• If You Are Having Trouble Logging In with Your Old Username and Password, Please use this Forgot Your Password link to get re-established.
  • There is no better time to show your support for SuperCub.Org than during our annual calendar campaign! All the details are HERE

Drawing for Firewall-Mounted Crankcase Vent tube

Jasperfield

Registered User
NC
Is there a Piper drawing for a firewall-mounted crankcase vent tube available? If so, how may I get a copy?

Thanks,
Jasperfield
 
try not to ever attach it to firewall or engine mount... to minimize vibration transfer......

Your gonna have to explain that one Mike, my crankcase vent is attached to the lower engine mount tube just like Piper did with friction tape and after 12,600 hours it is the original swedged tube. Just installed one on a rebuild but used Adel clamps.
 
This is how Piper did it.
98940061.jpg
 

Attachments

  • 98940061.jpg
    98940061.jpg
    692 KB · Views: 2,004
We do lots of things to improve on how Piper did it. If the vent tube is connected to the engine there's no flex in the line when the engine shudders and shakes. It all moves as a unit. How can that not be better than attaching a tube to a rigid point? It may be a minor detail but minor improvements are still improvements.
 
Mike made a standoff to support the breather and the left Pmag blast tube. I don't remember exactly where he landed it on the engine and can't find a detail picture.

Why hang the breather down below the cowl? I remember a Cessna 172 AD that required a whistle hole and for the breather be cut off above the bottom cowl. I did it on my 180 and the oily belly went away. I don't know what's right or wrong but I want the breather to vent. It doesn't need to be vacuumed by the slipstream. I don't miss the oily belly.

Found the AD link. http://www6.landings.com/cgi-bin/get_file?pass=12345&ADS/1982/82-07-02.html
 

Attachments

  • IMG_0718.jpg
    IMG_0718.jpg
    725 KB · Views: 336
Last edited:
The crankcase vent is attached to the engine via a rubber hose. I have never seen a vibration issue with the end of the tube mounted to the lower engine mount tube. Like I said, my Super Cub has 12,600 hours and still has the original tube. The vent is going to blow out some oil regardless, there is now PCV valve on any airplane I have seen. Running the stock vent out into the slipstream puts the oil out there vs. on my firewall. I have installed air/oil separators and baby bottles to eliminate this issue. On my own airplane I just varsol it off every now and again, my airplane isn't very pretty or clean.

The reason I pointed out how Piper did this is because I see a lot of changes to how the Super Cub was originally assembled. Did a 100 hr./annual inspection on one out of a rebuild shop in Alaska with lots of years of experience under their belt. Took quite a while to swing the engine to pull the mags because of an issue with them. Piper ran everything so that you disconnected the tach and two bolts and swung the engine. I see this and similar issues a lot. When you change something on the airplane it usually effects 2-3 other things and takes some forethought. Not saying everything Piper did was right but I believe they were good at what they did and I have to think 3-4 steps ahead before I change or modify something. This opinion comes from rebuilding 5 Super Cubs that had never been recovered before and some of the things I found that get lost, molested and changed in most rebuilt Super Cubs I have worked on.
 
Drum brakes and three on the tree are how Chevy did it back then. Some things from the old days weren't that good. To each his own.
 
Steve, your text said " there is now PCV valve on any airplane I have seen" (emphasis added). From the context I assume you meant there is NO PVC valve....

Nonetheless, as always I really appreciate you guys who know what you're doing discussing this sort of thing. It's a great learning experience for me.

Thanks. cubscout
 
I'm allot more picky than Piper......

hung off the exhaust muffler support I'm made... didn't want the mufflers hung from motor mount either with the parts that came with them...(Vetterman)

having trouble uploading the picture.....
 
Steve, your text said " there is now PCV valve on any airplane I have seen" (emphasis added). From the context I assume you meant there is NO PVC valve....

Nonetheless, as always I really appreciate you guys who know what you're doing discussing this sort of thing. It's a great learning experience for me.

Thanks. cubscout
Yes, I meant no PCV valve. I'm all thumbs on my phone. [emoji13]

Sent from my SM-N900V using SuperCub.Org mobile app
 
Yes, I'm using Larry Vetterman's exhaust.

I have seen a photograph of some of the work Darrel Starr did on his incredible SC restoration which shows the "drain tube" portion of the crankcase vent system. It was fabricated and mounted onto the firewall prior to firewall installation (probably during test-fitting, etc.) It has several curves bent into the 3/4"(?) aluminum tube and is mounted onto the firewall with clamps. As I recall, the discharge end of the tube extended below the firewall, and the intake end had a "bubble" flare formed into it for receiving a flexible tube.
 
Back
Top