info(at)flylightning.net
Guest
|
 Posted: Fri Aug 19, 2011 2:31 pm Post subject: Trobleshooting a temperature reading. |
 |
|
Recently during some flight testing I noticed an odd reading on the EIS of one of our LS-1s. About 30 minutes into my flight the oil temperature had gone to 350 and stayed there.
I do check it regularly during flight testing so I knew it hadn’t slowly gone up as if there was a problem. Also my oil pressure was right around 50 psi so it must be an error.
With the sending unit disconnected the EIS from GRT will read 59 and will never come up, so if its 80 out and your oil temp is 59 when you climb in to start the wire is probably disconnected.
IF the wire should wear thru and ground out on the engine block it will go to the other end of the spectrum. Mainly because the probes work thru resistance and than give and indication.
So in this case my oil temp probe must have been seeing different resistance hence the higher temp. Sure enough the wire had been rubbing on the bottom of the last cly head and worn straight thru to the wire.
Cut the wire out and installed a new one and problem solved, oil temp around 210 after a WOT climb to 5.5k and than 185 after 15 minutes of cruising around, not bad for a new motor.
So I guess the lesson learned is look at your indication and cross check other things in that system, had the oil pressure been 0 or really low I would have suspected a serious problem. Since it wasn’t I simply landed normally and went to looking at the probe.
On to a different probe for fun is the oil pressure unit on the front of the 3300. This is a VDO unit which will sometimes have two lugs. One says G for Gauge, the other W for work or in normal speak a Hobbs.
If you are hooked up to the W the EIS will read 76psi, if it is simply disconnected 0. Have had this hooked up wrong on a few occasions to find a 80psi reading on a first start.
If the unit should go bad during flight, it will usually start reading high than eventually read 76 all the time. Should it go the other way you have a problem.
I guess the short story of the oil pressure probe is that if it is connected wrong or goes bad it will normally always go high. IF it goes the other way you probably have a problem.
Thanks for reading.
Nick Otterback
Arion Aircraft LLC
[quote][b]
| | - The Matronics Lightning-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
http://www.matronics.com/Navigator?Lightning-List |
|
|
|
Get Email Distribution Too!
FAQ
Search
Memberlist
Usergroups
Register
Profile
Log in to check your private messages
Log in
