. Imagine if your motor is doing 3600 revs per minute (rpm) that is 60 up and downs per second. Think of the pressure at the little end so often and then comes a head wind and battling pushing your boat against it. There is more pressure on the little end and a small crack appears that is not visible to the naked eye and then it shatters. Has anyone heard of a rod going through the side of the block in a Seagull? All for the sake of a piston.

Hugz, full of joy

[pat777]

Imagine if your motor is doing 3600 revs per minute (rpm) that is 60 up and downs per second. Think of the pressure at the little end so often and then comes a head wind and battling pushing your boat against it. There is more pressure on the little end and a small crack appears that is not visible to the naked eye and then it shatters. Has anyone heard of a rod going through the side of the block in a Seagull? All for the sake of a piston.

Hugz, full of joy

Hi Hugz,

Thanks for the information about the rpm, that's a lot of "ups and downs" in a second! There must be some pressure put on the piston at that kind of speed. There's no chance of us coming across a head wind though. My partners in this boating endeavor (Dad and Brother), only go out on fair weather days. There is no chance of getting them out if there is any sign of wind or rain. But yes I get where you're coming from. So far everybody who has replied has recommended that we change the piston over so I guess it would be fairly foolish to not take on board the advise. There is still that glimmer of curiosity though as to what kind of compression that we could achieve with the dud piston.

Anyway stand by for pictures of a very sorry looking seagull with rod peeking out through the side of the block. I'd say it would give everybody a good chuckle at my expense if it did happen all right.

Cheers Pat

[pat777]

We took the other 102 apart and that piston was in even worse condition than the first one I put up pictures of, so I'm guessing this piston trouble must be a fairly common occurrence in these old abused seagulls. We decided to order a couple of replacements from John @ sos. Charles Uk had recommended getting the earlier model piston, with the wider deflector. John only had two of the earlier type piston in stock, so we were lucky there.

... your cylinder has a bridged transfer port, which means using a late model piston with the narrow deflector which will shroud some of the transfer ports restricting it's ability to scavenge properly, so you will have to find yourself an early piston with the wider deflector & new rings.

Thank you to everyone for the advice. We are still waiting on the delivery of the flexhone so I would say it will be a while before the two 102's are put back together.

Below are a few pictures of the two damaged pistons and also the two sent from John @ sos.

Cheers Pat

Damaged pistons


Damaged pistons


Damaged pistons


Damaged pistons


Replacement pistons


Replacement pistons