Blow-by on a high compression motor-remedies?

[MrNasty]

Hi all, New to this forum, but not new to XS's. I race a vintage sidecar with a 750 kitted 447 motor, 10:1 compression, Megacycle cam, etc. My question is in regards to blow-by. I have my motor set up with adequate venting, top and bottom end (with one-way check valves) but unfortunately get a lot of oil blowing into the catch bottle. Not a big problem on the short tracks, but a big one (and costly) on the longer tracks.

So here is my question: Is there any way to have my catch bottle drain BACK into a low-pressure part of the motor (possibly the sump for the starter motor) that will get circulated back into the motor? Thoughts? Suggestions?

Also, for those of you running 10:1 / 750 kits (with an oil cooler) for a racing application, what volume of oil do you run?

Thanks, Doug D.
USCRA #82

 

[blackbetty]

Doug, I can't answer your question but I'd like to see a pic of your rig

 

[MrNasty]

uploaded a few

 

[Punkskalar]

I have found that I have to run a slightly lower amount of oil to keep that from happening. And oddly enough, running my valves on the "looser" side of spec calms it down as well.

Also, I typically gut my breathers and install a "filter" made from a 3M Scotchbrite type pad. Also make sure you are running the camchain oil scraper inside the head. All of that has curbed the blowby quite a bit for me.

 

[blackbetty]

I took the liberty of posting your pics man, so radical:

 

[Punkskalar]

I took the liberty of posting your pics man, so radical:

Oh god yes!

 

[Jack]

Check out the Krank Vent system

 

[hotdog]

Hi Mr Nasty - I would like to know about your Dellorto jetting. Are you running with the Heiden/Mikesxs jetting supplied with the Dell kits they sell..??
Or have you had to swap some brass.?
Regards.

PS - I like the twisted headers & 2-2 supertrapps.