blow by improves performance?
 

A while back, I posted and asked about running the blow by from a 4 stroke engine back into the tank 1. to prevent a lot of cleanup, and 2 to possibly increase tank pressure...like a pump. Well, I did it on my TT 91 fs, and it works...it works really good! The engine actually seems to run better, and I had virtually no clean up to do when I was done.

Now, back to reality...This has to be too good to be true..right? I have never seen this done before, and if it was a good idea, it seems that I would have...but I have only been in the hobby for a year.

Anybody have any thoughts on possible detrimental effects. A guy at my LHS said that it was not meant to be a closed system and it should be left open, but he gave no real explanation of what might happen if I did run it this way.

Thanks,
Kevin

RE: blow by improves performance?
 

Where is the exhaust going if the case vent causes more mess than it?
Do you have the tank vented or muffler pressure?

Kirk

RE: blow by improves performance?
 

I'm not sure I understand what you mean by "Where is the exhaust going if the case vent causes more mess than it?"

The exhaust pressure goes into the tank along with the blow by.

Kevin

RE: blow by improves performance?
 

Kevin:

Sorry, you're doing nothing new. Some manufacturers vent the crankcase to the intake between the carb and the valve, others vent it to the exhaust as yu are, in effect, doing.

Yes, it keeps the plane cleaner, and no, it doesn't hurt anything.

Bill.

RE: blow by improves performance?
 

No need to be sorry Bill:D That's GREAT!!!!!!

Thanks for the info all,

Kevin

RE: blow by improves performance?
 

Hey Kev,
Sorry- I should have been more clear.
Usually the exhaust spews out a ton of oil and gunk that gets all over the plane, where the case vent leaves just a little oil running back from the line.
I chimed in last week on your post about my Senior with the exhaust running to the back of the plane and the case vent tied into it.
This is the only way I know of to keep everything clean.

Kirk

RE: blow by improves performance?
 

For exhausr extensions on two-stroke engines, Aero-Trend markets large diameter silicone tubing. It can be used on 4s engines, but it doesn't last too long because of the heat.

For an example I've attached a picture of the right engine nacelle on my Tiggerkitty, the fairly big blue hose near the center of the picture is the engine exhaust.

Second pipcture is one engine with the cowling off, the muffler outlet goes into the pipe at the firewall.

Last picture is the engine with the beer can cowling (True!) in place.

I usually get no more than a small amount of oil on the ends of the hacelles and the underside of the stab and elevator.

Bill.

RE: blow by improves performance?
 

Nice plane Bill, what size engine is that? The carb looks like it should be on a .46!

Boomstriker, my 4 stroke doesn't spew fuel out of the exhaust. It burns pretty efficiently. Now my 2 strokes do, and there is no hope for keeping them clean unless I had a setup similar to yours. The only grime I get on my plane with the 4 stroke is the blow by, but no more thanks to all the input.

Thanks all,
Kevin

RE: blow by improves performance?
 

Kevin:

The "Beer can cowling" should tell you the engines are pretty small, the plane has a pair of AMD 0.061 engines. Wing span is less than a yard.

And thanks for the kind words, it's the plane in my avatar.

Bill.

RE: blow by improves performance?
 

Well, I've heard a lot of different reasons for guys suckin' on suds, but I have to say....I like Bill's best!! :D

Gary

BTW, if ya'll want to keep the exhaust residue on your plane to a minimum....fly one like the pic below. ;)

RE: blow by improves performance?
 

Gary:

I had intended to use Coke cans, but when I went to my local convenience store to get a six pack, Schlitz Malt Liquor was cheaper than Coke.

True story.

Bill.