Need help with engine ID

[Laurie]

G'day, I am halfway through rebuilding my engine at the moment and I am having trouble finding piston rings.
I believe i may have a R 839 but I am not sure....the bore size is nearly 56mm.
The engine has come out of a toro lawnmower and has had the number plate removed, They were branded as continental engines...Frustrated at the moment, I hope someone can help me

 

[mojobaby]

Hi Laurie, this is what I found: in 1961, Renault brought out the R3 and R4 simultaneously. The R3 had a 603cc engine and the R4 had 747cc.
The R4 had a bore of 54,5mm, perhaps that's your engine. My 845 has a 58mm bore
https://en.wikipedia.org/wiki/Renault_4

 

[malcolm]

Sounds like it could be an 839 Ventoux engine with 782cc capacity. Bore size would be 55.8mm. A search for toro on the forum might put you in touch with other owners from Australia who might know a bit more about these engines and where to get the bits. I don't know a thing about them myself.

 

[Laurie]

that sounds correct to me..55.8mm bore...which Renault cars were these in?

 

[Laurie]

the more phone calls i make the more difficult this seems...i need oversize, as i intend to hone cylinders out to the maximum 56mm I have managed to source replacements for 2nd ring and oil ring...but the top ring which is chrome i cant get...its a different width

 

[mr-reno-139]

Maybe fit a new set of pistons and liners as then you will get more power think there is 2 sizes of gudgeon pin though
Not swapped bits my self Angel may know much more

 

[angel]

782cc engines had always 16mm gudgeon pin press fitted in connecting rod.
Paul is right, a lot easier and cheaper to fit 58mm pistons / liners from 845cc engines, than boring existing liners. Have you found 56mm pistons from another engine that fit? If so, don't they come with their own rings?