Crankcase ventilation, without the hassle?

[Fingolfin]

Hello everyone, it's been a while!

Mog's engine has no positive crankcase ventilation system, but plentiful oil leakage. The engine is 948cc with a vented filler cap and rocker cover with breather pipe, but the carburetor, an H2, has no port to take a hose from the rocker cover. The air filter is non-standard and has no port. I could order a later carb, but those are expensive (doubly so with shipping to America). I could drill into the inlet manifold, but that's a modification I'd rather not do.

So I came across this kit from ESM, which is supposed to be for a brake servo vacuum takeoff: http://morrisminorspares.co.uk/shop/pro ... ts_id=3635 But my thought is, couldn't it be used for crankcase ventilation too? Am I correct in thinking it would work (assuming they come back into stock)?

[Fingolfin]

I assume I'll need a PCV valve and a flame trap also, but both of those can be purchased easily off eBay, or from my local auto parts shop. If I do in fact need these two items, in what order should they be connected?

[mike.perry]

There should also be a breather pipe on one of the tappet chest covers which should be sufficient.

[Fingolfin]

There is a breather pipe coming down from one of the tappet chest covers, yes, but how can that be sufficient? It allows air in but doesn't suck any out, right? I'm given to understand that generating slight negative pressure in the crankcase is best...but I'll admit I don't fully grasp the issue.

[bmcecosse]

Yes - that will work fine, and is essentially what I did on a Mini engine. The hole will be far too big (far too much suction!) - so you will need to reduce it to 1/8" diameter. I used a servo take-off - filled it with araldite, then drilled the 1/8" hole. Connected to a breather (rocker cover is ideal) and it sucks away the nasty fumes very nicely - with some fresh air entering through the cam follower breather to keep the engine nice and 'mayo' free. It will of course upset the idle slightly, but you just need to compensate for that with the idle screw, and mix nut till you get a setting you are happy with. This is where a PCV valve helps - it doesn't upset the idle. Just a thought - if your carb is fitted to the manifold with a black phenolic spacer about 1/2" thick (it should be) - you could drill a hole through that and fit a tube to give you the necessary suction port.... If you don't like it you can just plug the tube at any time.

[Fingolfin]

Excellent! Thanks, Roy. I do in fact have a spacer, but it's not just a spacer -- it's one of the funky induction heaters fitted to Minors sold in cold climates. I believe the spacer portion is not phenolic or any kind of plastic, but actually a hard wood (upon inspection it appears to have woodlike grain). Thus I imagine the metal spacer at ESM would be better, but in any event I will be certain to shrink the hole down to 1/8". The breather will connect at the rocker cover.

I will obtain the PCV valve -- they seem to be "cheap as chips." And I'd planned on resetting the idle. Do you suppose I require a flame trap also, or would I be all right without it?

[bmcecosse]

I never had a flame trap - it's not ever likely to travel back up a 1/8" hole.....

[M25VAN]

So I came across this kit from ESM, which is supposed to be for a brake servo vacuum takeoff: http://morrisminorspares.co.uk/shop/pro ... ts_id=3635 But my thought is, couldn't it be used for crankcase ventilation too? Am I correct in thinking it would work (assuming they come back into stock)?

Maybe something like this could do the same job and a lot cheaper.
http://www.ebay.co.uk/itm/161079048005? ... 1439.l2649

[bmcecosse]

But look at the postage!

[Fingolfin]

Perhaps this then? http://www.ebay.co.uk/itm/Solex-New-Car ... 3a64c83db1 It appears to have the right shape, and the takeoff pipe looks like a smaller diameter, too. Dunno about postage though...I'll have to ask.

[bmcecosse]

Blimey - it's crazy expensive , but would do the job. Just make an adapter from plastic/wood/aluminium etc.... can't take for ever - surely. Or - drill and tap the manifold and screw in an 1/8" BSP (or NPT...) nipple - and then reduce the bore to 1/8".

[Roni]

This might help -
http://www.holden.co.uk/displayproduct. ... de=070.350
It does have a small bore hole but there is room to enlarge it.

[Matt]

Im interested in this induction heater... I have never heard of one before! Any chance of some pics?

[Fingolfin]

Matt, this is the best photo I have of the induction heater:[frame][/frame]As you can see, it has coiled heating elements around the inner circumference. The "ear" on the rearward side has a screw-in post for a wire, and the hidden manifold side of the heater has two metal tabs for earthing. I have not actually tried the heater, as my climate usually isn't cold enough to require it, but I believe it is actuated by simply attaching a wire, and then detaching the wire when you don't want it active.
[frame][/frame]A view from above shows the screw-in post. Behind the post is a bullet-shaped protrusion that I muse is some kind of transformer, as 12V wouldn't be great for rapid heating, but I really do not know.

[Fingolfin]

By the bye, I did go on and purchase the adapter I found. It's true it was rather expensive, but I felt it was worth it, primarily because I have very limited time to work on the car (one weekend only, unless I want to wait for Thanksgiving break in late November), and so a "fit-and-forget" item is valuable. I have also bought a PCV valve for cheap, and I'll purchase hose from a local auto parts shop when I'm doing the job. Might be this weekend...

[bmcecosse]

Excellent - great pictures. Good luck with it! Let's see the inexpensive PCV valve please?

[Fingolfin]

Not the same listing, but this looks like the same valve: http://www.ebay.com/itm/Standard-Motor- ... d8&vxp=mtr

[Declan_Burns]

Fingolfin,
That looks very similar to the one I installed on my MG TD, except mine goes to both sides of the inlet manifold (twin carbs). It works very well. Make sure you plug every source of infiltration air. This will then force air to be drawn in at the leaky places eg the crank scroll. The carb will more than likely need resetting. I also fitted a flame trap from a Land Rover. I measure -12mbar pressure at tick over. It has practically eliminated oil leakage.
Regards
Declan


Current (not final) installation[frame][/frame]
Manifold tapping point during test set up[frame][/frame]
Test set-up showing U-tube on the right to measure engine vacuum and the rubber glove (Aldi ) on the oil filler .[frame][/frame]

[Fingolfin]

Thanks for that, Declan. I didn't fit a flame trap, and only have one carb, but otherwise I think my setup is similar in concept to yours. Here's mine:[frame][/frame][frame][/frame]
Air is drawn up from the valve cover through a short rubber hose to the PCV valve, where it is then directed through hose and a stepped vacuum pipe (the center white portion) to the manifold/carb interface. Quite simple! And I have already noticed lessened leakage, though it is not cured -- that will take more effort.

Thanks to everyone for their advice.

[George Smathers]

Fin, that should work fine but if it still leaks you can run an oil catch-can. I have very high pressures in my slightly built-up 1275. I installed an oil catch-can reservoir that is fed off a pipe in the timing chain cover. It is vented to the atmosphere so it really bleeds off pressure and prevents oil leakage at the rear of the engine.

George