I've changed the valve over, the PCV valve Id used did have a smaller internal hole. I'll leave the canister off unless I notice an increase in fumes, the tank is different for FI, flow and return, not sure about venting.
Vents are the same, the only difference I can see between our 73 & the 77 is it goes into the air filter on the carb motor whilst the 77 goes to charcoal canister. I’ve looked at our crankcase breather, that had some sealant on the gasket looking at the seat.
No, the carb crankcase vent is direct to the airfilter with no back pressure, oil vapour condenses in the breather box and drops back into the sump.
Is the valve an emissions part? Closing off the crankcase ventilation at idle or what does it do? Sorry for being thick. If it's for emissions and broken I'd ditch it personally, it sounds like volunteering for a headache.
thanks Geoff! I knew the oil vapour collected here and dropped back to sump. I assumed, perhaps wrongly, that the little mushroom vent acted as some form of low pressure release.
Swapped the PCV valve for the "topran" valve, it's relieved the crankcase pressure to an acceptable level. I discovered the EEC valve on the air filter box was faulty, hence loosing vacuum before reaching the dizzy, so connected dizzy direct to plenum Checked engine timing, 7.5 static and 28 degrees all in with vacuum disconnected and plugged. Reconnected vacuum went for a drive and found massive hesitation under load, checked timing and found dynamic timing was 50 degrees with vacuum connected. I disconnected and plugged vacuum and it drove okay. (Basically turned it into a 009 dizzy) I have an accuspark svda distributor, is 22 degrees of vacuum advance normal beyond centrifugal advance?? I took off the vacuum canister added a couple of circlips as packers to reduce travel and tried again...hesitation gone and dynamic all in at 35 degrees with vacuum connected. I may have gone too far and could remove one "packer" and get around the 40 degree mark, if that's better?? Now I have erratic idle/stalling when hot...it goes on and on!!
