Has anyone installed a pre oil system on an IO 360?
I’m wondering where to pickup the oil source into the pump.
I’m wondering where to pickup the oil source into the pump.
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Pre oil system
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There is a plug at the bottom of the sump.
I would advice against a pre oil system.
If it fails in the air, you may have no oil pressure.
Good luck
I have a pre-oiler on my IO-360. As mentioned above, I use a pickup on the sump and return at the top of the engine. I also use a pressure switch so it comes on in case of a low oil pressure situation (like before starting the engine) and set it to 25 PSI. Since most of the wear on our engines is on starting, I believe this may help. Also, while I doubt it will move enough oil to save my engine if the oil pump fails, it may give me a few more minutes (seconds?) of engine power. Because it is completely separate from the main oil system, I don't believe it will cause an oil pressure failure from the main oil system. A large leak might cause a problem, and any extra plumbing increases that risk, but I feel the benefits are worth the risk. There a cheaper switches but the pump will burn out pressure switches that can't handle at least 10 amps and most of those switches are 3 amp max (ask me how I know!).
Have seen many references to various Toyota engines easilly hitting the .5M mile mark. Somehow they achieve this without pre oililng. We hear about this start up wear from guys like mike busch, but believe he just makes this stuff up.
BoydBirchler
Well Known Member
A few RV people have put an accumulator in the oil system to keep from having oil pressure loss while doing short length inverted maneuvers.
Many of these planes, with this inverted oil system, have a valve at the accumulator that they can turn off before shutdown keeping accumulator oil under pressure that can be used for pre-oiling, by turning the valve open just prior to the next start.
Many of these planes, with this inverted oil system, have a valve at the accumulator that they can turn off before shutdown keeping accumulator oil under pressure that can be used for pre-oiling, by turning the valve open just prior to the next start.
Funny you should mention this concept. My system generates about 25 psi and is useful for pre-oiling the bearings but not the cam shaft, which according to a very experienced IA, is only oiled by slinging oil from the spinning of parts on a Lycoming. The accumulator, which I believe was originally designed for race cars, concept is one I considered but it requires me to do something (remember to turn off prior to shutdown) and mine is automatic. Mine will also operate for any length of time the oil pressure is down but the accumulator is gone in seconds. But neither will create sling with an engine that is not moving. Both systems are an incomplete answer to pre-oiling. The same IA recommend ZDDP being added to the oil to reduce the tendency for the oil to run off leaving the metal bare.
While the cam lobes are oiled in part from oil slung off the crank, each cam journal (4 in total) has a pressurized oil feed and will spray oil on the lobes as well. Also, each lifter bore has a pressurized oil feed and the exiting oil will also spray on the lobes.
Well, let's say that using one's intellectual capacity for a second will confirm that theory, at least to a certain degree.
An engine sitting for a moment or longer has its oil P dropping... the results are a thinned oil film, which will break or run off places given enough time.
OTOH critical places such as journals will retain their oil film, albeit thinned, for a very long time, witness those of a crank or a cam when taken apart for an o-haul or other guts work.
Pre-oiling might restore the oil film to a running engine's quality, in some parts, before having fired it up.
Still, IMHO à pre-oiling system ain't worth the added weight and complexity, as it will only aid in places fed by oil galleries which probably retain their oil film anyway, instead of places where most wear occurs such as piston rings - cylinder interference.
I can see the added risk angle: a series of fittings that causes a pathway to oil pressure loss in flight if they come apart.
It occurred to me that there's also a corresponding safety/redundancy angle. Could a pre oiler act as an electric backup oil pump, much in the same way we have electric backup fuel pumps in case the mechanical pump fails?
It occurred to me that there's also a corresponding safety/redundancy angle. Could a pre oiler act as an electric backup oil pump, much in the same way we have electric backup fuel pumps in case the mechanical pump fails?
krhea
Well Known Member
After an overhaul on my 0-320, and without any prepacking of the oil pump, using the starter only it took 14 seconds of turning the engine with the starter to bring up 50# oil pressure. Everything was lubed with assembly lube. I don' t think the oil drains off in that clearance. But i fly weekly or more often. I also took a video.
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How often do the mechanical pumps fail? And is the addition of the electric pump (additional cost, weight, complexity, maintenance) worth covering that risk? Everything in aviation is a tradeoff - and sometimes the juice ain't worth the squeeze.
I have redundant ignition (we've all had fouled plugs or a bad mag), redundant injection computer boards (I've lost one in flight), redundant fuel pumps (lost one), redundant alternators (lost a couple), redundant radios (lost a couple) in just over 3500 total hours, just over 2000 in my RV. I've never lost an oil pump, nor do I know anyone who has. I know it has happened - my point is that it's rare enough to be along the lines of buying a lottery ticket.
But lets follow that logic for a minute - you have a backup electrical oil pump. You are flying along and get an alert for low oil pressure. By the time you get over the initial panic, realize what has happened, figure out to reach over and flip on the switch, and let the oil pressure come up, somewhere between 7 and 10 seconds without oil pressure has gone by. You are NOT going to trust the engine is without damage - I certainly would not - which means a teardown is coming anyway. You are more likely to make it down to the ground in one piece, yes, but only in the case where the mechanical pump itself gives up and not for the (much more likely) case of oil starvation due to some sort of leak. You're still boned for that one.
Please don't take this as hacking on you - certainly not - just trying to demonstrate the risk versus reward equation and following it logically. I've also had a couple "unplanned landings" due to items I didn't have a switch for in the cockpit. Been there, done that. Bought the T-shirt but not the farm.
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For the record, I agree with this rationale, I just wanted to express a possible advantage.
It wouldn't be too hard to rig the pump for off/auto/on where a pressure switch engages the pump below, say 30psi, with an alert light, and then you switch to manual on. 7-10s could be pessimistic if there's a big red low oil pressure light high in the panel with an on switch right next to it. Presumably there's no air in the feed or return from the pump at that time, so pressure could be near instant.
But if it tells you anything, I don't want the weight or complexity either.
See post #3. I just went with a pressure switch (no on or off switch) and a warning light comes on my EFIS.
sansoneservices
Well Known Member
Busch says pulling jugs is dangerous. I won't tell him the # of jugs pulled every year
