Rear Cam Plug, Cup in or Out?


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By 54Customline4dr - 14 Years Ago
Dumb question: my cam is binding up soon as I install the plate, before even getting the cam gear on.



I think my rear cam plug may be driven in just a little too far. It's installed cup out like a freeze plug. I think a few gentle taps with a rubber mallet may do the trick. I just want to make sure thats correct. The factory manual doesn't really specify of have any clear pictures. I know thrust should be .003-.006 once the gear is installed.



Thanks
By MoonShadow - 14 Years Ago
Are you using the right spacer behind the cam retainer? It has a chamfer on the inside edge that sits against the camshaft. If you use the outer one or reverse the inner it can cause a drag. Chuck
By 54Customline4dr - 14 Years Ago
Yes, I learned that with a ford six last year lol. Almost threw away the old sludge covered cam without grabbing the spacer.



I don't even have the gear bolted on yet. As soon as I slid the cam in it seemed to bottom out. As soon as I tighten the plate it binds.



BTW, did they do away with the cam gear counterweight after 1954? I've been going crazy looking for it but I can't remember it there was one on my 57 core. It has another keyed spacer that looks like it takes the place of the counterweight under the fuel pump eccentric. I had my rotating assembly balanced. I can always take the one out of my 239 when I swap.
By MoonShadow - 14 Years Ago
The keyed spacer is fine. They did stop with the counter weight in the later engines. Can you put the cam in and see how deep it sets in the block? It could be striking the cam galley plug at the rear.  Can a dead hammer tap on the end of the cam drive the plug out a bit? Just thoughts. Chuck
By oldcarmark - 14 Years Ago
I believe the edge of the plug should be level with the area of the block surrounding it.I found that the plug on mine was too far in(installed by machine shop) and I could not get the cam in far enough to even install the cam retainer.Put the old cam back in and tapped the plug back level with the block.There is a cam end play spec and I think it is .003.
By PF Arcand - 14 Years Ago
Interestingly, there was a recent article, by our moderator, Ted, about the installation of the rear cam plug in YBM., issue #105 July -Aug 2011. So you are likely on the right track. The gap should be at least 0.025" & to use a moderate amount of sealer on the plug to avoid an oil leak. Also says to also check the Thrust plate for cracks.
By lowrider - 14 Years Ago
Good timing on this question. I have an engine on the floor that I'm building and have run into a bit different problem. Without a rear cam plug installed, thrust washer in correctly, new chain & gear it feels like I have 0 end play. I want to try a different thrust washer but they are hard to find. I'm afraid if I install it like this it will break the thrust plate like in Teds article.
By Ted - 14 Years Ago

Once the cam has been fully installed into the block, double check that it sits behind the face of the block before installing the cam retaining plate.  If the front face of the camshaft sits flush or in front of the face of the block, then the cam plug will need to be addressed.  If this is the case, then the problem could be as simple as the cam plug being driven in too far or the wrong thickness cup plug being used.

 

Regarding installed camshaft end play, it’s always recommended to mic both the spacer and the cam retainer plate and insure that the spacer is 0.004”-0.006” thicker than the cam retainer plate.  This will insure the aforementioned cam end play values.  If the cam spacer is the same thickness or narrower than that of the cam retaining plate, then the cam shaft will bind when the cam gear is tightened to the camshaft.

 

And as has already been mentioned, any lack of cam end play can potentially break the cam retaining plate whether it’s a result of the cam plug being too far into the block or inadequate clearance at the cam gear.  Using a belt sander on either the cam spacer or the retaining plate can fine tune the cam end play clearance values.

 

Here’s the link to the article that was recently published in the Y-Block Magazine.

Rear cam plug installation

By 54Customline4dr - 14 Years Ago
Thanks All,



A couple taps with a rubber mallet and I have plenty of clearance now. I just made sure the rim of the the plug is flush with the block. Should be able to hold 40 psi.



I remember a big thread on HAMB about cam plugs but I think it was regarding FEs.
By Hoosier Hurricane - 14 Years Ago
The plug does not see 40 psi.  There are two holes drilled longitudinally through the rear cam journal which would relieve any pressure behind the cam.