0360 low oil pressure

Aircraft powered airboat discussion.
Post Reply
Edub
Southern Airboat Member
Posts: 25
Joined: Thu Dec 27, 2018 6:31 am

0360 low oil pressure

Post by Edub »

Trying to figure out an issue with my motor. It’s an angle valve 0360. Cold idle oil pressure is right at 45-50 with hot idle pressure at 30-35. While cruising the pressure goes up to around 65 but after running for a bit drops off and will fall down to 20. If I stop and let the boat idle pressure will come back up to 30-35. I pulled the oil screen in the sump and it looked fine. I pulled the pan today and there is no debris or anything blocking the oil pick up. Where is the next place I should check? Another thing to note is oil temp never goes higher than around 120.
User avatar
John Fenner
Southern Airboat Member
Posts: 2985
Joined: Tue Feb 14, 2012 12:26 pm
Location: Miami(Cuba) Fl.

Re: 0360 low oil pressure

Post by John Fenner »

The temperature seems cool to me, so rule that good, main pickup screen, clean sump and no debris is also a good sign, now, what does the oil screen "filter" look like "between magnetos"? The oil pressure regulator is just above cylinder #3 and if you were to add a washer to the spring pack and the pressure builds, great, if it stays the same, you either have worn bearings "doubtful" or an open oil gallery that feeds a prop governor or a cover that is dumping oil pressure, the numbers are not too bad as what you describe, I would not be too concerned.
I never finish anyth,,,.
BobBrack
Southern Airboat Member
Posts: 104
Joined: Thu May 22, 2008 8:12 pm

Re: 0360 low oil pressure

Post by BobBrack »

Sometimes it can be as simple as a piece of trash/carbon on the plunger for the oil pressure bypass port. Pull it and inspect both the plunger and the seat for trash or pitting from corrosion. If my memory is correct that engine will have a ball bearing used as a plunger but I cant guarantee that. Getting old sucks!!!!
User avatar
Slidin Gator
Site Supporter - IV
Site Supporter - IV
Posts: 1301
Joined: Sat Feb 03, 2018 11:33 pm
Location: Jupiter Farms, Florida

Re: 0360 low oil pressure

Post by Slidin Gator »

This thread covers inspection and adjustment of the oil pressure regulator.

https://southernairboat.com/phpBB3/vie ... re#p688064
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.
Edub
Southern Airboat Member
Posts: 25
Joined: Thu Dec 27, 2018 6:31 am

Re: 0360 low oil pressure

Post by Edub »

John Fenner wrote:The temperature seems cool to me, so rule that good, main pickup screen, clean sump and no debris is also a good sign, now, what does the oil screen "filter" look like "between magnetos"? The oil pressure regulator is just above cylinder #3 and if you were to add a washer to the spring pack and the pressure builds, great, if it stays the same, you either have worn bearings "doubtful" or an open oil gallery that feeds a prop governor or a cover that is dumping oil pressure, the numbers are not too bad as what you describe, I would not be too concerned.
Would adjusting the oil pressure regulator be indicated since all other numbers look good it’s only after being warmed up and while cruising that the pressure falls and even then if I let it idle it will come back up to normal limits. Would an adjustment to the regulator increase pressure while idling and while cruising?


Sent from my iPhone using Tapatalk
Edub
Southern Airboat Member
Posts: 25
Joined: Thu Dec 27, 2018 6:31 am

Re: 0360 low oil pressure

Post by Edub »

Slidin Gator wrote:This thread covers inspection and adjustment of the oil pressure regulator.

https://southernairboat.com/phpBB3/vie ... re#p688064
Could this possibly fix the issue of the low oil pressure at cruise only since the pressure is fine at idle


Sent from my iPhone using Tapatalk
User avatar
kwanjangnihm
Site Supporter - IV
Site Supporter - IV
Posts: 2287
Joined: Sat Mar 30, 2013 8:23 pm
Location: Bartow FL

Re: 0360 low oil pressure

Post by kwanjangnihm »

Edub how many hours on your motor? Did this issue just start? 120 degrees oil temp does seem low.

from an another low oil pressure thread: viewtopic.php?t=72622
He'll cut your throat, baby, stick you in the back, drive off in your Cadillac.
He's more trouble than you think, he'll kill your sugar, leave you in the drink.
User avatar
Slidin Gator
Site Supporter - IV
Site Supporter - IV
Posts: 1301
Joined: Sat Feb 03, 2018 11:33 pm
Location: Jupiter Farms, Florida

Re: 0360 low oil pressure

Post by Slidin Gator »

Edub wrote:
Tue Nov 23, 2021 12:19 pm
Slidin Gator wrote:This thread covers inspection and adjustment of the oil pressure regulator.

https://southernairboat.com/phpBB3/vie ... re#p688064
Could this possibly fix the issue of the low oil pressure at cruise only since the pressure is fine at idle


Sent from my iPhone using Tapatalk
dub,

Pay attention to what Bob and John are telling you. Your issue reads like you have excessive leakage/bypass somewhere and a bad gauge. Leakage always get's worse as the oil heats up, leading to lower oil pressure. Which brings us to the temperature, the 120 is hard to believe given that the oil seems to be heating up, leaking more, leading to low oil pressure. If 120 is actually correct, you should be able to hold your hand on the hot side hose to your cooler all day. I would get another gauge for a second opinion.
Edub wrote:
Mon Nov 22, 2021 6:12 pm
Cold idle oil pressure is right at 45-50 with hot idle pressure at 30-35. While cruising the pressure goes up to around 65 but after running for a bit drops off and will fall down to 20.
That's oil getting hot.
Edub wrote:
Mon Nov 22, 2021 6:12 pm
If I stop and let the boat idle pressure will come back up to 30-35.
That's oil getting cooler. No way you have this much swing at just 120.

