Crankcase Breather on A65 Champ

gusc · Post by **gusc** » Mon Aug 07, 2006 16:47

Is there a specific reason the breather end is on the left side, like propwash direction?

I did a lot of research on breathers a couple of years ago but don't remember anything about one side or the other being better.

I could eliminate a lot of breather hose and routing nuisance by changing it to the right side or center.

I eliminated a couple of low spots in the hose but would like to move it away from the left side.

Ron Babos · Post by **Ron Babos** » Mon Aug 07, 2006 18:02

gusc: My breather is on the right side of the plane and engine. Pretty much straight down to the air outlet and firewall. It's on the right side of the engine which is #1and #3 cylinder because the case studs go to the left side which would crowd things . The right side has more room between the snout and #3 cylinder for the breather elbow.
Ron

gusc · Post by **gusc** » Mon Aug 07, 2006 18:53

Ron,

Thanks. I didn't want to mess with it even though it doesn't appear to be venting any oil of any consequence. I know that some aspects of crankcase breather installation are critical so I didn't want to take any chances.

I know that the line is not supposed to be in the slipstream where it will cause a high negative pressure in faster planes but might not make any difference in a Champ!

How far below the firewall is the end of yours?

Mnflyer · Post by **Mnflyer** » Mon Aug 07, 2006 19:59

Hi Gus mine is like Ron's on the right side of the engine and it ends up in the cowl it doesn't stick below the cowl at all. I guess if your not venting any oil thats a good thing, I don't think I'm losing much oil but even a drop on the belly makes a mess, and I know it drips onto the drip pan I plane under the engine in the hangar. I just found a site yesterday about a breather elbow modification to cut down on oil venting out the breather.

gusc · Post by **gusc** » Tue Aug 08, 2006 02:44

GB,

Mine drips at rest also but Continentals are supposed to drip oil!!

I don't see any on the belly. My hose ends just inside the colwing up against the firewall of the right side.

I think that it is not supposed to hang below the firewall and that is the way I will rig mine.

Tell me more about the breather elbow modification.

You want it to vent out the breather. If it doesn't it can vent through the front crankshaft seal. The breather is better. In MN you probably need a small hole in the vent tube just a vew inches above the end also. This is in case the vent tube end freezes and plugs the tube.

Nathan K. Hammond · Post by **Nathan K. Hammond** » Tue Aug 08, 2006 12:52

Gus,

The mod is fairly simple. Remove the 90' Elbow fitting at the engine, find a piece of brass tubing that can slide into the engine-side of the fitting. Braze in the tube, and cut it off so it stick out about an inch or inch-and-a-half (someone will have to back me up on that measurement, I don't have the data in front of me.)

The thinking is oil runs down the case wall and flows into the breather fitting. With the modification, oil is less likely to drip into the brass tubing and it also cuts down on the oil that splashes into the fitting.

All in all, it probably takes about an hour to do the mod, start to finish. And I think it cuts down on the blow by, and keeps the belly a little cleaner.

nkh

Mikek · Post by **Mikek** » Tue Aug 08, 2006 14:05

Nathan K. Hammond wrote:Gus,

The mod is fairly simple. Remove the 90' Elbow fitting at the engine, find a piece of brass tubing that can slide into the engine-side of the fitting. Braze in the tube, and cut it off so it stick out about an inch or inch-and-a-half (someone will have to back me up on that measurement, I don't have the data in front of me.)

The thinking is oil runs down the case wall and flows into the breather fitting. With the modification, oil is less likely to drip into the brass tubing and it also cuts down on the oil that splashes into the fitting.

All in all, it probably takes about an hour to do the mod, start to finish. And I think it cuts down on the blow by, and keeps the belly a little cleaner.

nkh

Ron Babos · Post by **Ron Babos** » Tue Aug 08, 2006 14:44

gusc: What I have is hose from the elbow to just under the cylinders at which point a short piece of the original whistle tube is installed. From there it continues with hose to the bottom of the firewall. With the warm air coming down from the cylinders blowing on this should maintain venting should the opening at the firewall freeze up in winter.
I agree they will all drip sitting there after flying. They also drip in flight. Finding the exact outlet location will make a difference as to whether the drips end up on the boot cowl bottom or travel out with the cooling air outlet missing the aircraft. I'm flush with the chin at the moment and after an hours flying I will have a trace amount of oil smear on the bottom of the boot cowl. I plan on cutting the hose a 1/2 inch up from there and see if I can find that sweet spot. Mind you, I run my 65 close to 2300 all the time so it will puke a bit more than say 2150 rpm.
The breather extension may or may not help as I have found out with a shop rebuilt C85. These engines and up have a fuel pump lobe on the camshaft and it acts like a big oil slinger and can throw a bit more oil out of the breather. In this particular engine, in a Cub, the extention made no difference and he ended up putting a long hose on out to the step. After landing, it will drip a six inch circle on the ground or his foot.

