Positive Crankcase Ventilation:
These older carbs have a tendency to plug up the vacuum passage to the PCV valve restricting vacuum due to a lot of things.
Multi-viscosity oil
Too cool of engine temp not allowing condensation to evaporate. Get me going on cooling system thermostats some day🙂
Wrong or faulty PCV valve. AC Delco has a 100 numbers but another company has 5 to replace the hundred. Remember a PCV valve is a METERED vacuum leak. Cannot tell you how many cars I fixed by installing a correct PCV valve. Buy the right AC Delco and be done with it.
I see a lot of cars with a PCV valve in the left rocker cover and the PCV air intake in the same cover. They need to be in opposite sides. The engine has to breath.
When you remove the valve covers to change the gasket make sure the oil returns are clear on each end of the cylinder heads. They have a tendency to plug on engines that are not properly maintained preventing the oil from returning to the crankcase and leaking into the valve guides.
OK.....off soap box for tonight
Y'all have a great evening
These older carbs have a tendency to plug up the vacuum passage to the PCV valve restricting vacuum due to a lot of things.
Multi-viscosity oil
Too cool of engine temp not allowing condensation to evaporate. Get me going on cooling system thermostats some day🙂
Wrong or faulty PCV valve. AC Delco has a 100 numbers but another company has 5 to replace the hundred. Remember a PCV valve is a METERED vacuum leak. Cannot tell you how many cars I fixed by installing a correct PCV valve. Buy the right AC Delco and be done with it.
I see a lot of cars with a PCV valve in the left rocker cover and the PCV air intake in the same cover. They need to be in opposite sides. The engine has to breath.
When you remove the valve covers to change the gasket make sure the oil returns are clear on each end of the cylinder heads. They have a tendency to plug on engines that are not properly maintained preventing the oil from returning to the crankcase and leaking into the valve guides.
OK.....off soap box for tonight
Y'all have a great evening