• Hi Guest!
    You can help ensure that British Car Forum (BCF) continues to provide a great place to engage in the British car hobby! If you find BCF a beneficial community, please consider supporting our efforts with a subscription.
    There are some perks with a member upgrade!
    **Upgrade Now**
    (PS: Subscribers don't see this gawd-aweful banner
Tips
Tips

Positive Crankcase Hoses

Share this page

Y

ynotme2

Senior Member
Offline
Hey Everyone,

After starting the TC up I noticed I was getting a oil drop under the car. I then traced it down to the dip stick. Oil was coming out of it under a pressure of some sort. Then I noticed that the flex hose from the back of the head was coming around and feeding into the right side of the block (right side when you are at the back of the car and facing the front of it). When I pulled the house the leak stopped. I reasoned that the hose was the PCV. But no valve was there. I noticed on my air filter box that there was an inlet on the back of the box. I assume for the head hose? But does the block outlet on the right side also fed into the air box? Does it require a "T" connection between the 2 hoses to fit into the air box? Any help would be appreciated.

Thanks

Tony
 
When the hose is pulled are you getting pressure from that hose -can you feel air from it?

Bruce
 
Which of course indicates there is pressure and that would be going into the crankcase forcing oil out. Question is how much pressure, is it correct and if not where is it coming from?

Have you done a compression check on each cylinder?

Bruce
 
I must admit I'm a bit confused about the routing of your vent hose. Sounds like it goes from the head to the block. There shouldn't be any available fitting in the block to hook up a pcv, as the original breather on the Kent block is used as an oil drain for the head ( that's the funny rubber extension between the block and the head on the right rear of the block.) The breather from the right side of the head should go to the fitting on the back of your air filter backing plate. There might be a pcv if the breather hose went directly to a vacume source on the intake manifold
like other cars, but with no serious vacume available from that source on the air filter backing plate, a PCV valve wouldn't work. My hose is just a straight tube with no PCV.

If indeed somehow your breather goes from the head to the block, then that makes it a closed loop system, and would handily explain why the excess crankcase pressure is escaping through the dipstick. ( except for your oil fill cap, there would be no other openings to the atmosphere other than the dipstick.)
 
Type R,

Thanks for the information. I now understand. The rubber thingy between the head and the block goes to the intake manifold. It looks like my air filter assembly has the hole blocked off. It looks like it was fiberglassed over. Don't know why though. I understand the PO bought the air filter assembly used. I wonder if they blocked it off or it came that way and he didn't know that it was for the breather. I guess I will have to drill a hole in the air filter assembly to fit the hose. Thanks again. I couldn't understand why the hose from the right side of the block as you described was connected to the one at the back of the head of the engine. Didn't make sense to me.

Tony
 
I must admit I'm still a little confused from your description of the rubbery thing between the head and the block going to the intake manifold.. That part should be a stand alone piece that simply carries oil draining back from the head to the block, and should have no provision for any venting whatsoever.. The only venting should be from the right side of the head at the rear, and should be a hole in the head just behind the rear most intake port with a grommet and a hose, which goes to the air cleaner backplate. The hose would be quite short and virtually straight. Still, my car is not a Europa, so maybe they are different ( Didn't think so though )

I'm sure you'll figure it out.. Have fun!
 
I've been watching this thread and am confuzzled as well. The downpipe from head to block on T/C engines had no "third" take-off on any one I've ever seen. The crankcase breather was as described by TRB above: 1/2" metal tube through the hole in the side of the head, slight kink in it to allow it to fit into the carb airbox at the back. Both ends sealed via a rubber grommet. IIRC there was a bracket at the airbox end to secure it in place with a bolt, too.

FWIW: I've done a nifty replacement of that oil downpipe on several engines by using the aluminum aftermarket rig that replaces VW pushrod tubes in-situ. Two threaded pieces (one I.D., one O.D.) and "O" rings. Some MacGyverin' is required, but it makes a good positive seal with no leaks and no need to goober up a replacement with RTV and force it into place.
 
Back
Top