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mountainman
07-06-2009, 09:40 AM
The threads in my tr3 block where the water drain tap goes are completely gone and the little brass tap just slides
in the hole. Please,I would like some opinions on what I should do. JB Weld???
Thanks
Greg

Mickey Richaud
07-06-2009, 09:51 AM
Hey, Greg -

I would think a Helicoil insert would fix you up.

https://www.helicoil.in/

Mickey

TR3driver
07-06-2009, 10:40 AM
:iagree:
Helicoil is a brand name; the equivalent inserts are available from other sources as well. I buy mostly Recoil brand as they are usually less expensive.

Don't recall the threads on that tap offhand (I can check if need be) but I think they are straight, SAE bolt threads; not pipe threads.

Might be worth making sure you have the right tap; many later cars used a different tap with, as I recall, 1/8" NPT threads.

Tinkerman
07-06-2009, 01:08 PM
Ahhhhhh, so thats what that hole is for! I knew that the hole was there and had, sure enough, forgotten about it. Sheechhhh glad I hadn't put any coolant in.

Tinkerman the forgetful.

PeterK
07-06-2009, 02:49 PM
Are the threads on the drain gone or the threads in the block?

Should be the same threads are the water drain on your radiator.

If you do re-tap it, note that there is a very close (~3/4") piston liner directly behind the hole in the block. Don't want you to drill through your liner.

mountainman
07-06-2009, 03:49 PM
Are the threads on the drain gone or the threads in the block?

Should be the same threads are the water drain on your radiator.

If you do re-tap it, note that there is a very close (~3/4") piston liner directly behind the hole in the block. Don't want you to drill through your liner.
Peterk, It is the threads in the block. Thanks on the heads=up on the liner. That's another reason I am leaning toward something besides re-taping and using a helix-coil. I plan on keeping the anti-freeze up to par and don't see any reason why I will need that drain. Who JB Weld be an option?
Thanks again
Greg

martx-5
07-06-2009, 04:37 PM
I'm not a big fan of JB Weld for this type of problem. I understand your concern for not drilling through the liner. Take a pencil (or whatever fits closely in the hole) and stick it in to see how much space you have back there. What you're interested in is the space between the back of the hole in the block and the liner itself. If it's about a 1/2" or more there shouldn't be a problem with drilling and tapping. If your unsure about the use of a heli-coil, you might want to consider a tapered pipe plug. Perhaps an 1/8"-27 will work, but if that's too small (which it probably is), go to 1/4"-18. I'm just not happy with a JB Weld type fix here.

Andrew Mace
07-06-2009, 06:35 PM
I plan on keeping the anti-freeze up to par and don't see any reason why I will need that drain.Well, no matter how well and often you maintain the system with flushes and refills, at some point you'll want that access to the block, because crud <span style="font-weight: bold"><span style="font-style: italic">will</span></span> build up there, and you'll want some way to get it out! Been there, done that...too many times!

DNK
07-06-2009, 06:55 PM
You know ,while working on the V8 in the wedge and crawling under the motor to pull the clutch line I happened to notice that that particular motor has 2 drains.
OF COURSE THIS WAS WELL AFTER I HAD STRIPPED THE FRONT OF THE MOTOR APART AND GETTING COOLANT ALL OVER ME AND MY FLOOR.

TR3driver
07-06-2009, 07:14 PM
You also need to open the drain valve to do a proper flush.

The liner is plenty hard and won't have a pilot hole through it, so no worries about damaging it IMO. The only real problem will be whether the special tap will cut the threads deep enough before hitting the liner. If necessary, you can grind down the end of the tap to make it more nearly a "bottoming" tap, but I don't think it will be necessary. Most Helicoil taps are already a "plug" configuration, rather than "taper".

Most likely, you won't need to drill at all; the "skinned out" diameter is a very close match for the "tap drill" diameter and the tap will ream out the difference as it cuts the new threads. But be sure to hold the tap square to the hole while getting it started.

I agree with Art, wouldn't even try JB Weld or similar. Too much heat/vibration/pressure; plus too much to lose if it lets go.

Adrio
07-07-2009, 02:23 PM
I was able to tap that hole with the appropriate and normal lenth (as in not ground shorter) tap and install the stop ****.

Tinkerman
07-07-2009, 03:00 PM
Good on yer Adrio. Always nice when something works right! I particularly appreciated your post because it has saved me some grief. I have a block drain ordered and will put it in straight away after I get it.

Cheers, Tinkerman