Running the breather line uphill over the top of the engine and then down along with the breather extension is the best solution usually. If it is still throwing oil after this, the only real fix would be honing and new rings.
Ron

Nathan K. Hammond · Post by **Nathan K. Hammond** » Tue Aug 08, 2006 21:08

Thanks Mike, thats the article I was looking for.

nkh

gusc · Post by **gusc** » Wed Aug 09, 2006 01:11

Ron,

I have the rise from the elbow, this is supposed to give any condensing oil a chance to run back into the engine. Without the rise all oil will surely drain out the hose.

I presume that what you are saying is that the elbow extension works on the A65 but not the higher hp ones?

What is the purpose of the short piece of whistle tuba and what is whistle tube? Is this the no-freeze hole? If so, why not just make a hole on the high side of the hose ?

Why do you cruise at 2300 rpm?

My Navion had the breather exit just behind the exhaust so it burned the oil mist. I thought at first that this looked pretty dangerous but finally realized that there was no danger of fire.

Nathan,

Thanks, this seems to be a pretty simple solution.

Mikek · Post by **Mikek** » Wed Aug 09, 2006 07:33

gusc wrote:Ron,

I presume that what you are saying is that the elbow extension works on the A65 but not the higher hp ones?

This will work on cont a65 up thru 200 on the 0-200 cessna has it all ready made 2000 price $ about 265.

What is the purpose of the short piece of whistle tuba and what is whistle tube? Is this the no-freeze hole? If so, why not just make a hole on the high side of the hose ?

The hole needs to be up by the engine case and muffler to get the heat.
Hole also should be in the metal tube to hold it form, in the hose it might weaking the hose and it could close up.

Why do you cruise at 2300 rpm? Ron why?

Many people say that this little engines need to be run and that they will last longer and the heat generated will also evaporate the moisture build up.
My Navion had the breather exit just behind the exhaust so it burned the oil mist. I thought at first that this looked pretty dangerous but finally realized that there was no danger of fire.

Nathan,

Thanks, this seems to be a pretty simple solution.

Mikek · Post by **Mikek** » Wed Aug 09, 2006 07:42

[quote="gusc"]Ron,

I have the rise from the elbow, this is supposed to give any condensing oil a chance to run back into the engine. Without the rise all oil will surely drain out the hose.

Would you not want the condensing oil to get out of the case? This can not be good for the engine and these engines need to get the heat above 170 -180 f for a period of time to get rid of it.
Mikek[/i][/b]

Ron Babos · Post by **Ron Babos** » Wed Aug 09, 2006 08:05

Mike, gusc: I will reply to these questions, but the women is forcing me to go golfing

right now. Later.
Ron

Ron Babos · Post by **Ron Babos** » Wed Aug 09, 2006 15:23

gusc: Mike answered it pretty much, but I'll expand on it a bit. The whistle tube may have been an original breather tube made of aluminum. In an area under the engine it has a cut across the tube and the front area of the cut tube is pushed down about 1/4 the tube dia. I made a new one at about 4 inches long and put it inline with a regular neoprene breather hose. Since I don't have a muffler I chose under the cylinders for the heat source. Should the breather opening freeze at it's normal hole at the bottom, the whistle won't. No mist or oil comes out of it in normal operation.
I didn't say you could not use the breather extension on the 65, but it was developed for the higher horsepower higher rpm engines which will naturally tend to throw more out the breather.
I run my 65 at 2275-2300 all the time for many reasons. My Champ is heavy, as it was a 7dc with wing tank and Cleveland hydraulics, large tail and so on. At 2150 rpm it's a pig. At 2300 the engine is smoother, the plane gets on the step and goes. Just works and feels better.
I like my oil to hit at least 170-180 for temp. At 2300 rpm along with no cool tins on the bottom of the case and the opening under the prop of the nose bowl plugged all year, it will never go over 185.
Below 170 degrees on the oil you are making water inside the case and when running the breather over the top of the engine more water will run back into it. Oil temp must be kept high enough to minimize this.
The A-75 and 65 are basically the same engine and the 75 is redlined at 2600. The pistons and exhaust valves are the only thing that will allow this rpm over the 65. At 2300 all day with the 65, it is not even close to hurting the stock pistons or exhaust valves. Notice the tbo for the 75 is the same. Then theres the A-80 which is the same as the 75 except for higher compression (65-75 same) and is rated at 2700rpm. This engine showed the limits of the crankcase. Many cracked.
Many engine builders will joke about the 65 as having two throttle positions like idle and full, but most will say they will give less trouble if run hard. This may very well be true on a constant diet of 100LL.
By the way, I absolutely suck at golf. It's a good thing I can fly

Ron

Mikek · Post by **Mikek** » Wed Aug 09, 2006 21:37

[[quote]quote="Mikek"][quote="gusc"]Ron,

I have the rise from the elbow, this is supposed to give any condensing oil a chance to run back into the engine. Without the rise all oil will surely drain out the hose.

Mikek