stid2677
SPONSOR
I love gadgets for sure,, and if I'm tinkering AKA (working) on the plane, I may be exempt from other task.
Thankful for the incredible amount of knowledge here.
O-360 Lycoming Crankcase Vent
- Thread starter stid2677
- Start date
I love gadgets for sure,, and if I'm tinkering AKA (working) on the plane, I may be exempt from other task.
Thankful for the incredible amount of knowledge here.
supercrow
FRIEND
Smith Pond near Millinocket, Me
Glenn, I have been using one without the separator for a year and a half. I do have the check valve tee in line in case the unit in the tailpipe should coke up. Have removed it a couple times and checked and it is clean. The tailpipe unit is available as said as an automotive part. You can take it off and shake it just like a pcv valve. Pleased with mine so far and no oil mess anywhere. They claim more HP, but I can't tell you if it does or not. It may but I have done no tests to try to verify.
cubdriver2
FRIEND
upstate NY
No , but thinking about it. Bottle works fine but my wife can smell it while flying
Glenn
When I get back to my airplane I’ll rig a vacuum gauge to measure crankcase pressure with and without the kit hooked up. Any reduction should be beneficial. Pulling blow-by vapors out has to be better than passive venting or obstructed venting with a bottle. It’s not a direct comparison since my before and after involved 2 engines but there’s no question my oil stays cleaner now.
akavidflyer
FRIEND
Soldotna AK
My oil turns dark pretty quickly 3-5 hours. Typical 0320, anything over 5.5 or 6 qts and its blown all over the belly in short order. Will sit at 5.5 qts for many hours of flying. I have a filter and I am hoping that the ASA kit will help with multiple things. All 4 cylinders 76/80 or better as of last months annual. Should know next week if there are any improvements!
CamTom12
Registered User
Huntsville, AL
That’s good to hear, actually. I just did a short oil change after a long period of inactivity and I was shocked how dark that oil with only ~6 hours on it was. Looked much worse in the sample jar than it did on the dipstick.
You just eased my mind a bit!
I have exact same engine and same results. I was looking at the ASA kit a few months ago so I will be very interested to see how your engine reacts.
I said I’d test it, so here’s what I found. I bought a Bosch pressure-vacuum gauge that came with a nice tapered stopper, perfect for my 3/4” vent hoses. I checked crankcase pressure and the exhaust fitting line’s pressure from idle through 2300 rpm. I was surprised to find both values stayed pretty even regardless of rpm. My crankcase vent makes 1/2 psi of positive pressure. Not alarming but I really didn’t know what to expect. My vacuum line draws 3” of vacuum +/- 1/2” of variation that wasn’t rpm related although it was more stable at 2300. The needle wanders a little at all rpms. The net result is the crankcase runs at about 1” of negative pressure. I did talk to ASA about adding a second fitting in the other tailpipe and was told not to bother. One does the job. I believe them. My vacuum kit is staying on.
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wireweinie
FOUNDER
Palmer, AK
Ok. Dumb question here. What exactly dictates the pressure inside the crankcase during engine operation. I guess all I've ever considered is the amount of blowby from the rings. Does the movement of the pistons effect this or do they cancel each other out, i.e., one piston moves into the bore as another moves out. What other factors are in play?
Web
Web
There’s lots of info on the net about crankcase windage and how engine builders manage it. Aircraft engines aren’t built like car engines so you need to keep the differences in mind, but clearly some of the issues apply. What I find interesting is the common thoughts about windage level in the crankcase. That’s the idea that more than 6 quarts of oil allows oil to get whipped into a mist and sent overboard at a greater rate than with less oil. In Lycoming engines the sump is isolated from the crankshaft and all other rotating parts, so why is oil pushed out the breather when running high oil levels? Anti Splat says it's slung from the accessory case gears. When they do dyno runs they use a tall breather so the spray drips back into the case. That makes sense.
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BC12D-4-85
SPONSOR
Fairbanks, AK.
Can also come from both ring and exhaust valve blowby in worn engines. Oil goes black quicker than when new.
Gary
Gary
Somebody asked for pics of my installation. Here’s the only important part, the tailpipe fitting. I put it where it fits with some clearance for engine shake. I can peek into the tailpipe and see the fitting, so checking it for coking is simple. I don’t recall whether in instructions say, but I made sure the vent line and exhaust fitting all ran downhill so any drops of oil got blown out instead of pooling. The hose end from the safety valve is visible between the tailpipes. The oil separator needs the outlet port above the engine’s return port. Easy peasy.
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Steve Pierce
BENEFACTOR
Graham, TX
Did you put that gauge in your crankcase vent? If so was there any other way for the engine to vent? To test for blow-by from excess crankcase pressure I have always modified an oil cap and read it there leaving the crankcase vent open. A snorkel style Piper cap fits the Continentals I have done it on and I modified a Lycoming dipstick/filler cap by drilling a hole and taping it for a fitting.
