The Ford Barn

Ralph Moore · 11-22-2010, 09:02 PM

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 · 11-22-2010, 09:18 PM

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

52merc · 11-23-2010, 01:22 AM

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

Mart · 11-23-2010, 03:36 AM

Yes, sounds like .030" over.
Mart.

Ralph Moore · 11-23-2010, 08:10 AM

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

Walt Dupont--Me. · 11-23-2010, 08:52 AM

Sponsored Links (Register now to hide all advertisements)

Patrick's 520-836-1117 Walt

Ronnie · 11-23-2010, 07:59 PM

Try these numbers

Sealed power 1014p .030 .040 .060

Ronnie

52merc · 11-23-2010, 08:53 PM

patricks or egge have all sizes of pistons brgs ect ect

Neal · 11-23-2010, 08:53 PM

Quote:

Originally Posted by 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?

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

Neal

Ralph Moore · 11-23-2010, 09:59 PM

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

Merc Cruzer · 11-23-2010, 11:07 PM

You might want to try Joblot...

Ralph Moore · 11-24-2010, 10:33 AM

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 · 11-24-2010, 10:53 AM

How about Motor City Flathead in Detroit.

rotorwrench · 11-24-2010, 11:46 AM

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

11-22-2010, 09:02 PM	#1
Ralph Moore Senior Member Join Date: Oct 2010 Location: North Pole, Alaska Posts: 1,470	1952 Mercury Bore size? 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?

11-22-2010, 09:18 PM	#2
Bruce Lancaster Member Emeritus Join Date: May 2010 Location: Madison, NJ Posts: 5,230	Re: 1952 Mercury Bore size? 3 3/16...blocks were the same. At 3 3/16, you have enough metal for a LOT of rebuilds.

11-23-2010, 01:22 AM	#3
52merc Senior Member Join Date: May 2010 Location: new zealand Posts: 1,054	Re: 1952 Mercury Bore size? 3.3/16 standard bore ford n merc merc has different pistons & crank this takes merc to 255 ci

11-23-2010, 03:36 AM	#4
Mart Senior Member Join Date: May 2010 Location: Solihull, England. Posts: 8,755	Re: 1952 Mercury Bore size? Yes, sounds like .030" over. Mart.

11-23-2010, 08:10 AM	#5
Ralph Moore Senior Member Join Date: Oct 2010 Location: North Pole, Alaska Posts: 1,470	Re: 1952 Mercury Bore size? So, I'm looking in my catalogs and nobody lists Mercury specific pistons. Who is a good source for these?

11-23-2010, 08:52 AM	#6
Walt Dupont--Me. Senior Member Join Date: May 2010 Location: Gardiner Me. Posts: 4,200	Re: 1952 Mercury Bore size? Sponsored Links (Register now to hide all advertisements) Patrick's 520-836-1117 Walt

11-23-2010, 07:59 PM	#7
Ronnie Senior Member Join Date: May 2010 Location: Canada Where it snows Posts: 2,058	Re: 1952 Mercury Bore size? Try these numbers Sealed power 1014p .030 .040 .060 Ronnie

11-23-2010, 08:53 PM	#8
52merc Senior Member Join Date: May 2010 Location: new zealand Posts: 1,054	Re: 1952 Mercury Bore size? patricks or egge have all sizes of pistons brgs ect ect

11-23-2010, 09:59 PM	#10
Ralph Moore Senior Member Join Date: Oct 2010 Location: North Pole, Alaska Posts: 1,470	Re: 1952 Mercury Bore size? Thanks all. I didn't think to look at the piston tops.

11-24-2010, 10:33 AM	#12
Ralph Moore Senior Member Join Date: Oct 2010 Location: North Pole, Alaska Posts: 1,470	Re: 1952 Mercury Bore size? 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.

11-24-2010, 10:53 AM	#13
Byron Warwick Senior Member Join Date: May 2010 Location: Corunna, Ontario, Canada Posts: 309	Re: 1952 Mercury Bore size? How about Motor City Flathead in Detroit. __________________ IT'S NOT YOUR AGE, IT'S YOUR ATTITUDE !

11-24-2010, 11:46 AM	#14
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,436	Re: 1952 Mercury Bore size? 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