Quick question...

The crank breather on a 165 block, just below the inlet manifold... Should it have anything in it..?? Like a pipe..?? Mine just appears to be a metal cylinder with a rubber bung and a plate lower down the cylinder..

Is that right...?

Cheers

Pete

Yep thats right You can fit an elbow and connect to a catch tank if you like.

David

Sounds like its identical to the breather in my 205 block. There is a push in elbow fitting in mine also. Inside this push in fitting used to be a spring loaded plunger. Ive since removed the spring and plunger and piped to a catch tank.

The purpose of the plunger is a PCV (positive crankcase ventilation), vacuum from inlet manifold pulls on it, opens the valve and allows the gasses to be recirculated into combustion chamber and burnt off (hence in the donor the valve is connected to inlet manifold on std carb). When venting to catch tank there is no vacuum - hence the modification. You cant vent this into twin webers . bike carb set ups hence why catch tank is needed for this type of set up.

I had a little issue last week in that the rubber seal had perished resulting in it leaking and allowing the valve to fall out. Ive since refitted a better 2nd hand seal and also sealed it in place with polyurethane sealant.

On my2.0 Pinto with standard carb and inlet manifold I have fitted a plastic elbow piece to the valve and connected it to the inlt maniold using the take off nearest the cooling outlet. As Darren says above, in this set-up the manifold vacuum opens the spring loaded valve in the valve and draws the crankcase gases back into the inlet manifold where they are burnt off in the combustion process.

Thanks

Can you just put a filter breather in the top then, and let it breathe that way..? Is there enough positive pressure in the crank case to push the valve open..?

Going Bike carbs so vacuum isn't really an option

Cheers

Peter

In my experience there isnt enough positive pressure in the crankcase alone to open the valve. It really needs vacuum from the inlet manifold as well.

I believe you can buy new breather adaptors for use with catch tanks (alloy?? Burtons??)

i modded the existing PCV valve quite easily. The end where the rounded plunger is at is swaged over, i carefully ground this away on bench grinder until the plunger and spring came out then dressed up the resultant sharp edge. Cleaned it all out with some thinners, fastened rubber tube to it and other end to catch tank. Secure the rubber tube so it doesnt try and drag the breather adaptor out of the rubber grommet (ive now sealed mine in).

The only issue i have seen is that my catch tank is a basic bottle, would have been better to have a baffle plate inside or some mesh as some use to slow the vapours down and allow them to condense (if that is what needs to happen).