[airguy]

Does anyone here use the engine pre-oiler devices to supply oil pressure to a cold engine just before start? I've seen two basic types, an electric pump and an accumulator style. Do they work well enough to be worth the weight and complexity? How would you even know without running to TBO and tearing down?

 

[Mel]

My opinion (yes I have one occasionally) is that pre-oilers are not that great. Yes they help, but the primary thing in a Lycoming that needs pre-oiling is the cam lobes. A pre-oiler doesn't do this. The cam lobes are oiled only by "splash" with the engine running.

 

[mahlon_r]

Unless you modified the crankcase and installed oil nozzles to squirt oil on the cam lobes during build up. Then during the pre oil procedure and during operation the lobes are being pressure sprayed rather then relying totally on splash.
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.?

 

[pierre smith]

Fly more

Hey guys,
Just fly more and the lobes will stay wet!

Seriously though, my late boss had a P-51 which ate cam lobes since they ran directly on top of the rocker arms. After he started adding 10% STP, the lobes lasted and lasted and...since it doesn't evaporate/drip off like 20W50.

Mahlon, is 1 pint of STP OK in a 4 banger Lyc?
Regards,

 

[Walter Atkinson]

Since the vast majority of wear occurs in the first 30 seconds of startup, pre-oiling cannot do anything but help. It would be nice if this included the cam lobes, but it doesn't. It still is a very good idea on airplanes that are flown infrequently. If you fly at least once a week, I'm not sure it would make much difference.

Walter

 

[penguin]

So roller followers are a good idea?

Pete

 

[captainron]

Hey guys,
Just fly more and the lobes will stay wet!

Seriously though, my late boss had a P-51 which ate cam lobes since they ran directly on top of the rocker arms. After he started adding 10% STP, the lobes lasted and lasted and...since it doesn't evaporate/drip off like 20W50.

Mahlon, is 1 pint of STP OK in a 4 banger Lyc?
Regards,

Pierre, technically, STP is a "viscosity index improver", which just means that it raises the viscosity of whatever oil is mixed with it. One of the products that I used on new engines is sold by GM called Engine Oil Supplement, or E.O.S.. General Motors found it protects cam lobes from wear during engine break-in. This is a reason you shouldn't change-out the factory oil too soon after you buy a new car. I don't know if it's still used since everything has roller cam-followers now.

B.T.W., how much STP did he add to the P-51? Our T-28 holds 16 gallons of oil; the Mustang is probably more!

 

[pierre smith]

10%

Hi Ron,
Jack Sliker (my late boss) added 10% of the total oil as STP. I also used it in my T-6 since I saw the difference it made in his -51 [which Wiley Sanders, (Troy, Alabama) bought.]

I don't remember the amount because I don't recollect how many gallons the Mustang held. The year was also 1975, so time helps Senioritus set in too

What a difference 30 years makes....my son's Honda Element calls for 5W-20 year 'round!
Regards,

 

[captainron]

Hi Ron,

What a difference 30 years makes....my son's Honda Element calls for 5W-20 year 'round!
Regards,

This is one of the disappointing things about roller followers in the aircraft engines,-that they can't take advantage of lighter weight oils for less internal drag and better fuel economy. I'm seriously looking at the ECI engines with oil nozzles instead of rollers.
Fewer moving parts, reduced chance of something coming apart, etc..
I'm sure rollers are tested and "almost" bulletproof, but if that one roller pin walks out, or if the little locating pin in the grove on the follower body breaks, you will have bigger engine problems than just worn cam lobes.Time will tell, and we have asked for change..... Lycoming thinks they are okay.

 

[pierre smith]

20W50

I curently use 20W50 Philips in the 6A.

Back in the eighties when multigrade aviation oils came out, I was flying a Cessna Agtruck with an IO-520 Conti that had Cermichromed cylinders and they recommended Philips 20W-50 and so I started using it. I could not believe the drop in oil consumption and how clean it was after 33 hours (we changed at 3 times/100 hours) running the engines at 25" X 2500 RPM all day long hauling 200 gallon loads.

Since this was exactly what I saw and flying 400-500 hours a season in 100 degree temps sometimes, hauling heavy loads, I was sold on the oil and the reason I use it today.

The PT6-15 in my Air Tractor uses Exxon 2380 synthetic oil and it gets changed once a year around 400 hours and is as clear as water then. (1000Hrs is usual)!! That oil is as thin as water, yet the CT wheel spins 37,500 RPM at 100% and runs all day long at 95-97% of that!

