Author Topic: Crankcase ventilation without vents  (Read 1668 times)

Offline Armycook

Crankcase ventilation without vents
« on: May 03, 2017, 12:01:57 AM »
So this is part 2 of the engine issue. Was able to replace that old distributor with the 123 so that's done. I mentioned that this 1275 A series did not have any vents except for the rocker cover hose outlet going to the HIF carb. So no timing chain cover and clutch bell housing breathers. It was starting to leak from under the timing chain cover seals so I figure I'd do a quick fix until maybe after MMW2017 and then i'll pull the motor and replace it all with vents.

Right now I made a 90 degree 5/8" fitting going to an oil catch can and i'm using a spare rocker cover with a vented oil cap and plugged the HIF carb vent. But that 1QT can gets full of oil after driving for 20 mins only.

Im thinking i should just forget all this quick fix, skip MMW again and pull the engine and replace the bell housing and timing chain covers with proper vents.... But if i'm pulling the motor i might as well sort the internals especially the piston rings and rebuild it since i'm starting to smell fuel in the oil and it has a little blowby smoke.

Are there any other ways to have good decent ventilation to relieve the pressure without pulling the engine? I just want to be able to delay the major fix so I can keep driving it til the June event.

Offline Willie_B

  • CREW
  • 1380cc
  • *****
  • Posts: 692
  • Total likes: 38
  • Karma: 7
  • He who laughs last, thinks slowest.
    • Lilburn, GA,
Re: Crankcase ventilation without vents
« Reply #1 on: May 03, 2017, 05:26:48 AM »
If you are using an electric fuel pump you can vent the block off plate.

Offline Armycook

Re: Crankcase ventilation without vents
« Reply #2 on: May 03, 2017, 06:33:10 AM »
that's what i'm using now but it's spitting way too much oil. i tried using those aftermarket ones that is round with a baffle but man those two studs will not come off with the two nut method.

Offline gr8kornholio

Re: Crankcase ventilation without vents
« Reply #3 on: May 03, 2017, 06:38:04 AM »


There is this option, but I don't think it has baffling so may run into the same oil problem.

http://www.dsnclassics.co.uk/retrosport-shop/engine-accessories/breather-for-fuel-pump-hole-retrosport-1-2/
I am the GR8KORNHOLIO! Are you threatening me?

Saussie Aussie 1965 Australian MK1 Mini.
"Beavis" - 07 MY/MY MCS, B/MY Konig Daylites, JCW sideskirts, TSW springs, TSW lower rear control arms -- Exploring the country with new friends since 11/09.

Offline Armycook

Re: Crankcase ventilation without vents
« Reply #4 on: May 03, 2017, 07:01:37 AM »
Yeah i wasn't expecting that it will fill up almost a quart of oil driving on the freeway for 20 mins.

i'm thinking of directing the hose and feed it to the rocker cover and have another fitting from rocker cover to the catch can with an air filter. Is this gonna be good for the engine when i'm bypassing the oil filter feeding it straight to the rockers though?
« Last Edit: May 03, 2017, 07:22:14 AM by Armycook »

Offline MiniDave

Re: Crankcase ventilation without vents
« Reply #5 on: May 03, 2017, 09:50:11 AM »
You're not bypassing the oil filter, everything that goes thru the bearings and such gets filtered first, so you're OK there.

Where did you have the catch can mounted? It has to be way up high on the firewall, not down low. Maybe bring the hose into the bottom of the catch can and vent the top, that way the oil can drain right back down again? Also take a chore boy and put it in the can, that will let the vapors out but pull the oil out of the airstream and thus keep the oil in.
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline Armycook

Re: Crankcase ventilation without vents
« Reply #6 on: May 03, 2017, 09:56:54 AM »
Hi Dave the catch can isn't low. Maybe level with the cylinder head just next to the voltage stab box

I also have steel wool inside the can
« Last Edit: May 03, 2017, 10:04:30 AM by Armycook »

Offline MiniDave

Re: Crankcase ventilation without vents
« Reply #7 on: May 03, 2017, 11:02:21 AM »
Then I don't understand why it's pushing so much oil out clear up there......
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline Armycook

Re: Crankcase ventilation without vents
« Reply #8 on: May 03, 2017, 11:17:44 AM »
The oil stays in the can when it gets there. i just don't like it that it's draining so much oil from the block.

