De smog – eliminating the A.I.R. pump

De smog – eliminating the A.I.R. pump


This was a relatively simple little water pump “idler” to make. That is the only function of the smog pump on a desmoged engine. It is possible to use two belts on an engine equipped with a mean green alternator, but I don’t remember what belts and don’t have a mean green. Any way, I had some spare flat stock and a chunk of solid round stock sitting around. After some quick measurement of the smog pump, I drew up a little “plan” for the idler bracket. It took a little while at the junk yard to find an idler pulley that was even close. I think the idler from a 3FE would be perfect, but I couldn’t find one that was cheap.

Here is the finished product.

Idler pulley out of an ’86 Nissan 300 ZX. I think the same/similar pulley is used on Toyota pickups with A/C (I think at Schuck’s it is Factory Air #45902). It fits perfectly in place of the smog pump and uses the original belt and all the mounting hardware. Adjusts just like the smog pump did.

I used the solid round stock for the pulley stand off, drilled and tapped for the pulley mounting bolt. The round stock was also used for the adjuster tightening bolt and the bottom of the bracker. Again drilled and tapped as needed.

smgpmp02.JPG (172833 bytes) smgpmp03.JPG (171026 bytes) smgpmp06.JPG (146045 bytes) smgpmp05.JPG (93370 bytes)

Here was the original plan. I deviated a little in the final version. A larger diameter pulley would be ideal and I had to adjust the angle of the top of the bracket to take up the slack from using a smaller pulley.

idler bracket 1.jpg (63659 bytes) idler bracket 2.jpg (69884 bytes)

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