Sump plug thread

shropshire lad · Post by **shropshire lad** » Thu Apr 03, 2008 8:21 pm

I have almost completed my part re-build and rewire of a 54 gls. During an oil change I noticed that sump plug (g/box side) was loose. I tried to tighten but found that the plug thread was stripped. The plug was held in with plumbers tape,so can anyone tell if a helicoil insert is possible without the drilling and what is the plug next to it for.

Cheers

Alan

Biscuit · Post by **Biscuit** » Thu Apr 03, 2008 10:05 pm

There is only one plug in the bottom of the crankcase, so what you have god knows. Helicoiling without drilling is not possible. You can, apparently, do the job in situ with grease on the drill to catch the bits, but I believe the only way is a complete strip down.

Don Madden · Post by **Don Madden** » Fri Apr 04, 2008 2:41 am

What kind of plug? Short stroke & later cases have a grub screw blocking a drillway for the oiling system. Do you have the original 1954 cases?
Cheers, Don.

pto · Post by **pto** » Fri Apr 04, 2008 3:06 pm

Helicoiling without drilling may be possible if all traces of the old thread is missing ( completley stripped) metal from the helicoil tap can get into the engine so cover the tap with grease, take your time and keep it straight!

Don Madden · Post by **Don Madden** » Fri Apr 04, 2008 5:40 pm

In the US, most auto parts stores carry a variety of self-tapping repair drain plugs. I have seen them in expandable rubber also. Perhaps you can find one of suitable size.

And a problem with the earlier cases is the lack of clearance from the drain plug to the crankshaft chamber above, which limits how long the tap can be run up.

When the magnetic filter, which is longer than the old plug, was introduced, they relocated the drain to allow more clearance.

Cheers, Don.

poplargreg · Post by **poplargreg** » Fri Apr 04, 2008 5:54 pm

There might be a (very small) market for a miniature version of the expanding plug used to block soil pipes when testing for leaks. It is a 4" (depending on pipe diameter) rubber doughnut with a steel washer top and bottom and a through bolt and nut.

When the nut is tightened, the doughnut expands and seals the pipe.

shropshire lad · Post by **shropshire lad** » Fri Apr 04, 2008 8:21 pm

Thanks for the info. The introduction of the magnetic drain plug explains why I have 2 fitted - thanks Don. What to do next.....hmmm.

Alan

Don Madden · Post by **Don Madden** » Sat Apr 05, 2008 3:57 am

If it were mine, I would first try to locate a self-tapping repair plug & plan to install a helicoil on the next stripdown. Be wary of plumbing type plugs as the rubber may not be oil resistant.

The original drain plug was fitted in a thick region of the case & if a second was drilled elsewhere the metal may not be thick enough to hold a plug securely.

Helicoils are a standard practice of experts to repair such damage but I prefer the work with bare cases as these engines have a primitive filter.

Cheers, Don.

shropshire lad · Post by **shropshire lad** » Sat Apr 05, 2008 4:53 pm

Thanks for the info Don. I think a temporary self tapping bung is the answer.

Cheers, Alan

Locust · Post by **Locust** » Sat Apr 05, 2008 6:01 pm

Alan
What size is the thread on the drain plug.???
It is sometimes possible to tap it out to a gas thread and put a gas plug in as a temporary measure untill you have a major strip down.
Graham