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Posted by: JOEPROPER Feb 14 2018, 01:35 PM

So, I'm getting my '75 2.0L back together and want to eliminate the A.I.R system. What are guys doing to eliminate the tubes in the cylinder heads? Install and cap them off or install something to block off the passage in place of the tube?

Posted by: jcd914 Feb 14 2018, 01:45 PM

Easiest way is just to leave them in (or reinstall) and cap them.

You can plug the holes but it requires 10x1.0 bolts that are just the right length.

Jim

Posted by: rdauenhauer Feb 14 2018, 03:19 PM

Another problem is that if you've never had them appart, after 30+ yrs they are likely coked in place and you risk further work if they don't come out clean.

Posted by: bdstone914 Feb 14 2018, 03:21 PM

I do not agree with leaving them in and capping them.

When the smog antlers are not there holding the tubes they can back off. Had this happen more than once. The long tube on a shaking engine will loosen the threads. remove them and plug them. I think a 1/8 NPT tap works. Use red Loctite. Stock is a 10mm fine thread. Had a friend who blew out a tube and walked to the Home Depot to get a bolt to plug it.

Bruce

Posted by: johnhora Feb 14 2018, 03:30 PM

actually you can use this rear brake part...



http://www.pmbperformance.com/catalog/item/1925563/9748923.htm

also you can get them for 911 heads...same issue...two different styles

Posted by: JOEPROPER Feb 14 2018, 03:55 PM

All good information. Thanks for the help! Looks like I have some unexpected work ahead of me as Rich called it, one broken tube in the cylinder head. Will need to drill and try to extract.

Posted by: Philip W. Feb 15 2018, 08:31 AM

not long after I bought my 75 I had a sudden rattle and loud noise- not knowing what it was it stopped, got a trailer and towed it down to the local shop- it didn't take too long for Bob to diagnose my problem- This AIR system was removed and one the bolts used to cap it had backed out- lodged somewhere against the tin making that rattling noise - before that I didn't know anything about a smog system- that's been atleast 5 years plus now- pretty sure they reinstalled that thing with loctite

Posted by: Krieger Feb 15 2018, 09:51 AM

IIRC they are the same as the 911 plugs. Call Engine Builders supply in Reno.

Posted by: Mueller Feb 15 2018, 10:01 AM

Safety wire or make a locking tab to prevent them from backing out. I too had one back out while driving, made a bracket with a bent tab to stop it from turning.

Posted by: JOEPROPER Feb 20 2018, 05:03 PM

I drilled and installed a Helicoil in the port. Was not as bad as thought it would be. Opened the hole a bit to fit the tap and the insert, red loctite and done. Now waiting for the PMB delivery so I can install the plugs described above.

Thanks for all the help!