Threaded plugs in Mg cases

[neilca]

I had someone email me about threading the plugs in the case halves. He need to remove the plugs to do a proper cleaning. I had done this to my fist race engine and leaned some lessons. First not all plugs are easily threaded due to design of the engine.





To clean the main galley I would remove, destroy, the rear galley plug. Then take a drift to knock out the front plug. Thread the aft plug and reinstall the front plug and epoxy in place.



The oil relief is best cleaned by removing the oil sending unit and the lower relief valve. This gives you good access and you don't have to remove any plugs. To clean out the side oil relief valve you wil need to remove the large plug at the bottom and it is easily theaded with a 1/2 NPT pipe tap. No drilling needed.



Here is the piston behind the lower plug. As you can see I had to use a lot of sealer and extra work to get this to seal and not hit the piston. Just leave this plug alone.

[KTL]

Thanks for the detailed images and your experiences Neil. I had looked at the passages and also thought there are a few that can be left in place because they can be cleaned/accessed by the pressure relief caps nearby.

That lower, vertical piston is a tricky one. Be the intersecting bore threaded or not, it seems like that piston could be hung up a bit by the edge of the intersecting bore. Looks like it'd be wise to make sure there's no sharp edge on that intersection?

The pictures are very helpful for people to see that the plugs have to be not too long, or inserted too deep, to avoid interfering with the piston.