Cross threaded block drain plug

[mf01]

This weekend, I wanted to figure out how to drain my block. Apparently the previous owner or his mechanic cross threaded the drain plugs on the block. I bought the boat last April, so this is the first time I pulled them. The plug up near the water pump was fine. They go back into the block and appear to work fine. Are there any options to fixing these? I do all the maintenance myself, but I really don't want to rethread these in the block. Also, I'm worried that if I unscrew them again, I'll eventually wear them down.

[SquamInboards]

RE: Cross threaded block drain plug

It will probably be difficult given the location of the plugs but the ideal way to fix it is probably boring out the original threads and tapping the new plug hole with the appropriate diameter as to match the next larger size drain plug.

[mf01]

Re: RE: Cross threaded block drain plug

It will probably be difficult given the location of the plugs but the ideal way to fix it is probably boring out the original threads and tapping the new plug hole with the appropriate diameter as to match the next larger size drain plug.

That's the only thing I could think of, but that area would be hard to drill out. I was hoping there would be some other option.

[Red57Bird]

What about installing the Easy Drain kits (http://skidim.com/products.asp?dept=1044)? You can install them once and not have to worry taking them out. This assumes that the threads aren't totally buggered up. In that case, my guess is that you'll have to re-thread.

[mf01]

I tried to install a small pipe from home depot (for a shower), but it wouldn't go due to the threads. I'd have to crank those down and cross thread them in there.

[DanielC]

Pipe threads are tapered. If there is a fair amount of thread showing on the plug when it is in the hole, there is probably enough material to thread straight again. Get a pipe tap, of the right size, and carefully restart the tap straight. The tap at first will want to follow the bad threads, but if you carefully hold the tap straight, it will find the old straight threads, and go into them. Turn the tap a turn at a time, remove it, and try the plug. Do this until the plug goes in straight, but if you do this too many times, the plug will bottom in the hole, and you will need get the next bigger pipe plug size.