Wet vs Dry Vacuum Pump

[Fastglasair]

I am curious of opinions out there. I currently have a wet Vacuum pump on my
Glasair I-RG. I am considering adding an M-20 vacuum pump oil separator just
for the vacuum pump since I also have a Christen inverted oil system separator
which takes care of the Crankcase breather. I am also considering changing to a
dry vacuum pump. I am tired of loosing a quart every 4-5 hours and oil mess on
the belly. What should I do? I do plan to use the plane for some hard IFR, I
will be working on getting my instrument rating this winter. Will the M-20
catch 90% or what percentage. Anyone out there using this M-20 model 600WP unit
for vacuum? at $360.00 I don't want to be disappointed.

[[email protected]]

If you already have a wet pump (robust vanes, 2000 hr life?), I can't
imagine why you want to switch to a dry pump with average MTBF of 400
hours. I don't know how good the M20 is - Airwolf is another separator
that appears to have a little more robust design, but probably either
will work.

[[email protected]]

If you already have a wet pump (robust vanes, 2000 hr life?), I can't
imagine why you want to switch to a dry pump with average MTBF of 400
hours. I don't know how good the M20 is - Airwolf is another separator
that appears to have a little more robust design, but probably either
will work.

[Colin W Kingsbury]

"Fastglasair" > wrote in message
...
>
> I am curious of opinions out there. I currently have a wet Vacuum pump on
my
....
> the belly. What should I do? I do plan to use the plane for some hard IFR,
I

Keep the wet pump. If you fly real IFR you need to replace dry pumps every
500 hours. There's a lot of us out here with dry pumps who'd rather have
wet.

-cwk.

[Chuck]

On Thu, 16 Dec 2004 04:41:59 GMT, "Colin W Kingsbury"
> wrote:

>"Fastglasair" > wrote in message
...
>>
>> I am curious of opinions out there. I currently have a wet Vacuum pump on
>my
>...
>> the belly. What should I do? I do plan to use the plane for some hard IFR,
>I
>
>Keep the wet pump. If you fly real IFR you need to replace dry pumps every
>500 hours. There's a lot of us out here with dry pumps who'd rather have
>wet.
>
>-cwk.

Got that right, I'd rather have a wet pump. Lets see - longer life,
fewer $ for replacements, more reliable... What's not to like? Some
oil on your belly?

Oh, but don't think that a dry pump will keep your belly clean. It
gets oily etiher way. Stick with the longer-life, more-reliable wet
pump and put in a seperator to catch more oil.

Good luck.



Chuck
N7398W



P.S. -- Lotsa planes loose a quart every 4 to 5 hours, even WITH a dry
pump!!! You should see what some of the training planes at a local
school eat up. What's the old joke about "Fill the oil and check the
gas"

[[email protected]]

The commentators so far are referring to the excellent advantages of
the wet
pump for IFR.

Far as I know, none of the separators work very well with negative Gs.
I have
a wet pump and the Walker (airwolf now) and if I do a 0 G parabaloa, I
get oil all over the belly.

If you are doing both acro and ifr, the dry pump might be better.
Bill Hale Loveland CO

[Doug]

One thing about oil seperators. They collect water. Water freezes. Then
they don't let the crankcase breathe at all. This is for some
installations, some are in a warm spot. Depends. Keep an eye on it.

[Helen Woods]

From what I understand, not only does the wet pump last MUCH longer,
but when it dies, it dies gradually rather than going belly up while you
are in a cloud, on an NDB approach, one very dark night. I fly hard IFR
and would never give up my wet pump.

Helen