22 replies to this topic

[Spider]

Getting Fresh Air in - You can go to a Vented Oil Filler Cap, but personally, I'm not crazy about them as there's always a little oil stain on the rocker cover around them, but I do use them on some cars and put up with it.

 

On the Moke as it works in very dusty conditions, attention to crankcase sealing, making it totally dust and water proof needed some careful consideration. Here, I have a inlet on the rocker cover, which is plumbed, via a one way valve, to the filtered air side of the Air Intake to the Carb. This could also be done with the 'stock' set up, but not via the plugged barb on the Air Filter case, as that's on the non-filtered side. I also wouldn't put such a take off too close to the carb as the air pressure usually gets lower around here (with all the stock parts) and so instead of feeding air to the crankcase, will try to draw air from it (hence in part, why the one way valve).

[grizzler73]

I was wondering if the timing cover one was necessary on a comp car, I had noticed it was not bothered with on a number of engines. I was intending to use braided oil cooler pipes and connectors for my system as then you know it is the right type of material.
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[nicklouse]

On a comp. car you want as many as you can.

Transfer case. Fuel pump opening. Timing cover. Rocker cover.

[Spider]

Yeah, like Nick, I too like LOTS and big ones. I'll scan and put some photos up a little later.

[nicklouse]

With a race engine the reason is to let the air move without there being any high pressure trapped air as that will find the path of least resistance. That may well be a seal or a gasket.

[Spider]

With a race engine the reason is to let the air move without there being any high pressure trapped air as that will find the path of least resistance. That may well be a seal or a gasket.

 

Here's a pic of my Race Car shortly after I bought it (this is back in the early 80's!)

 

 

It had two Big Breathers from the Rocker Cover to the Oil Catch Tank. I didn't really understand or appreciate it all at that time and hey, it had an Oil Catch Tank, she'll be sweet!

 

How wrong was I on that!  First outing resulted in being Black Flagged,,,,,,,,

 

Only then did I look at what the other guys were doing and looked in to it for myself. Another 3 Breathers went on it and no more issues.

 

In these set ups, from up top to down below, there, a number of restrictions in the way and so they don't readily breath as much CFM as they need to, so in hind sight, just having them on the Rocker Cover alone was daft considering that the Pressure isn't built up in the Rocker Cover, but the Crankcase, which eventually, via some small flow paths can end up in the Rocker Cover.

 

But hey, in my defense, not a mistake - a learning experience!

[grizzler73]

But I guess if the breathers are routed through the rocker cover if there is oil being pushed through it will go into the rocker and then mainly back into the engine rather than into the catch tank, duly noted the more breathers the better! Just out of curiosity, is there more pressure in the crankcase the higher the Compression ratio?  

[nicklouse]

nothing to do with pressure. air movement. pressure only builds up it the air can not move.

 

comp engines tend to rev higher and for longer. so shift more air.