hello

do i need breathers? so yes why or why not?

the engine is a 350 1988 SB
it was before a tpi engine now its a carburated engine.

i have dress up my engine a little and don`t want to make a hole i the new valve covers for the breathers.

whats happen if i don`t use a breather?

thanks dennis

 

You collect moisture in the crankcase. When mixed with certain combustion by-products, you get acids. Acids are not good in a crankcase.

 

You have to have some sort of venting of the crankcase or pressure will build up and blow out seals. Usually the valve cover gaskets and/or the shaft seal on the distributor.

 

I suggest a good PCV setup, breather in one cover pcv valve to the carb in the other. This will prevent your oil from turning into sludge in the crankcase. I would rather have a clean engine inside than out.

 

If you are clever you can hide the breather setup pretty well.

You can put the hole on the back of the cover near the firewall and run it to the carb or a remote breather/ oil sepperator.

Depending on the manifold design the vent/breather can vent from the lifter valley too. Older SBC's were vented like this. A tall single plane is ideal for this but even an airgap can be modded.

 

Any reason you couldn't run the PCV valve to the vacuum fitting in the manifold behind the carb?

 

You'll lean out the cylinder on that runner.

 

PCV valve is best run to the big port on the carb designed for it. Typically this port vents in the middle of the carb flange, helping to distribute it more evenly between the cylinders.

I've tried it on the intake manifold vacuum fitting and...... it worked exactly the same. Go figure. Old Pontiac engines have a similar setup, FYI. Can't be that horrible, right?

 

Well, the vac port is perched right on top of the #8 runner. That makes sense.

In the quest for a cleaner look, especially on the front half of the engine, I'm gonna look some more.

I'm still running a Q-Jet and may look at the port on the base of the carb where the power brake vac tube goes.

I can move the PB vac hose to the #8 runner vac port.

Thoughts on that?

 

The PB line is fine in the manifold port.

 

okey thanks

but there is a new problem now!
i need 2 big vacuum ports now one for the powerbrake booster and one for the pcv valve.
there is only 1 big vacuum port on the holley carb.
i want to use the vacuum port on the manifold but the carb is to close on the port!
there is 1 cm space left between the underside of the carb and the top of the vacuum port!

what to do now??

 

Use a thicker gasket, and see if you can fit a right-angled fitting into the manifold port.

 

Wouldnt you tend to suck up or blow out a good bit of oil since there are no baffels back there to stop this from happening?? Ever run the breathers on the right side of a round track engine???hehehehe. Or simply put the valve cover on upside down? (And yes you CAN do that with valve covers made for round track)

 

Using a tall cover will give you enough room to use some sort of baffle.

 

Yeah, but thats only if you know how. And some people shouldnt be allowed to own tools much less take on making and installing/welding on a baffel!!LOL

 

No need to weld, use a baffled grommet.