350 sbc

[patina]

I scored a 350 that i think came out of a fuel injected van. Theres no numbers on the back of the block only gm 5.7 stamped in to it. The plan is to convert it carb. I have a set of carb heads to go on it as well. Im not the best with engines. But i was wondering if i could use valve covers with no breathers and drill a hole in the back and use a pvc valve. Or is there another way to get around using valve covers with no breathers.

The reason why i want to go with no breathers is because i am after this look.

http://www.ebay.com/itm/251155424429?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2648

Forgive me for dumb questions.

Jason

 

[Montana Rat]

Ya... you can relocate your PCV valve but you still need a source for air for your PCV valve to work properly. I have heard stories of seals being sucked in and damaged because of no air source.

Scott

 

[Dirtyrat]

Ya... you can relocate your PCV valve but you still need a source for air for your PCV valve to work properly. I have heard stories of seals being sucked in and damaged because of no air source.

Scott

I'm not following you here [S, many old engines had no "source" but rather just a breather....

Without a breather at all you would likely blow out the seals, PCV = positive crankcase ventilation

 

[Montana Rat]

You are right... The breather is an air source. Without an air source for your crank case you may damage the seals. your PCV valve is not an air source because it is under engine vac. The pcv valve is causing a suction internally in the engine...an outside air source like a breather or a tube coming from the air cleaner will fix the internal vac in the engine. hope this makes sense.

Scott

 

[Dirtyrat]

Yes, there is a source for fresh air to enter the crank case through a breather, or a vac source somewhere in the intake tract, then fumes and air are sucked back through the PCV valve and into the intake and burnt.

So I guess in actuality, it would be possible to "suck in" the seals if you had no source...

 

[patina]

i know i need to keep the pvc valve but how i do i allow the top end to breath while using top pans with no breathers?

 

[Dr Crankenstein]

Put a breather tube in the intake manifold.

 

[chevellelovermichael]

breather in the manifold is how all the older, pre emissions stuff was done. when I lived in california, I had to have my 64 malibu air sniffed, and to make it pass, i just hooked a small vac. line to the manifold breather, and that was passable.

 

[RPM]

Put a breather tube in the intake manifold.

Engines that used this type set up also had a road draft tube in the back of the block. Inside the block was a baffle to keep oil from getting out. Later model blocks don't have that provision for the road draft tube.

 

[26Troadster]

you really don't need a pvc as they where made for the clean air act, all they do is pull all the fumes back to the intake so it could be burned it the motor. i have ran just breathers on some motors and have used a crank case evacuation system where we had a tube in a angle on the headers to draw the fumes from the motor, but if you are running any back pressure on the exhaust it will not work.

 

[Dr Crankenstein]

Engines that used this type set up also had a road draft tube in the back of the block. Inside the block was a baffle to keep oil from getting out. Later model blocks don't have that provision for the road draft tube.

Yes, I'm aware of that. I'm suggesting the tube as an inlet "source" for a PCV system. The PCV should take the place of a draft tube. Am I wrong to think this?

 

[sgtpontiac]

Nope...you are not wrong.....

Yes, I'm aware of that. I'm suggesting the tube as an inlet "source" for a PCV system. The PCV should take the place of a draft tube. Am I wrong to think this?

needs to draw some air into somewhere.....doesn't matter where but needs a breather and a pcv to work properly.....jmho

 

[chevellelovermichael]

a pcv is for emissions use only. if it needs tested by your state, then you need it, if not, you only need a breather. it just keeps pressure from building in the crank case. crank case evacuation set ups are used in racing applications, for wide open throttle conditions, and also helps to seal rings.

 

[maverickmk]

If there is not a way to get air out of the crankcase then you will start having gasket leaks, dipstick tube leaking/blowing oil, etc. There is pressure created by the motor when it is running. That pressure needs to be be relieved by some sort of device, ie. breathers, PCV, etc. But as was said before, a PCV was originally created for emissions purposes.

 

[junk]

The heads on that motor should be a decent head. Assuming its got the F.I. heads they should be center bolt valve covers. Ive seen those heads drilled and tapped to except older valve covers in stock car racing. Alot of smaller clases dont allow the use of vortec style heads. Ive built many engines with and without crankcase ventilation. I chose to run a pvc valve in my dads 46 panel because he and especially my mom doesnt want to smell the vapors or essentially the blow-by the engine produces. I have 3 circle track engines 2 which just uses valve cover breathers and one that has an exhaust scavenging vacuum system. The one with the vac system has low tension oil rings so it needs the vacuum in the crankcase to help the rings to scrap the oil off. Either way its your choice. If it were mine and I wasnt going to rebuild it, Id have a pvc valve in it just to minimize the oil mist.

 

[Rhynorock]

They do make a side mount breather, dunno if that would interest you or not.

http://www.speedwaymotors.com/Racing-Engine-Breather,8948.html

Kinda stupid money for a breather but it may solve your problem.

 

[Torch]

PCV also keeps your oil cleaner
crankcase vacuum isn't a bad thing. Racers have run engines with vacuum pumps to increase horsepower. the less pressure on the bottom of a piston, the harder the pressure on top will push