Do I have the right replacement carburetor spacer? See below.



OEM vs Atkins

 

i think there are only two, and its embossed in the plastic, 1480 is the 81-85 and then there is 88 something for the 79-80 cars.

in 2025 one could 3d print their own, and add/delete vacuum nipples as needed

 

There are at least two variants, 1 stamped 1480, which is the one that I have from Atkins, and isn't suitable for - don't quote me - 1979 and 1980 Australian delivered RX7s. The other is the one stamped 8871, which is the one I need. There could be a third or fourth variant. So to answer my own question, the 1480 variant is not the right spacer as it has different vacuum passages. And this is probably why I can't get the secondaries to come on like they used to.

I'm in contact with riggs-vintage-mazda and he said he has something but he's on break atm and will check his supply next week. Let's see how that goes. Fingers crossed.

With respect to 3D printing a spacer, I can see that being tricky. One would need to remove the bottom and top gasket on the spacer to expose the unique vacuum passages...

 

Some time with a compressed air source, or even a spray can of penetrating oil or something, will easily tell you which vacuum nipples go to which passages,

 

I used a smoke machine to help identify passages, but the problem is the replacement carb. spacer I have (1480) has different cutouts, or holes, that are incompatible with the holes on the intake manifold, and do not align, or link up, with the carb.'s throttle body.

 

You are probably right about the wrong spacer, but don't forget that even with the right spacer, if you put the gasket in backwards (easy to do since it "looks" symmetrical, the secondaries won't open either.

Carl

 

the 1480 spacer won't work for a US 1979-1980 car either

 

Noted: correct placement of carb. spacer. In contact with various wreckers for a spacer that matches the pictured OEM spacer.

 

So it seems. I'm working with an Australian delivered model (SA22C).

 

What year SA22C? Didn't all the 1st gens in the world (outside of the use) have VINs that started with SA22C for 79-85?

You could go mechanical secondaries instead to work around it until you get the right spacer.

 

Well, it was sold to me as a 1982 model. The VIN is SA22C... My model came fitted with a thermal reactor, and part sellers seem to identify gaskets for the thermal reactor as 1979 and 1980 models. So I'm bit confused there. I know it has Series 2 interior, and wheels.

Tried researching the procedure for mechanical secondaries. Still can't quite my head around how to do it properly.

The 8071 spacer arrived, severely clogged, but now clean. Picture below. 8071 on the left, 1480 on the right.


8071 and 1480

It's installed. One improvement I noticed was being able to get the trailing mark on the crank pully to line up with the indicator pin during ignition timing setting. I think the 1480 spacer blocked off the vacuum signal to vacuum advance canister on the distributor.

It looks lmore ike a fuel pump issue now. 02 sensor reads 14.1 to 14.3 during idle, but jumps to 17+ on acceleration. It's not the carby, can't be, I've had it rebuilt, and tested on another engine. So, I can't be entirely sure if the 1480 spacer is the reason why my secondaries aren't coming on atm. Onto to fuel pressure testing next...

 

here in the US, vin SA22C is 79-80. there's a sticker in the driver's door jam with the month/year date of manufacture.

 

If you are in Australia you might want to check out ausrotary.com as well as posting here. You may find someone local that can help you too.

The timing normally has zero vacuum at idle. To make sure, disconnect you vacuum advanced to set timing at idle. It could be a hose is misplaced or one of these is causing vacuum when it shouldn't.

 

Thanks for pointing that out. There are two canisters on this distributer. Photo below.


SA22C OEM distributor

Disconnect (and plug) both? I've been making adjustments with just the one (the one with two screws, photo above). Are both adjustable? Or is just the one with the two screws?

On another note, I'm now seeing erratic fuel pressure readings (0.5 PSI to 4.2 PSI) with fuel pressure guage connected in series with the carburettor, ignition on, engine off. I've checked fuel pressure with main feed line disconnected, thumb pressed on outlet hose and I get a steady reading of 4.1 PSI. It's just when I connect to the carburettor, fuel pressure readings become erratic. To make sure it's not the fuel pump, I replaced it yesterday with a new one, with a new fuel filter, and I cleaned the lines (vent, return, and main) with petrol system cleaner. Confirmed clean, and leak free with smoke machine. And I still get the erratic reading, with a lean air/fuel ratio ipon acceleration.

I now suspect the carburettor, that I paid to get rebuilt. It could be the accelrator pump, or maybe the needle and seat. Returning the carb. to the rebuilder next weekend (15 Feb. 2025). Will update.

 

Only the trailing vac advanced can be adjusted (thats the one with the 2 screws). It is for adjusting the timing gap from the leading advancement which really can't be adjusted. The lead timing is adjusted by rotating the dizzy when you loosen the nut holding it. Oh and yeah disconnect both just to make sure.