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One quart low.

S2D

S2D

MEMBER
Montana
I was always taught to leave the engine one quart low cause the last quart would always blow out anyway. Until an old timer asked me how the hell is it going to blow that last quart out. the oil level is quite a ways below the crankshaft.
Since then I have always added the recommended oil and have never seen that problem. Most engines I've run will make it to the next oil change before it gets below 6 qts so I just change oil instead of adding a qt.
Anybody still leaving it a quart low?
 
Steve Pierce said:
Depends on the engine. Some I do and some I don't. Some blow it out and some don't. PFM.
Click to expand...

Same here! My 100hp x O-235-C (from a PA-12) always blew the first quart out in less than a couple hours and then ran happily on the next quart for over 13 hours. My O-320 on the other hand seems to do fine without blowing anything out, yet an identical set up in another aircraft in the hanger blows the first quart out quickly as well and then runs for many hours on the next one.

Wayne
 
My O-320 goes through a quart about every four hours it does not care if I start with eight quarts or six quarts. From the looks of my planes belly I would have to say it is being blown out I would like to find a simple fix for this without installing a recovery system. My engine is factory new with about 900 hrs on it.

Cub_Driver
 
So my big question is: why would it blow that extra half inch of oil out of the sump? Every engine I have that blows oil continues to blow oil.
I'd be interested to see if all those that keep their engine a quart low would accurately figure how long it took to use 2 quarts- from 7 to 5- then try it again from 8 to 6. And see how much difference it really makes.
I haven't tried it so I don't know.
 
S2D said:
So my big question is: why would it blow that extra half inch of oil out of the sump? Every engine I have that blows oil continues to blow oil.
I'd be interested to see if all those that keep their engine a quart low would accurately figure how long it took to use 2 quarts- from 7 to 5- then try it again from 8 to 6. And see how much difference it really makes.
I haven't tried it so I don't know.
Click to expand...

Think of that recipricating group as a large fan. The closer the oil is to it the more chance that there is of drawing/blowing the oil from the pan into a mist and out it goes through the breather. In a 383 Magnum (and other engines from the muscle car era) there is what is called a "windage" tray to stop exactly this. The tray in the oil pan is there to keep the crank from picking up the oil at high rpm as per the above senerio.

Wayne
 
I know that the O-235 and O-290 with the crankcase vent up front have a little different problem. There is a small grove cut in the case halves that lets the oil from the front main bearing back into the sump. I have seen many O-290s throw oil out the breather and I have installed a deflector in the elbow and tried other fixes but someone told me they fixed it by enlarging the slot to let the oil out and keep it from getting blown out. I haven't had one do it lately but it worked for him.

cub_driver I think your rings are worn. I had an O-235C1 that used a quart every three hours and had compression in the 70s. When it went to a quart every 2-2 1/2 I changed the engine and tore it down. No catastafic wear just no bevel left on the rings. It had 2600+ hrs on it.
 
If I put more than 6 qts in my 0320 it blows oil down the side of the aircraft.

Torch A real cub pilot not a wanna be.
 
Another thing to consider, folks is that, frankly, the dipsticks on these things aren't exactly micrometers. I doubt that any dipstick can accurately measure the oil quantity in an aircraft engine that is standing at a 30 degree slope of its oil pan, the total range is about two inches, and the stick is seated sorta in the same spot every time.

Over fill an engine a bit, and it blows out the excess. When it's at a happy level, it stops spitting oil out.

If it says 6 quarts, you put in a quart and it spits it out on the next flight, but stays at the 6 for the next ten hours, I'd assume that that is where that engine would like it's oil level to be kept.

Good enough for me.

Try putting a 185 on floats sometime, and have an inexperienced pilot go fly it. They'll put an extra three quarts in every time, because the dipstick is no longer accurate, and they didn't notice the two X's on the back of the stick which represent the acceptable range for floats.

Oil everywhere, and it'll turn the engine into a drooler forever. If the engien doesn't want more oil, don't try to force it.

