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  #1  
Old 05-15-2018, 11:21 AM
tullow tullow is offline
 
Join Date: Nov 2007
Location: Paris ( France )
Posts: 38
Default Oil pressure/temperature problem

Hi all,
I recently discovered a small crack in the crankcase of my IO360 A1A which was seeping oil. So I removed the engine and did a complete disassembly and rebuild with a new crankcase. The only other work entailed grinding the valves and cleaning the pistons and cylinder heads of the carbon that had built up. Now the engine starts and runs perfectly as it always has done BUT and it's a big but, the oil pressure and temperature are way off the normal figures that I had become used to i.e. - 55psi/ 220? instead of the previous 75 psi/ 175?. in cruise at 2000ft OAT 15?c/60?f at 140 kts.
I have changed nothing on the baffles or oil cooler installation.
I have added the maximum permitted number of washers to the oil pressure relief valve to try to bring the pressure up to normal. I checked the Vanatherm valve in boiling water and it "opens" by 0,165 in.(Is that enough?) So apart from an oil cooler that has suddenly become clogged (and why would that happen?) I'm running out of ideas.
Any information or ideas would be very much appreciated.
Mike
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  #2  
Old 05-15-2018, 11:47 AM
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FasGlas FasGlas is online now
 
Join Date: Mar 2014
Location: Prescott, AZ
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Hmm, maybe you should take a look at the sensors and ground wiring just to make sure you're getting an accurate reading. When you R&R an engine you remove wires and grounds, just make sure they are all back where they belong.
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  #3  
Old 05-15-2018, 12:40 PM
cajunwings cajunwings is online now
 
Join Date: Jun 2007
Location: new iberia la
Posts: 768
Default Oil Pressure

I always try to ?T? in a mechanical direct reading gauge to the existing system and compare readings simultaneously.

Don Broussard
RV9 Rebuild in Progress
57 Pacer
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  #4  
Old 05-15-2018, 12:55 PM
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DanH DanH is offline
 
Join Date: Oct 2005
Location: 08A
Posts: 9,500
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Quote:
Originally Posted by tullow View Post
I checked the Vanatherm valve in boiling water and it "opens" by 0,165 in.(Is that enough?)
Per the Rosta drawing, 0.160" between 150F and 185F.
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RV-8 SS
Barrett IO-390
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  #5  
Old 05-15-2018, 05:59 PM
alpinelakespilot2000 alpinelakespilot2000 is offline
 
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Posts: 3,646
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Quote:
Originally Posted by DanH View Post
Per the Rosta drawing, 0.160" between 150F and 185F.
Dan, could you point me to this drawing just for my reference? Thanks!
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Ellensburg WA
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  #6  
Old 05-16-2018, 05:59 AM
mahlon_r mahlon_r is offline
 
Join Date: Jan 2005
Posts: 1,025
Default

Did you check Main bearing clearance? Also are you sure you installed all three 1/8 pipe plugs on the rear face of the case?
Good Luck,

Mahlon
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  #7  
Old 05-16-2018, 06:29 AM
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DanH DanH is offline
 
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Quote:
Originally Posted by alpinelakespilot2000 View Post
Dan, could you point me to this drawing just for my reference? Thanks!
I have to ask you to contact Rostra Vernatherm directly:

https://www.vernatherm.com/

BTW, there's a page here everyone should see...the core of our units:

https://www.vernatherm.com/thermal_actuators.html
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Dan Horton
RV-8 SS
Barrett IO-390
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  #8  
Old 05-16-2018, 06:36 AM
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rv8ch rv8ch is online now
 
Join Date: Feb 2005
Location: LSGY
Posts: 3,201
Default THERMAL ACTUATORS (WAX MOTORS)

Quote:
Originally Posted by DanH View Post
...
BTW, there's a page here everyone should see...the core of our units:

https://www.vernatherm.com/thermal_actuators.html
I never would have guessed! Thanks for sharing this, amazing information!

Quote:
A wax motor (thermal actuator) is a linear actuator that converts thermal energy into mechanical by exploiting the phase-change behavior of waxes.
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http://rv8.ch
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  #9  
Old 05-16-2018, 07:26 AM
lr172 lr172 is online now
 
Join Date: Oct 2013
Location: Schaumburg, IL
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Quote:
Originally Posted by mahlon_r View Post
Did you check Main bearing clearance? Also are you sure you installed all three 1/8 pipe plugs on the rear face of the case?
Good Luck,

Mahlon
+1
Something in the oil circuit is flowing more oil than designed is the most likely cause of the low oil pressure. I would inspect the mating surface for relief ball. Make sure there are no nicks or gouges. Did you re-use your relief spring? If not, make sure it is correct. After that excessive bearing clearance is the next likely suspect followed by an opening somewhere in the circuit.

Larry
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  #10  
Old 05-16-2018, 08:02 AM
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FasGlas FasGlas is online now
 
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Does your oil pressure start out low or does it drop from the suspected high oil temps? Low oil pressure running at normal oil temps (~ 185F) would be a separate problem then low oil pressure when the oil gets very hot (ie: 220F). Perhaps you need to separate your two issues to see if they are not related or connected. Very high oil pressure can increase oil temps but this is not your issue. Loose clearances will lower pressure but not increase temps, tight clearances will increase temps but will also increase pressure. I agree that you should check these readings against other instruments just to be sure.
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