1981 mercruiser 260 crankcase ventilation

[mkulin]

What is the original way the crankcase ventilation was done. Some monkey put 2 pcv valves on the two breathers and now at higher rpms I have oil in my bilge some from the valve cover grometts some from the dipstick. Im guessing no or hollowed out pcv valves?

 

[Bt Doctur]

The things your calling pvc valves are hollow inside.Thats normal because at cruise power there is almost no vac to suck the fumes out of the engine.
The hoses are routed to the flame arrestor to suck the fumes down the intake
If you have normal pvc valves, their incorrect and will result in high crankcase pressures to blow the oil mist and vapor out of whatever hole it can find

 

[mkulin]

T^hanks but if they rattle they are pcv valves which both do, hence the oil coming out any orifice it can find. Yhx for the confirmation

 

[Bondo]

but if they rattle they are pcv valves which both do

Ayuh,.... They should be wide open plastic elbows,...

 

[mkulin]

thank you its a quorum!

 

[Bt Doctur]

part # 47957

 

[mkulin]

part # 47957

NLA

 

[Bt Doctur]

try 97850T 90 degree fitting

 

[mkulin]

Thank you!. Or I will hollow out the two PCV valves already there.

 

[mkulin]

Just so I understand both connections use the elbow and terminate at flame arrestor. How does the air get into the crankcase I have a sealed oil cap should I replace it with a breather type?

 

[Bondo]

Ayuh,.... Combustion gases can escape past the rings,...

No need to change anything,....

 

[Scott Danforth]

a 1/2" copper elbow either 45 degree or 90 degree works as well. 5/8 heater hose slips right over it

 

[mkulin]

a 1/2" copper elbow either 45 degree or 90 degree works as well. 5/8 heater hose slips right over it

great tip thanks!