rear access oil galley plug

[49 Caddy]

  Had a 49 Caddy 331 cu. in. lower half re-built and the machine shop is having a hard time finding a convex plug/he called it an oil galley plug.  Goes in the rear of the block where the transmission bolts to it.  He said it is not under pressure, but was not in the bunch of freeze plugs that came with the rebuild kit.  Approx. 1 1/8" o.d.  Anybody got suggestions? 

[Jay Friedman]

I suggest you google "Dorman Freeze Plugs" and you might find what you need.

Your machine shop no doubt has already done this, but there are several smaller freeze plugs back there and one, if I remember, is hard to see, so they should make sure they plug them all up after cleaning out the galleries.

[Daryl Chesterman]

You can use the following Clevite chart to find what you need.  Use a caliper to measure the exact diameter of the opening for which you need the plug, then refer to the chart to find what you need whether it be convex, cup, or the material is steel, brass, or rubber.  If your machinist does not have availability through his suppliers, try NAPA, or another automotive machine shop.  NAPA will have to interchange the Clevite number to their "Sealed Power" part number.

     https://www.mahle-aftermarket.com/media/local-media-north-america/pdfs-&-thumbnails/catalogs-and-literature/engine-parts-hd/ep-30jd-06web.pdf

Scroll down to page 18, the beginning of "expansion plugs" (sometimes referred to as "freeze plugs").

Daryl Chesterman

[Cadman-iac]

Glen,
The description you say your machine shop gave you sounds like the cam plug at the rear of the camshaft. That's the only "oil galley plug" that doesn't have any pressure in it, although it is right at the rear camshaft bearing which does have pressurized oil to it, so without this plug you will still have quite a mess with the engine running. Unfortunately I don't know the exact size of the plug in question, but hopefully this will help you identify the one you need.

  Rick

[49 Caddy]

  Thanks for the response.  I was beginning to think mine was the only 331 like that.  (Not many responses)  I'm sure there are others who have encountered this issue in the past.  Either that, or the plug was not meant to be removed when the block is tank dipped and rebuilt.  Thanks again.

[Cadman-iac]

It's normal for that plug to be removed for a rebuild. I would not trust any shop that doesn't remove it. For one, it's not possible to install the new cam bearings with it in place.
Unless I'm wrong about which plug that is in question here, but I don't know of another plug for an oil galley that has no pressure in it. You might want to ask your machinist if he was referring to the cam plug, or something else just to clarify.
Also,  are you doing the rest of the assembly on your engine, or is the machine shop doing this? If they're doing it, then they should know exactly what plug it is. If you're doing it, looking at the hole where it goes, you can see the end of the camshaft and the edge of the rear cam bearing. There should be a slightly larger machined ridge around the hole that the plug actually seats in.
I mention this because you were unclear about who was doing the final assembly on the engine. Unfortunately I don't have a 331/365/390 engine sitting around without a transmission attached to it to look at right now. (I have one of each).
I hope I have helped.

Rick

[49 Caddy]

  The machine shop has assembled the short block.  All that is lacking is that plug.  The rebuild kit I supplied did not have a plug that size & they are having a hard time finding it.  I just ordered another expansion plug set from another Vendor hoping there is one that size included.  Thanks for answering.

[The Tassie Devil(le)]

Whenever I strip an engine block down, I make sure that I save that Cam plug, as a lot of suppliers don't include that plug in their Welsh Plug kits, as it is not an actual welsh plug in the true manner, but a Cam Plug.

I have re-used them, as they never fall out as there is minimal pressure, as the oil from the cam bearing flows back into the sump.

Bruce.

[49 Caddy]

  Thanks for replying.  They have discarded it thinking there was a new one in the bag of plugs w/my rebuild kit.  Now I have the task of finding something that will work.  They have had a couple weeks to find one.  I am going to pick the block up and find something myself.  It can sit in my shop as well as theirs and at least I know it wont get misplaced or damaged.

[49 Caddy]

  Problem resolved.  Plug was 1 1/8" & it was for an oil galley at the rear of the block to the left of the cam plug.  Picked the block up day before yesterday.  Thanks for input from those who responded.