Smog/Air Pump Removal

[RoadsterJay]

Hello again all,
Yet another question from the newby. Just a refresher.....I got a 68 1600 with stock SU carbs. Now, as all the California boys know we don't have to smog anything that is a 1973 or older. So......my natural instinct is to remove anything and everything that can give me free ponies. Removing a pully device seems like a good idea!!!!! Anyone got some feedback on removing the air pump??? What all will I need besides some brass fittings or something to fill the holes in the intake manifold? Thanks a bunch!

[RoadsterJay]

Can anyone help me on this one??????????????

[DatsunBucky]

RoadsterJay-

I don't know if Nissan used the same pieces, but we had a '71 240Z that we "de-smogged" (illegally) back in the 70s. We gutted the air pump, so it still looked like it was supposed to, and then cut off the air nozzles below the screw threads and crimped and soldered the ends shut. We put everything back on so it would pass the roadside inspections we had to put up with back then. The only thing we noticed was an immediate 2mpg increase, both city and highway. We didn't notice any other performance loss or gain.

Like I said, I don't know if the airpumps are the same, but if they are, then with the vanes removed, the barrel spins in the pump body with only the drag of the bearings. Everything would still look legit, but you'd have the performance gains of having removed everything. Not to mention the "I beat you, and I still have the smog pump" factor. Besides, I, personally, don't like the look of holes "plugged" with something.

For the record, I have always been in favor of "Q-Ships" (WW2 reference), they being the exact opposite of the rice crowd...make it fast, but make it look as close to stock as possible, not leave it stock and try to make it look fast.

This is only my opinion and does not necessarily reflect the views or opinions of the management.

[S Allen]

Just remove all the emisssion stuff and plug off any openings with caps as you suggested. Keep the smog pump and anything else you remove in a box some where just in case the Gov gets a hair up you know where and changes the smog laws. That almost happened recently. You should recurve the dizzy to the early specs or get one of Gary Boone's EI dizzys. I highly recommend one of Gary's EI units. The car should run better with all that stuff removed. I meant to give you some feedback the other day but got side tracked.

Steve

[spl310]

To follow what Steve said, I agree that you should keep the smog stuff - just in case. To plug the head, you need more than just some pipe plugs. You need some allen head cap screws. I forget the exact size, but they should fill the void below the plug down to the top of the exhaust port. If you don't put those in, you get a chirping sound.

[oilleak]

Yeah - What Sid Said. If you pull the air injection manifold off the head you'll see that the hole for each injector has a larger diameter threaded portion and a smaller diameter smooth version. You need a pipe plug with the right thread - sorry I don't remember the size - for the upper portion but you also want to put a dowel down the smaller diameter portion to prevent the chirping. The dowel should be the same diameter as the injector nozzle and the length should be just to the top of the exhaust port, not sticking down into it - trick is the dowel needs a head on it to prevent it from falling into the port. Maybe a small bolt with a smooth shank above the threads - just cut to the right length would work.
If you're going to leave all the smog stuff on to keep the smog police happy, you could just have a shop cut each nozzle on the stock air manifold a bit shorter and weld it up inside. that would solve the problem and you'd be able to tell uninitiated rice boyz that it's an OE Nitrous system - I'm sure they'd be mighty impressed and wouldn't realize it feeds the exhaust ports.

[S Allen]

I am fairly certain the plug size is 10MM X 1.5 Pitch. I had the local machine shop make up a set. Tom Walters used to make several runs a year. Ralleye may have them.

Steve

[spl310]

As I recall, I used a standard plumming fitting. My head had some goofy plugs in there already, so who knows what was going on with it.