mentorman

My Feedback: (2)

I noticed on the new FL70 os that the crankcase vent is plummed into a secondary nipple on the muffler. Would this work to clean up the plane by exhausting crankcase waste out the muffler or will it hurt. Was thinking about adding the extra nipple on one of my fourstrokes just for kicks, what do you think?

Richard L.

My Feedback: (24)

I think the new FL70 has a different pressure system. If you connect the crankcase vent to your exhaust, the back pressure from the muffler will push against the crankcase vent and prevent oil from coming out. Without proper venting, excess pressure will build up inside the crankcase, which is not what you want.

mentorman

My Feedback: (2)

Thats what I was thinking also, but how different can a fourstroke get? It was a novel thought.

Richard L.

My Feedback: (24)

A better way would be to route the excess oil from the crankcase back into the carb, which is what OS pumpers and YS are already doing. A four stroke can get quite different.

RaceCity

It can't be any worse than the Surpass II arrangement where the crank vent is plumbed into
the carb. Doesn't work a lick. Makes a huge mess.


If you think about it....you'll note that crankcase pressure is likely opposite of exhaust pressure.

Venting the crank into the muffler wouldn't create any problem in that case, and I'd venture a
guess that OS ran a few of these FL-70's before they finalized the design for market.

If it didn't work....it'd never made it past the prototype phase.

How about just spending a few extra bucks on the Surpass II, venting the crank overboard and being
done with it.

??

I have a number (3) of these .70s. It's a fine motor...sans the environmental "mods".

'Race

mentorman

My Feedback: (2)

I like os, just dont have any of their fourstrokes. Why doesnt their surpassII system work? I have saito, thundertiger and magnum, I route the vent to under the cowl, not a big deal, just getting lazy plus I like to tinker, but not at the expense of my beloved motors...

Richard L.

My Feedback: (24)

I have a .91 Surpass II pumper, and it's working just fine, thank you. Not a single problem after 150 flights so far. The only mess is coming out of the exhaust. There is absolutely nothing wrong with plumbing the crank vent back into the carb.

dustbin

For some reason, the only SURPASS II that really created headaches was the 1.20[:'(]! Had the C13 carb. EVERYONE with whom I've talked to who owned one had ZERO success with that engine[sm=thumbdown.gif]. Really caused a flood on xBxx when the SURPASS III came out. My OFB actually GAVE his away! Even I didn't want it, and I consider myself good with engines. The smaller displacement models did not seem to have a problem.