I’ve had the semi normal, stuck oil galley plug (along the side of the pan rail). I went the easy out route, then the drill it out method. I got it out with stepping up the drill size little by little. I got into the threads, just enough in the 7 o’clock position, to barely see where the thread are, for only about 3 threads. I have ran one of the other good plugs in, and it tightens up, like I think it should. My question is: Do I leave it and use thread sealant? Do I drill it out and tap it one size bigger? Which I think would be 1/4” NPT? Or have the machine shop do it? It’s going there to be cleaned, new cam bearings and the rotating ***embly balances. My fear is, is that tapping it bigger could crack the block. I know that may seem like a low percentage odd, but I have heard of the galley bosses on the rest cracking, which has my concern up. Any advice is greatly appreciated.
early blocks used 1/4" plugs. I'd just use sealer on it and run it...but you might also see if tapping it just a little deeper might clean it up? you could also try one of the fancy newer sealers that folks talk about on the brake fitting threads. a couple blocks I have on stands.
You should use sealant anyways. Not sure how much meat is there, but you could use a welsh plug (after drilling to the proper size) like SBCs have been using in the front of the galley’s for a long time. Edit, just noticed you said pan rail, I was thinking on top of the block
I'd use sealer, and tighten them up. If you do try to clean the hole with tap, be careful, just chase it, don't try to cut more threads. Did that once on the coolant drain on side of SBF, made it to big that the plug wouldn't fit anymore(well), and had to drill and tap to next size NPT.
I’m glad you said chasing, I was going to run my regular NPT tap in just to clean up the threads. In these pictures you can see the damaged threads and how far one of the plugs that came out clean goes in, I tightened it fairly decent to see. With that being said, I think, unless everyone says I’m wrong, with sealant and the plug being able to tightened that far, I maybe just fine? Thoughts?
I'd run a tap in it one turn past snug, then see how the plug fits...sneak up on it, take out a tiny bit of metal, check the fit a couple times, etc. try to get it flush, but no further.
Yup, tap in, just enough to make sure that every single thread is shiney clean. Make sure your plug is super-clean too. Apply a good sealer. We used Loc***e 545 on all fittings at my company. Remember, this only has to hold back at maximum pump pressure, and at maximum operating temperature, so no need to put the plug in gorilla-tight, just monkey-tight.
Like the guys said,,,,,sneak up on it . The pipe tap is a taper thread,,,it gets tighter as you go . I do believe it is a good idea to get it done before the machine shop cleaning,,,to get any grit out of the oil p***age. This is an easy fix,,,,don’t sweat it,,,,you’ll do fine . Tommy
Thanks guys from the replies, I feel better about it! I'll follow everyone's advice for sure! I'll ordering Loc***e 545 tomorrow, just so it's here when stuff comes back from the machine shop. Thanks again!
You might want to add a br*** radiator pet**** (drain plug) instead of a plug in there... Makes it easier to drain the block when changing antifreeze....
I do have one other question, as I roll this guy over to start taking out the plugs on the opposite side. What advice does everyone have for trying to take the remaining ones out to avoid having to have to (I read that last part 4 times to make sure it makes sense) drill them out. I know it may be hard to avoid at a certain point, but I just want to make sure I’m do all I can to keep from it.
I never removed the particular plugs you are working on but I have used a lit candle and dripped hot wax on the threads of the plugs for the lifter galleries in SBC’s. The wax will wick into the threads and lube them enough to ease removal.
What I learned working at the machine shop....heat the plug red with a torch, put a few drops of oil on the threads, smack the plug with a hammer, and use the CORRECT properly fitting tool to unscrew the plug. If it feels like it's gonna strip at the first attempt, let it cool, then repeat as necessary. It will come out eventually.
I thought about using heat, but would you want to get the block hot like that? Even with a small torch tip, seems like the block would absorb a lot of heat?
It doesn't cause problems. Heat the plug just long enough to get it red. You'll see the block itself transfers heat away from the plug quickly, and does not stay very hot in one place. OTOH, you could just leave the plugs in and let the machine shop remove them.
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