Mike Vivion
 
mvivion said:
Another thing to consider, folks is that, frankly, the dipsticks on these things aren't exactly micrometers. I doubt that any dipstick can accurately measure the oil quantity in an aircraft engine that is standing at a 30 degree slope of its oil pan, the total range is about two inches, and the stick is seated sorta in the same spot every time.

Over fill an engine a bit, and it blows out the excess. When it's at a happy level, it stops spitting oil out.

If it says 6 quarts, you put in a quart and it spits it out on the next flight, but stays at the 6 for the next ten hours, I'd assume that that is where that engine would like it's oil level to be kept.

Good enough for me.

Try putting a 185 on floats sometime, and have an inexperienced pilot go fly it. They'll put an extra three quarts in every time, because the dipstick is no longer accurate, and they didn't notice the two X's on the back of the stick which represent the acceptable range for floats.

Oil everywhere, and it'll turn the engine into a drooler forever. If the engien doesn't want more oil, don't try to force it.

Mike Vivion
Click to expand...

Mike has the right answer again. :D
 
Steve Pierce said:
cub_driver I think your rings are worn. I had an O-235C1 that used a quart every three hours and had compression in the 70s. When it went to a quart every 2-2 1/2 I changed the engine and tore it down. No catastafic wear just no bevel left on the rings. It had 2600+ hrs on it.
Click to expand...

Steve I have over 900 hours on a factory new 0-320 all cylinders except one are in the high 70s or at 80 one is in the mid 70s could I have one cylinder causing me this trouble?

Cub_Driver
 
cub_driver said:
Steve Pierce said:
cub_driver I think your rings are worn. I had an O-235C1 that used a quart every three hours and had compression in the 70s. When it went to a quart every 2-2 1/2 I changed the engine and tore it down. No catastafic wear just no bevel left on the rings. It had 2600+ hrs on it.
Click to expand...

Steve I have over 900 hours on a factory new 0-320 all cylinders except one are in the high 70s or at 80 one is in the mid 70s could I have one cylinder causing me this trouble?

Cub_Driver
Click to expand...
My two cents are you have to be very cautious of compression readings when it's an oil usage issue. I bought a C182 about 12 years ago after the prepurchase showed that all 6 cylinders were 75/80 or better. We then found that it ate (no leaks) 5 qts of oil on it's first 4 hour cross country :( . Apparently there was so much oil in the rings that they made a nice seal for testing. So the compression test is is a false indication as to the integrity of an engine, in my books, and all other avenues must be looked at as well :eek: .

Cheers,
Wayne
 
My engine that used 3 qts an hour for years had compression in the 70s and the plugs were always clean. What I have learned is that the rings have a bevel and that bevel wears and allows pressure from the combustion chamber to bypass the rings and that pressure goes out the crankcase vent with vapor oil in it. Lycoming allows up to a quart every three hours. I wouldn't worry to much about it. It also could be that the rings were never seated properly causing the cylinder walls to be glazed. I have had good luck removing the cylinders, putting a cross hatch in them with a pineapple hone and installing new rings. Like I said in my previous post when I tore the engine down I didn't find any real wear other than the rings. I had been doing oil analysis every 100 hrs. with normal wear.
 
2 cents,

I run the 0320 with 6 quarts, except if I know I am not stopping for 5 hours? Then I add one more (if the weather is hot) The extra quart add a small degree of cooling.

I do agree that ring/piston/ cyclinder choke is a major contributor to oil throwing.

My current 0320/160 with 400 hours since major, uses only 1 quart in 25 hours, then a little more till fifty hours. I have noticed the greatest improvement in oil consumption was the addition of an "oil filter".

Seems the oil consumption starts to creep up when the oil starts to get dirty?????

Tim
 
Tim,

I have noted this as well, particularly in engines which have filters, and we run to 50 hours on the same oil. While I still go 50 hours on filtered oil, I'm having thoughts about changing the filtered oil at 25 hours, just like on the unfiltered setup.

Oil does "wear out", according to Ben Visser, and other oil gurus.

Mike Vivion
 
Well this has been a interesting and possibly expensive post for me :roll: I sure thank you folks for your advice I am still running within limits but I doubt my oil consumption will get better on its own are there additives that can help? How much should I expect to pay for a top overhaul? If my rings are shot do I have a choice in rings to install? What oil filter would you suggest for my cub?

