Dino Saga 060430___Air Injector Spacers

Dino Saga 060430___Air Injector Spacers

Ferarri had a hard time with the US smog police. Webers and lots of cam overlap were exactly the wrong way to go for the Green folks. No one had gotten to the point of changing gasoline so catalytic converters could last. Adding air to the exhaust was the only way to burn the gas that just went through the engine for “driveability” reasons. It worked but wound up putting a blow torch inside every header tube. Headers had to be made out of stainless and glowed red all the time. Cooked firewall, alternator, starter and trunk. Solution was to cover headers with insulation and thin steel heat shields. Worked but the mild steel heat shields started rusting immediately.

Air for the injectors came from a pump on a special mount on the front of the engine. This mount held the alternator (modified with a tail shaft), a clutch and the air pump. Clutch locked up from 0 to 4500 rpm and then let loose (Dino engines just come alive at 4500 RPM so no big deal.) Air went from pump to nozzles mounted in exhaust spacers at the heads. Spacers were aluminum castings, 3 in front and 3 different ones in the rear. It was Rube Goldberg but Smog Gurus bought it. Dino came to America. Owners killed air clutches almost immediately. Cars could still pass Smog tests with Very Careful Tuning. Had to leave most of the other parts so inspector could see that all was there. By mid 90s rules tightened and no carbureted Ferrari could pass; but 25 year old cars became exempt. I already had air lines out but had never been caught. Had plugged the holes in the aluminum spacers. This was the only perennial problem in my 20 year life with the Dino. Could not find a permanent plug. Would blow one every 3-5 years. Amazing how much attention you get taking off from a stop light with one open exhaust header.

First attempt was to bore and tap to 3/8” pipe. Then plug with short steel plugs with Allen Hex drive cavities. The three front spacers lasted 18 years. Rear spacers were another story. Maybe gaskets. Heating and cooling allowed plug to loosen, hot gasses to erode and plug to blow out. Used all kinds of adhesives. All blew out. Finally put a stainless clamp around rear spacers and made plugs captive. OK until I did first engine rebuild.

While engine was out I had a machine shop bore spacers just under 5/8” and cut some aluminum rod to ½” length. Pressed rod into spacers and peened spacers to hold rod in place. Worked for 6 months and a plug blew. Had to pull the engine for a million other reasons so had a second chance on the plugs. This time I drilled and tapped 10-32 through spacer and plug. Installed stainless screw and peened that. Hope this cures the problem permanently.

Lots of talk on Fchat about headers and insulation. If there is no air injection, you don’t need insulation. Euro cars had none. If steel shields are rusted, strip and throw them away. Headers are stainless and will last forever. If you race the car, small heat shields are good over alternator and starter. If you do not push car forget it. I have 187,000 miles on my Dino and have had no shields for the last 135,000 miles. So far so good.

John
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