engine pre-oilers

airguy · #1 11-14-2006, 08:09 PM

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 · #2 11-14-2006, 10:14 PM

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 · #3 11-15-2006, 04:40 AM

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 · #4 11-15-2006, 07:32 AM

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 · #5 11-15-2006, 08:15 AM

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 · #6 11-15-2006, 07:25 PM

So roller followers are a good idea?

Pete

captainron · #7 11-16-2006, 03:32 AM

Quote:

Originally Posted by pierre smith

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 · #8 11-16-2006, 05:07 AM

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 · #9 11-16-2006, 05:42 AM

Quote:

Originally Posted by pierre smith

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 · #10 11-16-2006, 08:01 AM

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,