Mystery Piston Set - can anyone help?

[philb]

Hello

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

[RobPearce]

They look too tall for a 1500. Possibly 1300? The extra oil control ring at the bottom is not a Triumph standard feature but won't necessarily make them incompatible.

[Nick Jones]

IIRC some of the early engines (1200, 1600six) had the fourth ring but the split skirt is not something I remember.  More associated with slow-revving long-strokers, so I reckon something older.

What diameter are they?

[RobPearce]

10 minutes ago, Nick Jones said:

What diameter are they?

The box says "size 2.90" which I took to be 2.9" diameter, which is pretty close for a 1300.

[philb]

Thanks for all the replies so far.

As Rob says they are 2.90" diameter but don't look like any phots I've found on the net for a Spit 1300.

I can't seem to get the Sa193 number to come up in any searches.

Any thoughts on the hand written numbers on box lid? Looks like 15 - 9?

Thanks