Crankcase ventilation - how much is too much?

[86mud]

Hi all

my 186 has three vents out of the tappet cover - the actual oil cap , then two other hoses - one hose is connected to the air cleaner (but the plastic barb into the air cleaner is broken) and the second pipe closer to the firewall end of the tappet cover is connected to the inlet manifold.

Is this correct? Seems too many. I was looking at new tappet covers and the ones on ebay only have on vent pipe.

Help????

Cheers

[VladTepes]

This is a Lycoming engine, but is a good example of excessive crankcase ventilation...

[mick88]

This is a Lycoming engine, but is a good example of excessive crankcase ventilation...

Nah!
That is called throwing a leg out of bed!

[mick88]

Hi all

my 186 has three vents out of the tappet cover - the actual oil cap , then two other hoses - one hose is connected to the air cleaner (but the plastic barb into the air cleaner is broken) and the second pipe closer to the firewall end of the tappet cover is connected to the inlet manifold.

Is this correct? Seems too many. I was looking at new tappet covers and the ones on ebay only have on vent pipe.

Help????

Cheers

It most likely has a tappet cover from one of the later blue or black engines.
The 186 engines just had a breather at the front and a point at the rear where the pcv valve plugged into and the other end of that hose conected to the inlet manifold below the carburetor.
Make sure you keep the breather at the front or your motor will leak oil around the cork gaskets when it gets a few revs up.


Cheers, Mick.

[86mud]

Hi Mick

When you say keep breather at the front, do you mean the breather in the cap or the additional breather that I have that runs into the air cleaner?

Cheers

[bee utey]

The breather to the air cleaner should have a foam element on it inside the air filter can, they were a service item from Holdens that should have been regularly replaced. If you've got the vented 186 filler cap you should just block the hose, or get a foam breather for it and fit a later flat filler cap instead. Your rocker cover is probably off a later motor than the 186, as rudimentary emission controls were introduced around 1971 with the HQ 173/202 series.

Element looks exactly like this one:

68 96 GM Breather Element Crankcase Ventilation 6 Pack | eBay

Acdelco FB59 Breather Element | eBay

[mick88]

Hi Mick

When you say keep breather at the front, do you mean the breather in the cap or the additional breather that I have that runs into the air cleaner?

Cheers

The standard early type breather like was fitted to the Holden engines of the late sixties is the one I mean. It has a steel mesh in it and should be washed out in kero at every oil change. There are are racey looking aftermarket versions with a paper element in them available at speed shops for about $30 if you want something that will make it look like it goes faster.
Here are some examples of engine breathers.
You no doubt have one similar to on the blue motor, however your motor would have originaly looked like the last example.

Cheers, Mick.