Oil Galley Plugs - What tool to remove?

[CaliGold]

Hey guys, I've just started on my rebuild and want to get those oil galley plugs off the engine block. It seems a 1/4 ratchet drive is too small and a 3/8 ratchet drive is too big.

Any recommendations on where to get this square drive tool? How to make one?

 

[Blaine B.]

Adjustable wrench?

Dunno. They are probably in there tight, you'll probably have to heat the block. But an adjustable wrench should work considering you heat it up so they aren't so stuck that you round them off.

 

[CaliGold]

They square drive on the plugs are female. An adjustable wrench cannot work.

 

[Blaine B.]

Ohh. I was looking at a picture of a 4.0 and it showed that they were male.

Maybe it's different between the years.

 

[5-90]

Probably 8m/m or 5/16" (about the same size anyhow.) You can grind down opposite sides of a 5/16" or 8m/m hex key to make it fit - and it's cheaper than what the tool trucks will want for something purpose-built.

You'll also need a torch. Have the torch head in one hand, and a block of paraffin wax in the other. Heat the plug only to dull red (focus all your heat on the plug,) and then take the torch away. Touch the wax to the edge of the plug immediately. Let it cool down a bit, and you should be able to remove it.

When you heat the plug, it expands and forces the hole in the block open. Then, the wax melts on contact, and wicks down in between the threads of the plug and the threads in the block. This helps to free the thing up. Letting it cool just gives the wax some time to work.

Replace the plugs. They're usually a standard pipe thread, so you can get them at the hardware store without too much trouble (3/8" NPT is the most common I've seen, but it could be something strange. Take an old plug with you when you go to match up.)

 

[CaliGold]

Thanks for the info 5-90. After reading your post, I'm glad I ended up having the machine shop take them off. Your suggestion of grinding down a hex key seems to be a good way though. When I get the block back, I'll give it a thorough cleaning, ditch the stock plugs, and stick in some new plugs per your advice with female allen type heads so I can torque them down.

 

[5-90]

Thanks for the info 5-90. After reading your post, I'm glad I ended up having the machine shop take them off. Your suggestion of grinding down a hex key seems to be a good way though. When I get the block back, I'll give it a thorough cleaning, ditch the stock plugs, and stick in some new plugs per your advice with female allen type heads so I can torque them down.

Your typical "flush" pipe plug will have a recessed square drive - usually in a common size (1/4", 3/8", or 1/2" - unless you get something stupid big.) Oil galley holes are typically threaded 3/8" NPT, which usually (oddly) uses a 3/8" square drive.

Get the brass ones - no worries about rusting, and brass doesn't tend to seize on iron or steel like iron plugs do. Also, be sure to use some variety of sealant - PTFE pase or RTV will both work. Tapered pipe threads are designed to provide a pressure seal, but they typically need a little help.