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Got my new freeze plugs from Vintage.
What's the proceedure for installing these?
Does the convex side go to the outside?
Should I also use Permatex or some other sealant?
Once installed in the block, do you have to "centerpunch" the
freeze plugs to expand them? If so, what tool is best to use?

Any help appreciated............

The "dimple" should be inward with the edge on the outbound side. Most are installed with a flat surface chunk of metal (like a decent-sized socket (bottom side)) and a hammer. An old mechanic's trick is to use thread sealer around the edge to help seal it although I haven't tried this myself. Don't over strike with too much power or you could damage the block. No center punching is necessary.
Gary

Ok, good, thanks for the tips. I've installed other freeze plugs before on American hardware but the plugs
were hat shaped. I just needed to confirm from one of you M37 people that what I was about to do was
correct. Too much time and money invested in the rebuild to screw it up now.
Thanks again..........

Freeze plugs, welsh plugs and expansions plugs are all very similar but there are two basic varieties.

The flat disc that has a gentle curve or bulge in the middle. This disc is inserted into it's block hole which has a ledge that only allows it to go in so far with it's bulge or convex area facing outward. It's edge is trimmed with sealant before installation and once tapped in place solidly against the ledge in the hole you use a flat nose punch about 10 % the size of the diameter of the plug and make a sharp blow against it with a hammer to set it. Often called dimpling the plug.
The Dodge 230's and 251's I've seen have the disc type plugs.
Disc type plug.

The cup type plug is cup shaped and is installed with it's open side outward and the hole in the block usually has no ledge to restrict it's travel. These are installed properly with an appropriate driving tool very similar to a bushing driver set that presses against the outer rim of the plug as it is pushed into position flush or just a tad recessed. Again the rim is trimmed with sealant before installation. You can improvise in the driver department but just be careful to drive against the rim and not the center of the plug.


Cup type

Most of these plugs come in either steel or brass.

Thanks Cuz:
Good info. on the correct way to install the two types of freeze plugs.

Don't know whether you have steel or brass plugs, however it is best not to install steel plugs as they will rust over time on the inside and begin to seep, then leak, etc. Brass plugs are readily available and will never cause issues from rusting. Their life expectancy is far longer.

Thanks for the info. Rust is always the enemy.
I'll check locally for some brass plugs.

FYI, the freeze plug set has 10 pcs. in it. 9 of them are for the engine block. The smallest one is 1 3/16" and is for the
top the head. Drove me crazy trying to figure out where the little booger needed to be installed. Will sleep better now.
See TM 9-2320-212-20P, see pages 7 & 18, item 5.

... they are called by many names, but Core Plugs are the correct terminology.

Tanner

How do you define correct? They are labeled by the Army in the parts catalogs as expansion plugs. As I have posted already they are known by many names both based on their construction and their purpose. Core is a purpose when referring to the casting process and holes left behind. Expansion is a description of how they are installed or function. Welsh is a designer's name. Freeze plug has been used since the 30's. Correct depends on where you stand in the system. It's like the trading of monikers for lifter and tappets. Yes one could post 10 dictionary references supporting each. But they aren't necessary in a friendly forum where the idea is the topic and the terminology used is that which the majority understand.

Tanner wrote:... they are called by many names, but Core Plugs are the correct terminology.

Tanner

Many names for sure. Our vendor knows them as either the saucer type or the dish type. This insures that we get the correct type of plug for a given application.

GOOD MORNING,
The only FREEZE OUT PLUG to use in a marine application is the brass plug, but I have used the expandable rubber plugs with great success. easy to install and remove, to drain the block. they come in a wide range of sizes. FYI. BOB

Bob:
Great idea. Rubber plug might be very useful when a freeze plug lets loose in the middle of nowhere and you
need a quick and easy fix to git 'er home. If they're not too expensive, could keep one in the
on board tool box for emergencies. Guess only the ones on the side of the block or the head would be accessable
for roadside quick repairs. Still a great idea in a pinch.

Call them what you will and we will all know what is being referred to. Yet in all honesty Tanner is correct, core plug. The reason being is the only reason they are in our blocks and heads is that they are the holes that casting sand is gotten out of a freshly cast piece which needs internal water passages. I went out to the shop for a smoke and grabbed 6 different styles out of stock just to show the range of plugs.
Top row left to right
Deep cup with dimple (may take extra pressure because of shape)
Shallow cup
Convex disc
typical cup
Bottom row
Rubber expansion
All copper expansion (well made and costly)

I disagree. There is no one perfect name for them. There are a lot more applications for expansion plugs then just the sand cast core plug hole. They are used in the ends of oil passages, cam bearing holes and drilled service passageways. They are found in the end of hollow cranks that use oil pressure ported there to control units such as props and screws.