S30Driver

I will be very interested to hear the outcome of BackDoorZ's ethanol free gas test. My car has the stock green injectors, a Pallnet aluminum fuel rail, stock manifold & soon to install my chromex coated main heat shield.

After much searching for the holy grail of exhaust studs, I ended up taking Zed's advice and a Nissan dealer parts guy put me onto a set of M8 upgraded studs for the 300zx turbo & pathfinder. They are grade 8.8. Turns out that in the world of double ended studs, it is very hard to match the A & B lengths that Nissan used. The A length needs to be 14mm (the short side that goes into the manifold) and every stud I found in M8 was 10mm on the A side. I did not want to sacrifice the other 4mm of thread into the head. The Nissan part number for the studs is 14065-V5004 Here is my kit I assembled for the manifolds, now just waiting for my heat shield & other stuff to come back from Performance Coatings ....

This might help you out on the injector screws. Go to any big industrial nut and bolt place and ask for ..... Stainless Steel M5 x 30mm metric socket head cap screws & the stainless M5 lock washers (12 needed) A long 4mm allen wrench is nice to have for them too. I just purchased some and they were $5.15 for the 12 stainless allen screws and a whopping 45 cents for the 12 lock washers. I don't know what nissan charges but it might be higher.....

Be certain to only use fuel injector hose clamps for the connection to the rail. They are solid as opposed to the cheap gear clamps with the slots. The injector clamps won't cut into the fuel line when tightened. Hopefully they came with your rebuilt injectors.

For what its worth, here is a pix of the number 2 exhaust port with the missing liner. Need to get better lighting and a better cam to show more detail. The 2 pieces I found in the down pipe flange area were rounded steel from the liner.

Thanks for the info Zed, I share your concern. However, I will live with it for now. maybe address it at some point in time when I have to remove the head. Too bad I can't get #4 liner out to give it some balance.

In other news... if you look at my 2nd picture, you can see that the liner is missing from the #2 exhaust port (N47 head). I actually found some pieces of it hung up in the downpipe area - hopefully the rest made its way thru the system to the muffler. I am wondering if this has any impact on the motor - good or bad. Is it possible to remove the other liners? Any thoughts....

Hey Zed, i like your theory.... Also, I think Nissan knew they had an issue, but it didn't show up until years down the road - many heat cycles and fatigue setting in. If you look the later ZX manifolds, they modified the design, slotted the ends to allow for some expansion and give. When I was still in Denver, I had a good friend that was an old Nissan service manager - he gave me the stud grade info and was generally a very knowledgeable guy. Wish he was out here. If I have to settle for grade 8 - then I can live with that.

Before you took the cam sprocket off from the old head, did you check to see if it was on position 1, 2, or 3 to compensate for chain wear / stretch? I assume you have not put a new timing set in. Might be something to check when you get the new head on. Hopefully it was not on 3 already.... Best of luck - let us know when the great fireup is about to happen....

How did the weld on the intake work out, and what was the cost? Just curious because I probably would have just sourced another N47 intake that was undamaged, the non egr ones are probably getting hard to find. Can't wait for the first fire up with new head! Best of luck ....

Hi Zed, I know you have a high level of knowledge on Z cars, maybe I was not clear with my intent previously. I assumed most everyone is familiar with why the number 6 stud always shears off flush with the head. I believe it is due to the long length of the 6 cyl manifold which bows over time causing it to put extreme tension or pressure on the 2 end studs in the vertical direction. The stock grade 7 stud can't handle it, the nut is fine. Nissan used pinch nuts which are 1 use only, eliminating lock washers, if you take them off - you are supposed to replace them. Pallnet sourced & used to sell a kit with 10.9 grade studs due to this problem. (I have his fuel rail on my car) I just hate fixing things twice, and my goal is to end up with good quality hardware that won't corrode, has extra strength for those extreme end studs, installed with some anti-seize so I will never have to worry about them.

Site - yes, my intake is N47 and the egr portion of the manifold was in good shape. I am deleting the egr however. Ya - Rossiz's intake was interesting, glad I didn't have to deal with that. Come the think of it - all his threads are interesting.... waiting to see how his new head works out.

