The Ford Barn

macdonge · 04-26-2019, 04:47 PM

Hi all. Embarking on my first flathead rebuild ('39 Merc 239 c.i.) and need to know whether the large hole goes up or down on the front cam bearing. I'm aware that it must go up on the rear bearing. I found instructions in a Lincoln Mercury Overhaul Manual (for the 3rd gen engines) that said "Install the front cam bearing so that the larger of the two holes will be at the bottom.."

Thanks in advance for any advice on this.

Ronnieroadster · 04-26-2019, 04:58 PM

Its a matter of ones preference. The bearing will work fine in both directions. I personally prefer the large hole on top just like the rear bearings orientation. Having the smaller hole located in the bottom allows more bearing surface to support the cam shaft. Not a big deal but in my eyes at least more is better for support of the cam and the added pressure being applied by the valve train pushing the cam downward somewhat.
Ronnieroadster

macdonge · 04-26-2019, 05:42 PM

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Exactly what I was thinking Ronnieroadster.

04-26-2019, 04:47 PM	#1
macdonge Senior Member Join Date: May 2015 Location: Frelighsburg, QC Posts: 166	Front Cam Bearing Orientation Hi all. Embarking on my first flathead rebuild ('39 Merc 239 c.i.) and need to know whether the large hole goes up or down on the front cam bearing. I'm aware that it must go up on the rear bearing. I found instructions in a Lincoln Mercury Overhaul Manual (for the 3rd gen engines) that said "Install the front cam bearing so that the larger of the two holes will be at the bottom.." Thanks in advance for any advice on this.

04-26-2019, 04:58 PM	#2
Ronnieroadster Senior Member Join Date: Dec 2010 Location: East Coast in CT Posts: 1,697	Re: Front Cam Bearing Orientation Its a matter of ones preference. The bearing will work fine in both directions. I personally prefer the large hole on top just like the rear bearings orientation. Having the smaller hole located in the bottom allows more bearing surface to support the cam shaft. Not a big deal but in my eyes at least more is better for support of the cam and the added pressure being applied by the valve train pushing the cam downward somewhat. Ronnieroadster __________________ I use the F word a lot no not that word these words Flathead, Focus and Finish "Life Member of the Bonneville 200 MPH Club using a Ford Flathead block First Ford Flathead bodied roadster to run 200 MPH Record July 13, 2018 LTA timing association 200.921 First Ford flathead roadster to run 200 MPH at Bonneville Salt Flats setting the record August 7th 2021 at 205.744 MPH reset the record in 2024 to 211.830 running to mile four. Top speed 2024 mile five 220.672 exit speed 221.587

04-26-2019, 05:42 PM	#3
macdonge Senior Member Join Date: May 2015 Location: Frelighsburg, QC Posts: 166	Re: Front Cam Bearing Orientation Sponsored Links (Register now to hide all advertisements) Exactly what I was thinking Ronnieroadster.