Adding a drain plug 727

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Princess Valiant

Princess Valiant

A.K.A. Rainy Day Auto
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So would it be as easy as buying a napa drain plug, drilling a hole and welding a standard nut on the inside?

Will the drain plug seal in a regular nut?

Where is the best place to put a plug..... side or bottom ?? I was thinking on the rear vertical part of the pan.

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Do you plan on draining w/o checking the filter? One doesn't change the oil very often, so why not drop the pan, replace the paper filter and check the band adjustment?
 
Because it’s SO much easier to drain the pan and then remove it without oil going everywhere. Way less cleanup.

The drain plug seals against the pan with a washer just like and engine oil drain plug. So a regular nut welded inside will work fine. Yes the rear of the pan on the vertical surface is nice so it won’t tear off of it bottoms out.
 
I know this isnt a 727 pan, but shop on the offroad websites. I picked this deep pan with drain plug for $50 shipped on sale at a jeep website last december. Gonna use it on my sons 42RH. Theres lots of mechanical stuff that cross pollinates to cars on the 4x4 websites.

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So much less mess to deal with when a pan has a drain plug. Especially when you have to lay under car.
 
I typically weld a steel pipe coupler 1/8” or 1/4” to side of pan near the bottom edge and use a pipe plug - it also gives option down the road to add sending unit to pan if you want trans temp gauge. Make sure it is steel and not cast steel. Cast steel looks like it has formed bars (like Home Depot cheap) and get an electrical conduit style- real steel and smooth outer housing. Sometimes on the plumbing or electrical section of most hardware stores. Or oven better a hydraulic 1/8” or 1/4” coupler. Dependent on your taste for size. Typically galvanized so you need to grind off coating to bare metal. I like to drill hole in pan and slide the fitting inside 1/2 way- looks cleaner.

SN- draining down pan is way easier with plug vs. dumping oil all over the place when changing the filter.
 
DON'T weld a nut on the inside of the pan. Think about it; picture it in your head. The nut will act as a dam and not allow you to drain all the fluid (and funky sludge) out. Get a bung fitting and weld it to the outside of the pan, being careful not to warp it- it's only thin sheetmetal. Or, by the time you buy the bung & plug and weld it all up and straighten it out, you could have just bought the pan with a plug...
 
$35.73 for a new chrome pan with drain plug on ebay...or just unscrew the neutral safety switch..let it set overnight..remove switch..run for 10 seconds..
 
Steel pipe couplers can be difficult to find. One place they exist and you can sometimes get time free is on the ends of 20' lengths of pipe. In this locale, steel couplers are not to be used in has piping so unplated pipe "protectors" are not used

You can get "although usually heavy" steel couplers at a place specializing in industrial/ tractor hydraulics

Yet another option is a steel pipe bushing. You want UN plated, plain steel. You could, to reduce size, turn the bushing down "some" in a lathe, or even chuck it into a pipe nipple "rig" in a drill/ press and grind it down

Sure too bad Ma didn't think a little before "not" installing drains!!!
 
AND NOW ANOTHER ANNOYING STORY from the old days

When I was stationed at NAS Miramar in the early 70's our shop was located WAY out towards the W end of the runways. We had permission to do work on our cars "when off duty."

One afternoon I was out doing something and our "less mechanical" Chief (CPO) came out to change oil in his 67 Chev. Asked me "how."

I said "you know how to get it jacked up safely"

"Yes." (we had a big ol' floor jack)

"Well" I said "Get it up, go look for a drain plug on the engine and pull it out and let all the oil fall out."

I don't remember if he was changing the filter. likely not

So some time later, he comes over, says "It starts and run but now IT WON'T MOVE"

Of course!!!! Some trans shop HAD INSTALLED A DRAIN in the transmission and YOU KNOW WHAT THAT MEANT!!!

Not only had he drained some of the transmission, but had poured 4 or 5 quarts of new engine oil in on top of the old oil still in the engine!!!
 
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I use an old oil pan plug and the flat piece that holds it. It’s spot welded in the oil pan, easy to get off. Then you have a low profile to get all but just a drop on oil out. Best is heating the spot to dimple it down lower. Like one said lowering the pan full of oil is a pita.
 
Here is a factory pan from a truck. See where they chose to place the drain plug. Also the nut on the back is spot welded in 2places. All is does is hold it so the drain plug gasket can seal.

Don’t need to get crazy with welding it on, the surface needs for be flat to seal with a washer.

it doesn’t need to be very big either, a 3/8” bolt will do just fine, ATF is thin and drains easier than oil.

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413 said:
Here is a factory pan from a truck. See where they chose to place the drain plug. Also the nut on the back is spot welded in 2places. All is does is hold it so the drain plug gasket can seal.

Don’t need to get crazy with welding it on, the surface needs for be flat to seal with a washer.

it doesn’t need to be very big either, a 3/8” bolt will do just fine, ATF is thin and drains easier than oil.

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That’s the same piece I used and described above
 
I have done this several times. I just used a large nut/bolt with an oil pan bolt gasket. I weld the nut on the outside of the pan, cut the bolt so it doesn't protrude into the pan any more than necessary. I'm not worried about tearing it off, my cars aren't low riders. Cost? Nothing. Just time.
 
bought a pan from a newer torque flight from rock auto. my pan wouldn't stop leaking as the sealing flange on these get flaky after a while. new pan was deeper and had a drain plug. bonus. dosen't leak and easy to drain. was cheep.
 
furyus2 said:
I have done this several times. I just used a large nut/bolt with an oil pan bolt gasket. I weld the nut on the outside of the pan, cut the bolt so it doesn't protrude into the pan any more than necessary. I'm not worried about tearing it off, my cars aren't low riders. Cost? Nothing. Just time.
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I can honestly say that I've never bottomed my car out to where the ground touched driveline parts.
I have no idea what the hell kind of driving does that. I guess if your rock crawling main street lol
 
moparmat2000 said:
I know this isnt a 727 pan, but shop on the offroad websites. I picked this deep pan with drain plug for $50 shipped on sale at a jeep website last december. Gonna use it on my sons 42RH. Theres lots of mechanical stuff that cross pollinates to cars on the 4x4 websites.

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Agreed! 49.95 on IH Scout website.
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