The comments in this post made sense to me thanks for your help.

Cub_Driver
 
Cub Driver,

Find a good engine shop, or a mechanic you trust, and have them take a look at the engine, with a full explanation of the issue. That's a lot of oil, but still legal.

DON'T put a "recovery system" on an airplane up here in Alaska or anywhere else cold. These things will freeze up and push the nose seal out of your engine. Then kaput.

It's possible that, as previously noted, you can get away with pulling the cylinders, honing them, and installing new rings. That will cost some, but it isn't like getting into the bottom end of one of these things.

If you're lucky, it just wasn't broken in right, and the rings never seated.

Mike V
 
oil consumption

Cub-Driver: When troubleshooting start with the easy stuff. Clean your engine with solvent, then make sure your oil is coming out the breather(not your accessory case area). If the oil is coming out the breather, then you need to check your case pressure, this will tell you if you have a cylinder(s) pressurizing the case. If it is reading too high a pressure, this is where things can start to get expensive. But if your rings are just sticking due to excess lead or carbon(burnt oil), you can sometimes clear it up by adding avblend at your next couple oil changes. Look for excess deposits in the combustion chambers and oil that gets dirty(turns black) too quickly after changing for clues. Do these things before pulling and honing cylinders.
 
Mike V

Thanks I have been warned of the recovery systems in cold weather in the past. When I bought my plane from an old polar bear hunter he had a hole drilled into the top of the breather tube just incase it froze up on the outlet and produced the results you mentioned. Thanks for the reminder.

nanook

I am sure the oil is through the breather so how do I go about checking the case pressure? What pressure is acceptable? I do have a can of avblend on the shelf waiting for my next oil change I never though about lead fouling on the rings I am always flying low and hardly ever lean my engine. How many hours should I be able to run my oil before it starts to look dirty?

Thanks

Cub_Driver
 
cub_driver,

I would suggest a BC oil filter adaptor, uses a Champion CH4808/10 filter, It is STC'd for Supercub and will accept the vernitherm if you have one.

Another contributor to oil consumption is "poor warmup" proceedures, To many people don't allow their engine/ parts to warm up. This causes excessive piston slap and can result in broken rings. I have also seen this cause carbon to be dislodged and caught in the ring lands, causing rings to brake or further scuff pistons/cyclinder walls. Another byproduc is condensation forming in the engine, this causes rust and premature wearing.

Having spent 30+ winters in Alaska flying cubs, I am guilty as the next guy in doing inadequate preheating. Unfortunately we often only heated the engine till the dang thing would start? I would suggest one of the new blanket heaters on the sump and also the cylinders (if you are fortunate enough to have 110v? If not heat the engine till you see the oil temp come off the peg a 1/4" before starting then (don't let the engine Idle at low temp but run it at 1000rpm till things stablize (just an opinion) I can tell you I have run several 0320's to past TBO with out having to top them.

I also used to change the oil religiously at 25 hours and never left my plane with out running it for more then 10 days! (do not just go out and "turn it over" this does more damage then never running it!!

As for cost. Check with John Alsworth or maybe PM Dave Caulkins

Tim
 
A quart every 4 hours isn't that bad. I'd put a baby bottle on it and run the piss out of it. If you do put a bottle on, my guess is the amount of oil you catch won't equal what you're losing. (Valve guides?) If it's making good power, it ain't broke. If it ain't broke.....don't fix it.
SB
 
I agree with Stewartb. Run the AVBlend or Marvel Mystery Oil for a while and see if your consumption improves. The crankcase pressure can be measured by hooking up an airspeed indicator to the dip stick. I modified an old dipstick by drilling and tapping it for a hose fitting. You will ruin an airspeed indicator in the process. I would use the Avblend or MMO and run the piss out of it first.

The B&C filter adapter is the best deal in my opinion. I have installed them all and prefer it. No hoses, more room in the accesorry section and simple. Just my opinion.
 
