VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc Freeze Plugs

I am rebuilding both a 1940 and a 1948 Chevy 216 engine. I already purchased the 1 5/8" Brass Freeze Plugs for the blocks. Question #1. Is it wise to install the freeze plugs with any sealant? Is so what? Also, is it recommended that I purchase the 2" diameter and the 5/8" diameter freeze plugs also in brass? If so, are they still available?

dtm

Dave,
I use Permatex #2 on core plugs. Just a little for insurance.

I have used this on all mine for the last 35 years.

http://www.rectorseal.com/index.php/rectorseal-no-5/

Is the '48 Dales? If so, what did you find happened?

I should let him tell the whole story, but the bottom line is that while driving about 100 miles from home, the #2 connecting rod decided to wipe out all of the babbit material. You can imagine the hammering sound. All of the other rods are good, mains are good. These were NOS GM Connecting rods.

Should I still be looking for 2" diameter brass freeze plugs for this engine? cause I can't find them yet.

dtm

freeze plugs
Maybe here.

Dave

The last 2 overhauls on my '40 I've just used what NAPA had for freeze plugs (not brass). With the way we keep coolant in the cars now I have not had any problem with freeze plugs rusting out or leaking during the last 50 years. I've never used sealant on freeze plugs but then I very seldom ever use sealant on anything unless it is something I can't get cleaned up good.

I agree with the use of sealant....or the non-use.

I agree to.

i use brass freeze plugs in my sbc's and bbc's that are destined for NCRS judging as originally no manufacture's logo were on the factory installed plugs. the brass ones from summit or jegs lack logos. i too use sealant(permatex) but before i install the brass babies, i glass bead their exposed surfaces so they will hold engine paint. mike

I use permatex #3 or a brown paste branded "stag" for freeze (welch) plugs and generally replace all though the 1 behind the camshaft isnt so important.
Tony

Hello Mike:
Good idea about glass beading them in order to hold paint better. I will do that.

dtm

Well, I guess you found the 2"?

I also had hit the brass plugs with some self etch primer after they were installed, then I would wipe the overspray off the cast iron area's just leaving the brass covered with the primer, never had a problem. This was on SBC's and W blocks

Going back to what "chipper" said...It is a "misnomer" to call them "freeze plugs", the term is "core plugs"...When all they are there for was to pull the inside support of the block casting out through those holes...Then, were bored to fit the plug...

I have never seen one prevent a block from cracking in freezing weather...

the blocks i've seen crack all did so below the level of the plugs. perhaps the plugs were pushed out by the ice, but the water level below the plugs would do the splitting/cracking of the case. mike

If the water level is below the plug I would think the water would just push upward into the air space? I also had seen the low cracks, on the W blocks most cracks I have seen, were high cracks from plug to plug up to the deck.

Hi John,

I have discarded 4 216 blocks with cracks always on the driver's side of the block. All were at the same height on the block as shown in the pictures. In Michigan water freezes from the top down. When the top freezes over the remaining water expands as it freezes cracking the block. This becomes even more complicated if the bottom inch of the water jacket is full of a sand like rust (corrosion) caused by a lack of thorough, regular, flushing of the cooling system. Check out the following post to see what is inside a poorly serviced engine water jacket.

Overheated cooling system

Those core plugs (freeze plugs) play an intricate part in all engine rebuilds. They provide an easy access to the bottom of the cooling jacket for removal of years of contamination. Can you imagine not having the plugs, and trying to clean out this contamination in a block?

Thank, Mike


http://i1321.photobucket.com/albums/u560/41chevymike/IMG_1085_zps4e2e8445.jpg



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http://i1321.photobucket.com/albums/u560/41chevymike/IMG_1099_zps414decb0.jpg

Great photo's...Let that be a lessen for those who neglect their cooling system...Like me...

The 2 inch freeze ( core ) block on the front of the 1940 216 engine was easy to find at NAPA. The oil galley freeze plug on the front of the driver's side is a problem however. I used my dial indication and the oil galley hole in the engine block measures approximately .566" - .568" in diameter. I went to the NAPA store and they sold me a 9/16" diameter steel freeze plugs for this application. Unfortunately, 9/16" freeze plugs ( cup style ) measures about .565" in diameter. That makes this an easy slip fit in the block. The freeze plug goes in until it hits the rough casting in the hole which is about 1/2" deep in the hole. The freeze plug at this point is totally in the block about 3/16" deep. Can I use this loose fitting freeze plug by applying Permatex to it, since there is minimal oil pressure pushing against the freeze plug?

Also. I can't find the 1 31/32" camshaft cupped freeze plug for on the back of the engine block. Any ideas?

dtm

Dave,
Take a socket or other metal cylinder that is just a little larger than the ID if the cup. Tap it into the cup expanding it a little before inserting it into the hole in the block. Add a small amount of your favorite sealer (I like Permatex # 2) in the hole and tap the cup into the block. The expanded cup will be held in place by the friction and sealer prevent seeps or leaks.

If the 2" cup has a sufficient wall thickness sand off a little material from the sides at the bottom of the cup. Only remove the minimal amount so you can insert the cup into the hole. The tap it in place with a little sealer. Alternately take a Dremel or file or burr and remove a tiny bit of metal from the hole making it closer to 2". Sealer and tap it home.

I suspect you can use a domed disc type plug in that application as well. They are made slightly smaller than the hole and expand their diameter when the center bulge is flattened.

Thanks Chipper. I will "expand" the 9/16th plug tomorrow just a little bit. Stay tuned for the results...............


dtm

Dave,

Regarding the access plug at the rear of the camshaft, I'm pretty sure you'll find that a 50 mm cup plug will fit. 50 mm is 1.9685", while 1-31/32" is 1.96875, so you can see the difference is very slight. Napa carries metric plugs.

Cup plugs come in two styles--deep cup and shallow cup. You want the shallow cup, if available, because the lip of the cup must be flush with the back of the block so it doesn't interfere with the fit up of the bell housing. You can use a deep cup, but you'll have to cut the lip down.

This plug can be a little tricky to set because there is a step at the start of the bore.

Note that there is a small drain hole in the bore for the rear cam bearing. This allows excess oil from the rear cam bearing to drain back into the sump and prevents any oil pressure from building up between the plug and the back end of the camshaft, thus eliminating any additional thrust on the camshaft or the plug. Make sure this drain hole is clear and that the plug does not cover it up after installing.

Mark

Cylinder Block Expansion Plugs are almost all in. A local automotive machine shop stocks the 1 31/32" shallow cup plugs. The 2" welch plugs were easy to find. Now comes the problem, finding two 19/32" diameter cup plugs. They go on the front end and rear end of the block. They are access plugs for the oil pressure line which is on the driver's side of the block. This is the raised protion of the block about 5 inches above the oil pan that runs the entire length from the front to the back of the block. If you install an original AC L-4 external oil filter, the rubber oil pressure line taps into this oil pressure area in the block.
So now I will look for the 19/32" diameter cup plugs. I believe that they are: Group # 1.531, Part # 836082 and are called Oil Pressure Pipe Plugs.

dtm

The 1952 book lists 3835577 for that cup shaped plug. Was used in 235 engines till their end of production.