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This is a new to me car I'm getting back to road ready.
things I know
1983 GX (Canadian only)
Rats nest/emissions deleted
45 DCOE weber
Direct fire leading w/msd
Possible Street Port no papers or proof
Engine bay uncertainty right now is 2 vaccume lines one from the charcoal canister to nowhere just open, the other canister line runs back to the tank. Where does this line go to?
Open vaccume line on the oil filler tube where does this go?
There are two barbs on the charcoal canister. The small one leads to the gas tank. The large one leads to the crank case vent (below the oil filler neck). The upper vent on the oil filler neck is intended to connect to the purge valve. If you cap it, the charcoal canister will eventually fail as oily positive crank case vapors will get pushed through it. If you leave it open, it is best to put a filter on it and change it periodically. In fact, if you leave it open, you don't really need the hose to the charcoal canister as it will never suck evaporated fumes from it.
The third option is to connect a purge valve again. The valve has 3 connections. The large port on the bottom goes to the filler neck. The small port on the bottom goes to your intake manifold (anywhere that sees vacuum). The small port on the top is the tricky part. On the Nikki, it connects to a port just above the throttle plates. It only sees no vacuum at idle and moderate vacuum just above idle. This opens the valve while cruising to reclaim evaporated gas from the crank case and charcoal canister. The canister is vented at the bottom, it is not a sealed unit, and thus you cannot have the purge valve open all the time because it would cause a vacuum leak and fast idle. The reason I say this is tricky is because your carb may not have a port just above the throttle plates. The only way to get it functioning properly without that port is to put a vacuum solenoid on it that can be controlled at specific RPMs by an ECU.
There's something else you are missing, and that's the vacuum advance for the distributor. Nothing is connected to the two diaphragms. The way this works with the factory rats nest is that at idle the diaphragms see no vacuum as the solenoids they connect to are turned off. This allows a low idle speed at 0 degrees of timing (corresponding to the mark on the pulley). Above 1000 RPM the solenoids are opened and the diaphragms see vacuum from another port slightly above the throttle plates (higher than the purge valve, but still close proximity to the throttle plates) and the timing is advanced 7.5 degrees (15 degrees for trailing). On an automatic transmission car, the diaphragms see vacuum from a port below the throttle plate as soon as you put the car in D or R to boost torque. Upon deceleration the solenoids close immediately to retard timing. The change in timing is mostly for emissions and low idle speed, but its something you should check if you want to get the maximum power out of the engine. There is also centrifugal advance of 10 degrees built into the distributor which adds another 10 degrees at 1,500RPM, but you can run a lot more timing than what that will provide. Long story short, if you don't have those diaphragms connected, don't set your timing using the marks on the pulley if you want to make maximum power.
The one flapping around on the oil filler neck probably attached to a barb at the base of the carb filter base plate so that it would suck the air out of the tube into the intake while running. I had my Dellorto doing this for a long time. Worked ok for years that way. Kept the gunk out of the tube.
I just noticed, the car has the oil pump outlet (front cover) going to the rear input. That's not advised. The oil needs to run through a cooler that has an internal or external oil temp thermostat or to a beehive (water-air) cooler. The front mount is better choice.
There is something I never quite understood regarding the vacuum advance. Everyone says it's just for partial throttle emissions so you can run lean while cruising, but they also say you want somewhere between 22-24 degrees total timing at high RPM full throttle. If you look at the workshop manual (page 36 of '85 engine electrical), the centrifugal advance only accounts for 12.5 degrees maximum advance. How do you get the full advance if you start at 0 degrees at idle? Is it actually double what the test reading is?
Anyway, you may not need the vacuum advance, and I doubt you'll get the vacuum signal you want from the DCOE carb that properly advances it at the right time.
the vac advance needs to be connected to a metered or ported vac source. which means at idle there's no vac until the throttle is opened. i don't know if those 2 bbl carbs have that. i run without it on mine.
the vac advance needs to be connected to a metered or ported vac source. which means at idle there's no vac until the throttle is opened. i don't know if those 2 bbl carbs have that. i run without it on mine.
I ran mine off the intake on my Dell for a long time, it just made the idle lumpy. Having vacuum advance gets you to full advance quicker when you mash the pedal, really makes a difference in reponsiveness of the engine on acceleration. Also at ~4K the dizzy is at full advance no matter what you have hooked up. I time my car at 4K to make sure its at the advance I want, something like 26 deg if I remember right.
02-20-19, 06:57 PM
