Hi all,

Bought a 185 that had flown only 10 hours in 6 years.

After about 30 hours of tach time oil analysis showed all levels returned to normal but a vibration started to occur more and more.

To make sure it was safe we pulled the lifters. Lifters cam and crank looked fine but found broken inner valve springs.

Sweet! Fixed that and replaced all pushrod seals.

Put it all back together and now the oil pressure is ~30 in cruise. (In green arc but barely). About 10 PSI less than it was before the engine work. I have pictures from cruise in July showing oil pressure right in the middle of the green arc in cruise then pictures of it the day after the engine maintenance bottom of the green in August.

So for 30 hours of tach the oil pressure was “normal” then immediately after maintenance it’s lower.

I’m hesitant to blame the gauge as that would be quite a coincidence.

Oil temps are normal and even at lowest idle the oil pressure stays in the green.

Bump the oil pressure and call it good? Or try and figure out why oil pressure dropped? A couple of the push rod seals didn’t appear to seat well as there is some oil leaking.

Since then my chip detector illuminated twice as well but only had minimal sludge on it no big chunks and nothing in the screen. However, it had not illuminated in the previous 30 tach hours.

Sending in another round of oil analysis. Waiting on Blackstone (4-6 week turn around)

Any ideas? Thanks.

Current cruise oil pressure now

I will be following this subject with very keen interest.

I'm have a similar issue with my 0-360. Previous the oil pressure was normal, but high oil temps. Once the oil temp issue was resolve; new baffles, oil pressure dropped to the low end of normal and "wandering". It's been suggested that the copper pressure sense line might have a leak, maybe a cracked flare and allowing air to entry the system.

Lettucelord wrote:Hi all,

Bought a 185 that had flown only 10 hours in 6 years.

After about 30 hours of tach time oil analysis showed all levels returned to normal but a vibration started to occur more and more.

To make sure it was safe we pulled the lifters. Lifters cam and crank looked fine but found broken inner valve springs.

Sweet! Fixed that and replaced all pushrod seals.

Put it all back together and now the oil pressure is ~30 in cruise. (In green arc but barely). About 10 PSI less than it was before the engine work. I have pictures from cruise in July showing oil pressure right in the middle of the green arc in cruise then pictures of it the day after the engine maintenance bottom of the green in August.

So for 30 hours of tach the oil pressure was “normal” then immediately after maintenance it’s lower.

I’m hesitant to blame the gauge as that would be quite a coincidence.

Oil temps are normal and even at lowest idle the oil pressure stays in the green.

Bump the oil pressure and call it good? Or try and figure out why oil pressure dropped? A couple of the push rod seals didn’t appear to seat well as there is some oil leaking.

Since then my chip detector illuminated twice as well but only had minimal sludge on it no big chunks and nothing in the screen. However, it had not illuminated in the previous 30 tach hours.

Sending in another round of oil analysis. Waiting on Blackstone (4-6 week turn around)

Any ideas? Thanks.

It’s posable you have introduced some crud that got under the seat of your oil pressure regulator. I’ve only seen this once myself but in a late case Ponk’ed 180.
Pull the pressure regulator, ha ha ya I know, then get a mirror and I light and look in the hole. The one I found was a tiny chip of metal from an unknown source laying inside the bore/seat.
If I recall this engine made pressure until the oil warmed then sat at the bottom of the green or a couple needle widths bellow.

Rocket

I think the first thing to do is hook up a proper manual gauge and compare to the Cessna gauge then assess from that point.

rocket wrote:

Lettucelord wrote:Hi all,

Bought a 185 that had flown only 10 hours in 6 years.

After about 30 hours of tach time oil analysis showed all levels returned to normal but a vibration started to occur more and more.

To make sure it was safe we pulled the lifters. Lifters cam and crank looked fine but found broken inner valve springs.

Sweet! Fixed that and replaced all pushrod seals.

Put it all back together and now the oil pressure is ~30 in cruise. (In green arc but barely). About 10 PSI less than it was before the engine work. I have pictures from cruise in July showing oil pressure right in the middle of the green arc in cruise then pictures of it the day after the engine maintenance bottom of the green in August.

So for 30 hours of tach the oil pressure was “normal” then immediately after maintenance it’s lower.

I’m hesitant to blame the gauge as that would be quite a coincidence.

Oil temps are normal and even at lowest idle the oil pressure stays in the green.

Bump the oil pressure and call it good? Or try and figure out why oil pressure dropped? A couple of the push rod seals didn’t appear to seat well as there is some oil leaking.

Since then my chip detector illuminated twice as well but only had minimal sludge on it no big chunks and nothing in the screen. However, it had not illuminated in the previous 30 tach hours.

Sending in another round of oil analysis. Waiting on Blackstone (4-6 week turn around)

Any ideas? Thanks.

It’s posable you have introduced some crud that got under the seat of your oil pressure regulator. I’ve only seen this once myself but in a late case Ponk’ed 180.
Pull the pressure regulator, ha ha ya I know, then get a mirror and I light and look in the hole. The one I found was a tiny chip of metal from an unknown source laying inside the bore/seat.
If I recall this engine made pressure until the oil warmed then sat at the bottom of the green or a couple needle widths bellow.

Rocket

I like this ^^^^

MTV

Provided the engine appears to be running well, my first step would be to hook up a test gauge and find out what the oil pressure actually is.

I’m reminded of the Skywagon featured in a Saavy aviator story from 2019 where a 185 experienced zero oil pressure on startup away from home. A local AP/IA held the owner and airplane in a “hostage situation” demanding a complete tear down and overhaul.

Problem turned out a result of a small aluminum piece blocking the oil pressure relief valve. Upon rectifying the PRV issue the next start showed normal oil pressure.