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Low oil presure on rebuilt c90-8

sibbeston said:
In the paperwork I got with the engine it states the engine was modified to accept the 0-200 cam. Any idea what this may have been?
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who did the work, call them. We dont need to know who did the work but what did they say when you told them theres no oil pressure? Is it actually a 90 hp case? And why ruin a 90hp case to put a 200 cam in it? Which cam 626608 or 643067?
 
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It's a zero time engine. I started it and no oil pressure. So I primed the pump and tried again. No pressure. I pumped oil in the right gallery and tried again. No pressure. Then pumped a few litres thru the left gallery plug. I got around 5 psi.
So ive run it five or six times for 20 seconds or so each time.
I have the sump and case cover off and no metal. I've about run out of ideas but today I'll pump oil thru the oil galleries and see if it builds any pressure or seems to be dumping out internally.
I have a person coming over to look at it with a fresh set of eyes today but at the point where I think I'll have to look inside.
 
When I put my C85 together for my J4 I couldn't get the pump to prime. I took the front galley plugs off one at a time and used my shopvac to suck the oil up to each side. Worked, had good pressure next start

Glenn
 
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Can you do that? Surely it requires insets in the case - I have heard that neither cam bearings nor cam journals ever wear out. That's why the beaings are just the case.
 
Mystery solved.
I realized I have a fuel pump cover to inspect the front of the cam.
Brown bear got it. The bolts were missing from where the vacuume pump gear used to be. Oil was dumping out thru the holes.
I have to tear the engine apart still but it sure is nice to know it's a simple fix.
Thanks for all the help. It's great to have all this collective wisdom available.
Cheers
murray.
 
Glad you found it .We were able to install bolts and safety wire them by going through the vacuum pump mount hole.
That would be hard to do with only the fuel pump hole .
Doug
 
MVC-002S.JPGMVC-015S.JPG
Same thing happened to me years ago on a small Continental.
 

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Hello Guys!!
Men, i have installed in my Pa18 experimental a C90-8F overhauled and im with the following problem:
When i start the engine the pressure gets 70Psi on 1000Rpm but when the engine is warming up the pressure goes falling down and when i get oil temperature at 90C the oil pressure reaches 20PSI at 2200RPM.
Someone knows what is happening with my engine?
The engine is zero hour from overhaul with standard sizes and with a new oil pump!
This problem can be a wrong spring at oil relief valve??
Thanks for help guys!!
Hudson
 
Seventy psi is too much. Spring should be adjusted for 60. Twenty is too low for cruise on a brand new overhaul. The spring/ relief valve are probably not the problem, since it seals on startup.

However, if you just generally had low oil pressure, the dirt on that relief valve would be the first place to look. Since this thread started, I built up (with care) my Stroker, and at ten hours the pressure dropped. Piece of dirt on the relief valve. 100 hours now, and I get 50 at cold idle and above 40 at cruise, 180+ oil temp.
 
Hi guys!
Thanks for tips! I checked oil screen and is clean!
I'm gonna check the valve relief for some dirt.
Its strange because it has pressure on start and until about 40 Celsius but then the pressure goes dpwn bellow 30 and stabilize at 20 and temp reaches 100Celsius...
Guys, im running with AeroShell 100 Running due to breaking time, do you know if its normal to engine gets hotter in this fase???
Thank you so much!
Hudson
 
3 things, i can think of, bad oil pump number one and the easiest to fix, you say new oil pump what did you do there? was the accessory case brought back to spec? no 2, lots of clearance between the cam and case, always get the case halves lapped if you arent going to check the clearences. no 3, big clearences between the cam followers and case. somewhere when the oil gets thinner its getting by. (ALL JUST A OPINION!!)
 
Check the oil pressure gauge and line for snotty oil, clear the line of any crud. If there’s any in the line it probably made it to the gauge too. Those issues have given me a few gray hairs, and I was seeing the same indications on the gauge.
 
Hi TempDoug, thanks for your suggestions!
My accessory case was overhauled and the pump gears where new! But when we assembled the oil pump we dont took any measures so the pump can be a problem...
 
Hello CenterHillAg.
Yes, im gonna do this! Clear the gauge and line, but do you think that any crud there would cause this effects on measure of oil pressure?? 70psi when cold and 20 when hot??
Thank you!
Hudson
 
My issue with the line and gauge was on an R985. First takeoff of the the day indicating 95 psi, by the time I landed 20 mins later it was indicating 70 psi and still dropping, and 10 psi at idle after landing. We blew the line out and put a new gauge in, and my normal psi numbers were back.

