My 6-71 Blower rebuild, Part 6: Cleaning metal chips from inside rotors.

[@shawnramsay1851]

I always thought you were over doing the chip removal but after doing this a few times I see why you are so vigorous!!! Those chips just keep coming.......

[@MakerCave]

Yeah, they are stubborn little buggers. There are lots of places for them to hide inside the extrusion of the rotors, so it takes a while to get them all out. My vacuum attachment was just something I decided to do for convenience, so I wasn't dropping shavings everywhere, and so I knew that as soon as I got something floating around inside the rotor, it would head out the vacuum hose!

[@jefftaylor7511]

Good videos. Good camera and explanations. Thanks!

[@shawnramsay1851]

Not only did I need to shorten the plug but lighten it as well. I weighed the factory plug at 6.0 grams ,the new plugs I purchased from Papco were thicker and longer weighing in at 10.8 and only lightening up to 9.5 grams when made the same length. I had too use my bench style belt sander and take some off the back as well as bore the plug slightly to hit 6.5 and thought that was close enough? talk about time consuming!!! Lol what brand of plugs did you use?

[@MakerCave]

I think that I got them from a local NAPA. I will check my records when I get back home tonite to see what I used, and reply back here.

[@johnhartley5071]

Out of curiosity, why gasket sealer... Which I assume is like amber tack or whatever permatex calls it, that stringy sticky red stuff... instead of loctite? Interesting videos though. I'm thinking about building myself a 671 blower for a 55 Chevy with a small block. Should be WAY cheaper than buying one from like Dyers or BDS... And you don't get that ugly billet stuff with their logo on it.

[@MakerCave]

You know, I don't know if any sealer is even necessary, as it looks like the factory just drives the plugs in dry. I used sealer as a hedge against any liquid fuel possibly migrating inside the rotor casting. Yes, I think that Loctite red would be fine as well. It would certainly hold the plug in place well, and provide some sealing to boot. I looked at the rotors of a small bore 6-71 that I have lying around, and those plugs are actually staked in place from the factory, with small punch marks, like from a flat chisel. I might actually do that when I rebuild that one for my "spare" blower next winter, that is stake the plugs back in then take a very light cut on the lathe to remove the upset material on the end of the rotor after staking. If any Professional blower builders chime in here, they may offer up an alternate method of sealing/retaining plugs :)

[@shawnramsay1851]

@@MakerCave no professional here but i was contemplating removing all plugs then replacing with teflon machined plugs?

[@MakerCave]

Teflon is one of my favorite plastics, but it has no "memory". If you dent, or deform it, it does not spring back. Although it is very slippery, it probably wouldn't keep a reliable press fit in this application. Also, to keep those rotors balanced at high RPM's, you don't want loose plugs jiggling around inside there. The cup plugs may not be an elegant solution, but they are perfectly adequate (and reliable) in this application. Thanks for watching!

[@shawnramsay1851]

@@MakerCave This idea was from professional blower builders not mine. Unsure what exact material they use though?

[@MakerCave]

@@shawnramsay1851 Well, some race blowers are also stripped with Nylatron at the rotor edges, so clearly this material survives the normal operating environment, inside a race blower. If I remember correctly, Nylatron is impregnated with Molybdenum Disulfide which makes it very slippery. There are different grades of Nylatron, but I recall that some are good to around 300 degrees F. Also, I have a bunch of 5/8" thick Gray Nylatron that I have machined in the past, and it seems to machine nicely, and not as gummy as regular Nylon. It feels harder, so Nylatron would probably work as a plug. If you have any race customers that turn lots of RPM's and high boost, it would be easy enough to try, and then do a teardown inspection after a few races, or the entire season. If the plug would become loose, it shouldn't be able to damage the end plate because of the MoS2 impregnated in the plastic.