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Threaded Hole in the Tractor Block?

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Tinkerman

Tinkerman

Darth Vader
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As I stand in front of the engine on my left there is a threaded 1/2 x 20 hole on the lower side of the block. Actually about opposite the fuel pump. What goes there? Oh Ho, could it be a drain valve?

Anyhow, need help from some one who knows. Can't see it even with all of the engine pictures I have.

Thanks, Tinkerman
 
On the right side of the engine, opposite the fuel pump, there is a coolant drain hole. Needs a bolt with a crushable copper washer to seal it.
 
I have a drain valve petcock at that location. Don't know if it's 1/2-20, but that size appears to be about right. It might be a pipe size. US pipe in about that size would be 1/4"-18 NPT. BPSS (parallel threads) would be 1/4"-19 IIRC.

EDIT: If you want, I'll yank the petcock out (the engines sitting on the floor) and measure the thread pitch and diameter.

Anyway, Moss shows it here as item #27. There is a washer also shown, so I'm sure it's not a tapered pipe fitting.

Well, I yanked the brass petcock out, and it is definitely 1/2-20 threads. There is a fiber washer (as Moss indicates) on there. No way would have my petcock drained anything...it's plugged solid. /bcforum/images/%%GRAEMLIN_URL%%/wall.gif Well, I haven't gotten to the engine yet.
 
Sure makes sense to me.
As I have gone around to shows and meets I make a pest of myself taking pictures, however there are some places that you can't get to and take a picture.

So thankee for the help :smile:
Tinkerman
 
By the way mine was mostly plugged so I cleaned it out and that's why I knew the thread stats.

Tink
 
Aloha Tinkerman,

It is quite common for that drain hole to get plugged with sediment, rust and general crud. I think this is because that area of the block is the least turbulent in terms of coolant flow and "stuff" settles there. Poking around with a wire through the hole will stir it up so it can be drained out. I do this periodically and it really helps to keep engine temperatures in the normal range.
 
I think the petcock should be replaced with a plug, unless you're running pure water for racing and you need to change it often, but then i'd still replace it cause they leak (when not plugged).
Rob
 
In case you wonder what plugs up the drain valves here's a photo...
IMG_1949.jpg
 
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