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TR2/3/3A How do I get rust out of block drain hole on TR3A

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TuffTR250

Jedi Warrior
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How do I get the rust/crud out of the block drain hole on a TR3A? I have been able to get the stopcock out of the block ( and the stopcock was totally stopped up with crud), but I can't get water to come out. With a sharp pick I have been able to dig a small cavity in the back end of the block hole. I have also used a 90 degree pick to try to get the rust from around the inside of that small hole. But still no liquid comes out. Is there a way to clear that hole without tearing the engine apart? Thanks for the help!
Regards,
Bob
 
Point the pick slightly upwards and continue to poke. This should eventually free the obstruction. Don't hammer on it too hard to not damage the #4 liner.
There should be several threads here already covering this topic.
 
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NeedsCleaned.jpgcleaned_up.jpgtap_hole_outside.jpgHere's a few pictures of what you may be dealing with. My first picture is after I removed the liners and the rust is obvious. The next pic is what it looked like after a little work with a wire brush on the end of a drill. The pic from the outside shows that the passage in the block is not a complete hole, that is, it slopes towards the underside of the FO8 gasket. It's as if that 'depression' was made as an outline of a finger pressed into the tapped hole. I think if your passage is very rusted, you could take a small drill bit, and use it to remove the rust being careful not to drill into the block -which is much harder and you should easily be able to tell when you are drilling rust, and when you are drilling steel.

Keep picking and good luck,
Jerry
 
In order to drill "around the corner", I took some heavy steel wire, smashed the end flat and ground a point, making a crude spade bit. I could then bend it into shape and twist the end back and forth, helping work the sharp end through the crud. Took several hours, but eventually I was able to work a path through the crud and get some water out. Since the steel wire is relatively soft, there is less worry about damaging the liner or the threads in the hole than using a hardened drill bit.

Of course, that still leaves a lot of crud piled up around the rear liner. To really get it clean, you'll probably have to remove the liner.

Another route that might be worth trying is to squirt some phosphoric acid into the hole and let it work on the rust. It should chemically dissolve it, leaving behind a gray powder that is easily scraped away. Might take several alternations of digging and letting the acid soak. I found "Etch and Prep" in the paint department at Home Depot, which appears to be mostly phosphoric acid. I've not tried this approach, but I will if problem presents itself again.
 
New reality show - British (Car) Pickers?

Scott
 
I finally got back to digging out the rust from the block drain on my 3A and was able to get it open. It took a lot of digging and picking (but no grinning). I ended up very carefully and gently using a 1/2 - 20 tap in the hole (same size thread as stopcock) and that dug out the rust in a large enough hole to then allow me to pick at the outer edges of the hole with a right angle pick. I made sure I put plenty of heavy oil on the tap and was careful not to wedge against the threads used to screw the stopcock into the block, and also careful to not drive the tap in against the piston sleeve.
Regards,
Bob
 
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