Clive J
Joined: 03 Nov 2007
Posts: 340
Location: UK
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 Posted: Mon Sep 19, 2011 7:18 am Post subject: Oil pressure videos |
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You may have seen other postings I have made regarding the pressure within a Jabiru engine oil system.
I feel those of us with engines which have pressure pulsing created by the relief valve have an opportunity to improve the situation.
I believe the pressure pulses are responsible for many of the cooler failures that have been experienced around the world.
Pulsing with hydraulic systems can spoil flow and create back pressure and fatigue.
I am working on an alternate shape to the relief valve tip which will, I hope, eliminate the pulsing.
When I have done this successfully I will share the design with everyone.
I have been in touch with Jabiru and suggested it was worth looking into but as yet have had no indication they feel it is an issue, their suggestion seemed to point to an issue with coolers only.
Below is listed the videos.
Late 2200 with hydraulic tappets:
http://www.youtube.com/watch?v=Kf5FUScRSIM
Early 2200 solid lifter, serial number 596
http://www.youtube.com/watch?v=oWI3I5iOq8k
Early 2200 solid lifter no 2, 700 series
http://www.youtube.com/watch?v=c_5or47YxcY
Mid 2200 solid lifter no 2, 1300 series
http://www.youtube.com/watch?v=a6mVuaWk4Ao
3300 solid lifters Serial number 828, the oil cooler on this engine has distorted.
http://www.youtube.com/watch?v=k6LgiSakBSk
3300 with Hydraulic lifters serial number 1460
http://www.youtube.com/watch?v=q_TCQtrfUHc
3300 with Hydraulic lifter with relief valve plug shaped to a point, engine 1460 again, compare this to the previous video, look at the sweep of the valve needle.
http://www.youtube.com/watch?v=bnRlyl20HaY
See here for still photos of the valve tip, this was simply done with the valve in a drill chuck and a needle file.
http://groups.yahoo.com/group/jabiruengines/photos/album/439839736/pic/list
A couple at attached for the Matronics listers.
<<pointed relief valve plug.jpg>> <<standard shape relief valve plug.jpg>>
If anyone is curious about their engine the gauge is an 1/8 npt, 10 bar – 160 psi and you can see how quick and simple the test is. It would be good to find when the pulsing started.
It doesn’t seem to be there up to late 700 2200 engines. But is there by mid 1300s. I’ve only had access to 6 engines since I started looking into this.
When engine is running the pulsing is still there but the gauge is hard to read as the needle is a complete blur. That is why I did these tests with engines cranking.
The pulse on my 3300 is a drop of 20 psi where the valve lifts and then it re-seats allowing the pressure to build again. I could see this when turning the prop by hand.
Regards, Clive
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