O2 sensor and egr bung sizes/thread

I have a 97 4.0 and got this header and down pipe

http://www.summitracing.com/parts/WLK-88744/

thing is it has a freaking egr port and the o2 sensor is on the passenger side of the downpipe so they want you to splice and extend the o2 sensor wires. I want to plug their o2 bung and put one in closer to the stock location, and since none of the years they say its for even have an egr I need to plug that too.

Does anyone know for sure the size/thread of these bungs so I don't have to do a bunch of guess work?

thanks fellas :cheers:

You already bought it?

That's more likely from Pacesetter and was "rebranded" as Dynomax (Dynomax doesn't list it on their own product site).

The EGR port was there for earlier Renix based engine.

I believe they are 18X1.5 mm but they are typically labeled as O2 bungs.

Strange, says 94-98 and as Saudade pointed out the EGR last year was 1990!

Wow, $334 bucks?

This is my favorite: http://www.ineedparts.com/index.php?target=products&product_id=15343

Return it, buy the header I linked, spend the rest of the money on a free-flowing CAT-back system, that will outlast the Dynomax and get you a bigger performance gain.

My .02 worth.

The HEGO uses a standardised thread - M18x1.5. It will typically take a 7/8" wrench.

The EGR on RENIX looks like it may be some standard SAE flare, but I have not yet identified it. I'd like to know - so I could see about getting plugs for the thing...

It is a Pacesetter header. The bung is there for vehicles that need it. As shipped, the bung is welded onto the pipe but, there is NOT a hole in the pipe. Good luck getting it to fit together. I tried it a few months ago (bought it from JC Whitney) and had extensive conversations with Pacesetter. Bottom line is that they use two different assembly lines, one for the actual header and one for the two to one pipe. The header, as delevered, was miss matched by .25". At no point in the production process does Pacesetter bother to check to see if the parts will mate. Pacesetter told me to "just pull the pipes together and force it to fit. I returned it to Whitney. Best thing about them is that they do not care why yuou want to return something, they have a no questions ask policy. I did, however, advise them as to the fitment problem.

thanks for the info guys

luckily I didn't pay anywhere near the summit price for this (if I had it would have gone directly back, but for $120 shipped I'm willing to modify it to work), and like o-gauge my 2 into 1 is off as well, but only by about 1/8" I'm hoping I can cut the brace between the 2 pipes, spread the pipes, and re-weld the brace without putting too much stress on the joints. I got this to replace my cracked APN header and like the idea of no pre-cat and no kink in the downpipe. Unfortunately mine most definitely has the hole in the pipe on the egr bung uke:
I actually like the fact that its mild steel vs stainless too, it shouldn't crack as easy since its not as brittle as SS, and if it does crack it will be easier to weld

I'd probably just weld the EGR bung till it's blocked off and forget all about it :gee:

FoMoCo said:

thanks for the info guys

luckily I didn't pay anywhere near the summit price for this (if I had it would have gone directly back, but for $120 shipped I'm willing to modify it to work), and like o-gauge my 2 into 1 is off as well, but only by about 1/8" I'm hoping I can cut the brace between the 2 pipes, spread the pipes, and re-weld the brace without putting too much stress on the joints. I got this to replace my cracked APN header and like the idea of no pre-cat and no kink in the downpipe. Unfortunately mine most definitely has the hole in the pipe on the egr bung uke:
I actually like the fact that its mild steel vs stainless too, it shouldn't crack as easy since its not as brittle as SS, and if it does crack it will be easier to weld

Click to expand...

Good luck with it. When my exh mani cracked ('88) I searched for a header and only found the Pacesetter as a "bolt on". After reading a whole lot of threads regarding it's poor fit, I went with an stock manifold.

Double check the flange thickness. I recall some saying it was thinner so they needed to use some "half moon" spacers to level out the mounting hardware. Seems like Pacesetter was including these for a while as well.

Hopefully, this is not an issue anymore.

I've been running the Pacesetter header for 5-6 years without issue. To block the EGR port I found a 7/8 x 18 plug that fit perfectly. Not a common size plug, but I found one through a racing parts supplier out in Wisconsin, Pegasus Racing? maybe...

FoMoCo said:

Does anyone know for sure the size/thread of these bungs so I don't have to do a bunch of guess work?
thanks fellas :cheers:

Click to expand...

Checked the spare Bosch O2 sensor and the threads are 3/4" x 16 NF.

Charles

That makes a lot more sense to me - metric threads on an SAE-sized 7/8" part would be too chrysler-like. Wait a minute...

kastein said:

That makes a lot more sense to me - metric threads on an SAE-sized 7/8" part would be too chrysler-like. Wait a minute...

Click to expand...

Except that 7/8" = 22mm which is what my O2 wrench says. (OK, it's not *exactly* 22mm but it's close enough for the wrench)

CharlesS said:

Checked the spare Bosch O2 sensor and the threads are 3/4" x 16 NF.

Charles

Click to expand...

Really? Interesting. I'd heard rumours that there were some SAE-threaded HEGO sensors out there, but I'd not consciously found one (as long as it threads into the hole, I don't care. As long as my wrench fits, alles gut.)

Mixing SAE wrenching with ISO threads - or the other way about - is something I've seen often enough before that it doesn't bother me. And, a Torx-wrenching screw (internal or external) can go either way - you won't know until it's out and you measure it (there's only one standard for Torx-wrenching screws, and it applies to SAE, ISO, tapping, sheetmetal, ...)