Lost Frost plugs

-
Actually you should not need any sealant at all if the plug bores are in good condition. I used to use sealant till I had a couple of plugs blow out in a circle track application. Racers get angry when they have to get off the track due to scorched feet and over heated motor. 2 separate incidents and I started using Permatex Sleeve Retainer--That was over 10 years ago. Many many frost plugs and cam plugs later not one leak and not one blow out. I think I'll just keep doing what I'm doing. J.Rob


I've always used a very thin "skin" of sealant on them and make sure they're in far enough to clear the bevel. I haven't had any issues with leaks, seaps, or popping out but I know it's more common when using brass plugs. The old manuals had instructions for retaining straps for them in circle track apps.
What happens when you try to remove the plugs to wash the block? Do you have to heat them?
 
Actually they come out about as difficult as a rusty crusty 30-40 year old plug but cleaner, however truth be told--Why would they need to come out after a rebuild? Normally once I build an engine--the frost plugs never have to come back out---Installing frost plugs is not that big a deal. Use sealant, don't use sealant--your choice. J.Rob
 
Actually they come out about as difficult as a rusty crusty 30-40 year old plug but cleaner, however truth be told--Why would they need to come out after a rebuild? Normally once I build an engine--the frost plugs never have to come back out---...

for at least another 30 or 40 years... thanks for the tip.
 
Actually you should not need any sealant at all if the plug bores are in good condition. I used to use sealant till I had a couple of plugs blow out in a circle track application. Racers get angry when they have to get off the track due to scorched feet and over heated motor. 2 separate incidents and I started using Permatex Sleeve Retainer--That was over 10 years ago. Many many frost plugs and cam plugs later not one leak and not one blow out. I think I'll just keep doing what I'm doing. J.Rob

Well good. And I'll do what's worked for me over thirty years.
 
Actually they come out about as difficult as a rusty crusty 30-40 year old plug but cleaner, however truth be told--Why would they need to come out after a rebuild? Normally once I build an engine--the frost plugs never have to come back out---Installing frost plugs is not that big a deal. Use sealant, don't use sealant--your choice. J.Rob

I'm amazed if you've never had a previously rebuilt engine apart for any reason. If the block gets washed during a freshening I pull them just like the oil plugs and cam bearings. I suppose I don't have to beign it's just the cooling jackets and there's other ways to get things out - but I've always done it. Just an old habit I guess.
 
I know every machine shop I have ever used.....or worked for pulled them out. It's pretty common practice.
 
I looked around where the car was stored and look what I found..

View attachment frost plugs.jpg

When to install the new ones...my son had been doing the exploring so far..and both are behind the darn headers....arghhh..

Started to work on them and my hands weren't steady enough so waiting for son to be home from school. had to buy some landscaping stuff and that we did tonight so tomorrow,,,,when the light is good, we shall try to do the install. I *really* don't want to pull the engine again..but if we have to, we shall..

Ian.
 
I looked around where the car was stored and look what I found..

View attachment 1714722207

When to install the new ones...my son had been doing the exploring so far..and both are behind the darn headers....arghhh..

Started to work on them and my hands weren't steady enough so waiting for son to be home from school. had to buy some landscaping stuff and that we did tonight so tomorrow,,,,when the light is good, we shall try to do the install. I *really* don't want to pull the engine again..but if we have to, we shall..

Ian.

It seems as though the engine must have had water in or there was some sloppy work done on the engine.
 
We had installed the rad and hoses but left the drain plug on bottom the the rad was open.No water or antifreeze had been added..I guess we should have in retrospect..

I cannot think of any reason water would be in there unless it was tested after the rebuild ??

If there was water, why didn't the ice go up instead of forcing the plugs out..

I realize that it is now a moot point but I like to understand the whys....
 
Ian, I would pull that engine...not only is it way easier to install the plugs and ensure they are seated properly, but to give it another look over to make sure nothing else is amiss!! Costs ya nothin but time to do it.
Sucks but better safe than sorry....JMO
 
When they "ran it in" with an electric motor, even though there is no combustion taking place it would still generate heat from friction - and I am betting that they had some water in the cooling passages for this reason, to avoid overheating the rings and taking the temper out of them. Unless you removed the pipe plug drains (one per side just above the oil pan rail) on either side of the block any water that may have been in the block would not drain out, as the feed holes to the water pump housing are higher than the level of the block drains and core (frost) plugs. I would be pulling that engine, and looking very closely along the sides of the block for hairline fractures. There is no other possible explanation for why the plugs were pushed out, other than freezing. I have seen more than one block ruined by having water remaining in the bottom of the cooling passages.

Look at the other plugs, and see how many of them are partially pushed out as well.

A good friend of mine with a 440 in a race car Duster only ran water for coolant. He thought he drained it all in the fall by removing the lower rad hose, and then it sat all winter and cracked the block behind the starter.

Have a very good look, it is easier to find out now rather than later!
 
Ian, I would pull that engine...not only is it way easier to install the plugs and ensure they are seated properly, but to give it another look over to make sure nothing else is amiss!! Costs ya nothin but time to do it.
Sucks but better safe than sorry....JMO

When they "ran it in" with an electric motor, even though there is no combustion taking place it would still generate heat from friction - and I am betting that they had some water in the cooling passages for this reason, to avoid overheating the rings and taking the temper out of them. Unless you removed the pipe plug drains (one per side just above the oil pan rail) on either side of the block any water that may have been in the block would not drain out, as the feed holes to the water pump housing are higher than the level of the block drains and core (frost) plugs. I would be pulling that engine, and looking very closely along the sides of the block for hairline fractures. There is no other possible explanation for why the plugs were pushed out, other than freezing. I have seen more than one block ruined by having water remaining in the bottom of the cooling passages.

