Mystery Pistons

[philb]

Hello

I put this question in the Chat section and just realised this might be more visible so repeated below

I was sold these pistons years ago as suitable for a Spitfire 1500. I didn't need them at the time but have since discovered they are not for a Spit 1500.

They are Sheepbridge Engineering Precision Pistons. The label reads Reference: SA193, Make: Standard, Size: 2.90 +020.

As you will see in the photo the word Triumph has been written on the box in ink.

Would appreciate any assistance in identifying which engine these are for.

Thanks

Phil

 

[Gt6s]

Lower oil control ring THOSE ARE OLD !  Likely as the box says for a Standard.

[drofgum]

I did a little checking and I can't find any Standard engines with a 2.90 bore. The only engines Standard Triumph made with that bore are the 1296 and 1500 which of course were introduced after the Standard marque was dropped.

The early Post-war 1800 did have a 73mm bore, but that is distinctly smaller that the 73.7mm equivalent to 2.90"

I have seen four ring pistons for other marques intended to control oil consumption in well-worn engines, but when bored to an oversize that seems excessive.

Cheers,

Paul