crankcase oil gallery plugs

[riorex2002]

on cleaning out my crankcase oil gallery passages i have removed the alloy end plugs and intended to replace them with the aftermarket screw plugs but on closer lnspection i find that some of the interconnecting passages run very near the end of the plugs.This precludes the use of any plug longer than its diameter from being used in those locations as this would tend to partially block the connecting oil gallery ,plus if i use a short plug i would not have enough of a taper to be safe.
i guess i will end up replacing these plug with standard plugs but relying on interference plugs in a major oil gallery does not give me a warm feeling.Does any one in this group have any thoughts or ideas on this situation
Rex

[Dan_]

 find that some of the interconnecting passages run very near the end of the plugs.This precludes the use of any plug longer than its diameter from being used in those locations as this would tend to partially block the connecting oil gallery ,plus if i use a short plug i would not have enough of a taper to be safe. i guess i will end up replacing these plug with standard plugs but relying on interference plugs in a major oil gallery does not give me a warm feeling.

Bob Hoover of Air VW fame urges threaded plugs.


If you don't have enough of a boss for threads, you may have a case that had to be machined with a setup outside the standard deviation.  You may want to find another case.

Pipe threads taper, and extreme care has to be exercised when tapping them or the plug will go too deep.

I think we had a member from TX that blew a plug... Maybe he will have a comment on it.

Which plug exactly are you talking about..?

[Will Weidner]

I don't have my case here at the moment (it's out being machined), so I don't know about the location that has the interconnecting passageway close to the outer surface.  I was wondering if you could tap it as deep as necessary to seat the plug.  Then screw the plug home, make a reference mark on it and the case, then remove it.  Now you can go at the plug with a Dremel tool or whatever, and groove it in such a way as to re-establish the interconnecting oil passageway.  Then you can re-install the plug, lining up the reference marks.  If you're concerned about it not being tight enough because you drove it home twice, you can stake it.  You might want some lubricant on it when you tighten it the first time, then whatever sealing compound you use the second time.

[riorex2002]

the boss i am looking at is the second boss after the pump outlet,and yes Will,your method is one good option.After reading that Bob Hoover recommended it ,i will pursue threading it.Just one more thing to watch out for.When i get out to my hangar again i will look to see if there is a straight shot from the inside of the case that i can use to drill it clear after installing the plug.The depth you tap too is critical in this instance as the sealant that is used on final installation will have a bearing on the final depth that the plug will stop.There is not much meat round these bosses and i can foresee cracking it if its to tight

[Will Weidner]

If you have a straight shot that would be ideal.  Might need a long drill.  A drill stop might be a good idea too.