Eaton rattle/tick?

[exdeath]

Making a new thread to follow up on:

http://www.svtperformance.com/forums/engine-tuning-214/647034-supercharger-pulley-cage-assembly.html

after isolating the noise to the blower and not the pulley cage.

Further research on "eaton" + "tick" or "rattle" reveals that it's a common problem with the Eatons, a plastic coupler disk that connects the drive snout to the driven rotor. I've not seen anything on SVTP about this, but the 3800 M90 guys seem to know all about it.

That would explain why it's so quiet and why I was unable to locate the noise source for so long or blame it on the supercharger at first.

This coupler is "floated" in the middle of the front housing between the driving and driven hubs and isn't touching the rotor or snout case at all. This is why it was so hard to find it all this time with a stethoscope even though the noise was right under my nose the whole time driving me nuts. Nor is it bolted or positively fastened, it's merely floating and held tight in the space between the two hubs by the pressure of the snout bolts.

Here is a good article describing and illustrating the elusive rattling/ticking sound emanating from an Eaton at low RPM which is otherwise in perfect condition and working fine:

How to replace an M90 snout coupler without removing the entire blower

 

[mu22stang]

Mine's always had a nice rattle to it, and I've read about this issue with the coupler. Thanks for posting that write-up. Is this just a piece that typically wears? If so, what's the expected life once the wear/rattling begins?

 

[Posi]

If you need to order a replacement get it from zzperformance.com

 

[exdeath]

Took a video, youtube squished it but oh well.

[ame="http://www.youtube.com/watch?v=nrR59hhM1Rk"]YouTube - Eaton M112 noise source[/ame]

Only rotational backlash at low speeds. Other than that, no end play, no bearing or gear noise when turning with constant force applied, nothing else, just backlash when starting/stopping.

Coupler confirmed? Any Eaton experts care to chime in?

The fact that it only makes the rattle noise at low RPM cruise or idle, especially coasting, when the speed of the drive system isn't enough to keep constant force on it, that it would slop around and make noise.

It's not a loud knocking like that while running through, it's a very faint rattle that almost sounds like a distant erratic inconsistent cricket.

 

[Posi]

Quite honestly if you can't feel any backlash at all it's probably fine. Take the tb/plenum off and literally hold the rotors a little (with the car off! sorry had to say it) and then move the pulley back and forth. See if you can't feel any backlash then from side to side.

 

[exdeath]

Quite honestly if you can't feel any backlash at all it's probably fine. Take the tb/plenum off and literally hold the rotors a little (with the car off! sorry had to say it) and then move the pulley back and forth. See if you can't feel any backlash then from side to side.

*confused* I just said backlash at low speeds without constant force IS all there is. See above ;-)

I know what I have to do and all, I'm 99.99% positive it's the coupler. There is no inertia on the pulley yet when I'm making the noise in the video.

I just thought I would document this and generate discussion, due to it being quite elusive to track down a slight but irritating noise, in hopes that others can benefit. If only for the fact that all my problems I inquire about on SVTP seem to be unique and not previously covered or well documented. Now it will be for the next person.

 

[dynobobstieg]

It is common for the coupler to go bad in the M90's, not so common for the M112 Eaton's.
They are fairly inexpensive to replace if needed.
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[Posi]

*confused* I just said backlash at low speeds without constant force IS all there is. See above ;-)

I know what I have to do and all, I'm 99.99% positive it's the coupler. There is no inertia on the pulley yet when I'm making the noise in the video.

I just thought I would document this and generate discussion, due to it being quite elusive to track down a slight but irritating noise, in hopes that others can benefit. If only for the fact that all my problems I inquire about on SVTP seem to be unique and not previously covered or well documented. Now it will be for the next person.

That's what the forums are for.:beer: Let us know if you end up taking it apart and what you find.

I'm in injection molding and I could easily make a mold myself to make that part. Sell it a lot cheaper too. Hmm......

 

[exdeath]

Take the tb/plenum off and literally hold the rotors a little (with the car off! sorry had to say it) and then move the pulley back and forth.

:lol::lol::lol::beer: