flathead camshaft covers

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fifty-one f-1

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I have two flathead camshaft gear covers. It is going into an 8BA motor. I am to the point on my rebuild to install the cover over the gears. I am using a Mercury 8cm cam. They look similar except one is a thicker cover. Is there an advantage to using either cover? Maybe I am over thinking this and I can use either cover. I assume the thicker cover is the correct cover because it has part number for a Mercury car 1cm 6653 that would match the cam? I did not take the motor apart, but I am finishing the project. Really appreciate the help. camshaft gear cover 1.jpg

camshaft gear cover.jpg
 
fifty-one f-1 said:
I have two flathead camshaft gear covers. It is going into an 8BA motor. I am to the point on my rebuild to install the cover over the gears. I am using a Mercury 8cm cam. They look similar except one is a thicker cover. Is there an advantage to using either cover? Maybe I am over thinking this and I can use either cover. I assume the thicker cover is the correct cover because it has part number for a Mercury car 1cm 6653 that would match the cam? I did not take the motor apart, but I am finishing the project. Really appreciate the help.View attachment 536600

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Use the merc oil cover since you have it. I have found that 8BA's use the stamped steel cover while Merc use the cast cover. Don't know why?
 

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Stampings deform easier than castings. Castings crack easier than stampings, Which feature do you prefer? .:D
 
While you're working in this area of the engine, don't forget to check/replace the idler gear bushing. I overlooked this while doing a rebuild and my engine sounded like a rod knock. :mad: Replaced the idler bushing and all was right with the world again! :)
 
mcgarrett: Thanks for posting that piece of info about idler gear bushing.
I was not aware of that malady.
 
Now this is interesting . The 53 mercury 255 I just assembled has a boss in the cast cover to give the idler gear shaft support on the outer end. I wonder when and why that happened? Tim
 
Also keep in mind that on the 8BA it’s possible to install the idler gear backwards. If it’s backwards it will not engage the oil pump. Just something to watch out for.
 
Thanks for all the reply's. Angledrive I did already install my plug on the front of my motor thanks for the reminder. Mcgarrett I think I will replace the bushing seems like cheap insurance. Ken I have a book that shows the correct install, thanks.
 
19Fordy said:
mcgarrett: Thanks for posting that piece of info about idler gear bushing.
I was not aware of that malady.
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After pulling my engine TWICE trying to find the source of the knocking noise in a new rebuild, I was discussing the problem with an old time flathead hobbyist and he asked if I checked the bushing. When I took the drive/idler cover off I noticed the idler gear was wobbly and loose. I installed a new bushing and put it back together. Once the engine was back in I held my breath and cranked it up. Noise was gone!! I had simply overlooked paying proper attention to that important part of the engine.
 
I have an 8CM,,,,1949 Mercury engine,,,,,,mine came with the stamped cover .
My engine seemed to never been apart,,,other than having a valve job done to it .
The insides were in excellent condition and only needs a slight bore to clean up the cylinders .
 
Jack E/NJ said:
Stampings deform easier than castings. Castings crack easier than stampings, Which feature do you prefer? .:D
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I prefer a 1/4 inch thick flat steel plate for the above reasons although we do not use the idler gear and shaft and rear cam gear. (dry sump)
 
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