Piston/bore clearance

[cgwymp]

Anyone know the spec for piston-to-cylinder clearance for an 8/1 (with aluminum piston)?

Cheers!

[mobile_bob]

i would expect .001" per inch of piston diameter, or about .005" for your engine

a forged aluminum piston can handle a bit tighter, but who knows if the aluminum piston is forged or not

i would think a minimum of .005" is in the ballpark
as measured perpendicular to the wrist/grudgeon pin between the piston and the sleeve

i doubt most folks check this spec, as there is little you can do about it other than replacing parts

bob g

[cgwymp]

Thanks!

True, there's not much that can be done, however it will be useful to know the spec to give to the machinist.  I'm having the cylinder block checked for squareness (don't have a particularly good way of doing that myself) and I figured whilst it's there, I might have him hone the cylinder a little bit because I don't entirely like the factory finish.  This engine is not sleeved.  By giving him the clearance spec (and the piston), he'll know how far he can go without removing too much material.  I suspect he may not be able to remove any, but I'll leave that for his call.....

Cheers!

[vdubnut62]

I'll bet a nickel that it's a cast piston
Ron

[cgwymp]

I'll bet a nickel that it's a cast piston
Ron

It's cast.  However, it is OE Lister-Petter.  Quality seems quite nice.  The piston itself is marked "Tushar" which is an Indian manufacturer....

[vdubnut62]

Well! Ain't that some s#!t. Indian parts in a Lister box. I'm sure the quality control is much more stringent for OEM boxed parts.
Ron