Super A 2" Expansion Plug

Wed Feb 23, 2011 7:36 pm

After removing the engine off my '48 Super A, I noticed the 2" Expansion Plug looked like it had been replaced and put in with a hammer! Any opinion as to whether this is any problem? The engine ran just fine, but figured while I was putting it back on, I should make sure.

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Any comments would be appreciated.

Dale Finch

Re: Super A 2" Expansion Plug

Wed Feb 23, 2011 7:43 pm

Dale, as long as there are no leaks it should be fine. If you are rebuilding the engine, then you can replace it if you want.

Re: Super A 2" Expansion Plug

Wed Feb 23, 2011 7:44 pm

A little bigger. :D

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Re: Super A 2" Expansion Plug

Wed Feb 23, 2011 7:53 pm

Don, how did you make it bigger?
Dale

Re: Super A 2" Expansion Plug

Wed Feb 23, 2011 7:56 pm

Never mind...I just realized that thumbnail had been inserted...thanks!

Dale

Re: Super A 2" Expansion Plug

Wed Feb 23, 2011 8:19 pm

Sure glad to see the picture session that Bigdog did at DSCF is being put to use!!

Thanks again, Mr. Darrell.

Re: Super A 2" Expansion Plug

Tue Mar 01, 2011 9:06 am

My opinion. If the expansion plug is covered, with say the bell housing, when the engine is installed - replace the expansion plug. Cheap insurance. If the plug rusts out you will need to split the tractor for a $2- repair.

While you are there - with the plug out - flush the block.

Re: Super A 2" Expansion Plug

Tue Mar 01, 2011 7:54 pm

How do you remove the expansion plug, and can it be installed without doing whatever someone did to this one? What would you flush it with, kerosene? How do you flush the engine? I.E. do you simply take the oil pan off and pump stuff in through the rear? Or do you have to take off the valve cover, head, etc? I was hoping NOT to do much actual engine work...this engine was running just fine before I got hold of it!!

I REALLY am the type of person that hates to do things half way...what's another task when you have it down to the bones?!! I look forward to your answer, and hopefully will be posting a couple questions later tonight with photos. Perhaps you can give me some more advice...

Dale

Re: Super A 2" Expansion Plug

Tue Mar 01, 2011 8:03 pm

Dale - the expansion plug covers an opening into the water jacket of the engine. If you remove it, you will see some scale / calcium buildup in the water jacket. The plug should pry off. You will find the replacement plug is a domed plug. Put a little sealant around the edge and place the plug in the hole. To expand the plug you tap the center of it with a hammer to collapse the center which expands the edge to make a tight fit. So all the hammer marks you see are not incorrect.

Re: Super A 2" Expansion Plug

Tue Mar 01, 2011 9:59 pm

Ooooh! Well, in that case, since the engine was OK, I think I will leave well enough alone. I just posted a new thread, and have one other one to post for some answers.

Thanks!

Dale

Re: Super A 2" Expansion Plug

Sat Mar 05, 2011 8:18 pm

i would replace both of those casting plugs and seal them with a little silicone on reinstallation. they mostly rust out from the inside, so you cant tell the condition untill its too late. simple to do, drill a hole into them and pry.

we all commonly call these plugs expansion plugs, or freeze plugs, but they are actually there to assist in the casting of the block. an old timer, aka Dad, corrected me. but they do function as freeze plugs in that they will push out when the block freezes....just before the block cracks!!!

when i was a boy, they called them Welch plugs. anyone know the origins of that term?

Re: Super A 2" Expansion Plug

Sat Mar 05, 2011 8:59 pm

Welch Plug...

http://www.britishcarweek.org/welch_plug.html

Re: Super A 2" Expansion Plug

Mon Mar 07, 2011 5:46 pm

Thanks Don! Learned something new that I can remember!! Grump