Keefer

My Feedback: (2)

Hi guys - gals....
I have an OS FS 70 Surpass with no crankcase breather port. There's a boss in the bottom of the crankcase between the main and front bearing, (below the cam), but it's not drilled out or tapped; just a blank boss.
There's no tap on the intake manifold, so I'm guessing it's not a "newer" Surpass.

Was there a version of the 70 that has internal passages to get oil down to the cam and keep flow moving?
Thanks!!
Keith

Hobbsy

My Feedback: (102)

Keef, check page # 21 here and then Part # 21, the FS 70s does not have this part. The second link should be your engine.

http://manuals.hobbico.com/osm/fs-70...i-p-manual.pdf

http://manuals.hobbico.com/osm/34000-manual.pdf

SuperNash

Keefer, my first gen 70 has a breather nipple. IIRC its on the underside of the main crank area where you describe the undrilled boss. Sounds odd that yours doesn't have one. If it were my I think I would drill & tap and get a nipple there (or, do the backplate, less disassembly required).

Hobbsy, that second link contains the usual section referring to after-run oil being injected via the breather nipple.

Hobbsy

My Feedback: (102)

It sure does, my OS Aplha .56 does not have one, I'm surprised more haven't chimed in here. It would be real easy to install one, I'd place it on the backplate though.

Keefer

My Feedback: (2)

Thanks all. I'll tap the boss that's on the bottom of the case. It's between the main and front bearings which, on SAITOs, was critical to keep oil flow though and past the bearings. Putting a vent on the back of the crankcase doesn't help the front bearing and camshaft at all.

Hobbsy

My Feedback: (102)

Many more engines have the vent on the back plate than on the front, I think that the (it is better for cam idea) is more in our heads than an actual fact. Even if you wanted to keep the oil out of the front, you couldn't.