Sure wish we could run synthetics in the Lycs. But I've heard that if you have a small oil leak with regular oil, you'll have a major one with synthetic. The shear strength of synthetics is far superior to dinosaur oil and I'd bet the cam lobes would go forever.
Regards,

 

[Rob Erdos]

So, About those pre-oilers?

Hi. Interesting thread, since not much is written about pre-oilers for flat engines. I fly some warbirds, and pre-oiling is mandatory in our organization for the old engines. I was assuming it would help in a Lyc too.

Anyone care to take a stab at a few specific questions?...

What proportion of RV's use pre-oilers? Do the engine shops recommend them? Is it worth the additional weight forward of the firewall? What systems are on the market?

Thanks in advance,

Rob

 

[David-aviator]

Hey guys,
Just fly more and the lobes will stay wet!

Seriously though, my late boss had a P-51 which ate cam lobes since they ran directly on top of the rocker arms. After he started adding 10% STP, the lobes lasted and lasted and...since it doesn't evaporate/drip off like 20W50.

Mahlon, is 1 pint of STP OK in a 4 banger Lyc?
Regards,

I don't know about STP but I am a believer in AVBLEND. It supposedly will keep the top end oiled between engine runs.

 

[Noah]

What proportion of RV's use pre-oilers? Do the engine shops recommend them? Is it worth the additional weight forward of the firewall? What systems are on the market?

Rob

Hi Rob, I would guess that less than 1% of RVers use pre-oilers. There was a guy named Joachim Beh on the Lycoming List who made his own, beautifully constructed pre-oiler which consisted of a panel-mounted plunger similar to a priming plunger with two check valves. Not sure if he is on this forum or not, but if you search the Lycoming list's Yahoo group archives you will find some really nice photos.

I always wondered why there wasn't a system which was essentially "ground support equipment" - used only on those occasions where you haven't flown in over a month or whatever - you pull one of the two oil gallery (galley? I always get confused) plugs at the front of the engine and install your pre-oil hose, turn on the flow from your pre-oil tank which is pressurized with shop air and has a diptube to draw oil from the bottom of the tank (old propane tanks work great for this if modified to add a diptube, ask me how I know). Once you've pumped in a quart or so, disconnect the hose and reinstall the plug, torque, and go fly.

This approach eliminates airborne weight, complexity, and leak points. You do need to make sure you torque the plug (safety wiring it would be a great idea too)

I had Mattituck add the cam squirts to my case so pre-oiling thoroughly wets the cam lobes and followers. They make a very fine atomized mist which soaks everything starting at the top of the case. Obviously, all of the journals are lubed as well.

With pre-oiling and a DIY dehydrator to remove water in the oil generated from combusting fuel, I would think your Lycosaurus would last a long long time, unlike the engine I just finished overhauling, which had badly spalled cam followers and a shot camshaft

 

[G3i Ignition]

Does anyone here use the engine pre-oiler devices to supply oil pressure to a cold engine just before start? I've seen two basic types, an electric pump and an accumulator style. Do they work well enough to be worth the weight and complexity? How would you even know without running to TBO and tearing down?

Yep, I run a 3 qt accu-sump (accumulator, air pres./ oil) system with an electric solenoid to activate. Feeds directly in to a modified oil screen housing. Works great, serves me 3 purposes, 1) pre oilier. 2) Provides oil pressure to engine during sever aerobatics. 3) Keeps 3 qts out of the motor from getting aerated when flying inverted. Defiantly the way to go, especially if you plan on doing 0 g?s and or negative hanging.

Thomas Shpakow
www.g3inition.com

 

[frankh]

Same here

I use a 1.5 qt plunger style (Morrosso) for the same reasons as listed above..seemless oil pressure when going from positive to negatibve G and back

Frank

 

[bharral]

Questions for those with Oil/Air Accumulators

For those of you using oil/air accumulators, I am curious about how much time is available (at zero or negative Gs) before the oil pressure drops off. Also, please advise if your aircraft has an oil-controlled Constant-Speed prop?

Thanks
Blake Harral
RV-4 N72RV

 

[rocketbob]

Hey guys,
Seriously though, my late boss had a P-51 which ate cam lobes since they ran directly on top of the rocker arms. After he started adding 10% STP, the lobes lasted and lasted and...since it doesn't evaporate/drip off like 20W50.

Merlins that haven't been overhauled in the last few years tend to eat cams because the chrome plating wears off the followers. There's a guy in Canada that has an STC for followers that have a carbide tip brazed to them, they're called "merlin fingers" and they completely eliminate the problem. The guys at Roush hand delivered a camshaft to a Reno racer this year that discovered a cam lobe that had completely worn down to round...and the thing still ran in that condition.

