Rebuilding engine... question?

[mullethunter3]

Hey guys, starting a engine rebuild here. Just wanted to ask a quick question. My magnet looks like the one pictured here (I stole it from another thread).


My question is:

Should I just clean off the epoxy that's left and leave it or clean off the epoxy that's left and re-epoxy it? I can't imagine that the epoxy on top of the magnets is contributing to much to the strength of the hold... but if I did, what kind of epoxy should I use? Is there a special one for this weird application?

Thanks!

-Amanda

[badguy]

I can't really give a definitive answer on this.  However, if there was enough shock to the rotor that it knocked off those chunks of epoxy, I'd be a little worried about what you aren't seeing.  My rationale is that the epoxy isn't heavy enough to just get knocked off by itself...the magnets probably shifted some and broke free those chunks.  I tend to be overly cautious with stuff like that though.  I had a rotor that looked a little better and ended up replacing it anyway. 

Just my $0.02 since nobody else has replied.

[mullethunter3]

Well, that rotor has 43,000 miles on it, so that's what probably knocked it loose. I have another (bad) crankshaft and (good) rotor, but I cannot get the rotor off of either crank because they are both out of the engine and sitting on my desk.

I'm pretty much forced to use this rotor.

[intergalactic]

Hey guys, starting a engine rebuild here. Just wanted to ask a quick question. My magnet looks like the one pictured here (I stole it from another thread).


My question is:

Should I just clean off the epoxy that's left and leave it or clean off the epoxy that's left and re-epoxy it? I can't imagine that the epoxy on top of the magnets is contributing to much to the strength of the hold... but if I did, what kind of epoxy should I use? Is there a special one for this weird application?

Thanks!

-Amanda

I used to design electric motors and I say it is fine. Any epoxy you buy is probably past it's glass transition temperature in that location anyways.

[badguy]

I used to design electric motors and I say it is fine. Any epoxy you buy is probably past it's glass transition temperature in that location anyways.

Say what?  Seriously, any chance you could explain that?  It sounds like you're saying that any commercially available epoxy will melt inside an engine at operating temperature...correct?  Either way, I'll defer to your experience on this one 



Amanda - why would having the crankshaft out of the engine make it harder to pull the rotor?  If you could clamp the crank in a bench vise it might not be that hard.  I guess it's a moot point anyway based on intergalactic's advice    Good luck with the rebuild 

[mullethunter3]

I don't have a bench clamp. I'm in college right now so I'm working with limited tools.

I think I'll just clean it up and use it. Thanks for your advice guys!

[gregvhen]

mullethunter, you in st. louis?