Lets talk about "freeze" plugs...

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YY1

YY1

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...or core plugs or expansion plugs or whatever...

Since I've had the pleasure of having so darned many of them fail recently, my analytical mind has been set in motion.

Here are my observations, thoughts and questions, in no particular order.


Is cost the only reason the factory used steel instead of brass?

The "correct" 1 5/8" plugs are really thick (if brass) and shallow.
This causes-
Difficulty in installation
A tendency to "pop" out if not fully parallel with the bore
A "ledge" on the bore inside the casting behind the plug, where sediment can build up and corrode through.

I'm fairly staunch on Mopar engineering, and prefer not to use gm parts, but the gm small block 1 5/8 brass core plug is a lot easier to install and seated correctly, places the plug face beyond the inner block wall, eliminating the ledge mentioned previously.

What's everyone else's take on this?
 
Do they make the brass ones that are deeper like the steel?

The freeze plugs are supposed to be put in the hole just past the bottom of the chamfer.

Use loctite, silicone, or whatever sealer you wish to help seal them.
 
I got a good set of deep brass one's at a machine shop.
A little smaller than my personal big brass ones - just saying'...
C
 
clhyer said:
I got a good set of deep brass one's at a machine shop.
A little smaller than my personal big brass ones - just saying'...
C
Click to expand...


It takes some brass balls to say something like that.... LOL!
 
If you install the Mopar style thick, shallow plug to just beyond the bore chamfer (about 3/32), you get the ledge effect I mentioned.

If you install the gm style that way, the plug protrudes into the water jacket, eliminating the ledge.

The depth also helps true up the plug inside the bore.

gm style dorman part # is 565-030 (or 565-031)


I've never used any sealant, and never had any leaks that lasted more than one (rare) or two (very rare) heat cycles.
 
YY1 said:
I've never used any sealant, and never had any leaks that lasted more than one (rare) or two (very rare) heat cycles.
Click to expand...


We used blue loctite on the freeze plugs on the block machining line that I worked on. That station used to get all gummed up and had to be cleaned periodically...
 
I am unclear which plugs you are talking about. Those that Mike linked to above are what I use. Are you talking about the almost flat style welch plugs? If so, those are incorrect for a small block.
 
There are shallow and deep core plugs available. I like the deep once in brass, because brass does not "grab" the bore as well so more width keeps them in place. I don't use steel anymore- they just rot too fast for my taste, and they rot from the inside.
 
YY1 said:
...or core plugs or expansion plugs or whatever...

Since I've had the pleasure of having so darned many of them fail recently, my analytical mind has been set in motion.



What's everyone else's take on this?
Click to expand...

Since by your own words that you've had "many" failures lately; have you given thought to HOW you are installing them?

Don't drive on the "inside", rather on the edge. Driving on the "inside" will have a tendency to draw the OD smaller as it enters the hole in the block. The current issue of "Hot Rod" or "Car Craft" (don't remember which) has an article about this very subject.


Good luck!
 
while we are on the subject, what is the preferred sealant for them ?
 
So much fun when the ones at the back of the block leak...:banghead:

IMG_0647_zpsacbb9d3e.jpg
 
Most good machinists will agree that a pliable sealant like #2 Permatex, is the correct product to use for sealing expansion plugs.
 
All the early Hemi guys over on The Hamb recommend JB Weld to seal them. I know. I couldn't bring myself to do it. I used Permatex #2.
 
MOPARMITCH said:
Most good machinists will agree that a pliable sealant like #2 Permatex, is the correct product to use for sealing expansion plugs.
Click to expand...

This is what I always have used. I always use brass plugs to replace steel. Never had a problem.
 
JBurch said:
Since by your own words that you've had "many" failures lately; have you given thought to HOW you are installing them?

Don't drive on the "inside", rather on the edge. Driving on the "inside" will have a tendency to draw the OD smaller as it enters the hole in the block. The current issue of "Hot Rod" or "Car Craft" (don't remember which) has an article about this very subject.
Good luck!
Click to expand...

Let me clarify-

I've had several failures of factory installed steel plugs on both my 2000 Dakota and my 1973 Satellite.

The ones I install myself turn out fine (with no sealant- ever- in 30+ years).

I am discussing the benefit/caveat of the sbc style thin/deep plug versus the sbm style thick/shallow plug.
 
Do you have a pic of the plugs your referring to. Pic is worth a thousand words.:toothy1:
 
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