Author Topic: 85 GMC 305 V8 Exhaust Air Injection Tubing Nut Size 22mm X1.5  (Read 584 times)

Offline rick69

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85 GMC 305 V8 Exhaust Air Injection Tubing Nut Size 22mm X1.5
« on: October 03, 2017, 11:33:39 AM »
I removed the air injection system from my 85 GMC 305 engine. I checked on the internet for the tubing nut thread size but could not find the info. My truck has the 2 large tubes that thread into the front of the exhaust manifold. I cut the pipes and then used a 22 mm deep socket to remove the nuts. I measured and suspected the nut thread was a 22 mm 1.5 thread so I ordered a 22mm by 1.5 nut from Fastenal. Sure enough, that is the correct thread size.  This has probably been posted before, but I could not locate this info on the net and hope it helps others in the same predictament!
I found Stainless steel drain plugs at BelMetric.com. DP22X1.5HSS product number.
« Last Edit: October 11, 2017, 06:18:20 PM by rick69 »

Offline DouglasBeale

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Re: 85 GMC 305 V8 Exhaust Air Injection Tubing Nut Size 22mm X1.5
« Reply #1 on: October 26, 2018, 08:06:48 AM »
Thanks Rick, I wish I found this post before. I had the same problem and spent more time searching the internet for the bolt and bolt size then I did taking them out and putting them in. I needed 8 - PAIR manifold plugs for my 86 K30 350 engine. I found them at NAPA - Part #: NOE 7041048 (they are oil drain plugs). They only went in about half way, and cost about $40, but turned right in no problem.
1986 Chevy K30
4WD Dually
Four Speed 117mm Transmission
NP205 transfer case
Quadrajet

Offline Ed4all10

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Re: 85 GMC 305 V8 Exhaust Air Injection Tubing Nut Size 22mm X1.5
« Reply #2 on: October 26, 2018, 07:07:02 PM »
Sounds like you need a set of headers on your beast now!

Offline DouglasBeale

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Re: 85 GMC 305 V8 Exhaust Air Injection Tubing Nut Size 22mm X1.5
« Reply #3 on: October 27, 2018, 09:00:59 AM »
Sounds like you need a set of headers on your beast now!

Yes sir... But it will probably have to wait till spring.
1986 Chevy K30
4WD Dually
Four Speed 117mm Transmission
NP205 transfer case
Quadrajet