I wouldn’t expect any pressure at the dipstick with an open crankcase vent, and for my purposes I don’t think that’s an important value for what I was testing. I wanted to validate that the negative pressure in one 3/4” tube was greater than the positive pressure in another 3/4” tube it would connect to.
Steve Pierce
BENEFACTOR
Graham, TX
That is how the manufacturers have you test for excess crankcase pressure, leaking nose seal, leaking rings etc.
frequent_flyer
Registered User
Arizona, USA
Wasn't the original objective to reduce crankcase pressure and, hopefully, make it negative? Before and after measurements at the filler neck would seem to be a good indication of whether that objective was met.
I ran the engine with and without the vacuum connected, measuring at the oil filler neck. The tapered plug fit very nicely. No measured pressure change with an open vent. A little needle jiggle is all. 1-1/2” of vacuum with the system connected.
akavidflyer
FRIEND
Soldotna AK
I was going to install this on my 0320 but with the sutton exhaust i would have had the hose hanging outside the cowling if I put the fitting in the tail pipe. I talked to Al at ASA yesterday and he confirmed that I can install it just upstream of the exhaust can on one of the pipes. He said that unless you have a really restrictive exhaust can with a lot of baffling that it will work just fine on a single pipe into the can and not the "tail pipe".
I will get it installed next time home and see how it does.
I will get it installed next time home and see how it does.
akavidflyer
FRIEND
Soldotna AK
It is one pipe going into the can. Since it is right above the can, Al said it will still create the vacuum as the other cylinders will be pushing through the can as well and keep it under constant vac. I have a couple vac gauges so I will rig something up and test it to see how the numbers compare to yours
BC12D-4-85
SPONSOR
Fairbanks, AK.
I assumed headers and downstream mufflers were internally under some positive pressure from exhaust...four pipes in and only one out. It'll be interesting to see the test results.
Gary
Gary
akavidflyer
FRIEND
Soldotna AK
The end of the pipe sticking into the exhaust is cut at an angle and creates a venturi effect. The one way check valve doesn't allow any blow back and it just creates the vac pulses.
Al is a pretty interesting guy to talk to and put things into terms that made it easy to understand.
He also has an oil pan heater heater coming out that is pretty much like a block heater for other vehicles. Goes into an a drain port in the pan and the heating element is bathed in oil No trying to clean the pan off and get a heating pad to stick to it etc.
skywagon8a
MEMBER
SE Mass MA6
Four intermittent alternating input pulses with one outlet makes for a smooth flow.
BC12D-4-85
SPONSOR
Fairbanks, AK.
^^^^Yes but the system is still under some pressure relative to ambient. Otherwise exhaust leaks wouldn't occur at cracks or loose fittings. I grasp the angle end of the vent creating a localized low pressure. A long time ago we killed off rough fish in lakes with liquid rotenone. I installed a 1/8" tapered pipe into the lower jet unit of an outboard that would suck a 55 gallon drum of the stuff empty in no time. The jet was under pressure...the tapered pipe created a localized suction.
Gary
Gary
Pressure? Not important. Flow is what makes the fitting work. Max flow occurs in pulses from the exhaust of each cylinder and the check valve prevents back flow between pulses. My experiment shows that it works. I’m more tempted than ever to add a second fitting in the other tailpipe to see if the vacuum doubles, but I’m not sure more is better. 1-1/2” of vacuum through a 3/4” breather is probably adequate to get rid of the bad gasses.
BC12D-4-85
SPONSOR
Fairbanks, AK.
I'd monitor the inside of the valve covers and oil color over time potentially influenced by combustion gas blowby. Just to make sure a slight vacuum didn't encourage greater flow of those byproducts. Maybe include some oil sampling and analysis before and after the mod for good measure. Just a guess however.
FWIW:
General info: https://antisplataero.com/products/crankcase-vacuum-kit-complete
Installation shown earlier: https://drive.google.com/file/d/0Bw...Mm8/view?resourcekey=0-bjv7WrhL5OwV8MGITutb7Q
And a service reminder: https://drive.google.com/file/d/1TcYBrzU_T8s5BIAGKGwOEqlV-3gGzP-L/view
Gary
FWIW:
General info: https://antisplataero.com/products/crankcase-vacuum-kit-complete
Installation shown earlier: https://drive.google.com/file/d/0Bw...Mm8/view?resourcekey=0-bjv7WrhL5OwV8MGITutb7Q
And a service reminder: https://drive.google.com/file/d/1TcYBrzU_T8s5BIAGKGwOEqlV-3gGzP-L/view
Gary
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Gordon Misch
MEMBER
Toledo, Wa (KTDO)
I was thinking the same thing, except to perhaps slightly reduce internal windage in a much higher speed engine. Also, the fact that there is a vacuum now suggests that there isn't much blowby at this time.
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