17 replies to this topic

[Mk1cooper]

When I got my car last March, The 1275 engine did not have any breathers or vents. The timing chain cover, transfer case/ clutch housing and the rocker cover did not have any vents at all. Although the engine was just rebuilt last October, I figure i might be able to still install vents using the mechanical fuel pump outlet and rocker cover. On the Works engine, I saw the use of Smiths PCV valve and i would like to understand where do I connect the mechanical fuel pump baffles cant hose and rocker cover vent hoses? I spoke to a local mini shop here who sold me the Smiths PCV valve and told me that I have to join those two hoses to a Y tube and then to the PCV valve to get sucked in the intake manifold. Mind you that I have a lot of pressure coming out of the crank so Im dependent on a baffled catch can. I did replace the air filter of that catch can into a sealed cap because I was having a vacuum leak. And i also replaced the rocker cover vented cap to a sealed cap. Am I doing this right?

I attached a drawing/ diagram how i did my engine vents. I asked a few friends and just trying to wrap my head around this still so please dont hesitate to give me suggestions. Thank you.

[Mk1cooper]

Diagram i made

Attached Files

•  43D06C59-FD56-4A61-9938-E0B99EFD4447.jpeg   38.59K   13 downloads

[Mk1cooper]

Heres a photo of my engine

Attached Files

•  9BF4DFE4-9B52-4498-97F1-A6F79C911963.jpeg   68.31K   13 downloads

[Spider]

I take it that the engine you have is a solid backed 1275 block, ie, not a Cooper S Block?

 

The Crankcase Breathing System is there for several reasons, which I suspect you are on to, but to work at it's best. it needs to draw air in and through as much of the Crankcase as possible, before being drawn off. In the Case of 1275's, the stock set ups do this by drawing Fresh Air in via the Rocker Cover (in one way or another) down in to the Crankcase and out via the Timing Chain Cover & Transfer Housing. The Smaller Engines draw off on the Tappet Cover and I find that on cars that do short runs, the inner lower part of the Block is nearly always rusty as a result.

 

In your case here, I'd be inclined to fit an Oil Separator to the Transfer Housing or if you didn't want to do that, from the Timing Chain Cover, or, if again, you didn't want to do that, from the Opening on the Back of the Block for the Fuel Pump, however for the system to work correctly, an Oil Separator should also be fitted local to here. To make the Oil Separator work proper;y, the Inlet should be around 2 times in dia on the Inlet to the Outlet.

 

Then plumb that directly from the Oil Separator to the PCV Inlet.

 

I'd recommend against the Catch Can. With the System working correctly, it is not needed, it's something else to find a home for and will only need emptying out periodically. The Pipe also in the drawing, from the Rocker Cover to the Catch Can should also be eliminated as it will by-pass much of how the system should work.

[Mk1cooper]

Thank you for responding. Yes this is an Austin America 1275 block bored over 20 with Kent 266cam and a later ported and polished Cooper S head with flat pistons sittong on a remote straight cut gearbox transmission. I installed the mechanical fuel pump vent hose and connected at the bottom of the catch can and place it high enough from the crank because when it was mounted elsewhere, i was filling up that bottle within 20 mins of hi way driving. With the bottle mounted high enough with the hose at the bottom i was able to let the oil to flow back to the crank. I placed stainless wool inside as a baffle. I already attached an aluminum block baffle type fitting at the crank side and its still spitting a lot of oil. Im very dependent on this catch can. I know a lot of you wanted to tell me to pull the engine out and install proper parts than deal with this but I want to prolong and save this engine. At least until I save enough money to pull the engine and buy all the proper parts and rebuild the whole engine. It might take me another year for that so Id like to maintain this as much as possible. So should I just eliminate the rocker cover vent hose and place a vented cap? i have spare rocker covers without the breather tubes. Also ive no idea how I can get an oil separator in between the crank and PCV valve.

[Mk1cooper]

I can install a vented timing chain cover as that’s easier to acquire than the transfer case housing. I just didn’t know where I’d put the hose to.

[Spider]

That your Catch Can was filling so quick could be of concern, however, it could well be that it simply needs the Oil Separator. The Pipework for these must have a bigger Inlet than Outlet for it to work properly.

 

If you don't mind pulling the Radiator out, then a Timing Chain Cover swap would be the better way forward.

[Northernpower]

I did something similar. I've driven quite a few miles with it and some of them very hard and it works very well. It may give you a couple of ideas, here's the link http://www.theminifo...-oil-condenser/

[carbon]

Should not be too much of an issue with a MD266 using standard lift rockers, but if you go for higher lift or a longer duration cam he standard PCV installation may make it more difficult to get a decent idle.

 

The build sheet for the '66 works Mini JBL172D in Brian Moylan's 'Anatomy of the Works Minis' makes interesting reading: 'Fume pipes: Std. Blank off Clack Valve, cut holes in hose.'

 

Also if you stick with the PCV set-up check the hole in the oil filler cap is no more than 1/8 inch diameter, and that the rubber seal around the filler is effective with no other places where air might leak into the engine.

[Spider]

Should not be too much of an issue with a MD266 using standard lift rockers, but if you go for higher lift or a longer duration cam he standard PCV installation may make it more difficult to get a decent idle.

 

This is one place where the later CCV set up is better. It works on Air Flow Rate rather than Manifold Vacuum (or lack there of).

[carbon]

 

Should not be too much of an issue with a MD266 using standard lift rockers, but if you go for higher lift or a longer duration cam he standard PCV installation may make it more difficult to get a decent idle.

 

This is one place where the later CCV set up is better. It works on Air Flow Rate rather than Manifold Vacuum (or lack there of).

 

That's what I am using now instead of PCV, and yes it does give a much better idle

[panky]

I fitted one to my mildly modified Traveller ( not the Smiths type) and had to go up from  AAU needle to an AAA

 

 

I think I'll be going back to the original closed loop system as I don't see any benefit from the PCV (engine still leaks oil  )

[Mk1cooper]

CCV? Is that another form of a check valve?

[panky]

Closed circuit ventilation. The crankcase vent goes straight to the stub on the carb with no vent to atmosphere.

Edited by panky, 14 November 2017 - 06:59 PM.

[carbon]

Panky, from the picture you posted it looks like you're connected to the inlet manifold, rather then the carb 'stub'.

 

Do you have a PCV installed, I can't see it in the picture?