strotter Posted October 2, 2001 Share Posted October 2, 2001 I'm putting together a late-model GM small-block for a swap into a 240. All is preceding well, but for one snag: what headers will both fit into a Z conversion, as well as provide an oxygen sensor? Failing that, is it possible to have a fitting tapped into the headers - say at the collector - to perform that function? Any suggestions would be appreciated. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted October 2, 2001 Share Posted October 2, 2001 Tere are wedl on O2 "bungs" available at any exhaust shop. They cost all of about $8 apiece and can easily be welded into the pipes by the exhaust folks. I used shorty block huggers on mine and had a set of these done on the pipes below the headers. No reason it couldn't be done in the collector as well but ceramic coating might make it slightly more difficult. I did have some welding done on my coated headers so it CAN be done (shrug). Not to worry, you've not run into a big obstacle there. Oh and welcome to HybridZ Whoops - you wanted to know what fit too (doh). Search on headers and you'll find info for both longtube and short. In my case I'm using FlowTech 1 5/8ths headers but they're supposed to be for straight plug only. Sanderson shorties won't work unless you run the cast ones. S&S makes some longtubes that work I think - search will show them. MSA sells those too it looks like. You may hae to work with a company to get them customized for final fit. I'm working with Rewarder myself on some straight plug shorties with 1 3/4 primaries. What heads are you going to run? [ October 02, 2001: Message edited by: BLKMGK ] Quote Link to comment Share on other sites More sharing options...
strotter Posted October 2, 2001 Author Share Posted October 2, 2001 >What heads are you going to run? So as to keep things simple, I'm going to either stick with the stockers (the 58cc X 1.84"X1.50") or something with an identical exterior shape. I've been flirting with the World Products Sportsman S/R Torquer heads (mostly because they're cheaper than a port-n-polish job, which I'm too chicken to do myself), but I'm not sure if they're still available with the 58cc chambers. The motor's out of an '89 Firebird, and there's a tremendous amount of bracketry and whatnot attached to the heads. I don't want to get all involved in making bracketry and whatnot if I can possibly avoid it. Quote Link to comment Share on other sites More sharing options...
Owen Posted October 3, 2001 Share Posted October 3, 2001 Should there be one oxy sensor for each bank, or just one where the pipes from the headers meet? (If they meet) Owen Quote Link to comment Share on other sites More sharing options...
strotter Posted October 3, 2001 Author Share Posted October 3, 2001 On the stockers, there's just the one on the driver's side, by the outlet. That's why I was thinking a fitting should be placed at the collecter of the header - that way it's reading the average reading for the whole bank. On an associated note, will the absence of AIR injection affect the sensor? Or, more exactly, does the ECM take the presence of fresh air in the exhaust stream into account when calculating mixtures/timing, and would it be confused without the extra air? Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted October 3, 2001 Share Posted October 3, 2001 if your looking at a set of world heads i have a set laying around that i could make a good deal on or even a trade..... world products S/R Torquer 305 heads 58cc combustion chambers 3/8 screw in rocker studs 1.94 intake,SS and undercut 1.6 exhaust,SS and undercut mild porting and alot of bowl blending,intake runners where 170cc,now i would guess them to be 180-185cc..heads are complete Except for valve springs,locks and retainers.the heads have about 7-10K on them.thats about all the specs. i can remember off the top of my head...well make an offer. later Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted October 3, 2001 Share Posted October 3, 2001 Welcome Scott. (Oh no, not another Scott!) Just kidding. I never thought about the air pump screwing up the O2 readings. I have almost finished dropping a 305tpi in my '73 240. It was out of a '91 Trans Am. Mine is bone stock. It is in the muffler shop as I write this. Should get it back tomarrow. I used Flowtech, ceramic coated blockhuggers. They fit pretty well. A little close to some of the plugs. And very close to the water temp sensors in each head. Because of the coating, my O2 is going into the head pipe as close as posible to the flange. The best tech at the Chevy dealership in town said if can't put it in the header, put it as close as posible to keep it hot. Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted October 3, 2001 Share Posted October 3, 2001 Scott, what school do you teach at in Lodi? I have a friend that teaches in Lodi. Quote Link to comment Share on other sites More sharing options...
