Race Engine Forum UK

Hello Guy,

Just a quick query regarding the breather ports on a Beta block. Current configuration is running a dry sump, breathing is done via the tank. I’ve got both ports blanked off and I’m using the larger port as an oil return for the turbo. All seems to work fine.

What I would like to do (better run for the oil return pipe and there is already a -10 threaded port attached) is use the smaller port as the oil return. I can't find a picture of a block that shows where the smaller port returns to and not sure if the hole to the sump would be large enough.

Can you see any problem in doing this?

Many thanks in advance,
Chris

Are you referring to ports 1,2 in the picture below?

From what you have described it sounds as if you have blanked port 1 and are feeding the turbo drain-down pipe to port 2?

Let me know if I'm right or if not please post a picture. You can use MS Paint to mark up.

GC

From what you have described it sounds as if you have blanked port 1 and are feeding the turbo drain-down pipe to port 2?

That is correct Guy. I would now like to swap these, so turbo drain into port 1 and blank port 2.

Thanks,
Chris

Port 1 is open to the crankcase - you can drain down there. From a practical point of view it is better to drain to the sump below the windage tray, rather than having the oil splashing around (given that it's dry-sumped) but really I only mention that before some else does.

For the record, the turbo is fed high pressure 'cool' oil and even if the crankcase is under positive pressure that incoming oil (that lubricates the unit) force the hot drain-down oil back to the crankcase/sump.
Some models eg Integrale have a one way valve on the drain down to prevent crankcase pressure and gas (& carbonised crud) going upstream to the turbo. I think I got that right anyhow, any Integrale expert welcome to remark.

I cannot tell you the crankcase pressure state on your motor, but I'm tempted to say that it will at depression or at least quite low pressure compared with a wet sump unit since the scavenge pumps are evacuating it - to some extent anyway nad the lower the crankcase pressure the more effective the turbo oil circuit will be.



GC

Many thanks for your reply Guy.

Yes you are absolutley right with regard the oil drain into the pan below the windage tray - that will be the best place, don't know why I didn't do that when I made the pan! I'll pull the pan off and weld a union on between the scavenge outlets.

Thanks again,
Chris