Look at the other plugs, and see how many of them are partially pushed out as well.

A good friend of mine with a 440 in a race car Duster only ran water for coolant. He thought he drained it all in the fall by removing the lower rad hose, and then it sat all winter and cracked the block behind the starter.

Have a very good look, it is easier to find out now rather than later!


Agreed on both counts. Something forced them out. I can't picture them just falling out.
 
I'm amazed if you've never had a previously rebuilt engine apart for any reason. If the block gets washed during a freshening I pull them just like the oil plugs and cam bearings. I suppose I don't have to beign it's just the cooling jackets and there's other ways to get things out - but I've always done it. Just an old habit I guess.
When rebuilding my engines for racing, I never bother pulling the plugs out after the first re-build; I keep the fluids clean, don't use straight water for coolant (this is rally, not circle track) and thus avoid rust, and don't worry about anything getting in there after the first go-around. I suspect the prior post presenting the same idea was in regards to race enigne rebuilds every season or more often.
 
What's the sleeve retainer for? You need some type of sealant on freeze plugs. Sleeve retainer is not sealant. It is a metal adhesive. Freeze plugs are held in by a press fit. They only need sealant. I like to use Permatex #2.

Very true. I would never trust a core plug without sealer.
 
Not sure if it's possible but could use a jack to support the engine with a 2x4 under the oil pan and remove one of the motor mounts. The engine could be jacked closer to one side so that it can be rocked to get a little more room. Just my thoughts.
 
Ian, I would pull that engine...not only is it way easier to install the plugs and ensure they are seated properly, but to give it another look over to make sure nothing else is amiss!! Costs ya nothin but time to do it.
Sucks but better safe than sorry....JMO

When they "ran it in" with an electric motor, even though there is no combustion taking place it would still generate heat from friction - and I am betting that they had some water in the cooling passages for this reason, to avoid overheating the rings and taking the temper out of them. Unless you removed the pipe plug drains (one per side just above the oil pan rail) on either side of the block any water that may have been in the block would not drain out, as the feed holes to the water pump housing are higher than the level of the block drains and core (frost) plugs. I would be pulling that engine, and looking very closely along the sides of the block for hairline fractures. There is no other possible explanation for why the plugs were pushed out, other than freezing. I have seen more than one block ruined by having water remaining in the bottom of the cooling passages.

Look at the other plugs, and see how many of them are partially pushed out as well.

A good friend of mine with a 440 in a race car Duster only ran water for coolant. He thought he drained it all in the fall by removing the lower rad hose, and then it sat all winter and cracked the block behind the starter.

Have a very good look, it is easier to find out now rather than later!

Agreed on both counts. Something forced them out. I can't picture them just falling out.


I fully agree with all the posts above. What if there is another one that you can't see that is nearly pushed out and it gives way at the wrong time causing you to ruin the engine?

If you pull the engine out, inspect it, replace all the core plugs as needed (myself, I would swap them all to brass as the left one already looks rusty), loop the heater hose, hook up the radiator while the engine is out of the car and pressure test the system. Having the engine out you can see a whole lot better than you can trying to do it in the car and you will know it was done right instead of having your b-hole sucking all the way up to your Adams Apple every time you take the car out.
 
The engine has never had water in it.

I spray painted it last year.

I am completely stumped.

Ian.

If you painted it and the plugs were there, there will not be paint in the holes. If there is paint in the holes then it is as Rusty said and they were never installed.
Never mind, I see you found them.
 
If you painted it and the plugs were there, there will not be paint in the holes. If there is paint in the holes then it is as Rusty said and they were never installed.

See the post #58 that Ian made above showing the picture of the two missing core plugs with green paint on them. In a previous post he already said no green paint inside the block.
 
Very true. The core plug bores are rough cast and need sealer. I would never trust a core plug without sealer.


We used Loctite on the block machining line that I was responsible for. It made a huge mess eventually that maintenance had to go in and clean regularly. If we didn't need loctite in the core plugs, then they wouldn't have done it. They would have saved alot of money to remove those stations from the line.

I would use loctite or some sealer on the cup plugs.
 
I would recommend pulling the engine and going over it to make sure.


If the cup plugs just fell out, then there is something wrong. They are interference fit and don't just fall out....

I would check the hole size to make sure that it is not too big or the cup plugs to make sure that they are not too small. The plugs don't just fall out on their own.

I would also check the other plugs to make sure that they are ok...

Loctite will also make them hold better and less prone to "fall out" again.
 
All the old Hemi guys over on The Hamb use JB Weld to hold the welch plugs in on early Hemis. I couldn't bring myself to do it. I used high temp RTV.
 
No, the core plug bores are machined and chamferred. The edge of the plug should be installed just past the bottom of the chamfer.

Right you are. Sorry for the misinformation. I corrected my post. I either need to build more engines or not rely on my memory as much. LOL tmm
 
I'd definitely pull it out and check ALL of them, I also agree with pressurizing it to make sure there are no leaks. I have also seen engines crack in the valley under the intake but to pressurize that, you would need to build plates to block off the water ports in the heads as well.....

Although, if there was only just a little bit of water in the bottom of the block, it may have just froze and popped those 2..... bummer though.....
 
-
Back
Top