Today's Message Index:
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1. 02:40 PM - New rocker arm bushings in (Lynn Matteson)
2. 03:06 PM - Re: New rocker arm bushings in (Kayberg@aol.com)
3. 04:22 PM - Re: New rocker arm bushings in (Lynn Matteson)
4. 06:32 PM - Re: New rocker arm bushings in (Don Morrisey)
Message 1
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| Subject: | New rocker arm bushings in |
So far so good on the new rocker arm bushings in my 2200. I installed
them yesterday, but was finishing up building an oil cooler tunnel,
so I wasn't able to fly it until today. I'd like to report gobs of
new horsepower, but this isn't the case...just back to the normal,
smooth operation. Gonna check the wear and the valve clearance in
15-20 hours, to see if I can find any changes, before I take it
across the country at the end of the month.
Lynn Matteson
Grass Lake, Michigan
Kitfox IV Speedster w/Jabiru 2200
flying w/275+ hrs
Message 2
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| Subject: | Re: New rocker arm bushings in |
In a message dated 5/11/2007 5:41:05 PM Eastern Daylight Time,
lynnmatt@jps.net writes:
So far so good on the new rocker arm bushings in my 2200. I installed
them yesterday, but was finishing up building an oil cooler tunnel,
so I wasn't able to fly it until today. I'd like to report gobs of
new horsepower, but this isn't the case...just back to the normal,
smooth operation. Gonna check the wear and the valve clearance in
15-20 hours, to see if I can find any changes, before I take it
across the country at the end of the month.
Was there much of a difference between the old bushings and the new ones?
Doug Koenigsberg
************************************** See what's free at http://www.aol.com.
Message 3
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| Subject: | Re: New rocker arm bushings in |
Well, the old bushings were a teflon-coated bronze over a steel shell
(TPFE, I believe they are known as) and for whatever reason, they
failed at...or at least I discovered them failed at...273 hours. I
decided not to replace them with the original style bushings, because
I don't know the history of how these bushings hold up under the
splash-lubricated, high-pressure (the valve spring), environment they
operate in. Now to be perfectly honest, maybe nobody else has had a
problem with these bushings, but I did, so I elected to try my own
"shade-tree engineering" and put in oilite bronze bushings. In doing
so, I decided to supplement the oil that ordinarily makes its way
into the side of the standard bushings. The standard bushings are
allowed (according to my owners manual) .004"-.010" side clearance. I
did not change this, but I did drill a .093" hole vertically into the
rocker arm, at exactly the 12 o'clock position of the rocker arm.
This will allow the oil a chance to run into the hole and help lube
the bushing.
If anybody cares, I'll continue to report how I installed the
bushings. They came 16mm wide and the rocker arm is 15mm, so I
shortened them on my lathe. I had pressed the old bushings out, and
after drilling the rocker arms for the oiling holes, I drilled the
bushing oil holes a little larger, then pressed them into place,
keeping the alignment of the holes in mind. They all came out aligned
as hoped, and then I had to ream the bushings to the size suggested
in the owners manual... .474"-.475". This provides for 2-3
thousandths oil clearance for the .472" shaft. I then swapped the
rocker shafts side-for-side, to enable the new bushings to ride on
the un-used part of the shaft. I also chamfered the sides of the new
bushings to further allow oil to make its way into the oil space
provided between the shaft and arm.
I've got to further say that I don't know squat about teflon in
engine bearings...my only use of teflon (that I know of) is frying
eggs in a pan....low (relative) heat, no pressure, and the eggs taste
fine. I wouldn't have eaten eggs cooked on the teflon that was
visible inside the removed bushings...they looked like the frypan had
been attacked with a steel spatula, if you'll permit me the kitchen
analogy. : )
Again, I'm not saying that Jabiru made a mistake, maybe I just got a
lemon, and if my "fix" doesn't work out, I will have no apologies to
make. My engine is in a Kitfox Model IV *experimental* airplane, and
that's JUST what I'm doing...experimenting.
Lynn Matteson
Grass Lake, Michigan
Kitfox IV Speedster w/Jabiru 2200
flying w/275+ hrs
do not archive
On May 11, 2007, at 6:06 PM, Kayberg@aol.com wrote:
> In a message dated 5/11/2007 5:41:05 PM Eastern Daylight Time,
> lynnmatt@jps.net writes:
>
> So far so good on the new rocker arm bushings in my 2200. I installed
> them yesterday, but was finishing up building an oil cooler tunnel,
> so I wasn't able to fly it until today. I'd like to report gobs of
> new horsepower, but this isn't the case...just back to the normal,
> smooth operation. Gonna check the wear and the valve clearance in
> 15-20 hours, to see if I can find any changes, before I take it
> across the country at the end of the month.
