rcb280z

Oh....and the rockers looked good too. Just didn't take pics.

I had the day off today so I decided to remove the valve cover and check valve lash and what ever else came to mind. Lash was off on #6 intake only. I adjusted valve lash in January so all is still good. Decided to look at my timing chain and cam sproket Then I checked plugs Taken with flash made them look too lean Then checked cam timing And then looked at cam lobes. They look good. Everything seems to look ok, what do you think? Ok too weird, pictures posted upside down. Why? They were right as I attached them.

Yeah the 8/77 through 78 280z fuel cut off is through the oil pressure circuit. You'll know what you have by looking at the harness connector at the AFM. If it is a 5 pin you have the later 77 through 78, IF everything is original. Mine is a 5/77 and I have a 7 pin connector. The extra 2 pins are the fuel safety cutoff in the AFM.

Yeah Cliff, Iv'e never done a hot one either. But I have never pulled the valve cover after a warm up to recheck either. Might try that just to know.

So I guess if you do it cold and don't hear any crazy valve train noise then just go with it. I have been doing it cold for almost 30 years with no issue. Must be more a preference. But I may try what Blue suggests just to see if I get any difference. Usually when I do an adjustment I always go one size above and below the actual measurement. If its 0.008 I found that if I check with a 0.007 (its loose) and 0.009 (usually can't get it in) Im guaranteed a good measurement. Maybe that's why I have no issues.

Can someone explain to me why a hot valve lash adjustment is more desirable over a cold one? I have always done a cold one only. Maybe I'm missing something by not doing a hot one. It seem to me like you wouldn't get a good one "hot" anyway. It takes time and I think by the time you get to the last cylinder the engine has cooled enough to not be right. (?)

I don't understand the same lash adjustment for both intake and exhaust. Did Dave offer an explanation?

Nice!

Don't go to sleep. Lauren is HOT!

Anyone know it the valve train components are interchangeable between the P79 and N47? I have the valves, springs, rockers etc. When I take my N47 head off to replace the HG, I figured I would go through the head and if I need anything I have parts available if they fit.

That shell has less rust than my passenger side frame rail! How nice. Post the process with pics.

Perfect. Just what I needed.

Thanks guys, thats what I wanted to hear.

I see, what looks like, most like the AEM 30-4110 wideband o2 sensor. Has anyone used it to calibrate the AFM on an injected L28? I'm sure its great for the carb's but how about FI. I was thinking of having the bung installed on my exhaust and just leaving the o2 sensor there and when I need to make adjustments to the FI for emissions testings I would hook up the gauge where I can see it while making my adjustments. Or maybe not mess with installing a bung and just sticking the o2 sensor in the end of the exhaust? Need a little advise on this one guys.

Exactly what I was thinking. I also have a broken water pump "long" bolt. Had to tap the front cover for a short bolt to get by. I can fix this issue as well. Got some things to think about for sure.

Hmm....good info guys. Ha! yes I have learned my lesson about the "chain wedge". I really need to look at my timing chain wear too. I had to put it on the number "2" adjustment due to stretch. So if I can get away with not replacing it I will. The only thing is, I just remembered, my front seal is leaking also. Guess I have something else to consider now.

rossiz, did you have much carbon build up on your valves? If so how did you clean it off?

Go for it Captain. I need a tune-able system. Especially owning a FI Z here in CA where I can't have CO output of 0.5 and above! If I had the :hellfire" I bet it would make things easier for me.

Good advise Mark. Thanks. Have to think about what do to do next. Don't really feel like doing the whole motor. But will if I have to.

Im with ya, my wife and I have watched it from the beginning. We to are addicted.

Never overheated. It used to run just past the half way mark I'm thinking like around 195. I now how an aluminum radiator and it runs dead center all the time. So you think I could leave the bottom end alone? I had thought about it a couple of times. I only have a P79 that has heavy gouges in the mating surface. It's ugly. But the cam, rockers, springs, everything looks really good. Even the valve stem seals look new. Picked this head up from a friend who was going to toss it out! Was going to do the P79 on a N47 with flat tops but changed my mind. Thought it would be even harder to pass the CA emissions if I did it. Anyway, guess I could transfer all the stuff over to my N47 head right? Or are the valves a different size? I can't remember off hand.

Crazy, I hadn't thought about checking rad pressure. Will have to investigate this. No steam out the exhaust after a couple minutes of cold start up. rossiz, I'm considering replacing head gasket. I have a Stone HG. Just need the other gaskets. Plus flushing everything to get all that stop leak out. Will probably have it flushed out before tearing it apart. siteunseen, that was going to be my plan, re-torquing head bolts but after research found that this may not be the best thing on bolts that haven't been messed with for over 20 years. So I guess I have to pull the head. I really don't want to do this right now. I did a compression test a few months back and found 2 cylinders about 20-25 psi lower than the others. They are not adjacent cylinders. But if I have to pull the head I may as well pull the whole motor and go through it. Or am I just doing unnecessary work? I did a "light" overhaul in '91 on this motor. Rings, main and rod bearings, valve seals, just the basics and it has over 100k miles since then. So it's time, I think, to go through it. What to do, what to do...

Those pics aren't that great so tomorrow I will try and get better ones.

About 8 months ago my 77 280 developed a coolant leak at the head gasket between 3 and 4 cylinder. I used a good quality stop leak and it did slow it down however, while I was working on my "leaky injector" issue I found another coolant leak. This one is near the firewall below the #6 exhaust port. It's about and inch forward of the corner of the head. Here is a pic. I guess with this new coolant leak I should consider doing a head gasket soon? Attachments_201532.zip Almost forgot one important thing. It starts leaking on cold start up and stops once the engines comes to temp.

Yeah, remember the day when....hopefully, as long as it wasn't life threatening, you did something stupid and you were by yourself? Everyone's had a brain fart moment. Anyway, yeah I'm glad it all worked out. I was just starting to get irritated when the new injector didn't work. But then I realized it probably sat on a shelf for awhile and was going to need to be "awakened" so to speak.