280zx Oxygen sensor/port issue
 

Replaced bad o2 sensor, it took too much force to remove the old one and it came out with the threads all completely flattened, now after attempting to install new o2 sensor, it flopped right out with it's threads flattened down. Is there a way I can safely seal the new o2 sensor in the port (the hottest part of the car) without the benefit of the threading working? I tried high temperature silicone gasket maker. . . it melted.

1981 N/A 280zx base - CA model

Ouch! There isn't much you can do to salvage the threads since they've been pulled out.

Four options:
#1: Get another exhaust manifold.
#2: Weld up that O2 bung, then drill a hole beside it & weld in a new bung.
#3: Weld up that O2 bung, then add a bung in the collector (you will need to lengthen the O2 wire).
#4: Use a tap to see if you can get any of the thread back.

thats not good
 

Yikes, I was hoping for some good news. Looks like no matter waht I have to remove the manifold, looks like a huge pain in the arse. I found a thread that has a bit of a walkthrough, though I'm scared I'll strip more bolts. Anyone have any extra advice on tackling this job? So far, it seems the intake manifold must come off too, gasket replaced, and then everything reassembled. Oh, and with no major mods, is looking for a nice header worth the few extra bucks?

I had some broken exhaust studs that I had to have replaced. I had the shop do that so it was almost no extra labour to put in a header.... go for it plus it already has the bung in it...

http://www.thezstore.com/page/TZS/PR...-04b/15-6017CH

http://www.thezstore.com/store/graph...e156017CHa.jpg

Other replacement Parts
 

Anyone have any suggestions for other parts worth replacing while doing this job? It is an awful amount of work to get down to replace the header and I found a good step-by-step guide, but it does not have any suggestions for replacing other parts that will be easy to access in the process.

Thanks

I would suggest replacing all the exhaust/intake manifold studs.

Replace all vacuum, fuel and coolant lines (fuel and coolant lines were so brittle when I did mine the first time they broke off rather then pulled off). PCV valve if you want. Replace the fuel rail with a Pallent rail (makes life a lot easier when you do your injectors). Replace all the injector, coolant sensors connections with newer connectors off of a GM fuel injected vehicle.

Definately the exhaust/intake manifold studs and if you get a header make sure it comes with a gasket. You can order the studs with the header. Most of the other stuff can be done independantly of replacing the manifold/header. All this stuff is on top of the manifold or on the other side of the engine bay. The PCV valve is fairly easy to get at with the manifold on but if you've pulled the manifold it's super easy. I've replaced my PCV valves but I haven't seen one that NEEDED replacing. I suppose at $5 a valve you may as well....

Replacing the connectors is a great idea as well. Personally I prefer to replace the connector by cutting the connector right at the plug and crimping new pins on the end of the wire and soldering them before inserting them into the plug then some water proof heat shrink instead of a boot. You can get them with a pig tail and connect them that way as well. They are called and EV1 connector if you're trying to find a replacement. And on that topic.... running a heavy ground from the body ground point right beside the battery to the ECU then run another ground from the ECU to the sensor ground on the manifold.... but we're getting a little ahead of ourselves here ;)

Thanks, just what I was looking for. As much as I dislike the fuel rail, pallnet rails seem hard to come by these days. I'll definetely replace the PCV valves and the hoses, that was the exact type of advice I was looking for, perfect.

It appears to me that any fuel injector work can be done later without having to repeat much of this labor, they look fairly accessible to me, except that nuisance of a fuel rail.

How many PCV Valves does this engine have? I am currently only aware of the one that's just forward of where the O2 sensor wire clamps down. Also, what about the hose on the PCV valve, did you swap that out? Happen to remember the size?

It's a formed vent hose that goes from the crank case to the PCV - you could just use a piece of hose that is oil resistant of the same diameter if yours is cracked otherwise you should be good to go. There is only one PCV as far as I know... Not sure of the size but you could check the PCV - around 1/2" IIRC.....

From my experience, if you are replacing it with just a rubber hose you will want to find a way to shield it from heat. Especially with a header...
They come with a silver-ish protective coating stock, from what I've seen (i've got three OEM hoses, two are out of commission), and a rubber replacement will dry and crack quick. Stock heat shields and some sort of thermal protection should keep it from turning to dust too fast... good luck!

Thanks for all the help, I'm amassing the parts now and will update with my successes and failures.

As I started buying the parts, MSA recommended these spacers for the manifold, they look like sturdy pieces of metal, and I won't be able to check if they are worn until I'm knee deep in the project, did anyone do this and notice these being worth replacing? They arent expensive, but the little things are starting to add up, as I am likely going to buy the bolt kit too.

Bolt Kit

Spacers

Oh yea those are stock spacers (or I'm assuming they are stock - my car had them on and everything else on the car was stock). They are cheap enough and you only need a hand full of them anyhow. You should be able to source the studs cheaper elsewhere but if you are ordering from MSA I'd just get the kit from them.