I have a 69 Lincoln 460 with an Edelbrock RPM and 1411 carb. I am ready to knock-out the plugs for the valve covers and was wondering what is the most efficient way to vent the crankcase. Would using two breathers on either side be more efficient than a breather and a oil fill cap? Does it matter?

Thanx
James

 

Depends on if you have any blow-by. Two breathers are better than one but to keep from getting oil fumes and oil drops off the valve-covers get a breather that has provisions to install a PCV valve and then run a line to your air cleaner.

Deen

 

Would it be better to tie both sides together and feed the line to the air cleaner or the PCV port on the carb? I would think that you would want to keep oil fumes from being burned and out of the combustion process altogether. The engine is a fresh rebulild so there is no blow-by, now.

I have seen quite a few different ways to do this, and was wondering what is best for the performance of the engine.

 

I was wondering the same thing. I just installed a new carb and new valve covers. If a person is not really concerned about all the emissions stuff is it necessary to run your PCV to your carb or will a second breather do the job? I'd like as few hoses as possible.

 

I prefer something like a Moroso crankcase evacuation setup. The problem with breathers is that you don't get any negative crankcase pressure. The problem with the pvc is that you get a contaminated intake charge. The Moroso setup uses two breathers which connect via hose to a one way valve you weld onto your exhaust. Works great.

 

I use a crankcase evac system into the header collectors and it works fine, no contaminated intake charge. I mounted both breather caps at the front of the valve covers to avoid sucking up oil that can collect at the back of the valve covers during acceleration even with baffles. You can see the hoses that go to the back of the engine and then down to the headers.

 

Do you have to have special headers for this set up or can you add it to any exhaust system? Also, where would I find this Moroso set up?

How important is negative crankcase pressure?

. . . soooo many questions.

 

Most of the mail order places carry Mr. gasket or Moroso systems, about $35 less hose. I've never heard of them being used with anything but headers, but who knows? Negative pressure means your pistons aren't working as hard on the way down, but, to me, the important feature is no contamination of the intake mixture.

 

Motor looks great, George!

It looks like the evac system is the way to go. A few more questions though...

1. Is there a difference between Moroso and Mr. Gasket besides iridite finish and $28?

2. With the evac system, I would cap off the PVC port on the carb, right?

 

The Moroso units have a slit cut into the tube that is welded to the header. It is pushed about 3/4" into the header to achieve the proper effect. The Mr. Gasket unit does not have this slit and in my experiance does not work as well as the Moroso piece.
On my Corvette (Blown) I found I had much more blow-by when using the evac system when running mufflers after the headers...in other words it was ONLY working when the headers were un-capped. Since the drag strip requires mufflers and you have to run mufflers on the street, I stopped using the evac system.
Not saying they don't work for others...just didn't work for me.

Deen
P.S. George, nice looking set-up!

 

The Mr. Gasket units I have come with a 3/4" metal tube that has a 45° cut on it that gets welded into the header. At idle (900rpm) there's a strong pull and reving it up produces a very strong pull from the exhaust in the breather cap. I run mufflers and pulled the header collectors with about three hours of run time and found no trace of oil. I think that's due to placing the breather caps at the front of the valve covers. Maybe forced induction is pushing oil out of the ring lands?

79BroncoJD, yes, you cap the PVC port on the carb.