strotter Posted October 3, 2001 Author Share Posted October 3, 2001 Well, about the AIR pump affecting the ECM, I can answer my own question: I was browsing through the JTR TPI/TBI swap book, and noticed on the very first page of the Exhaust chapter that leaving off the AIR gear "will not affect the ECM, or engine operation." D'oh! I've read that book from end to end half-a-dozen times, and still havn't absorbed it... As to the headers, I was thinking about using the Summit block-huggers. I'll have a fitting tapped into the driver-side collector, and be done. I've considered powder-coating, but I think the cost is a bit steep for the budget - especially when I think about how *many* things I've already spend money on, and how *many* things I'm gonna spend money on... Quote Link to comment Share on other sites More sharing options...
strotter Posted October 3, 2001 Author Share Posted October 3, 2001 Oh, and about Dan's question- I teach at Plaza Robles High School, which, though a part of the Lodi district, is actually located in Stockton. It's a Continuation school (kids with problems of various kinds: rough guys; problems at home; English second language; unplanned mommy; a few just plain lazy; that kind of thing). Challenging job - it's easy to teach people who want to learn, tough with people who don't, won't, or can't. Fun job though. A few of them are following this project very closely. Most every week, I'll have someone come up to me with with a "Chevy Power" magazine or something in their hand, and go "Dude! I been readin' up on this s**t! You gotta *turbo* that five-point-oh, man! Wicked harsh power, man! And **nitrous**! Dude! It'd be *scandlous* dude! Totally! Look at this s**t!" at which time the dog-eared magazine is shoved into my face showing me some chrome monstrosity with multiple turbos, quad carbs, nitrous, and 14:1 pistons, and then I spend the next ten minutes of lunch time explaining why I can't spend thirty thousand dollars on a V8 Datsun project, and besides, you can't commute in an AA fueler... Quote Link to comment Share on other sites More sharing options...
pparaska Posted October 3, 2001 Share Posted October 3, 2001 Dude! Thanks for the new vocabulary! I love the *scandlous* word (wish I could spell it). Had no idea that was in the venacular. I LOVE the "Wicked Harsh Power" phrase too. So much more inventive than the venacular I grew up with (70s,80s). Radical Dude! Quote Link to comment Share on other sites More sharing options...
Owen Posted October 3, 2001 Share Posted October 3, 2001 Hmm, seems like a lot of the sensors are placed on the drivers side. Any reason for that? Good tip on keeping the sensor close to the engine to keep it hot. Owen Quote Link to comment Share on other sites More sharing options...
Modern Motorsports Ltd Posted October 3, 2001 Share Posted October 3, 2001 There's actually 'crayons' for the perfect O2 location, it's not as close as you can get necessarily....you rub it on your exhaust and one melts at (just for ie.) 1000 degrees and other at 800 and midpoint is the optimal location...(not those numbers...I don't recall the real numbers...for any techies out there they can pipe up. Beware you install it where you have a decent access/angle to service it after (you will be servicing it) and it's protected from road-debris/wires not exposed overly etc. Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted October 4, 2001 Share Posted October 4, 2001 Hadn't heard about the crayons before. I imagine that with tubular headers, as opposed to cast iron manifolds, the temperature varies more, i.e. less mass to hold the heat. I seem to remember, correct me if I'm wrong Scott, the O2 was located very near the #7 port. I left the manifolds with the yard when I came to pick up the motor, so I could be off. I'll check my TBI/TPI book for pictures. Good point about serviceability Ross. Hope my piper is thinking about that now . Quote Link to comment Share on other sites More sharing options...
Guest kc6wfs Posted October 4, 2001 Share Posted October 4, 2001 02 sensors can give inacurate readings if to hot or to cold. Normal temps I think are around 750 deg. I just installed I 02 sensor for a gauge and it said around 2' from the heads. That seems to work very well. I'll take a pic of mine tomarrow and post a link here tomarrow. Oh I have the blockhugger headers. Don't laugh all!!!!! Dave Quote Link to comment Share on other sites More sharing options...
Dan Juday Posted October 5, 2001 Share Posted October 5, 2001 Thanks Dave, I'll print them out and give the to my muffler guy. Looks like I'll have to wait another day . Dumb muffler guy up and got busy. And I was stupid enough to tell him to take his time . Quote Link to comment Share on other sites More sharing options...
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