RV8Squaz

RV8Squaz

Well Known Member
Hey Guys,
I now have about 80 hrs on my engine and RV-8. The engine is a freshly overhauled angle valve IO-360. During break-in, I used Aeroshell 100 mineral oil. During my first 25 hrs, oil consumption appeared to be about 1 qt per 8 hrs. I did an oil change and ran Aeroshell 100 again for the next 25 hrs. Oil consumption remained at 1 qt per 8 hrs. I changed the oil at 55 hrs and switched to Aeroshell 100W Plus. My oil consumption increased to 1 qt per 5 hrs and has remained that way since. I know "high oil consumption" is a relative term, but what gives? I didn't expect the increase in oil consumption just from switching oils. I know I'm not throwing it out. My belly, firewall, and cowl are clean. The air/oil separator that is part of my inverted oil system is very effective. Any of you guys have a similar experience?

I know can't run mineral oil forever, but I'm thinking about switching back to it for the next oil change just to see if there are any changes. I'm also curious if 15W-50 would have any affect.

Thanks,
Jerry
 
My IO360 has only thirty hours on it and I am still running mineral oil. It is an Aerosport Power Engine and it throws up out of the breather anything more than about 6 1/2 - 7 qtz. Bart told me that was pretty normal.
You can smell the oil burning off on the exhaust as my breather directly outputs there for that purpose.
If I let it find its own level somewhere between 6 - 7 quartz, my oil consumption is much less than a quart per 8 hours, maybe 1/2 quart per ten hours or so.
So, I simply do not put the extra oil in it. Not sure if you are filling to 8 quartz or not. Just a thought.
Good luck.
 
JonJay said:
My IO360 has only thirty hours on it and I am still running mineral oil. It is an Aerosport Power Engine and it throws up out of the breather anything more than about 6 1/2 - 7 qtz. Bart told me that was pretty normal.
You can smell the oil burning off on the exhaust as my breather directly outputs there for that purpose.
If I let it find its own level somewhere between 6 - 7 quartz, my oil consumption is much less than a quart per 8 hours, maybe 1/2 quart per ten hours or so.
So, I simply do not put the extra oil in it. Not sure if you are filling to 8 quartz or not. Just a thought.
Good luck.
Click to expand...
My experience is the same as this post.

What kind of cylinders is Jerry using? CHROME cylinders will use a LOT more oil than the Nitrite or steel cylinders.

My steel cylinders use about 1 quart every 6 or 7 hours. I have over 2,000 hours on my RV / engine. Was down around 1 quart every 25 hours when it was only 25 hours through 400 hours.
 
I have a factory new Lycoming 0-360 A1A from Van's. I broke it in using Aeroshell 100, changing it at 1 hr, 25 hrs, then 50 hrs, all changes with new filters. I changed the oil at one hour to get rid of any machine particulate and preservation oil not drained in initial draining. I was using about 1 qt in 14 hrs. When I switched to 15W50 Aeroshell, my consumption dropped to about 1 qt in 20-22 hrs. I change oil and filter at 25 hrs so I haven't had the need to add. I put in 8 qts with the new filter. The level drops to about 7 quarts (maybe slightly higher) after running up to check the filter. The level reaches the 6 quart mark at about 25 hrs. I get very little oil residue on the belly of my plane.

Roberta
 
Yeah, I used Mineral until 50 HR's, then switched, it's hard to tell what gives, but leave mineral in it awhile longer would be my suggestion. We have new Superior Cylinders.
 
Thanks for all the quick replies. I have Cerminil cylinders and was told they break in very easy. I did all the proper stuff during break in. The oil consumption quickly stabilized at 8 hrs/qt. The oil consumption didn't change until I switched oils. In any case, even at 8 hrs/qt, it sounds like I have a lot higher oil consumption than the rest of you.

Jerry
 
Hi Jerry - I have cerminil like you, and I get 7-8 hours to the quart. I am beginning to think that the Cerminils just don't get the same level of oil usage as other treatments....but the engine is doing just fine!

