Help!!! Crankshaft seal keep blowing

You can run two valves if you want. Plenty of people do. I would get the pulse signal from the carb. If you go that route, you dont have to worry about oil getting in your pump or rerouting the PCV valve.
 
Hello all I have vented engine via : New block with billet sidecover & valve cover four ports In total mild build billet rod +.20 , billet flywheel , 292 cam , 27/25 milled 50 head, 24mm flat slide, F&B header, Ect.
Starts runs great blows case seals on either the Pto shaft side or the flywheel side over and over I’ve changed both same thing I looked around no info on this issue I need help!
You defiantly have to much crank case pressure, most likely poor ring seal, how ever when modifying one of these engines a good venting system is a must. I give my advice on this thread https://4cycle.com/karting/threads/crankcase-venting.106737/
 
You keep talking about a Crankcase Vent Mine only has one and its in the valve cover. Is that what you mean when you say Crankcase vent. Or is there another one on the side cover I dont see or have. Thanks
 
You keep talking about a Crankcase Vent Mine only has one and its in the valve cover. Is that what you mean when you say Crankcase vent. Or is there another one on the side cover I dont see or have. Thanks
No . It is one that you would add .
By drilling and tapping for a pipe nipple .
 
Here is an example I just pulled off google. If you buy a billet sidecover the holes are drilled and tapped for the fittings already.
 

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There is plenty of info out there why you should use a PCV valve but its not completely necessary. They are used in most automotive engines and I'm guessing they have a good reason.
Why do you want to fill the crankcase full of air on the up stroke if you don't have to? It then has to push more out.
With two holes in the sidecover it's probably less of an issue.
Paul at Paul's karts talks about this and sells the valves as well.
a multi cylinder automobile engine and a single cylinder racing engine are completely different things. one piston rising while another piston is falling the crankcase is at equilibrium. if you create a vacuum in a single, the piston has to overcome the vacuum in the crankcase on the upstroke robbing you power. you want it to both expel and suck in air so the piston is fighting nothing while doing 2 times the RPM of your automobile.
and secondly the one way valve can FAIL and if you put it on in the wrong direction it will always blow your seals.
 
You also have the oil return hole in the head so I'm not exactly sure how strong a vacuum it would make.
The PCV valve is something I have seen brought up by very reputable guys out there in all the research I have done. I will admit that I am new to building this type of engine. It would be nice to know exactly how strong this vacuum is.
Too much could be detrimental and just enough could help by sealing rings. It seems this would be an advantage if you are running methanol. Less fuel finding its way into the crankcase. Also trapping more air for compression possibly.
I always keep an open mind and you do make a good point.
 
So on a stock 212 just use the valve cover vent.? Run the hose down and leave open? Thats what I did on my 79cc
Thank you all
 
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