engine breather problem.

MOTORHEAD · #1 (**permalink**) 12-06-2012, 08:52 AM

My car came with the intake fill tube and breather cap, and the rear vent hose to the puke tank. Valve covers with no holes/breathers. Problem is I have switched to weber carbs and manifold,no front tube, only one at the rear, which can be a breather/filler or connection to puke tank. (want to keep puke tank) so, I have no place to add oil unless i go to caps on the valve covers, but don't like that look. W what did the original comp/sc cars do when equiped with webers ?

WardL · #2 (**permalink**) 12-09-2012, 10:11 PM

probably too slow, but you could add oil down your dipstick tube!

DougD · #3 (**permalink**) 12-10-2012, 03:24 AM

You could add it through the puke tank. If it's plumbed properly, it drains back to the oil pan and the intake anyway.

If it was me, I'd swap the pent roofs for a set with holes, with some nice chrome, original-type repro caps.

It's good to have venting anyway, regardless of the oil fill problem.

CHANMADD · #4 (**permalink**) 12-10-2012, 12:35 PM

The problem of the breather thing is a lot more than that!
PCV ( positive crankcase ventilation valve) could be hidden in the back of one cover and a breather where your puke tank is now.
Most of us forget that as much air is moved on top of the piston , the same is moved at the bottom , ie, in the crankcase. with a vacuum sucking that air out of the crankcase you can minimise the oil that is puked, removing the need for a puke tank. Leave it there unconnected if you have to have it to look good. not only does the vacuum help the puking it helps seal the rings,by illiminating the crankcase pressure under the rings,h helps to stop blowby. Why try to keep something that has been proven not to work?

MOTORHEAD · #5 (**permalink**) 12-11-2012, 07:00 AM

Thanks for the replys guys. The car was delivered with a 4 barrel and appropriate manifold which went away when I changed to the webers set-up. So that left only the rear manifold vent/fill option. Use the puke tank fitting and there is no fill available . My desire to use the puke tank (oil/air separator) is to be as original as possible, but what was the breather/fill set-up back in the day? At that time webers were not the "factory" race carburation , it was the single holley. I would think that the single aft vent would be adequate for the volumne of air produced by a healthy engine with normal amount of blow by.

MOTORHEAD · #6 (**permalink**) 12-11-2012, 07:06 AM

Anybody have knowledge or photos of an original 427 SC running webers? I have seen pictures where they were using the rear aluminum "S" shaped tall breather in both round (with filler cap) and rectangular versions. But of course those do not have provisions for a puke tank connection.

MOTORHEAD · #7 (**permalink**) 12-11-2012, 07:26 AM

eng pics...

CHANMADD · #8 (**permalink**) 12-11-2012, 10:41 AM

Most of those old cars had a breather on the manifold fill tube and a puke /vent tube , which just vented and puked oil to the street. You would not be allowed on a track like that. So they added the puke tank, with " ingenious" drain back capability. This was also the cause of all the oil misting in the engine compartment............Enter the..... pcv.....no piling, no mister up engine bay....
Hey , if I was going to do it properly with the. Webers, I would drill, tap and put a small barb into each runner, join them at a small junction, manifold, and then to a pcv. You could also run a remote breather or put a breather cap on your puke tank, for looks, and hide the outlet at the rear of the manifold. The breather tube will be under vacuum , so no need for a clamp, just pull it off to fill from the rear.....

CHANMADD · #9 (**permalink**) 12-12-2012, 10:17 AM

Just an added note , Once all the runners have a barb, to connect a vacuum hose too, one can use this to get the Webers perfectly balanced
Most motorcycle shops will have a set of 4 vacuum gauges all set up next to each . Connect a gauge to each individual runner and one can tweek the throttle balance and idle screws until an equal vacuum is had at each runner. Your motor will run the smoothest it ever has...

MOTORHEAD · #10 (**permalink**) 12-13-2012, 08:40 PM

Chann: The good news: I already have individual taps at each port running to a central plenum for possible future FI. The bad news: They are UNDER the manifold !!!!!!! But looking at all the ideas here, I think I can come up with a system that will work with puke tank AND pcv !! We'll see !
Thanks for the help !!
Ted