Exact size of bore .

[pooch]

Am getting a sleeve inserted to fix one bore.

Is the finished size after honing exactly 3.1875 ?

If so, what size should the piston be ?

Are domed pistons (for a 1948 motor) round and the same diameter each way and top and bottom ?

[bruce lee]

The piston needs to be measured and then the cylinder should be bored and power honed to the size the piston manufactor wants. Some pistons need more clearance than others. Forged piston clearance sizes will be different than cast piston and so forth.

[flatheadmurre]

Originally Posted by pooch

Am getting a sleeve inserted to fix one bore.

Is the finished size after honing exactly 3.1875 ?

If so, what size should the piston be ?

Are domed pistons (for a 1948 motor) round and the same diameter each way and top and bottom ?

Pistons are conical top being smaller then bottom and oval to compensate for heat expansion.
If your fixing an engine just measure another bore above the rings no wear on the ridge left.
And since the rest of the bores are used....theyre not going to be as tight as the new anyway.

[jake197000]

usually the standard bore size and oversizes are the finished bore size and the piston is made smaller the proper amount.....but that can vary depending onpiston maker and application suce as blower etc.never bore and hone with out pistons in hand.they can vary in a set also.enough that you have to adjust youf final hone size slightly.

[Ol' Ron]

The machine shop will Know all this, or you have the wrong shop.

[rotorwrench]

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First thing for me would be to determine what all the other bores are going to end up. Most machine shops will try to get all bores to match up to the same approximate bore size. Once you know what that approximate size will need to be, then you can get the pistons for that size so that all bores can be final sized & properly clearanced to fit the pistons you have.

[oldford2]

My machine shop will not bore or hone until I give him a set of pistons. He measures the old bores and tells me what he knows will work

[Capt Kirk]

Originally Posted by oldford2

My machine shop will not bore or hone until I give him a set of pistons. He measures the old bores and tells me what he knows will work

Mine does the same thing...sign of a good machinist.