>
>
> Was there much of a difference between the old bushings and the new
> ones?
>
>
> Doug Koenigsberg
>
>
> See what's free at AOL.com.
> http://www.matronics.com/Navigator?JabiruEngine-List _-
> ===========================================================
Message 4
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| Subject: | New rocker arm bushings in |
Lynn, excellent series of reports. Concise and well thought out. I'm not a
gearhead and I could follow.
Thanks, Don www.donsbushcaddy.comDon Morrisey's Skunkworks
> From: lynnmatt@jps.net> Subject: Re: JabiruEngine-List: New rocker arm bu
shings in> Date: Fri, 11 May 2007 19:25:17 -0400> To: jabiruengine-list@mat
att@jps.net>> > Well, the old bushings were a teflon-coated bronze over a s
teel shell > (TPFE, I believe they are known as) and for whatever reason, t
hey > failed at...or at least I discovered them failed at...273 hours. I >
decided not to replace them with the original style bushings, because > I d
on't know the history of how these bushings hold up under the > splash-lubr
icated, high-pressure (the valve spring), environment they > operate in. No
w to be perfectly honest, maybe nobody else has had a > problem with these
bushings, but I did, so I elected to try my own > "shade-tree engineering"
and put in oilite bronze bushings. In doing > so, I decided to supplement t
he oil that ordinarily makes its way > into the side of the standard bushin
gs. The standard bushings are > allowed (according to my owners manual) .00
4"-.010" side clearance. I > did not change this, but I did drill a .093" h
ole vertically into the > rocker arm, at exactly the 12 o'clock position of
the rocker arm. > This will allow the oil a chance to run into the hole an
d help lube > the bushing.> > If anybody cares, I'll continue to report how
I installed the > bushings. They came 16mm wide and the rocker arm is 15mm
, so I > shortened them on my lathe. I had pressed the old bushings out, an
d > after drilling the rocker arms for the oiling holes, I drilled the > bu
shing oil holes a little larger, then pressed them into place, > keeping th
e alignment of the holes in mind. They all came out aligned > as hoped, and
then I had to ream the bushings to the size suggested > in the owners manu
al... .474"-.475". This provides for 2-3 > thousandths oil clearance for th
e .472" shaft. I then swapped the > rocker shafts side-for-side, to enable
the new bushings to ride on > the un-used part of the shaft. I also chamfer
ed the sides of the new > bushings to further allow oil to make its way int
o the oil space > provided between the shaft and arm.> > I've got to furthe
r say that I don't know squat about teflon in > engine bearings...my only u
se of teflon (that I know of) is frying > eggs in a pan....low (relative) h
eat, no pressure, and the eggs taste > fine. I wouldn't have eaten eggs coo
ked on the teflon that was > visible inside the removed bushings...they loo
ked like the frypan had > been attacked with a steel spatula, if you'll per
mit me the kitchen > analogy. : )> > Again, I'm not saying that Jabiru made
a mistake, maybe I just got a > lemon, and if my "fix" doesn't work out, I
will have no apologies to > make. My engine is in a Kitfox Model IV *exper
imental* airplane, and > that's JUST what I'm doing...experimenting.> > Lyn
n Matteson> Grass Lake, Michigan> Kitfox IV Speedster w/Jabiru 2200> flying
w/275+ hrs> do not archive> > On May 11, 2007, at 6:06 PM, Kayberg@aol.com
wrote:> > > In a message dated 5/11/2007 5:41:05 PM Eastern Daylight Time,
> > lynnmatt@jps.net writes:> >> > So far so good on the new rocker arm bu
shings in my 2200. I installed> > them yesterday, but was finishing up buil
ding an oil cooler tunnel,> > so I wasn't able to fly it until today. I'd l
ike to report gobs of> > new horsepower, but this isn't the case...just bac
k to the normal,> > smooth operation. Gonna check the wear and the valve cl
earance in> > 15-20 hours, to see if I can find any changes, before I take
it> > across the country at the end of the month.> >> >> > Was there much o
f a difference between the old bushings and the new > > ones?> >> >> >> >>
> Doug Koenigsberg> >> >> >> > See what's free at AOL.com.> > http://www.ma
tronics.com/Navigator?JabiruEngine-List _- > > =========
====================> > >
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