I got the rest of the fuel rail and injectors out last night.  What a pain.  Injector retaining screws are JIS B1111 Phillips recess pan head screws, M5x0.8, 30mm long.  I hadn't seen that documented anywhere.  McMaster Carr has them in zinc plated steel (94387A338).  They have them in stainless, too.  But I'll stick with OEM finish, as I'd rather the screws corrode than the intake manifold.

Thankfully, the two screws stuck badly enough to wring off their heads are on #5 and #6, where access is better and heat is safer.  The one I drilled is on #1.  Hopefully, it'll come out easier than the others, since it's still partially buried under FI harness.  We'll find out tonight.

Edited March 17, 20169 yr by the_tool_man

Definitely replace the screws with the newer hex head type.  I got mine at my Nissan dealership, you'll see the part number in this thread.  S30Driver found some allen head type too, maybe Fastenal would have those?  

 

10 minutes ago, siteunseen said:

Definitely replace the screws with the newer hex head type.  I got mine at my Nissan dealership, you'll see the part number in this thread.  S30Driver found some allen head type too, maybe Fastenal would have those?  

 

I order everything from McMaster Carr when I can.  Their online catalog is one of the most comprehensive on the planet.  Their prices are a bit higher.  But you have to remember that it includes overnight shipping.

I considered using hex socket head screws.  And I may switch later.  Right now, I'm unsure whether to keep this car original or mod it.  My normal inclination is to mod it, as I've done my other cars.  But this thing is such a time capsule, I'm hesitant.  So for now, I'm replacing with identical.  I'm probably overthinking this.  But that's what I do.  BTW, I don't think hex head screws would allow room for a socket, because the heads are pretty close to the injector body.

Again, I'd recommend against stainless for these.  The primary reason is that they are somewhat weaker than steel, and more likely to wring off or strip the head.  A second reason is that they screw into aluminum.  There exists a likelihood that there will be galvanic action between the parts.  If you look at the galvanic series, zinc is very close to aluminum, minimizing the electrical potential for corrosion.  Stainless steel is much farther away from aluminum, and more cathodic as well.  This means the aluminum will corrode, albeit very slowly due to the mass ratio.

That was part of the reason I decided to switch to the 11mm oring style injectors with a pallnet rail..., no more need for the retaining screws or clamps.

When I went to Nissan to get replacements the parts guy said they quit making the round phillips head, superseded the newer part number.  That's how I ended up with hex heads.

If I mod this thing, I may try the Pallnet rail, as well.  I really like how that cleans things up.  Then again, I might just go with an aftermarket system altogether.  But that's later.

Do the injectors not come with O-rings?  I thought those were included.  But I haven't looked.  Thanks for the heads up, siteunseen.

With today's fuel and the fact that you live in a hot part of the country you'll probably experience some hot-start issues if you keep the stock system.  A few of those and the "time capsule" nature of the car will become much less relevant.  I like to experience the real problem myself, so maybe wait and see but be ready to work fast.  

2 hours ago, the_tool_man said:

Do the injectors not come with O-rings?  I thought those were included.  But I haven't looked.  Thanks for the heads up, siteunseen.

If you were referring to Wheee's post referring to an O-ringed rail, the Pallnet rail can be either the barbed (stock) or O-ring style to mate to the fuel rail.

The new injectors will come with the seals for the intake manifold.

 

Yeah. I should've looked at one before posting. O-rings are included.

They're not really o-rings. Just rubber shaped like zeroes. You'll get the big one for the body and smaller one for the tip. FWIW 

Plus a solid clamp, fj707t. Those have a different spray nozzle that I think is better. No small pin hole like the others.

My $.02 cents only.

True. But it's easer to type O-ring than "square-sectioned circular rubber gasket", lol.