Today's Message Index:
----------------------
1. 12:36 PM - Re: Foaming Oil (Marcus Bates)
Message 1
| INDEX | Back to Main INDEX |
| NEXT | Skip to NEXT Message |
| LIST | Reply to LIST Regarding this Message |
| SENDER | Reply to SENDER Regarding this Message |
|
Jon.....puzzling....I would first try changing the oil to another brand of M
ineral oil. No reason for oil to be foaming, except perhaps air getting int
o the oil tank. Might try routing breather pipe to another location. The s
cavenger pump is to return oil from sump and rocker covers. Unless it is su
cking air, there is no way it should make foam. I will be back in the Austi
n area tomorrow evening. I have a M-14 manual, and will check it. Tried c
alling Jill?
Sent from my iPad
> On Jul 11, 2021, at 1:26 PM, Jon Boede <jonboede@hotmail.com> wrote:
>
> New M-14P, still break-in period. Has been in the air but fighting with hi
gh oil temps.
>
> Previous flight end: 14.5L oil
> (week passes)
> Initial oil check: 10.5L oil
> Today flight end: 13.5L
> Oil is Aeroshell 120 (no W) straight mineral oil for break-in
>
> However... knowing that my oil wasn't really 10.5L because there wasn't +1
gallon of oil in the bucket, I ran the plane for 10 minutes outside the han
gar. Carefully warmed it up to 50C oil temp 100C CHT, oil pressure 6+, not o
ver 7. Cowl on.
>
> At the end of that period there was 16.5L of very aerated oil on the dipst
ick!
>
> Since the pressure was good and the OAT was only 80F I went flying.
>
> On take-off the oil pressure was 6.5 (I'd turned it up the previous weeken
d) and the oil temp was about 50C. T/O was performed at 760 MAP and 2600 rp
m, which was plenty enough power to get airborne.
>
> Two circuits around the pattern and the inlet oil temp got to over 70C and
was rising very, very slowly (i.e. not stable). CHT very reasonable, 150-1
60C at 680mm MAP, 2400 rpm once I levelled off. I flew at pattern altitude t
he whole time.
>
> Oil pressure continued to drop and temperature continued to rise. After t
he next circuit in the pattern, when oil pressure was about 3.7 and temperat
ure about 77C, I landed. Oil pressure on taxi-in was 1 and temp continued t
o be about 80C.
>
> Very aerated oil on stick, "foam" is what I'd call it. Was 16.5L with all
the air in it. Doing the math, that means about 25% of the volume of the a
ir/oil mixture was air.
>
> Brand new oil cooler. Brand new hoses. Oil dilution system has been capp
ed off.
>
> At this point the only non-stock components in the system are: Craig Payne
's oil filter, and a custom hose from Jill (that has a 90-degree swivel fitt
ing on each end).
>
> Any ideas how air is getting mixed into the oil? I'm pretty sure at this p
oint that both the high temp and the pressure drop are due to the air in the
oil but I can't understand how it's getting in there.
>
> Next moves are to bypass the oil filter and to try a different custom oil h
ose.
>
> I'm all ears as to any other ideas.
>
> Jon
>
> PS. My oil overboard tube is cut to face into the wind, but both the othe
r CJs in the hangar are similarly configured. It's not long enough to stick
out below the cowl and I don't think that the prop blast would be enough to
create aeration during the initial run.
Other Matronics Email List Services
These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.
-- Please support this service by making your Contribution today! --
|