engine serial number

[myhalfyFFR]

Good morning everyone, I have just finished completely overhauling a petrol LR engine, pistons, cylinder liners, valves, clutch, and I have noted the serial number - S 25104260 G – I kindly ask if anyone knows on which LR it was mounted, perhaps on civilian LR, given that my lightweight starts with 237xxxxx.
Thanks
Mauro

[AR4412]

Hi Mauro,

A 251 engine is a 7:1 petrol engine from a Series IIA. The S prefix denotes that it was a 'Service Exchange ' engine.

Kind regards,

[myhalfyFFR]

Thanks, Neil,
The 251 7:1 engine is designed to use low-octane gasoline, but can I use higher-octane gasoline?
In Italy, there's only one type of unleaded gasoline with an octane rating of 95, which works without any problems for my Halfy engine, which is a 237 8:1. But can this gasoline cause damage to the 251 engine?
Best regards,
Mauro

[AR4412]

The 7:1 engine will happily run on higher octane fuel, the same as the 8:1 engine. The only thing you may need to do is play with the ignition timing to find it's sweet spot. Was it fitted with hardened valve seats during the rebuild so that it can run happily on unleaded fuel?

Regards,

[myhalfyFFR]

Thanks, Neil,
The valve seats, valve guides, and valves were supplied and installed by a resurfacing shop, and they now only use products suitable for unleaded gasoline. The shop also resurfaced the cylinder liners, and I did everything else myself: pistons, main bearings, connecting rod bearings, and valve drive shaft. Now I practically have a new engine.
I'm attaching a photo.
Thank you very much.
Best regards,
Mauro

[AR4412]

Ooh. Shiny! We like shiny we do. Shiny, and cake. Mustn't forget the cake.

That's a nice looking engine.

Regards,