Piston Identification

[GeorgeS]

What piston do I have here? It's from a '61 Li150 S2, callipers measure at 57mm around the ring area, but I wasn't sure if the '4' after the 57 means 4th oversize even though the measurement doesn't suggest it.

And yes, I know it looks rather sorry for itself!

Thanks,
George.

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[wack 63]

Normally it would mean 57.4 mm. Measure lower down the piston skirt below gudgeon pin

[GeorgeS]

It's around 57.2 around the pin area & below.

[wack 63]

Plus it'll be worn

[GeorgeS]

Yes, it's had a seize at some point and hasn't moved for many years. It looked like this when we eventually got it out:

[B-Race Tuning]

That'll go again, . I also would suggest its a .4 oversize, but worn. Just need to find a .2 oversize cylinder and your away.

[GeorgeS]

I reckon you're right, measured the barrel the best I could and it's certainly more than 57mm, so I'll go with 57.4 new rings and measure them up.

Don't know if you're joking about running it again, but I'm going to give it a go! Both barrel and piston have cleaned up ok and I kind of feel that I owe it to the old thing to at least give it one more blast as standard before doing something more exotic with the engine.

Thanks,
George.

[Strummer10]

I tend to try and clean the old piston down and re use ....but this baby's had it's day lol

[B-Race Tuning]

George, unless thats the only piston of it's type in existence, Strummer is right in real terms. Yes, we may have all been there but unless a customer specifically wanted to re-use it that is toast, and I'd not bother from a reliability point of view. I'd also think the bore has to go up a size just to clean up properly. Simon.

[Grumpy225]

What's with the circle mark on the top of the piston? It looks like that's where your drift was hitting it to free it from the cylinder? If that's the case I wouldn't waste your time or money replacing the rings. Just get a proper piston and have the cylinder bored to match.