Cam plug retention

[philminotti]

The last time I installed a cam plug, I just ran a bead of RTV around it...I remember seeing a picture a while back of a plug that had a fender washer held over the edge of the plug by a screw that was drilled and tapped into the cam plug boss.  I can't imagine this is necessary, but I wanted to get some opinions...

[Phil Brown]

I have seen that kind of plug retention years ago with the local circle track guys on freeze or core plugs. Use an 8 or 10-32 screw tapped into the block with a washer that overhangs the plug ( one on each side of the plug). Definitely won't push the plug out and put water under the tires.

[jayb]

I've done that on multiple engines.  It only takes one time for that plug to pop out before you start doing things differently.  Either Permatex #1 (hardening) to hold it in, or 8-32 screws around the hole with washers in place to block the plug's "exit".

[Nightmist66]

I've done that on multiple engines.  It only takes one time for that plug to pop out before you start doing things differently.  Either Permatex #1 (hardening) to hold it in, or 8-32 screws around the hole with washers in place to block the plug's "exit".

Jay, are you referring to the core plug or the cam plug? I put the cam plug in dry and put some clear epoxy over it. The epoxy will chip and break if you need to remove it. JB Weld is a different story.

[thatdarncat]

I've done that on multiple engines.  It only takes one time for that plug to pop out before you start doing things differently.  Either Permatex #1 (hardening) to hold it in, or 8-32 screws around the hole with washers in place to block the plug's "exit".

Jay, are you referring to the core plug or the cam plug? I put the cam plug in dry and put some clear epoxy over it. The epoxy will chip and break if you need to remove it. JB Weld is a different story.

Jay Brown cam plug retention solution

[cammerfe]

Roush engines have the cam plug held in by 2-part epoxy.

KS

[blykins]

I've never had one budge, even on aluminum blocks, where the issue could really present itself.  I always just use silicone around the perimeter of the plug then drive in as usual.  I use a freeze plug driving tool to drive in the cam plug and it will usually take some of the convex-ness out of the plug.  I think that puts a little more press to the fit.  I then put silicone around the "gap" where the plug meets the block.

On all of your higher end SBF aluminum blocks, the cam plug is driven in against a shoulder, then there's a snap ring groove to keep it from backing out if it has the inclination. 

If the cam plug is moving, just think about what the cam bearings could be doing....that's why I always green-Loctite them into aluminum blocks.

[cjshaker]

Jay Brown cam plug retention solution

First time I've seen a weight welded to the back of a crank. What's the story on that?

[jayb]

That is a 4.75" stroke FE crank for my big SOHC.  Crower balanced it, and apparently that welded on piece was required to balance the crank correctly.  I've never seen a weight like that welded on a crank either, but I assume Crower knew what they were doing...

[BigBlueIron]

On pulling tractor engines (diesel) cranks have extra material (similar to the picture) added to every counter weight for balance.

[pbf777]

First time I've seen a weight welded to the back of a crank. What's the story on that?

     It's not that unusual to see weight added or subtracted from the crankshaft flange, and is completely acceptable, within reason of course.      This is often done because the value needing to be addressed is not clocked with an available surface of the existing counter weights or journal throws which might accept heavy metal or be readily lightened.  This issue of balance correction requirement being out of phase with the anticipated positions tends to be more prevalent in the "stroker" cranks, as it would seem the original engineering of the crankshaft was for perhaps a lesser offset, and then someone decided it just wasn't worth the time and money to provide a truly properly re-engineered unit for those of "stroker" applications.     

     Scott.

[pbf777]

Roush engines have the cam plug held in by 2-part epoxy.

     This has proven adequate for us, as unlike the cooling jacket core plugs, what is actually pushing on this cup-plug to cause it to be displaced?  If the crankcase pressure is this great, well maybe better plug retention isn't the solution.     And of course in the case of the FE, to avoid having the camshaft push the pug out, be sure to install the camshaft tunnel plug in backwards, oh,......... I mean properly!     

     Scott

[cammerfe]

Some years ago I did an FE engine build-up article for Mustang Illustrated Magazine at Roush's Prototype Engine Facility, the formal name, at the time, for the build location of all his NASCAR engines.

Among other additions, we re-did the oiling of a 'center-oiler' block. Part of the work was to use roller cam bearings. Doing so necessitated boring the cam tunnel to afford the extra diameter of the roller bearings, and re-grooving the bulkheads. The end result was that no oil escaped at the cam bearings---it all went to the mains, which was the idea in the first place.

The re-boring meant that the diameter of the hole at the last cam journal was enlarged and the 'normal' cup plug was unusable. The solution was to use a plug intended for a 385-series engine. But a cup plug intended to go in 'backwards' comes with the flange shaped differently than the usual. The solution is to bore a hole in a piece of half-inch plate, so sized that the plug, when pushed through, comes out the other side properly shaped to be inserted into the FE block. And the Roush guys used two-part epoxy to make sure it wouldn't come out, just as they were doing on a weekly basis with the NASCAR engines.

KS

[Rory428]

Depending on the version of the block plate , that is sandwiched between the block and the bellhousing, the cam plug can not come out anyhow, unless you have a plate with a large hole where the cam plug is.

[cammerfe]

We were aiming at having the least chance of leaking. You're correct about the plug actually coming out. Working with the NASCAR engine builders exposed me to a zillion small details that they do on a daily basis that had never occurred to me. It was a substantial education.

KS