K head problem pumping oil.
Turbo Mini Forums

I built a K head conversion for a friend who has just installed it and got it running on the first turn of the key.
However he has rung me to say that it has filled his catch tank with oil, it overflowed and lost most of his engine oil in less than 5 miles !

I feel he has plumbed the breathers wrong but need some clarification.

The oil return from the head has two small bore connections to the block supplied by SC bolted to the fuel pump hole on the side of the block. Both are flowing freely. The large bore tube from the front of the head goes to the large connection on the same block.

He has connected the small bore connection from the front of the head to the catch tank and a line from the catch tank to the last small connection on the block. This line from the head appears to be carrying all the oil that has been lost.

Should that line go directly to the block ?

Additionally, how does the engine breathe ? I can,t see any connection to atmosphere to allow this if that line is connected as I suggest.

All I will say is, the smaller the hose you use as a breather, the greater the velocity of the gasses that pass through it. Others experience as well as my own, these engine seem to be quite heavy breathers. The increase in blowby gasses increases the velocity in the small breather pipe will naturally pull oil with it, it’s the same principle that refrigerators use to return oil to the compressor.

In general you want to take the breather from as high up on the engine as you can. Maybe a 1” hose what you do with that then is up to you. I think the small bore hose on the SC system should go to collector that’s usually bolted to the mechanical fuel pump mounting. I’ve debated before why they use a large hose and a small hose both from the same point ending at the same point.

I opted to have a 1” oil drain welded onto the end of the head where the core plug is. This drains into the side of the original breather can, and there is a baffle to ensure the oil has to run to the bottom. This 1” hose also acts as the main breather from the head. I further modified the breather can so that it accepts a standard VAG oil filler cap. I added an oil separator again from a VAG car which takes the same oil filler cap. This is my main breather which is maybe 20mm ID. The breather location on the transfer case was modified slightly to allow oil to drain down through onto the idler gear quickly. I then have the two drains off the back of the block and one off the end of the head maybe 10mm ID. The breather outlet is plumbed into the inlet duct via a diaphragm valve and a PCV valve constantly draws into the plenum under vacuum conditions. So far I’ve only seen a film of oil on the inside of the breather hoses and the inlet duct is clean and dry. I’m sure there is some oil vapour getting through but not enough to be any more of a problem than it is on any OEM car. One good thing is that there is no oil film all over the engine bay.

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Thank you for such a comprehensive reply.

I too wondered at the idea of twp hoses of different sizes seeming to do the same job.

Speaking to JK today he maintains that the smaller hose is a breather only and should go to the catch can,

I have suggested to my friend that he puts it to the collector and then tees off the large diameter hose to the catch can, using it as both breather and oil return.

The installation is in his 1954 A30 which we believe is the first time this has been done.

I'd like to see that

It is intended to be at Le Mans Classic from 6 July.

The small hose from the head goes to a catch can.

You also need a breather from the bottom end, usually this comes from the transfer case breather hole to the catch can.

Don't connect the SC collector block thing direct to the catch can. It will just blow all the oil coming from the head back out into the can. The lines are too small aswell. Sounds like this is your problem couples with not having a breather from anywhere else on the bottom end.

Thanks Slater.
This installation is in an inline setup so no transfer case breather.
I agree the pipes are small for the purpose and I also agree that there should be some provision to have a breather from the bottom end.
The car is NOT going to Le Mans now, with these problems as yet unresolved.

Maybe you can get it from the dizzy hole?

In all honesty the breather from the head (small one) is a bit pointless. If the bottom end is well ventilated you don't need it. It's when the top end is better ventilated than the bottom you get trouble as the air is trying to go in the oppersite direction to the oil draining from the head.

I always run a pcv system on inline engines to stop them pissing oil out onto the clutch. Has it got one of those seal conversions instead?

Yeah, why didn,t I think of that ?
I used that on the A35 as well as two other large breathers and had no issues.
I have used various oil seal conversions on that rear main with very limited success. The only leak after the engine has stopped anyway !

talking of the rear seal, Chap I know has been looking for 1.3 ital motors for his minor,

I just hooked him up with a 1.3 Maestro engine which apparenly has a proper rear seal.

Post excavation.
The K head Austin now lives much further away from me and the owner has been sidetracked with other things -new bathroom, roof repairs, you know the kind of thing.

So the car has been sitting awaiting attention for along time and I spent a day recently trying to get it to run well enough to go on the rollers.

No 4 cylinder does not want to play with the others at anything under about 2500rpm and all cylinders are running miles too rich,plugs all black and sooty.
All the injectors have been cleaned and flow tested.

We don,t have the maps or the ability to analyse with a laptop but JK has suggested that the throttle bodies may need to be synchronised first. Synchoniser on order, but what is causing the richness as the map as provided by SC should be spot on given the number he has sold.
I have a theory that the NGK plugs don,t like the soot and are not firing cleanly now and have suggested the temporary substitution of plugs a grade hotter.
Comments please.

We may have to trailer the car to the rollers to get it sorted I feel.

Yeah plugs are definitely worth swapping for a fresh set.

drop fuel pressure .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

drop fuel pressure .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

Its a shame you can't plug a laptop in, just to check that the ECU is seeing feasible inputs from the likes of the throttle position sensor, water temperature, etc.
As the old saying about computers goes, rubbish in, rubbish out.

How do you not have the ability to plug in with an aftermarket ECU? I’m confused.
Do you have a wideband? If not, why not? Cheap as chips these days and an essential diagnostics tool. Yes, the NGKs may be fouled, but something fouled them - and the new ones will also foul at some point.

Edited by TurboDave16V on 12th Apr, 2019.

We have now bitten the bullet and booked it in for a while on the rollers.

First, to get it running reliably, second to run it in on the rollers and lastly to fine tune.

It will have an oxygen sensor fitted and plugged in to the ECU

And we WILL put a new set of plugs in !

And yes Robert we did drop the fuel
pressure but it made no apparent difference