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RVFlyer

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I'm putting out a call for help. After a couple of days enjoying Taos NM, including a sight-seeing flight yesterday, I came out to a small puddle of oil under my RV4 (O-320). Pulled the cowl, searched around, put a wrench on fittings (all tight), cleaned it up and decided to do a runup to try to determine source of problem.

Ran rough. Yes I leaned it for the high altitude...got a nice smooth increase in power there but otherwise moderate roughness. The oil pressure took just a second or two longer than normal to come up. When it did, it was significantly lower than usual. Normal is top of the green, 80#, now all it can do is 60# (bottom of green).

I am beyond my level of expertise so I need help. There are no A&Ps on the field. Closest according to lineguys are in Alamosa or Santa Fe. Any and all help or suggestions would be greatly appreciated (and financially compensated)!!

Cell 620-755-3883.
 
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If you can't find a leak, look again. If you still can't find one, then it may be coming from your breather. If so, pull your bottom plugs and look for one soaked in oil. That will at least isolate you to one cylinder hopefully.
 
aerhed said:
If you can't find a leak, look again. If you still can't find one, then it may be coming from your breather. If so, pull your bottom plugs and look for one soaked in oil. That will at least isolate you to one cylinder hopefully.
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i am betting he doesn't have many tools, someone nearby should offer to bring him a set
 
Will try it.

aerhed said:
If you can't find a leak, look again. If you still can't find one, then it may be coming from your breather. If so, pull your bottom plugs and look for one soaked in oil. That will at least isolate you to one cylinder hopefully.
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Thanks for the quick reply. I'm going out to pull the oil screen so I'll do the plugs as well. Good advice.
 
tools okay

bkthomps said:
i am betting he doesn't have many tools, someone nearby should offer to bring him a set
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Good thought Brian. Fortunately I lucked into a guy who opened his pretty well equipped hangar to me, so I'm fairly well set on the tool front. Thanks.
 
More ideas?

I checked the plugs....all okay. That wouldn't explain the oil pressure decrease anyway but it at least kept me from stressing about the whole deal for awhile.

I'm trying to dig up a new gasket before I pull the oil screen. Being as it is one of those days, I'm not trusting myself to avoid tearing it. Gotta find one and check it before flying again.
 
oil

Better check the lower oil screen in the sump too. That will probably show metal, if there is any, before the accy case screen.
 
There is a good mechanic at Alamosa with a lot of experience with RVs. Can't recall his name but he is hearing impaired. The phone number there is 719-589-9100.
 
Back in business...I think

Thank you to everyone who replied or called with ideas. VAF rocks.

It appears that it is fixed. The bad news is, I'm not sure what went wrong. The most popular guess is something stuck in the oil pressure adjustment plus a burp by the oil/air separator. I spent all day trouble shooting... Cleaned accy screen, changed oil, nothing suspicious in either one. Did multiple runups with good oil pressure, followed by cleaning up of random oil splatters that migrated from everywhere. In the end, I have it all cleaned, can't find any leaks, and it's running well.

Pretty soon I was out of reasons to not fly it so I put the cowl back on and took it for a test flight. All was well. Too tired to head home so I'll enjoy another evening in Taos and head home in the morning (unless the puddle re-appears or something else is amiss). I plan to stay out of the mountains and follow major highways, along with multiple stops to check on things.

Thanks again for the help guys! As is my tradition when VAF really comes through, a bonus donation will be sent to Doug in your honor.

Time for a beer, a steak, and a good night's sleep.
 
How did the flight back go?

Tom, I have been following your problems in Taos. How did the flight back go? Did you keep oil pressure and no problems? It must be the worst to not know what was causing the issue.
 
Safe at home!

rockwoodrv9 said:
Tom, I have been following your problems in Taos. How did the flight back go? Did you keep oil pressure and no problems? It must be the worst to not know what was causing the issue.
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I made it home with no additional problems. You are correct, not knowing what the problem was (and therefore whether it was/is really fixed) was especially disconcerting being in the mountains. I took off Sunday morning and followed the valley and highway south to Santa Fe, then around the mountains to Las Vegas, NM to check things out (about 45 min). I was on high alert checking pressure, temps, looking for smoke out the back, etc. Not a single hiccup. Dry belly at Las Vegas, topped off fuel and launched for home. Plane was still clean and had all of its oil after another 3 hrs.

On the way home I had a continual debate with myself regarding altitude....high in case if fails? or low in case of fire? Tailwinds up high tipped the scale and gave me a smooth, fast run to home. Fortunately, plenty of airports as options once I was out of eastern NM.

When the saga began, it felt incredibly lonely (no A&Ps, unfriendly terrain, etc) but, thanks to VAF, my home field mechanic, and a local EAA guy willing to loan tools, I had good resources in a couple of hours. I received good ideas and advice, all of which I took the time to follow up on, thereby giving me the confidence to proceed (with caution).

One interesting takeaway....when you are in a warm hangar working under the engine and hear the full fuel tanks gurgling, don't be surprised when fuel squirts out the vent and on to you. Reminded me of a baby spitting up with zero warning...just as funny too.

Thanks again!
 
RVFlyer said:
I Not a single hiccup. Dry belly at Las Vegas, topped off fuel and launched for home. Plane was still clean and had all of its oil after another 3 hrs.
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Good for you.

Any chance the puddle on the ground was there before you parked over it???
 
Mike S said:
Good for you.

Any chance the puddle on the ground was there before you parked over it???
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Good thought. That was what I first hoped, but when I started the engine it was very rough and down to 60# of oil pressure from its usual mid70s - 80 range. This combination of concerns is what led me to pull the cowl and find the mess of oil on the back of my engine.

One issue I'm still trying to understand was that on the first two run-ups following the discovery of the problem, the engine ran very rough (yes I leaned it aggressively for the high altitude). One thing I found later in the day was a significant amount of oil in the airbox. I think it ran through a vent/drain hole on the top of the box but hadn't found its way out of the vent/drain hole on the bottom. I'm wondering if the oil could have effectively fouled the induction air? This doesn't seem totally plausible as most of it was outside of the air filter, but it's worth considering.

Still running great today but my eyes will be closely tied to the oil gauges for quite some time.
 
RVFlyer said:
I think it ran through a vent/drain hole on the top of the box but hadn't found its way out of the vent/drain hole on the bottom. I'm wondering if the oil could have effectively fouled the induction air? This doesn't seem totally plausible as most of it was outside of the air filter, but it's worth considering.
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I wondered about that too... A little oil mist mixed with the air would rob some power for sure... Not sure why the lower oil pressure though. I wonder if the air/oil separator got a bubble in a hose somehow and you got a blockage there? That might give positive pressure at the breather?
 
good to hear your back

Tom, good to hear you didn't have any more issues on the way home. I can imagine the conflict on fly high or low. I think I would rather have to pick a spot quick than deal with a fire! Good luck figuring out what - if anything caused the pressure drop.
 
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