What would be the easiest and quickest way to vent an 1100 S engine,the reason i ask is a mate has just fully rebuilt his 1275 and has just started driving it , and it has developed an oil leak (not too serious) around the timing cover seal and he is thinking that it may be caused by a bit of crankcase pressure. Any ideas or suggestions would be much apprecciated. Thanks Colin.

If your running an elecrtic fuel pump the fuel pump blanking plate is a good place for a breather, needs a zig zag or gauze/pot scrubber to prevent oil entering the breather. Fitting a timing cover breather is also an option. Have a good look at the one on the rocker cover, it may have a late 998 type with a tiny hole in the end, if so, hacksaw the end off. Good luck with it.....

The best breathers on an 1100S motor would be the standard breather with the Smiths PCV valve sucking from the clutch housing oil seperator and the standard vented oil cap.

Since we did to Olli exactly what Morris 1100 is suggesting I have had next to no drop in the oil level and there is now no growing 'patch/pool' underneath either...

...additionally, this sorted our 'oil coming from under the cap' syndrome that we had a few months ago and I would suggest that it is the first place (and cheapest) please to start

K

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1969 Morris 1100 S Automatic

ahhhh......the interior smell of an old British car....

I run that setup (with a 45 Dellorto carb) on my revvy 1360 and it's fine, on our 1293 (twin HS4s) I run the breather line to the 2 vac ports on the carbs, that works fine too. It has an A series dipstick sitting in the A+ block, and doesn't leak a drop.
Make sure the flywheel housing breather isn't blocked though, rip the gauze out and replace with a SS pot scourer if it is.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Thanks for the help guys ,some food for thought, the mates engine does not have the clutch housing drilled out, nor does it it have a breather on the rocker cover, as an easy fix would it be easier to start with changing the rocker cover to one with a breather and catch tank and maybe check the cap, reason i ask this is because he is reluctant to pull the motor out ( unless he has no other option's) as he has put a lot of time into engine detail and body prep and doesn't want to possibly mark it if he doesn't have to.
Anyway , thanks again guy's and any more suggestions would be much appreciated.
Colin.

MiniMania in the US sells a baffled breather that bolts to the fuel pump flange.
I made one years ago for my 1310 to go there (unbaffled, just had a modified S breather can and the gauze on it) and found that over 4500 rpm the crank threw so much oil up there that it made like JB007...
So.. I bit the bullet, and drilled the flywheel housing for the proper breather.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I've also got a drilled clutch housing and std bolt on breather unit - although from there is it connected through a PCV and to the manifold a la DrMini setup.

The downside for you is that you really need to take the clutch housing off to drill it.
KB

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The other alternative is to use a timing chain cover with a breather. Not sure which Mini they are off but I bought one a couple of years ago for my 1100S based race engine. It's easier to pull off than the transfer case.

Pete

whats a smiths pcv valve?

i had a breathing filler cap on an alloy rocker cover and it spewed oil out of the cap,

so i put a steel rocker cover with a breather outlet and a non vented cap,
then i put both breather lines (other one is the clutch cover) to a catch can.

whats a smiths pcv valve?

i had a breathing filler cap on an alloy rocker cover and it spewed oil out of the cap,

so i put a steel rocker cover with a breather outlet and a non vented cap,
then i put both breather lines (other one is the clutch cover) to a catch can.

The vented oil cap is supposed to let air into the engine and not breathe fumes out.
If it is leaking from the oil cap it means that YOU have stuffed something up.
The system is supposed to create a small vacuum (and the oil cap stops it from turning into a big vacuum!) and while there is a slight vacuum oil will try not to leak past the seals. If you run the breather to a catch can there is nothing to stop the engine from trying to leak oil.

The Smiths PCV looks like this...

It is what was used on the 1100S Cooper S and other models.

Mk2 S with Police Pack twin HS4s didn't use that valve, the sidecover breather ran to the vac ports on the side of each carby instead.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

If my mate installed a pcv valve ,where would he connect the outlet hose to, seeing his motor does not have side covers like the S have? By doing this i assume to do the job properly he would have to drill the flywheel as KB suggested and connect it to there.
Thanks for your replies people you have been a great help as usual.




Colin.

You have three choices, the primary gear cover as suggested, a vented A+ timing gear cover, or the mechanical fuel pump apperture.

Get him to chase the oil leak down as well...some head gaskets will let oil dribble out from the rear corner behind the thermostat...it all ends up down the bottom and looks for all the world like a timing cover leak..

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.