You need to go through the entire oil system and make sure all is up to snuff until you find the culprit, start with the oil pressure regulator as it is easy. Your max oil pressure is within spec, but 30 psi below max spec, add some shims to bring hot running to 95 and see if the rest of your pressures don't fall in line. You already took care of one of the harder tasks with the oil sump and pick up screen. After the pressure regulator, check oil pressure screen and vernathane. Then it could be a passage like John suggests.

Repeating from the thread link:
Image
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.
User avatar
John Fenner
Southern Airboat Member
Posts: 2985
Joined: Tue Feb 14, 2012 12:26 pm
Location: Miami(Cuba) Fl.

Re: 0360 low oil pressure

Post by John Fenner »

Start with the simple things, check oil filter/screen, now, does it have a vernatherm or a plunger and spring a picture of accessory case will help, if it has the plunger as well as the vernatherm they will collide causing low oil pressure and full time circuit through cooler dumping pressure.
I never finish anyth,,,.
User avatar
Slidin Gator
Site Supporter - IV
Site Supporter - IV
Posts: 1301
Joined: Sat Feb 03, 2018 11:33 pm
Location: Jupiter Farms, Florida

Re: 0360 low oil pressure

Post by Slidin Gator »

John Fenner wrote:
Tue Nov 23, 2021 7:43 pm
if it has the plunger as well as the vernatherm they will collide causing low oil pressure and full time circuit through cooler dumping pressure.
Damn John, you have seen some screwed up setups :cheers:
I still think I-10 is the Mason Dixon line.
2013 Mike Stossel Boats, 13' x 7' deck over, IO-540, 74" NGQ less winglets.
User avatar
John Fenner
Southern Airboat Member
Posts: 2985
Joined: Tue Feb 14, 2012 12:26 pm
Location: Miami(Cuba) Fl.

Re: 0360 low oil pressure

Post by John Fenner »

Slidin Gator wrote:
Tue Nov 23, 2021 8:00 pm
John Fenner wrote:
Tue Nov 23, 2021 7:43 pm
if it has the plunger as well as the vernatherm they will collide causing low oil pressure and full time circuit through cooler dumping pressure.
Damn John, you have seen some screwed up setups :cheers:
Have seen many things, a friend had bought a rebuilt 360 that was a ditched water landing, the bitch kept overheating, we tore it apart, replaced bearings as they were smoked, put in 10:1 forged, proper valve job, went to put accessory housing on and was looking at the cooler plumbing ports, there was a banjo fitting where the plunger and spring goes, not in the upper cooler port, so essentially the cooler was plumbed in the plane and the airboat same way, closed circuit, problem solved, plumbed correctly, runs like a top, not sure what the N number was on the plane that ditched as the engine was a basket case when my late cousin got it several years ago, could've updated the crash landing report.
I never finish anyth,,,.
Uhairball
Southern Airboat Member
Posts: 305
Joined: Mon Aug 15, 2011 6:31 am
Location: Inverness, FL

Re: 0360 low oil pressure

Post by Uhairball »

John Fenner wrote:
Wed Nov 24, 2021 4:26 am
Slidin Gator wrote:
Tue Nov 23, 2021 8:00 pm
John Fenner wrote:
Tue Nov 23, 2021 7:43 pm
if it has the plunger as well as the vernatherm they will collide causing low oil pressure and full time circuit through cooler dumping pressure.
Damn John, you have seen some screwed up setups :cheers:
Have seen many things, a friend had bought a rebuilt 360 that was a ditched water landing, the bitch kept overheating, we tore it apart, replaced bearings as they were smoked, put in 10:1 forged, proper valve job, went to put accessory housing on and was looking at the cooler plumbing ports, there was a banjo fitting where the plunger and spring goes, not in the upper cooler port, so essentially the cooler was plumbed in the plane and the airboat same way, closed circuit, problem solved, plumbed correctly, runs like a top, not sure what the N number was on the plane that ditched as the engine was a basket case when my late cousin got it several years ago, could've updated the crash landing report.


Here is a fact that is rarely considered- 50% of the A&P mechanics and FAA crash investigators (as well as doctors, lawyers, etc) graduated in the bottom half of their class...
User avatar
John Fenner
Southern Airboat Member
Posts: 2985
Joined: Tue Feb 14, 2012 12:26 pm
Location: Miami(Cuba) Fl.

Re: 0360 low oil pressure

Post by John Fenner »

I know of many with degrees that have zero common sense, sadly, they breed and vote.
I never finish anyth,,,.
BobBrack
Southern Airboat Member
Posts: 104
Joined: Thu May 22, 2008 8:12 pm

Re: 0360 low oil pressure

Post by BobBrack »

There are IO-360 models that ran a constant speed propeller when they were on aircraft. These had a prop governer at the front end on the side of the case. If you have that type case you may be getting your loss of oil pressure from the gears not being in the case where the governer used to be. I see this more on the 540 models. Maybe take a few pics and share them with us and we may see something obvious. I have also seen where people use the O-290 accessory cover which has a separate pickup tube. This tube tends to crack over time from all the jolting from running dry.
User avatar
Deano
Site Supporter - V
Site Supporter - V
Posts: 4670
Joined: Thu Jan 06, 2005 11:16 am
Location: Inverness, FL

Re: 0360 low oil pressure

Post by Deano »

John Fenner wrote: I know of many with degrees that have zero common sense, sadly, they breed and vote.
It is a wise man who can succinctly state things the bulk of the population seem unable to casually observe. :salute:
"The suppression of uncomfortable ideas may be common in religion and politics,
but it is not the path to knowledge; it has no place in the endeavor of science."
- Carl Sagan
Post Reply

Return to “Aircraft Power Only”