Geico266

Geico266

Well Known Member
I've been looking for info and could not find anything on a search for info just on the IO-540.

I just adjusted the pressure screw so now my readings are; Takeoff (oil temp 100F) Cruise: 75 PSI, Hot Idle: 24 PSI :eek:

I still have 2-3 turns to go if I need it. It's the idle pressure that has me concerned. Is 24 PSI too low? If I bump the throttle it goes to 35PSI right away. I'm I worrying too much?

What are your readings with the 0-540 or IO-540?

Thanks in advance. ;)
 
The operators manual that I have says
All models except -F -J -N, Max 90 Min 60 Idle 25. -F -J -N, Max 90 Min 55 Idle 25
 
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Normally idle oil pressure is not critical. If you have enough pressure to keep the lifters pumped up, there will be enough for the bearings. Nothing is carrying much load at idle.
I wouldn't worry about a pound or two at idle.
 
Thanks Mel, they are hydraulic lifers, that makes sense. This is just one of those things that rattles around in my brain. The pressure was 65 PSI @ cruise so I bumped it up to 75 PSI. It sure is nice to know everything is hunky dory.
 
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I0-540 Operatiing Limitations

Where does one find all of the operating limitations for an I0-540. Oil press, Oil temp, CHT, etc?
 
dmaib said:
Where does one find all of the operating limitations for an I0-540. Oil press, Oil temp, CHT, etc?
Click to expand...

http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgMakeModel.nsf/0/ffae5a2bb5506dcc8625747a00650001/$FILE/1E4.pdf

Good Luck,
Mahlon
?The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
 
540's Rule!

Larry,
I have found on my Rocket's IO540 C4B5 that Multi Vis oil will change the numbers slightly on hot days, cooler temps, higher pressure at Idle.

Smokey
HR2

PS: Yep you worry too much...

Let's have fun out there!:)
 
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I'm running Shell 15w-50 now. Pressures are now in the normal range. Thanks to Bart & Sue at Aero Sport Aircraft Engines. They are the best!
 
I0-540 Operatiing Limitations

Thanks Mel and Mahlon. I had ordered an operating manual but wanted some data to set up my EIS/Vertical Power. The document Mahlon directed me to fills the bill nicely for now and has lots of other good information.
 
49clipper

Anyone heard of the oil pressure rising to out of limits (100+) on a decrease in rpm of about 100 for descent? I had this phenomomen happen this last week as I let down from 11500'. OAT was 9C, oil temp was normal at 185f, once I reduced power, it started climbing and went over the limit for my )-320-D1A (90). First time I have ever heard of that. I was worried about blowing the front seal and losing all my oil. Stayed that way til on the ground. On the next leg at 5500', everything normal at 80psi, and when I pulled back 100 rpm to letdown, there goes the oil pressure. that time it went to 96 and held till on the ground. What gives? Idle is 40, normal cruise is 79-81psi. Oil temp is solid at 185 all the time.
 
Not sure, but I would think that as the rpm is hitting a certain point, the demand from the prop governor, to hold that RPM, is lessening and thus because the prop gov is stealing less oil pressure from the engine, the engine's oil pressure goes up...
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at your own risk."
 
49clipper said:
Idle is 40, normal cruise is 79-81psi. Oil temp is solid at 185 all the time.
Click to expand...

Okay, so it might not be the sending unit. I know you are frustrated / concerned so here are a couple of other thoughts I have.

With the oil hot your idle pressure sounds just a tad high. The book says 25 PSI min and you are at 40. Cruise pressure of 75 would not hurt anything, you are at 80. Try turning down the pressure one turn or removing 1 washer.

My engine did the same thing as yours (for a few seconds) this Sat. This happened after I turned the oil pressure up 3 turns trying to get the idle pressure higher than 24 PSI. Mine went to 40 PSI and then I had the high oil pressure reading.

Also, while you are adjusting the oil pressure down a turn you might want to pull the spring and ball and check it out. Look at the seat and see if you can see anything abnormal (junk, ball wear, seat wear, ect.) You can also try re-seating the ball. I have not done this, but this is what I was told to do. Remove the spring and ball, and inspect. With a 1/2" brass / aluminum rod set the ball in the seat and give it a medium / lite tap with a hammer to seat the ball again. You might want to have an A&P / engine guru look over your shoulder while you do this.
 
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