There could definitely be more going on, but I like to start small and work towards the more expensive stuff when I have a problem.
 
Hudsonedu said:
Hi TempDoug, thanks for your suggestions!
My accessory case was overhauled and the pump gears where new! But when we assembled the oil pump we dont took any measures so the pump can be a problem...
Click to expand...

, it should be ok.
if a certified place did the case and you put new gears in
 
Seen something similar a little while ago. A small piece of aluminum was stuck in the pressure relief valve. We tore the entire engine apart and didn’t find anything, Figured it was left over from the machine shop. I’ve also seen twice where synthetic oil was added accidentally to miner oil during break inn. The filter clogged up with a crude jelly. Aero shell mineral oil and philips 20/50 don’t mix


Sent from my iPad using SuperCub.Org
 
No documentation, also both planes had challenger lifetime oil filters. They were rental planes and the renters accidentally added the wrong oil.


Sent from my iPhone using SuperCub.Org
 
Hello guys!
Today i changed my oil pressure indicator but not change! 80psi on startup and go decreasing at time the engine is getting hotter until 20psi at 100C...
So, im thinking about change the mag timming, i timed mags as shows on manual, left with 26 degrees and right with 28 but im gonna try the both at 24 degrees like O200, my question is if i bring the mags to 24 degrees it would change engine temperature???
Thanks for helping men!!!
Hudson
 
Hudsonedu said:
Hello guys!
Today i changed my oil pressure indicator but not change! 80psi on startup and go decreasing at time the engine is getting hotter until 20psi at 100C...
So, im thinking about change the mag timming, i timed mags as shows on manual, left with 26 degrees and right with 28 but im gonna try the both at 24 degrees like O200, my question is if i bring the mags to 24 degrees it would change engine temperature???
Thanks for helping men!!!
Hudson
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The only correct timing is the one on the dataplate.

Was your engine recently overhauled? What was the outside air temperature?

What kind of plane?
 
behindpropellers said:
The only correct timing is the one on the dataplate.

Was your engine recently overhauled? What was the outside air temperature?

What kind of plane?
Click to expand...

Hi behindpropellers!!
Was overhauled, i cleaned the cranckcase, got new cilinders, my cranckshaft where standard with brand new standard bearings! We used only camshaft, connecting rods and valve system parts like pushrods and rocker arms but all of they where in good conditions!
Outside air temp about 30Celcius, im in Brazil!
My plane is an experimental PA11!!!
Thanks for help me man!!
Hudson
 
Hudsonedu said:
Hi behindpropellers!!
Was overhauled, i cleaned the cranckcase, got new cilinders, my cranckshaft where standard with brand new standard bearings! We used only camshaft, connecting rods and valve system parts like pushrods and rocker arms but all of they where in good conditions!
Outside air temp about 30Celcius, im in Brazil!
My plane is an experimental PA11!!!
Thanks for help me man!!
Hudson
Click to expand...

1) Your engine was possibly built too tight - as it runs the oil heats up and looses viscosity. Who built it? Did they use plastigauge to confirm clearances?
or
2) Your oil pump clearances may be too loose. Did you put new oil pump gears in it? How did the rear case look?
 
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behindpropellers said:
1) Your engine was possibly built too tight - as it runs the oil heats up and looses viscosity. Who built it? Did they use plastigauge to confirm clearances?
or
2) Your oil pump clearances may be too loose. Did you put new oil pump gears in it? How did the rear case look?
Click to expand...

Hi Behindproppelers!!
So, an aircraft mechanic friend of mine that built the engine for me, we used micrometer to took measurements, i dont know what is plastigauge man.:oops:
I belive in this problem of my oil pump clearences too, we used brand news oil pump gears but the case is a used case but looked ok for us. I think its the main problem...
When we looked to our case, we saw that some guy putted one piece like a bearing inside the left oil gallery and the mechanic here talk to us that this metal piece is puted there when use a oil cooler, we tried to remove this piece from there but was impossible, and to avoid some problem, we connect the left oil gallery to right trough one hose, i dont know if it can be the problem but is other thing too... Bellow some pics of our engine and baffles made from the bowersflybaby site.

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I bet that's the problem. Start modifying these engines and you never know . . . I think I mentioned a couple years ago that converting from dash 12 to dash 8 can cause a serious loss of pressure, unless care is taken to properly plug a gallery someplace near the oil pump. Not an expert; I would never waste a perfectly good dash 12 that way.
 
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