 

[G3i Ignition]

QUOTE=bharral;385682]For those of you using oil/air accumulators, I am curious about how much time is available (at zero or negative Gs) before the oil pressure drops off. Also, please advise if your aircraft has an oil-controlled Constant-Speed prop?

Hello Blake,
With engine oil temp @ 180f the there is about 15 ? 20 seconds bleed down when the engine is not running and I switch the system on. In the air after flipping over to invert waiting for the Christian 801 system to prime I see a drop in oil press to a minimum of 50 ? 55 psi, were as in my Citabria flipping to invert, it went to zero psi for that brief (3 ? 5 sec.) moment, Citabria had the same system 801 C. Knife edging is extended 20 ? 25 seconds depending what side you knife edge on (lower oil pick-up tube high side) before there is fluctuations. The prop is oil controlled, do not see any rpm fluctuations. When pre-oiling cold, discharge @ 65 - 70 psi, temp @ 50f, 2 minutes. My system holds 3 qts.

Thomas Shpakow
www.g3ignition.com

 

[Dmadd]

Wondering

Would pulling the prop through 6 or 8 blades before starting do the same thing? (pre-oil everything)
Or how about letting that many blades go by before introducing fuel on the first start of the day?
DM

 

[ronschreck]

For those of you useing oil accumulators, where do you plumb into the engine? I am about to install a one quart Accusump.

 

[G3i Ignition]

Pre-lube & pressure feed location

Pre-Oiling is to lubricate (create a oil film on bearings, etc.) prior to any rotation of any parts. And have instant oil pressure on crank/start up. Pulling the prop thru several times prior to starting is just wiping the last shut down oil lubrication from all bearing and lifter contact surfaces. So when starting, you just removed quite a bite of left over lubrication.

Ron,
Good place to tap in for the accumulator is the rear of the oil filter adapter next to the thermostatic valve. Some have a pressure or temp. sender there. This can be drilled out and re-tap for a #10an fitting with a ??pipe connection. Just want to make sure that the acc. Oil is going to the flow to the bearings and no off pre-lubing the oil cooler and lines. I see if I have some pics on how I did this mod.

Thomas Shpakow
www.g3ignition.com

 

[bharral]

Good Afternoon Thomas,

Thanks very much for some actual data on the accumulator installation. I have always wondered about the "lubrication rate" on the Lycomings. From your data it sounds like a 3 qt accumulator plumbed into the oil filter adapter will provide 20 seconds of oil pressure to allow maneuvering in the zero or negative-g region. That would be assuming the hot oil flow rate with the engine stopped (the data you quoted) is not very much different from the hot oil flow rate with the engine running - not sure about the validity of that assumption.

However, if 20 seconds were available, that would suit my purposes just fine.

Assuming that you isolate the accumulator before shutdown (to hold the oil for pre-oiling prior to next start), what oil level do you run your lycoming sump (perhaps 5 qts in the sump and 3 in the accumulator?)

Regards,
Blake

 

[G3i Ignition]

IO-540 Supercharger & Manifold Oil Capacity

Good Afternoon Thomas,

Thanks very much for some actual data on the accumulator installation. I have always wondered about the "lubrication rate" on the Lycomings. From your data it sounds like a 3 qt accumulator plumbed into the oil filter adapter will provide 20 seconds of oil pressure to allow maneuvering in the zero or negative-g region. That would be assuming the hot oil flow rate with the engine stopped (the data you quoted) is not very much different from the hot oil flow rate with the engine running - not sure about the validity of that assumption.

However, if 20 seconds were available, that would suit my purposes just fine.

Assuming that you isolate the accumulator before shutdown (to hold the oil for pre-oiling prior to next start), what oil level do you run your lycoming sump (perhaps 5 qts in the sump and 3 in the accumulator?)

Regards,
Blake

Blake,
Your correct, 4-1/2 to 5-1/2 qts in the sump (acc.full charge @ 3qts.) when I go fly Acro. Cross country normal wings level ride 7 to 7-1/2 in the sump. My oil sump is modifide and very shallow for the supercharger install and that's why I don't see a whole bunch difference on the inflight loss of oil pressure during acro. After a oil service with 9qts in the sump my dip stick reads just slightly over 12qts. The 3qts that I lost in the mod., just went into the acc.

Thomas Shpakow
www.g3ignition.com