Paul
 
I have the same cylinders you have, Lycoming angle valve 200hp. Does every body posting have the same cylinders or are we comparing apples to oranges? I just did a very major overhaul about a year and a half ago and installed brand new Lycoming cylinder kits, we did nothing special just installed them as they came, there nitrite by the way. After 50 hours of Aero Shell 100 it was steady at one quart in eight hours, I then started using Aero Shell 15-50 and it stayed the same but has slowly gotten even better to an average of one in 9 to 10 hours, I think it?s at about 300 hours now. Some one did a poll on hear a wile back for this cylinder type Lycoming and I think the average was between 8 and 12 hours per quart.

I vote you dump that oil out and put back mineral oil, if it comes back then next time go for 15-50 if it does not come back then you might have a problem like ring gaps stuck lined up or something, other then this you need the pros to help.
 
What color?

I ended up with poor seating on a set of rings and the oil would darken to near black very quickly - litterally within a few hours -even though it was only burning a quart every five or six hours. Compression was great.

Although it is ok to tolerate consumption, you should not tolerate blowby that is contaminating oil. It will show up as premature wear on moving parts and higher levels of corrosion.

New rings, hone and 10 hours of hard running with mineral cured it. Now still nearly the color of new oil when oil has been in 25 hours.
 
One of the early posters mentioned something very valid - don't fill it full !

I run an O-320 - I always run at 5 - 6 qts, never blows any away - if I put an extra qt in it disappears.

Unless you are setting off on a very long trip I would run at least a qt less than full.
 
CFR 33.39

CFR 33.39 states:

"? 33.39 Lubrication system.
(a) The lubrication system of the engine must be designed and constructed so that it will function properly in all flight attitudes and atmospheric conditions in which the airplane is expected to operate. In wet sump engines, this requirement must be met when only one-half of the maximum lubricant supply is in the engine."

The way the CFR reads is that it has to "hold" twice the amount of oil needed to operate. It does not say that it has to "run" with that much oil in it so the sumps are big and as most have stated a lot gets thrown out if you keep it "full" to the max.

You don't need to get too paranoid about not having the sump "full." As mentioned above I also keep mine at the 5 to 6 quarts in an 8 quart sump knowing that I am one to two quarts to the good side. It is enough to keep the temps cool and keep the belly clean.
 
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I emailed our resident engine expert, Mahlon Russell, about my oil consumption changes. This is what he had to say:

"Jerry,
Saw your post but will answer here. If you want to pass along...fine with me.
Oil consumption is a relative thing. Average oil consumption for an angled valve IO-360 is likely a quart in 6 or7 or so. Average on a parallel valve is around 7-8 per quart. Some will do a quart in 25 and some a quart in 4. A quart in 5 isn't abnormal but isn't great either on that angled valve engine.
The molecule size for the weight oil you have will have an effect on the viscosity seal of the ring to the cylinder wall. Most times switching to a partial synthetic will make the oil consumption get better but sometimes it will deteriorate slightly, as it did in your case. I don't think that switching back to mineral will change the consumption when you switch back to AD oil. Sounds like you are as broke in as much as you are going to be. If the oil isn't turning really, really black in short order (under 10 hours) and you are not getting any plug fouling I wouldn't be too concerned.
If you do pursue this don't assume all cylinders are effected and causing an issue. One cylinder can take an engine that was otherwise doing a quart in 8 to a quart an hour. So look at them closely before deciding which one or all to remove. Cermi nil normally yields the same oil consumption average as nitrided in my experience.
Doing the switch back to 50 weight recording the consumption and then switching and recording the consumption will confirm it is an oil molecule thing.
Good Luck,
Mahlon"

I'm going to address the blow-by issue by taking a look at the plugs and maybe doing a compression test. I'm also going to either switch back to mineral oil for one oil change or 15W-50 as one of the earlier posters did.

Also to re-iterate I don't believe I'm blowing the oil out of my breather since I have a very effective air/oil seaprator which is part of my inverted oil and my belly is clean.


I have heard that these engines are supposed to be able to run on half the sump capacity, but in real life that is not the case on my engine. I have an angle valve IO-360 with a Hartzel constant speed prop and my prop will surge if I am below 5.8 qts and in a descent. I have a buddy with the same engine and prop, also in an RV-8 and his does the same thing when below about 5.5 qts. I usually keep my oil level below 7.5 qts as I typically refill when it gets under 6.5 qts.

Thanks for your help guys!

Jerry
 
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