Piston rings for my Tomos/Ailsa general Q on bore

[ronsealdeath]

Hi there,

this is a general question really. I have a 4hp Tomos outboard which I bought to fix as a seized engine. I was expecting rusted bore/piston but instead she has snapped a piston ring. There was damage on the other ring so I have had to remove both. There is no damage on the cylinder by the looks of it so all I need are some rings! But as you have guessed I can't get hold of spares.

So my question is can I install generic rings for something else with the same size piston? The manual says I have 42mm cylinder diameter on this motor. I havent got calipers but the piston looks to be about 41 to 42mm from using a ruler (not accurate I know). So can I just buy a ring kit for a 41mm piston or do I need to get a 42mm set? Assuming I can use any ring not Tomos specific ones.

I'm worried other rings will be too narrow as the ones I removed are 2mm thick. Can I just buy a new piston for another 2 stroke engine, do you think it would fit? If so do I buy a 42mm one or 41mm? This is bearing in mind I have a 42mm cylinder diameter. Sorry if these are dumb questions!
Cheers
Al

 

[carholme]

Re: Piston rings for my Tomos/Ailsa general Q on bore

Could give these guys a call or look around their site:

http://www.tomoscanada.com/

Maybe the have an outlet in the US

or:

http://www.tomos-aussenborder.de/

Gerry

 

[ronsealdeath]

Re: Piston rings for my Tomos/Ailsa general Q on bore

Hi thanks for the reply. I'm in the UK and we did have a couple of distributers but they appear to have gone bust. The german website is great and I can understand a bit of German but they are out of stock on the piston rings! Bit of a shame.

Anyone know any other engine that uses a 42mm piston with a 2mm thick ring? Long shot. Stihl chainsaws use a 42mm ring but its only 1.5mm thick. I'm guessing this will not work as the ring will be slapping around in its seat thus causing issues and possible failure.

Anyone got any ideas?
Cheers
Al

 

[carholme]

Re: Piston rings for my Tomos/Ailsa general Q on bore

Al;

Do you have the p/n for the rings as I am happy to call Toronto tomorrow and find out if they have any stock.

Gerry

 

[wifisher]

Re: Piston rings for my Tomos/Ailsa general Q on bore

If you could find rings that are a few mm oversize all you need to do is file/grind the end off to fit a smaller diameter. You can check the size by putting it in the cyl. and square it up with a piston. Remember you do need a gap on the end to allow for expansion. I don't know about your particular motor, just a way to use something close.

 

[ronsealdeath]

Re: Piston rings for my Tomos/Ailsa general Q on bore

Thanks carholm for the offer but in the end we took a piston from a similar motor and she slotted straight in.

Having spent an age unseizing bolts I got the gearbox off to find that has seized too! More problems to try and sort now!

Cheers for all the advice, I'll try some oversized rings on the spare piston to use as a spare.

 

[1946Zephyr]

Re: Piston rings for my Tomos/Ailsa general Q on bore

Well, 42 mm comes to 1.6535433070866141732283464566929 or 1.654 in short. It may be tough to find anything American that is in that size.