My awesome run with Minis continues.

There is engine oil in the weber filter since returning home with it. No noticeable smoke while running, or when accelerating. It does puff a noticeable amount of white smoke on startup, not a plume, but enough notice it.

It doesn't splutter, it doesnt run stupidly hot (190 F if sitting still in hot weather, 180 when getting along). It isn't using any coolant.

Engine is a 1380, 'rebuilt 3000 miles ago'. I have the receipt.

Can you get oil in the filter purely from having the engine venting into atmosphere, ie, nothing is plumbed back into the manifold ?

Would I be more likely looking at glazed bores or worn pistons ?

If the blow-by was related to a big end bearing, what is the best way to diagnose a dodgy big end ?

you're saying that there is engine oil in the air filter, but the engine breathers aren't connected to the air filter in any way?

If thats the case, then for engine oil to get to the air filter it would've had to come out of the engine, swirl around under the bonnet and then get sucked into the air filter...

If that was to happen, I'd expect a very bad smell in the cabin, and oil sprayed absolutely all over the engine bay



big-end bearings don't have anything to do with piston blow-by. Piston blow-by is where the air/fuel mixture goes into the engine "blowing by" the rings.


Does smoke and oil come out of the breathers if you give it a rev?

Take your oil filler cap off, put your hand over it the hole - there should be a gentle breeze. Give it a rev, there shouldn't be much more

Take it to a good mechanic and get a leak-down test done - he'll put an air fitting in the spark plug holes and there's a gauge that shows what percentage of air is leaking past the rings. I forget what is "normal"...

What air filter- many are normally oiled- (eg Ramflo, Unifilter socks, K&N, etc).
Are you sure it's engine oil.... I doubt it would get back into the manifold.

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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 replies.

I will give it another look over this afternoon as soon as I get home.

I will update with results.

Update.

Oil around weber air inlet hasn't accumulated since I wiped it all out the other day. I will keep an eye on it to see if it builds up again.

Oil is being pushed up the dip stick, when I pulled the stick out prior to wiping and re-measuring, it was all the way up the stick.

There is slight suction if you place your hand over the oil cap hole and seal it. I took the breather off of the rocker cover and plugged it while I did this.

Sounds like probably OK then.
Oil gets flung all over the dipstick and everything else when engine is running, it's a regular oil fog in there.

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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.

Are you sure this is oil and not fuel?



This is normal, oil gets flung around everywhere during operation, and for good reason.



Suction is normal too at idle. Best thing to do is make sure there are enough breathers, one on the rocker cover, one on the clutch housing etc. The more the merrier. I only run with 2 and it's fine.

If the car is running well and there's good power through the rev range with no rattles or knocking then it should be fine. BMC built the A series to self lubricate itself automatically

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Lillee - 1969 Morris Mini K

Breathers with those little blingy filters on are a waste of time. There is no positive ventilation, and the oil + water vapour clogs them up.
A proper PCV valve plumbed into the manifold (or vac port if SU has it) from 1 breather is much better on a road car. Notsosmellymate.

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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 can't be arsed finding the thread we were discussing it in, but I finally got around to trying a toyota (?) PCV on my HIF44.

If I run the vent hoses straight to the carb port the way the HIF documents say you can, I get erratic idle, to the point it's impossible to tune. If I put the PCV inline before the port, I get a better idle, but it pressurised the crank case and blew oil out the dip stick and main seal and ruined a near new clutch plate.

Have gone back to capping the port and running the hoses to a bottle. Just fine that way.

Smac,
The PCV valve is designed to go into a manifold only, not the carb. And, it only works 1 way round...

If it won't idle with the vac hose on the carb port, with no PCV valve, you need to block all other vents, it's getting too much air.
When they used these SU vac ports for ventilation on late motors 1975?> the inlet to the rocker cover was restricted to a 1.5mm? hole. And the cap was a sealed one.

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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.

Doc and others, I think a How to or a comprehensive post on the subject of breathers and pcv and vented/ non vented oil caps is required.
I have an old MG where I am going to rebuild the engine and want to replace the old form of crankcase vent and draught tube to stop oil coming out when it pressurizes.
The 64 850 we have rebuilt which still has some issues has an inlet through the carb air cleaner, the Clubman valve cover with condensor and the draught tube arrangement. I want to change it to stop it potentially dropping oil.
I've thought about catch can with draught tube coming from the top to create a venturi affect. Using mini type breathers on the side / tappet cover plates and the idea of using the redundant mechanical petrol pump plate to return oil to the crank case.
The PCV arrangement utilising the stock pcv that the factory put on seems a good indicator of where we should be going, perhaps with enhancements.

I would NOT fit anything in the way of a breather or return, to that fuel pump hole. Been there done that. Over 4000rpm you can't stop oil coming out there, the crank and rods toss oil straight at it.
www.minimania.com makes a baffled breather for there, it may work, but is not cheap. Flywheel housing breathers have oil problems too, on long LH bends at high rpm the primary gear tosses oil up it.. so eff it, I plugged that and now run the breather line from the rocker cover.
On a smallbore IMO the best bet is a Cooper S/998 Clubby sideplate canister, run to either a PCV valve on the manifold or to the vac port on an SU carb if it has one. Use either a plain filler cap or an S breather one (it works either way) and plug all other vents. This fixed MiniDave's leak problems.

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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.

Makes sense, cheers. Nobody has mentioned either of those two points before that I've seen (manifold only, and one port).

You can run from 2 breathers to 1 carb or PCV valve if you want- just use a Y-piece to join them.
Mk2 Oz Cooper S with Police Pack carbs (twin HS4s) ran from the sidecover canister to a Y-piece, then to the vac port on each carb.

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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.

Well that's what I was doing....but that was giving the crazy idle. When time permits I'll try it to the manifold via PCV.

Sorry for the thread hi-jack....