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Removing Air Injection Manifolds (and Exhaust Bolts)

Posted: Sat Apr 27, 2024 11:31 am
by tgreese
Nothing earth shaking here, but maybe of interest for a Saturday Afternoon. Mainly posting because no one else is.

I've had a Howell TBI kit for my J20 since last year, and just now getting to install it. Removing the air injection system (smog pump, "Air Guard") worried me. Now it's done and it was no problem -

J20PlugsInManifold.jpg
The plugs I used were from McMaster-Carr https://www.mcmaster.com/50925K435/ - I removed the o-ring and added a copper washer from a kit I bought from Amazon https://www.amazon.com/gp/product/B07G5 ... UTF8&psc=1

I first sprayed the fittings liberally with PB Blaster - only because that's what everyone says to do. Remembering what my mechanic friend would do for exhaust bolts, I got the manifolds as hot as I could by sitting at part throttle (maybe 2500?) for about 10 minutes. (He would zoom out and back a few miles on the nearby 57 freeway). This likely burned off all the penetrator (smoke!)

I then used a 6-point socket on my long 3/8" flex ratchet and they came out without breaking. Took some persuading to get the socket fully over the air injection fittings; once they were on, a little muscle and they loosened. I went around and got them all broken loose before they cooled much. The rearmost on the passenger side can most easily be reached from the ground.

Here they are on the bench -

J20AIManifolds.jpg
Look pretty good. I recall I replaced the check valves and smog pump long ago. This truck has had working air injection all the time I've owned it.

Removed stuff - more to do.

J20RemovedEFI.jpg

Re: Removing Air Injection Manifolds (and Exhaust Bolts)

Posted: Sat Apr 27, 2024 11:43 am
by tgreese
Reading through MysticRob's writeup at IFSJA: https://forums.ifsja.org/forum/tire-kic ... -o-d-452-2

A random comment - the air pumps will rust internally, lock up and be ruined if you put them on the shelf and don't lube the inside. I have heard of dunking in kerosene... I'd think anything like that, say old parts washer solvent, would be ok. I had a spray can of Fluid Film handy, spritzed the inlet and outlet and spun the pump. Seems ok, though it may never go into service again.

Re: Removing Air Injection Manifolds (and Exhaust Bolts)

Posted: Sat Apr 27, 2024 6:20 pm
by Stuka
I can confirm the pumps will seize up if not used, and it doesn't even seem to take that long.

Those bolts you found look a lot better than the ones I found way back in the day. Good info to have for anybody switching to EFI, which requires getting rid of the air pump as the O2 sensors will read wildly wrong things if its there.

Re: Removing Air Injection Manifolds (and Exhaust Bolts)

Posted: Mon Apr 29, 2024 12:21 am
by candymancan
I just broke mine off, and welded where the tubes were closed.. easy peasy