1952 Mercury Bore size?

[Ralph Moore]

Started looking at my 1952 Merc motor and the bore measures 3.220".
My book only has Ford measurements, but if the Merc was 3-3/16" like the Ford that would mean the motor was bored .030 over(.033 actually, probably wear of .003).

Is this correct?
Also where's a good source for Mercury pistons?

 

[Bruce Lancaster]

3 3/16...blocks were the same. At 3 3/16, you have enough metal for a LOT of rebuilds.

 

[52merc]

3.3/16 standard bore ford n merc merc has different pistons & crank this takes merc to 255 ci

 

[Mart]

Yes, sounds like .030" over.
Mart.

 

[Ralph Moore]

So, I'm looking in my catalogs and nobody lists Mercury specific pistons.
Who is a good source for these?

 

[Walt Dupont--Me.]

Patrick's 520-836-1117 Walt

 

[Ronnie]

Try these numbers

Sealed power 1014p .030 .040 .060

Ronnie

 

[52merc]

patricks or egge have all sizes of pistons brgs ect ect

 

[Neal]

Started looking at my 1952 Merc motor and the bore measures 3.220".
My book only has Ford measurements, but if the Merc was 3-3/16" like the Ford that would mean the motor was bored .030 over(.033 actually, probably wear of .003).

Is this correct?
Also where's a good source for Mercury pistons?

Clean off the top of the pistons. Should have the oversized measurement stamped on it. Such as .030.

Neal

 

[Ralph Moore]

Thanks all. I didn't think to look at the piston tops.

 

[Merc Cruzer]

You might want to try Joblot...

 

[Ralph Moore]

I forgot about Joblot. I used them years ago when I rebuilt my 45 pickup.

BTW the pistons are stamped .030. With only .003 wear(assuming they all check out that good) can I get by without boring, just cleaning up the pistons and re-ringing them and honing the cylinders out.

 

[Byron Warwick]

How about Motor City Flathead in Detroit.

 

[rotorwrench]

The Mercury overhaul manual lists .003" as max wear clearance between widest portion of piston skirt and the bore wall. You'll need to know the worst clearance of all 8 cylinders. If your bores measure .003" over a bore size of 3.1905" and the piston measured from top of bore nearest to intake side to bottom of bore nearest exhaust side on the skirt (widest part of the skirt) shows even more wear below 3.1905" then I'd think about boring it at least to the next size. To much play in there can lead to piston slap. The motor would be noisier with more clearance and rings may not seat very well. If all clearances are within the .003" with stock pistons then it should be OK for a budget overhaul.

Kerby