I should also add my fan is on for the vast majority of the time because I have it set to kick on at 160 because at 170 or 180 it gets way too close to overheating for my liking since it takes a bit to actually cool
All Small Six Weber 32/36 rough idle
- Thread starter beanmiester
- Start date
This relates to all small sixes
When I was trying to get mine to work, I put my fan relay on a switch. Even running full time, I couldn’t keep the carb from Vapour locking. That was without a phenolic spacer and without a heat shield between the carb and engine and with my gas line basically on the valve cover. My engine compartment is ridiculously hot but blowing hot air around the engine compartment was just enough to keep it from Vapour locking.
It’s better now that I’ve rerouted my fuel line but I need to install the spacer and head shields before I attempt the electric fan again.
That and why you have oil in the filter housing. I laid out the PCV system in post 169. Is yours correct? If there's oil in the filter housing it is not correct. Either the PCV valve is not functioning correctly, not routed properly, or the engine is very worn out. Oil in the air filter means a large % of the blow by is going up that hose into the filter, which should only be occurring on heavy throttle.
Getting this straight is more important than the shared vacuum port at this point.
A picture of your system would be helpful.
Also, nearly all carbs have a intake vacuum port on them, this could supply the trans.
On my intake with no vacuum port, I used a spacer with a port in it for PCV.
The line that ties into the blue metal line is how the vacuum is routed. Under the metal support is a tee that connects to the transmission.
I dont have a line that goes into the air cleaner and I don't see anywhere to hook one up to.
Dang it, I'm confusing threads again- my bad. Thanks for the pic. That Tee where the PCV comes in is in the worst possible place, oil can run directly into the booster. The Tee should be at /in the intake, with the PCV going straight into the intake, and the other vacuum sources coming in from above. A Tee that threads directly into the intake provides the best flow.
It's obvious you have an attractive planned-out engine bay. Looks nice. Rerouting the lines may not look as nice. I have spent hours on end routing electric lines and hoses for a clean look, so I get it.
Attachments
Last edited:
So from what I gather the pcv valve needs to be lower than the rest of the vacuum. So couldn't i add an elbow pointed upwards to get the same effect that the tee would?
This is mostly a what if. If it would work I can keep it as a backup plan or quick fix.
This is mostly a what if. If it would work I can keep it as a backup plan or quick fix.
That's better. No matter what, every time the vacuum spikes from low to high- like every gear shift, or decelerating- oily vapor is shot toward every far-end of the system.
It's a fluid dynamic characteristic- when vacuum increases in an airmass with heavy particulates, the particulates are drawn in the opposite direction of the vacuum source, and toward the walls of the constraining tube.
A good visual of this principle is the windshield repair kits. Some glue is put on a crack, and a suction cup applies vacuum. Logic would say the vacuum would draw the glue toward the vacuum cup. In reality, the vacuum causes the glue to move to the farthest, deepest recesses of the crack.
It will take a while for blow by residue to affect the modulator valve and brake booster, but don't doubt it's getting in there, because it is. The closer to the intake the blow by can enter it, the less of that oil air is available in the hose to activate the booster/modulator.
Probably overkill, I always isolate PCV from everything else. Even when, in one case, I had to buy a carb spacer and drill/fab a port in it for PCV and use the intake port for the rest.
It's a fluid dynamic characteristic- when vacuum increases in an airmass with heavy particulates, the particulates are drawn in the opposite direction of the vacuum source, and toward the walls of the constraining tube.
A good visual of this principle is the windshield repair kits. Some glue is put on a crack, and a suction cup applies vacuum. Logic would say the vacuum would draw the glue toward the vacuum cup. In reality, the vacuum causes the glue to move to the farthest, deepest recesses of the crack.
It will take a while for blow by residue to affect the modulator valve and brake booster, but don't doubt it's getting in there, because it is. The closer to the intake the blow by can enter it, the less of that oil air is available in the hose to activate the booster/modulator.
Probably overkill, I always isolate PCV from everything else. Even when, in one case, I had to buy a carb spacer and drill/fab a port in it for PCV and use the intake port for the rest.
Similar threads