There's also a huge opening with an air filter so no need to add more holes for the oil to drain back down if ever i remove the drain plug and replace it with a fitting with the hose. I just don't think the catch can will drain back all the oil back in the block as this can is tall and it's tricky routing the hose maintaining a good position for the oil to come back down with gravity because there's a lot in the way (carb and exhaust manifold)

Let's say i make that proper routine and maintained that hose lower than the drain level of the catch can. With me driving one way for maybe 20 mins, or even more that by the time the engine stopped running my can will be so full already. Is that standard that it creates that much pressure from that vent position of the block? I've only heard race cars doing this method.
« Last Edit: May 03, 2017, 11:29:46 AM by Armycook »

Offline MiniDave

Re: Crankcase ventilation without vents
« Reply #9 on: May 03, 2017, 02:06:33 PM »
No it should not be pushing this much oil into the can....something is wrong......the oil level in the sump is well below the level of the pipe in the fuel pump block off plate, so I wonder how the heck it's getting up there?
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline Armycook

Re: Crankcase ventilation without vents
« Reply #10 on: May 03, 2017, 03:14:43 PM »
It's weird. So i spoke to one of the mechanics that worked on this car when it was owned by the PO. He said the PO had some guy dictating that shop what he wanted with the engine build but did not finish. The mechanic had to shut the timing chain cover vent closed which he thought was weird. I saw the receipts and this engine went to three different shops. When i got it, the engine was running ok. I guess the PO did a really good job cleaning everything when i inspected it that i focused my attention looking for hidden rust spots and forgot to thoroughly check the motor as he showed me receipts of the build just last October.

Offline Armycook

Re: Crankcase ventilation without vents
« Reply #11 on: May 03, 2017, 03:17:07 PM »
This is what it looked like when I first got it. It even had an MSD rev limiter.

Offline MPlayle

Re: Crankcase ventilation without vents
« Reply #12 on: May 03, 2017, 03:17:53 PM »
I remember reading somewhere about why the breather adaptor for replacing the mechanical fuel pump absolutely had to be baffled.

The fuel pump port is completely open to the splash of the crank, rods, and transmission gears as the pump arm reaches through to the cam lobe.  As such, it get LOTS of oil splash as a mist.  If it is the only pressure outlet, that splash/mist gets blown along at a steady air push and will condense in the catch can.  The baffling of the adaptor breaks the flow of the mist and makes it condense on the baffles where it becomes heavier droplets that flow back into the case.


Offline Armycook

Re: Crankcase ventilation without vents
« Reply #13 on: May 03, 2017, 03:20:01 PM »
since this is the only vent so it's a heavier pressure then... makes a lot of sense.

Offline MPlayle

Re: Crankcase ventilation without vents
« Reply #14 on: May 04, 2017, 08:18:39 PM »
The discussion on my Moke thread about the tappet covers made me think to ask: does you engine have tappet covers?  If so, you could try to get one of the vented covers and use.


Offline Armycook

Re: Crankcase ventilation without vents
« Reply #15 on: May 04, 2017, 09:48:03 PM »
Not a cooper S block so no tappet covers unfortunately

Offline Armycook

Re: Crankcase ventilation without vents
« Reply #16 on: May 10, 2017, 06:56:16 PM »
rerouted a new hose that feeds the bottle from the bottom and repositioned the can. it works now :) it's still held by zipties but it doesn't spill through the air filter with a copper pot scrubber material as a baffle. thanks guys!

Offline sxsman

Re: Crankcase ventilation without vents
« Reply #17 on: September 27, 2017, 07:09:09 PM »
 Don Racine on his race mini his catch can drains back into the sump. Has I believe at least 3 breathers feeding it (flywheel,  rocker and timing cover)
Said he should have drained back into the sump years ago.  :-[

Offline MiniDave

Re: Crankcase ventilation without vents
« Reply #18 on: September 27, 2017, 07:23:47 PM »
Race engines turning high RPM with high G loads are different than street engines......I think what he's done will work fine now with a media in it to catch the liquid oil.....all the factory breathers are designed to drain back into the sump.
1989 Cooper Racing Green
2009 Clubman S
1969 Jaguar XK-E FHC
2004 Audi Allroad 2.7 TT

Offline Armycook

Re: Crankcase ventilation without vents
« Reply #19 on: September 27, 2017, 07:46:21 PM »
Iím still going to pull the engine out and probably do a refresh. Then replace the timing chain cover, clutch housing/ primary gear cover with the vents. i have a blowby so might as well check the piston rings and cylinders. Will do this after the San Diego British car day. Itís the last event of the year for me i think this car and myself will attend.