PCV valve

[Mr Frog]

Can anyone tell me whether the 105 1750cc and 2000cc engines have positive crankcase ventilation, and if so where the valves are and how to replace them?

[urraco]

Hi Mr Toad,
No there is no positive crankcase ventilation on 1750 & 2000 Nord engines in the 105 series thus no PCV valve.
A simpler system is used. A pipe connects the cam cover (which of course is connected to the crankcase) to the air cleaner allowing oil fumes and blow by from the motor internals to be breathed into the motor, through the carbys, and burned.

[Mr Frog]

thanks very much for that - what you have told me is different to the system described in my haynes manual, which features a PCV system in detail. the arrangement on my engine is the same as you have described. i am trying to establish why my plugs (one step hotter than standard) are fouling while at the same time i am not burning oil in any signifiant volume, and my valves, piston crown and head are as clean as a whistle!