Guys, On my 78 GTS, I can locate the 4 sample CO ports on the rear header, however haven't been able to get under the car to inspect the front header, and was wondering if it also has CO Sample ports. I have done a number of searches, but cannot find anything. Also, if they do have ports, where would they be located on the Front Header?
They SHOULD have been permanently installed up to the LH corner of the airbox. Sounds like it's "gone"...
Yes, all versions (originally) come with CO2 sampling ports, but they are in different locations depending on the version (and often get welded up as a poor repair) -- on the NA/US version the 5-8 ports are in the same place as the 1-4 ports (top of the exhaust tubes very near the cylinder head -- and a small network of tubes is used to bring them all over near the 5-8 dist -- Big Tex is implying that your small network of tubes is missing). On a standard/euro version, they are in more random locations on each exhaust tube of the 5-8 side. What version do you have?
I should have typed "beside the airbox"........they don't connect to it obviously! They might have failed from corrosion, if they leak, not much choice but to trash or replace them....
Thanks for all the help guys. My car is a North American model, however all of the emissions have been removed, and looks like the CO tubes have been as well. I can hear a leak from the front header, and would like to rule out the ports before I go looking for a crack. What is the easiest way to access the ports on the front header. Work from underneath the car, or become a contortionist and try accessing them from the top of the engine bay?
There isn't one Seriously, if you pull the LH rear wheel fender liner out, you might be able to look in from the end direction and maybe reach #5 and #6 from that end -- but unless you have the AC compressor out getting to #7 and #8 is either from the top or the bottom. The threaded part that can be screwed into the CO sampling port (instead of the tubes) to block it off is 110860 (and a CU washer) -- if you do a search on that PN you might get some threads with prior discussion/experiences.
I was setting up my carbs and got 0 CO from one of the front bank inspection tubes. Turned out one of the little tubes was cracked. Pulled the header (nice 5 minute job ) Removed the rusty inspection rail - 3 of the fittings were rusted solid and needed to be EDM'd out (another 5 min job ) Clean up the threads and install the new rail, and re-assemble everything else (5 more minutes) There! I got the whole thing done in 15 minutes. Seriously - It was some work, but it allowed me to Jet Hot coat the header, clean up a bunch of other stuff while in there, AND set the carb mixture. This was ~15 years ago and the front bank inspection rail was available. If you can't get an orig piece, you might look at brake lines. That's what I thought they looked closest to.
I made new testpipes for my 1976 US GTB, they were missing and plugged. I put in a tap to rew up the treads in the manifold, if I remember correct it is M14x 1 mm. Now the pipes are made of stainless steel and brass fittings, will newer rust away. All work is made from underneath with only one arm, NO SPACE but possible. Regards Jesper Image Unavailable, Please Login Image Unavailable, Please Login
Jesper, great work! Another quick question......is there any harm in removing the tubes altogether and welding up the ports?
IMO, that's like sewing your rectum closed to "cure" diarrhea . If your fitting/tubes are toast, clean-up the threads and get a set of the 110860 threaded plugs (a future Mechanic will thank you).
