18 replies to this topic

[Cooper-202S]

Having Bladed the crank & and fitted a windage plate (between the block and the gearbox) I realised that by largely reducing the amount oil flying around in the crankcase that I had robbed the cam shaft of a good portion of its lubrication.
To solve this I've opted for a Cross drilled camshaft, but;

Does anyone know by how much, if any, you need to open out the brass flow restrictors that are fitted in the oil risers from the mains to the cam bearings to allow for the extra oil a cross drilled cam shaft needs??

Any help would be appreciated before I spend the whole weekend trying to work it out.

Thanks in advance

[Paul Wiginton]

I never touched mine

Paul

[adcyork]

Even though you have fitted a windage tray, thats only stopping the oil flung up by the gears in the gearbox. The big ends are throwing oil out of the sides of the bearings all the time and they'll lubricate the camshaft fine i'd say.

Also all the oil that runs down the back of the engine after it has lubricated the rocker gear will make its way onto the camshaft.

[mini13]

yep, consider inline A engines, they get no oil flung up by the box and survive,

[MRA]

I think that you will find that the crank in an inline sits partly in oil... and therefore does throw oil up around the othe rmoving parts. However that said and done windage trays are a good way of "extracting" power that is normally wasted in churning oil around, so rather than knocking the windage tray, think positive about how to get enough oil around the parts that need it ?

for instance utilising the oil feed drain pipe from the pressure regulator, which normally just drops it in to the "sump / gearbox"

Cross drilling camshafts and opening up the oil ways just means that the oil pressure and or flow to the mains and bigends is potentially reduced, this could be catastrophic to the crankshaft what about "wasted" oil...... oil that is draining from the followers as another example.

[Paul Wiginton]

I use a cross drilled cam with drilled followers. The cam is 5 years old and not a hint of wear. My oil pressure is actually a bit too high if anything

Paul

[Sprocket]

I think that you will find that the crank in an inline sits partly in oil... and therefore does throw oil up around the othe rmoving parts.

Splash lubrication on a forced lubrication engine? I find that hard to believe!!!

http://austin-rover....ineaseriesf.htm

[mini13]

there is absolutley no way that the crank in an inline A series touched the oil in the sump....

I am horified that you would even think to entertiain the thought MRA.

[MRA]

Well I tend to stay away from inline A series

However there will be oil "leaking" out past the bearing shells, and the crankshaft will mostly turn this into mist which will lubricate other parts of the engine, but also help to cool the internals

Ok, what are the benefits of fitting a windage tray if not to reduce absorbed BHP ? and if so what absorbs this BHP ? simple it is the oil and the pumping effect of the crankshaft against this oil... now while most of you will never need this extra oil around pistons for instance..... and your gudgeon pin / small end of a conrod gets its oil from where exactly ????

Ask any owner of a mega high BHP turbo engine how they keep their pistons cool ? most if not all will tell you that they use forced oil aimed under the piston crown...... this is NOT a standard A series item and must be added.... up till that point they are splash fed by oil being splashed up under the piston crown.

So the splashing of oil around the engine helps to remove excess heat and lubricate the piston gudgeon pin within the piston or conrod whichever you have.

Edited by mra-minis.co.uk, 20 September 2009 - 09:18 AM.

[Cooper-202S]

Thanks to all who posted,
Paul I'll take on board your actual experiance with you engine and quit worrying for the time being.

The figures I have say that the Cross drilled shaft uses an extra 6 cuft of oil per minute at 5000rpm, i'm using a titan oil pump and an adjustable oil pressure regulator so setting up suffiecent flow and pressure shouldnt be a problem.

The only other issue I can think of is that the pressure sensor is between the pump and the filter not in the gallery itself, so its not necerssarily a true reading

Has anyone actualy measured the pressure in the gallery verses the back pressure from the filter?

[Cooper-202S]

now while most of you will never need this extra oil around pistons for instance..... and your gudgeon pin / small end of a conrod gets its oil from where exactly ????

Ask any owner of a mega high BHP turbo engine how they keep their pistons cool ? most if not all will tell you that they use forced oil aimed under the piston crown...... this is NOT a standard A series item and must be added.... up till that point they are splash fed by oil being splashed up under the piston crown.

So the splashing of oil around the engine helps to remove excess heat and lubricate the piston gudgeon pin within the piston or conrod whichever you have.

Oh there just had to be something else I hadn't considered didn't there.

So now i'm left wondering if I need to cool the pistons.

[bmcecosse]

The crank in an in-line A series certainly doesn't sit in the oil! Although they did dry sump them for Formula Junior - but mainly to ensure no surge on cornering. Never heard of a cross-drilled cam - crank yes, cam no. Can't see the point - it will be well lubricated by the spill from the big end bearings. Windage tray IS a good idea (don't see anyone saying otherwise?) because t it saves excessive oil flying around the block which the rods would otherwise have to push aside! Also stops exceeesive oil on the bores. If worried about piston cooling - it is of course possible to drill the rods to allow a squirt of oil from the big ends up into the piston crown area.

[mini13]

I thought you were an engineer?

think about what will happen if a crank hits a substantial amount of stationary oil at high rpm....

maybe you should stay away from all engines.

Well I tend to stay away from inline A series

However there will be oil "leaking" out past the bearing shells, and the crankshaft will mostly turn this into mist which will lubricate other parts of the engine, but also help to cool the internals

Ok, what are the benefits of fitting a windage tray if not to reduce absorbed BHP ? and if so what absorbs this BHP ? simple it is the oil and the pumping effect of the crankshaft against this oil... now while most of you will never need this extra oil around pistons for instance..... and your gudgeon pin / small end of a conrod gets its oil from where exactly ????

Ask any owner of a mega high BHP turbo engine how they keep their pistons cool ? most if not all will tell you that they use forced oil aimed under the piston crown...... this is NOT a standard A series item and must be added.... up till that point they are splash fed by oil being splashed up under the piston crown.

So the splashing of oil around the engine helps to remove excess heat and lubricate the piston gudgeon pin within the piston or conrod whichever you have.

[Cooper-202S]

I know the turbo boys run the oil jets to cool the pistons at high HP but
Can anyone say with some certainty where abouts in HP you need to start thinking about this.

I'm aiming for between 80 & 90Hp for the SPI, which seem to have a cronic overheating problem anyway especialy once you start modifying them.
(Ive rebuilt 4 so far this year and all the problems track back to overheating)

[mini13]

well, to be honest theyre not really needed,

"that" 315 hp does not run them and he does not have issues wih pistons,

but personally I run them.

you can get good jets from BMW, there is info on them on the turbominis site