I'll go with stewartb and steve also.........I have 200 hrs. on my rebuilt 0-320 and it uses about a quart every 4-5 hrs. Runs great and comps are all high 70's. Maybe I didn't get the rings seated properly but I am not going to change anything. I have one small engine leak off an accessory housing plate that I will seal next time I swing out the engine and my baby bottle catches very little of the oil consumed.
 
Thanks for the advice I will add a BC filter adapter and filter when my pocket book allows.

I am due for a 25 hr oil change so I will add the AVBlend according to its recomendations. I plan to hunt Caribou this week and am sure to put on close to ten hours plus I should be putting a few hours on the next week chasing moose and ducks. Hopefully I will start see a improvement at that time if not I will check the case pressure. I would like to have a better idea type of case pressure to expect, will it be inch of H2o or psi?

During winter I keep my plane in back of the house where it is plugged in and toasty warm before I had that option I always preheated with a red dragon heater. My preheats have always been good even in the summers I start my engine and run it at 1000 rpms until my cylinder head temps reach 200, I believe my warmups are sufficient. I am however guilty of shock cooling I don't know how I can avoid this flying in subzero temps.

I will keep you updated on my oil usage thanks again for the advice.

Cub_Driver
 
Thanks for the advice I will add a BC filter adapter and filter when my pocket book allows.

I am due for a 25 hr oil change so I will add the AVBlend according to its recomendations. I plan to hunt Caribou this week and am sure to put on close to ten hours plus I should be putting a few hours on the next week chasing moose and ducks. Hopefully I will start see a improvement at that time if not I will check the case pressure. I would like to have a better idea type of case pressure to expect, will it be inch of H2o or psi?

During winter I keep my plane in back of the house where it is plugged in and toasty warm before I had that option I always preheated with a red dragon heater. My preheats have always been good even in the summers I start my engine and run it at 1000 rpms until my cylinder head temps reach 200, I believe my warmups are sufficient. I am however guilty of shock cooling I don't know how I can avoid this flying in subzero temps.

I will keep you updated on my oil usage thanks again for the advice.

Cub_Driver
 
When Steve mentioned using Marvel Mystery Oil it reminded me two things. One, we always mixed it in the gas for a 145 Warner Scarab we had, and two I recently read an article in the Cub Club newsletter abut a fellow that had been testing his C-65 with a synthethic 2 cycle oil mixed in the gas. I think he said it didn't have the rocker clatter you normally hear with the 65, and some other points. Seems to me, it might be better than MMO in the gas, since it is made to burn, and is a synthetic (better lubricity). Steve, did you mean MMO in the gas or oil? Anyone heard of this, and what are your thoughts? What would the disadvantages of adding a syn to the gas? I think he was only adding 2 to 6 oz. per gallon (can't find the article).
Wilbur
 
Wilbur..........I've heard some guys :wink: use about 3 oz. MMO per 10 gals. of fuel. This works well especially if you are using auto fuel. Also a pint of MMO at oil change keeps things clean.

Be sure to mix well in a blender first !! 8)
 
One quart low

I had an A65 with a really thick walled vent hose. One day on very close inspection, I noticed a lengthwise slit in the hose close to the engine. An old timer said it was often done on purpose in case the end of the hose got frozen. The thick hose closed right back up and it looked like it would have held water, but not under any pressure. So I'll bet you could hook up a recovery bottle with this "safety valve". Don
 
Wilbur,
I've always added approx 3oz. MMO per 10 gallons of gas. It's easy for me since I dispense fuel from a 100 gallon tank in my truck. 1 quart MMO per 100 gallons. I was taught to do it and always have, with no detrimental effects. Something to keep in mind if you add the amount of 2-cycle oil you mentioned is that oil added to gas tends to lean your mixture because you're displacing fuel. I've watched guys burn their 2-strokes up in the cold by adding extra oil to the gas, when common logic is that it richens the mixture. It's quite the opposite. Watch out for detonation.
SB
 
Been adding MMO to the fuel for years and to the oil when stuck rings were suspected. Can't recall the ratio but it was per the can. Don't know about 2 cycle oil. MMO is tried and true. Military used it in round motors and all the antique guys have used it for years. I hadn't thought about the oil leaning the mixture.
 
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