Thanks for the insight you guys. I want the high grade studs for number 1 & 6, heat treated, for exhaust use. Nissan used grade 7 studs. The others don't suffer from the tension - breakage problem. Am replacing all the studs & bolts (except for the big intake bolts) because they were in poor shape and I don't want any issues with removal in the future. The last thing I would do is over tighten steel stud in a aluminum head beyond factory spec. I think Nissan used pinch nuts instead of washers - except on 1 & 6 which had washers.

Thanks siteunseen. I will keep those in mind, depending on what i find at the industrial fastener place i go to.

Late last year, I started developing an exhaust leak from the number 6 port which was... of course, broken off flush with the head. Probably has been broken for many years before I got the car. With the nice summer weather, I decided to replace the gasket & install all new high grade studs & bolts. Let PB Blaster go to work for a few days and went to work. I removed the manifolds and used left hand drill bits to extract the broken studs. (number 1 was also broken off - discovered when i removed the manifolds) Number 1 backed out by the time I got up to about a 3/16th bit. Number 6 refused to comply, so I drilled it out and re-tapped for the stud. Patience is definitely the key - accurate center punch mark, slow drill speed, cutting oil, don't overheat the small bit sizes. Chased all the threads and prepped the head for the new gasket. All is looking very good so far. Tomorrow, or the next day, will pick up the new stud & bolt hardware. Going to try and get grade 10.9 for the studs and 3 middle exhaust bolts. Grade 8 at least. Also, have the main heat shield and some other stuff at Performance Coatings for ceramic exhaust coating - Chromex. Should be ready in 3 or 4 days. Will be interesting if it has any impact on the minor heat soak issue I experience occasionally.... Will report back on that.

He mentioned that he had them powder coated. They look great.

With the headlights on, the load on the alternator goes up, changing the stress on the bearings - whatever is causing the mechanical noise. If it was a rebuilt alternator from a chain parts place, relatively new means nothing .... Replace it, and if not done already, with at least a zx internally regulated unit - a simple conversion, before it strands you.

The relay that usually causes the problem in the zx is the one behind the glove box. Its the green one, closest to the firewall of the three mounted there. Check to see if any moisture has gotten in there and corroded the connections. Easiest to access with the glovebox liner removed. Also, reseat the ecu connections a few times to clean up those connections (behind the left drivers side kick panel) the fuel pump relay gets its signal from this connector.

You probably got water / de-greaser / moisture inside the TPS (throttle position sensor). It's the small black box that sits on the side of the throttle body, has sets of contacts inside that will short if moisture gets inside, telling the ECU to cut fuel. Unplug the cable from it & see if the problem goes away, then blow it dry with compressed air or heat, clean the contacts. Cover it with a plastic bag when washing the motor area in the future...

Wow Sorry to see that happen to your car. Lucky though the other car was not higher & do damage to the hood or more. Looks like Dave's weld held up pretty good though....

The thermotime switch tells the cold start valve when to operate & enrich the fuel mixture or prevent it from injecting fuel depending on temperature. Your cold running drivability problems might be a problem with the wiring harness between the engine bay & ecu. Check those connections just after the wiring that leaves the thermostat housing. I think they are bullet connectors. And, try to resist the siren call of the su's for now....

I have Rb's on my car. I used a set of McGard spline drive lug nuts, part # 65454. The wheels take a conical seat, thin or tuner style lugs. You will never get a wrench or socket on standard size lugs with those wheels.

Go with Neapco or Spicer brands.

Welcome The depth of knowledge & detail by members in this forum is immense. Browse the archives, everything you need to know is there. And of course, members love to see pictures of your new project. Best of luck!

Turbo's ECCS system does not use a thermotime switch, since it has no cold start valve. Are you referring to the timer that controls the injector cooling fan? If you don't have it, download the 81 FSM with the turbo supplement. Study the ECCS section, it is very different from the EFI system. Follow the troubleshooting steps. Just to let you know, this thread should be in the ZX section.