High Oil Pressure

Having issues with a high oil pressure indication and looking for some help in troubleshooting.

Engine is a IO-540, built by Firewall Forward. Has 250 hours since OH.

Last weekend during preflight run, notice that oil pressure reading 90 lbs at 1800 RPM. Brought back to idle and it dropped to around 75-80. Ran back up to 2000 RPM and it pegged at 99 lbs.

Back at the hangar, was hoping it was an indication issue so replaced the oil pressure sensor. Started back up, reading at first was at 50 lbs at idle and during run up it stayed quite normal. After takeoff the pressure rose again and was over 90 lbs. Did pattern and landed.

At the hangar again, removed cowl and decided to drop the oil. Found a few pieces of metal in the oil but they were stuck in the sump screen and had to be picked out with a pick. Pretty sure they were there in the beginning.

Was still thinking it was an indication error so decided to install a new oil temporary oil pressure gauge in. Once competed did another run and the pressure seemed to be just fine. Ran up to 2100 RPM and it seemed to be normal. After about ten minutes of sitting, we decided to do a double check. This second run up indicated high pressure again.

Couple of thoughts:

1. Is the oil cooler or lines blocked. However, did not show any high oil temps.
2. Was there something wrong with relief valve. Removed and had an A&P inspect. Seemed to be normal.
3. Did the engine spin a bearing and that is causing the blockage. Debating removing a cylinder to scope.
4. ?????

Looking for any additional thoughts before we decide to completely tear the engine down.

Appreciate any comments or help.

How cold was it ? Was the oils temperature above 130?

Flying up north you learn to appreciate that fact that if you have to wait for the oil temp to get above 120. You won't be flying when it is 0-10 degrees outside. oil flows fine at 100 degrees. But if you take off with the temps at 100 your OP might me in the 90's for a couple minutes.

Jack

Oil temp was well above 100. The outside temp was in the 60's and is also stored in a heated hangar.

You are right, we spend a lot of time just sitting there waiting for the oil to warm up here in the north.

Brian,m
Have you backed off on the OP spring to see if you can get the pressure down... Did you change it over the winter?

Jack

If your other readings are normal swap out the sending unit... They do go bad

Jack

OP Spring has never been adjusted.
First thing was to install a new pressure sending unit.

Also read the post by dan Horton and made sure that the spring and plunger were removed.

Tonight we decided to bypass the oil cooler. Two runs, oil temp over 120. Never exceeded 75 on extra inline gauge. EFIS in plane again showed over 90.

What is considered normal oil pressulre on IO-540?

Had the same thing happen in my O-360 in the Cessna. All the kings horses and all the kings men did all the tests, to no avail. Since the engine had sat for a while before I bought the plane, I had the engine rebuilt (didn't need overhaul because all the parts were within new part tolerances). And after all that? High oil pressure.

Been there, done that, got the T-shirt.

Brian, make sure your EFIS sensor is well-grounded. I soldered a wire to OP sensor case and ran it to the FW ground forest of tabs. Pressure dropped to normal. (Dynon Skyview)

I had a similar occurence a while ago. It turned out to be a poor electrical connection. Go over every connection in feed side and earthing side, before you do serious work on the engine.

Hello Ed

In the end, how did you resolve the issue on your 360.

Brian

oil pressure

I have an IO 360 in the RV8. The Dynon D180 wouldn't come online several months ago. I called Dynon. They said to send it in and it would be repaired. All of my settings were lost during the repair and I had to re-program K factor, V speeds, etc. I noticed the oil pressure at start up was in the high 90s. Before the repair, the engine held a constant 76 psi when warm and cruising. It shows a constant 91 psi now at the same cruise settings. Nothing else was changed on the airplane or engine. I wrote it off as a result of Dynon making repairs to the unit.

Oil pressure is an EXTREMELY important engine parameter to monitor, if you don't have a reliable and accurate reading than you need to fix that, period.
A change in oil pressure can be a major indicator of a pending engine failure.

So last night spent a few more hours trying to isolate the issues. Used some high tech calibrated equipment from a friend that works on GE Turbines.

Tim, the owner of this plane contacted Firewall Forward and gave him some suggestions on what to check and look for before deciding to tear it apart.

During the test runs, all the calibrated guages were very close to what the EFIS was displaying. Max pressure on runs up to 2300 RPM never exceeded 85 lbs.

Not that this is a bad number, but why is it higher than in the past.

We then used a bore-scope and went through the oil dipstick hole to see what we could find. Once reaching the number 2 main bearing we noticed that one of the bearing halfs was pushed out approximately 1/8" compared to the other side. The question is, was this done when the engine was assembled or did it slip. A whole video was taken of the scope and sent to the experts for their opinion. Waiting to hear on the next step.

Here is a quick snap of the bearing. You will notice the split which is also right at the case split line.

Good Save!

I will be interested to hear FF's response. I can not imagine that this is acceptable, even if built this way. Those more familiar with this engine can tell us how large the oil supply hole is and how much oil flow the area is reduced. Also, the actual bearing area is reduced due to the offset. Most likely it is a remove and repair situation.

That borescope has really shown it's value!