Welch Plug Questions

[Jocko_51_B3B]

First Question: Any suggestions about what sealants work well for sealing the welch plugs?

Second Question: I just ordered a set of brass welch plugs from Summit Racing for my B3B because I was concerned that steel plugs could rust eventually. Then again, brass and cast iron are dissimilar metals which (I'm thinking) could set up galvanic corrosion. Any thoughts on this? I never heard of this being a problem, but since it occurred to me I thought I would put it out there.

 

[Los_Control]

I have no honest answer ... I put brass in mine, then read about others that have the same questions.

With the two different metals, the cast iron block seems like the weak link and it will fail before the brass.

Nobody seems to have a real life experiences with the block failing after using brass .... maybe it takes many years?

A brass water distribution tube is common, no issues reported there.

 

Just saying I have asked the same question but nobody seems concerned with it.

I just kinda quit thinking about it myself.

[billrigsby]

I am not sure on the sealant because the Machine Shop put mine in and mine were steel in fact.

 

As far as a galvanic reaction I'm not sure about that because we have always put brass fittings for oil lines water lines etc into engine blocks without any issues , however over an extended extended period of time there may be a reaction. I know stainless steel and brass does not.

[Dodgeb4ya]

No issue with using  brass core plugs.

Those are the only ones I will use.

Many factory flatheads have brass water distribution tubes and factory rear of block core plugs.

All factory Chrysler eights use front and rear brass core plugs.

They are not accessible for replacement....so that's a plus buying a higher line Chrysler I suppose.

Never a leaking plug behind the timing cover or bell housing.

Marine engines use brass plugs too.

[Jocko_51_B3B]

I found this little article about electrolysis in car engines. https://www.familyhandyman.com/project/coolant-testing-with-a-multimeter/

From what the article states, when using brass Welch plugs it might be a good idea to change coolant more regularly (or at least check it for conductivity) . I suppose sealant used when installing welch plugs helps prevent galvanic corrosion by reducing direct plug to block contact, but who knows? Talking about sealant, I've read that some guys like to used JB Weld, but is there a product out there made specifically for sealing core plugs?

Edited January 31, 2021 by Jocko_51_B3B

[JBNeal]

additional information - welch plug installation 

[Jocko_51_B3B]

Good info. Thanks JB.

Edited January 30, 2021 by Jocko_51_B3B

[David A.]

This is what the machine shop recommended I use for the welch plugs. So far I haven’t had any leaks and it’s been a number of years since I installed them. 

[Plymouthy Adams]

from day one of my messing with any engine, the use of Permatex has always been the go-to in all the shops I have ever been associated with.  The best seal regardless of your favorite snake oil starts with the mating surfaces cleaned very well and assembled free of coolant weep.  

[Dodgeb4ya]

Modern engines using aluminum heads, maybe iron blocks, brass and or aluminum heater cores, high tech head gaskets, and lots of vehicle electronics.....I would not use brass plugs....only factory OE type core plugs.

Our old flatheads don't have these issue's like with the more modern  delicate cooling systems.?

[Jocko_51_B3B]

I finally decided on Permatex Form-A-Gasket #1 to seal the Welsh plugs. After putting them in I thought they might look good polished up. Maybe polishing them is a little over the top but why not? So I used a little bit of Mother's Mag & Aluminum polish. It took about two seconds and they turned out pretty nice. The plug in the upper right corner got scratched from the brass drift I used to punch it down so to prevent scratching the other four I put a small piece of aluminum tape on the plugs before punching them down with the drift. That worked. No more scratches.

 

  

Edited February 9, 2021 by Jocko_51_B3B

[ggdad1951]

NICE!  I eventually painted over mine I left visible.