Sunday, June 6, 2010

Hayfever

I believe that I've confirmed that Hanky's oil allergy is a permanent condition, but only seems to manifest itself at highway speeds. Puttering around town, it seems fine. But when I get out on the road, sure as shooting, it's blowing oil. Not too much today, but it was a short drive to my mother's place. On the way back I decided to unhook the hose from the flame arrestor on the valve cover. Sure enough, there was oil all over the valve cover when I got home, in addition to all over and around the dipstick. Isn't that flame arrestor supposed to suck air from the air cleaner into the engine (to counter the PCV)? And wouldn't you think that having it unhooked would reduce the crankcase pressure enough that it wouldn't blow out the dipstick? Anyway, not sure what to do about it other than find a new engine to put in...

4 comments:

cromulent said...

The valve cover vent / flame arrestor is supposed to go to the air cleaner so blow-by in the valve cover gets sucked down through the carb. The connection actually pulls some vacuum on the crankase so disconnecting it actually increases crankcase pressure. The PCV connection works the same only it draws gases from the crankcase directly into the intake manifold below the carb base. Leaving both connected (as long as neither the arrestor or PCV are clogged) should mitigate some of the oil pukage you're seeing -- or at least lessen it as much as it can be.

But yeah, it's transplant time. I'll keep my eyes and ears open for good candidates. It seems like they are always lying around for cheap until you need one, but I'm sure we'll find one soon.

Evil Mr. Clean said...

That's what I thought too, but I coulda sworn that the shop manual's diagram of the PCV system showed that the PCV pulled from the crank case to the manifold and the flame arrestor pulled clean air from the air cleaner to the valve cover. I'll have to pull that out again and recheck it. Regardless, it's spitting oil everywhere at highway speeds, so...

cromulent said...

I could well be wrong, but I just can't imagine what purpose putting clean air into the valve cover would serve. There could well be some purpose I just don't understand. *shrug*

Oh well, keep the speed down 'til we find a donor motor. It won't be long, I'm sure. Maybe you can talk Brian T. out of Karl's old 304, the block for which is still at my shop on a stand. (Hint, hint. :)

Evil Mr. Clean said...

Yep, already talked to him about Karl's motors. He has the 304 from the parts truck too, which he says is a good runner. Would have to do a leak down on it to see how it rates before going to the trouble though. That disassembled one would be next on the list. Mike Moore offered up a contact who has a 345 in Nashville, but that's a bit far to go for an SV. Eric Foor had a 345 for sale too for $350, but Allentown is even a hike for a motor, but if it comes to that...

I also have the 304 in the white truck, but that one needs a thorough going through too. If I recall, that one had compression under 100 in a couple cylinders too.