1976 EFI Overhaul

[sscanf]

The clamps I did use were the ones that came with the new injectors. I will get some of those nice Gator clamps next time I put an order together but will use these meanwhile (assuming the injector manufacturer would supply clamps that will be sufficient for at least short term service). I'll roll it outside, watch closely, and be ready with a fire extinguisher the first time I give it a try.

Next question is on cleaning the old gasket material off the head. I spent an hour on it last night with some solvent (simple green) and a green scotch brite pad. It looks (and feels) good to me but I don't do this every day. Just how perfect do I need to get it? I started with a steel razor blade but got nervous about gouging the aluminum. I used a plastic scarper for a while then moved to the scotch brite. Is there a better way to clean it? How do I know when I'm done?

[sscanf]

Glad it was of help to someone. A couple of things I did not mention... I coated each of the o-rings with a tiny bit of motor oil, just like I do an oil filter before installation. I installed the injectors onto the rail before I screwed them into the manifold. This worked well except that the thick plastic spacer (which is not shown in the datsun diagram BTW) wants to fall off when you flip the whole thing over to install onto the manifold. I got past this by using a piece of tape to hold them until I they were seated, like so:

[siteunseen]

I used a 1" steel putty knife and some wd-40 to soften it up some. Then cleaned all up with the scotch brite pad. Worked for me.

[sscanf]

Next question: I have new studs in hand (the studs that hold the exhaust manifold). The old studs are out of the head . How much should I tighten the new studs? Just bottom them out or tighter?

Edited March 29, 2012 by sscanf

[Zed Head]

In general, I believe that studs are meant to be finger tight. It's the nut pulling up on the stud that provides the clamping force. Some people do tighten them in using doubled up nuts, which tends to keep them in the head next time you remove the manifold, but it will also pull the first thread or two up out of the head and add some deformation from the shaft of the stud. You're probably seeing some of that while you're removing gasket material.

[sscanf]

Yes, I did see some of that. The various scraping tools kept catching on tiny ridges around the stud mounting holes. In reading up on installing these studs I have seen both never-seize and lock-tight prescribed. Which is it? both?

I was goig through the exhaust parts last night and noticed that the z store sent me the wrong gasket with the header - I have a phone call to make. Probably not going to get this done over the weekend like I had hoped.

[siteunseen]

I'll guess no fuel injection holes on your gasket. That's what they sent me. I went and bought a Felpro which is supposed to be a good gasket, haven't used it yet so no opinion.

[sscanf]

A little more info on installing new studs - I found the following info at Auto Service Professional

In the majority of cases, screw the studs into the block FINGER-TIGHT ONLY, or with a very slight amount of pre-load (specific manufacturers may recommend as much as about 8 to 10 ft.-lbs. of pre-load). Do not double-nut the stud and tighten severely. Remember — the torque value given for the installation refers to the tightening of the nut only, not the stud itself!

If you desire a “fixed” installation (locking the studs in place for future servicing ease), the studs may be chemically adhered to the block threads. If stud removal is required in the future, the application of heat will break the compound down. If a locking compound is used, be sure to immediately install the main cap before the compound sets, to avoid any possible misalignment of the studs in relation to the cap. This means installing the cap and tightening the nuts to specs, before the thread compound hardens. This allows the necessary preload to be placed on the stud-to-block thread engagement before the compound hardens.

Remember: The use of a locking chemical really isn’t necessary, unless you want to ensure stud position during repeated and hurried main cap changes.

When installing the studs, simply make sure that full thread engagement has been achieved. In other words, make sure the studs "bottom-out," with all threads engaged.

I will be installing them dry (but with anti-cease on the nut threads).

[sscanf]

I just called the Z store and they had no problem sending me out a new gasket. I asked why an OEM gasket was no good and they told me it was because it had metal facing on the manifold side that causes a heat problem with the header.

[sscanf]

Quick update - I have the header and the EFI on. Now trying to figure out how to hook up everything. I am getting most figured out and the previous owner did mark many of the leads. Its taking some patience though...

[superlen]

If you get stuck, PM me and I'll give you my number. I can talk you through any of the hookup/debug of the EFI. I have been buried in the wiring diagrams and detailed operation of the L-Jet over the last two months while designing a replacement ECM/ECU.

-Lenny

[sscanf]

Its been a while.... So here is what happened:

April gets busy around my house. The grass starts growing, I have to mow it. The house needs painting, I have to paint it. The wood needs stacking, I have to stack it. etc.

The mower is now put away. The house is painted. The wood is stacked. The Z awaits.

So, here is what happened: I did get the EFI wiring hooked up in April and tried to start it. I used a combination of labels provided by previous owner, manuals, and wire memory to figure it out. Once this was done, the engine cranked just fine but there was no ignition at all, it didn't even try. A short investigation revealed that the fuel pump wasn't running. I put a meter on it. No (well, very low) voltage. That's when I was over-run with all the homeowner stuff.

Finally, two weeks ago, I drag out the EFI manual and turn to the most basic wiring diagram. Within 5 seconds I knew what my first problem was. The previous owner had removed the AC and there were a few dangling wires. Basically any wire I saw without a mate I assumed was part of the AC. This was not quite true. The EFI ground wire (red!) had been removed by the previous owner (and he did mention it but i recalled it as he had disconnected the fuel pump - and there was a dangling wire at the fuel pump that I reconnected). So, I sort through the "leftovers box" and, sure enough, I find the snipped off EFI ground wire. I take my time and nicely splice it back in. Roll the car out on the driveway, turn the ignition on (but don't crank it) and I hear the fuel pump! I leave it and inspect the fuel lines - its all good. I crank it for about 30 seconds and it fires!

It ran pretty rough for a few minutes but not awful after that.

It did not like to start at all, always took 30 seconds or so. I decided to replace the cold start valve (the only injector that had not been replaced). Now it fires instantly every time. Still runs rough when cold. Pulls strong after warm up.

What I have done so far

All (7) new injectors (with new hold down bolts, not screws!) and thorough throttle body cleaning.

New vacuum hoses.

New motorsport header and exhaust (not sure I like it - sounds like a truck to me)

All new brakes (drums, shoes, cylinders in back, calipers, pads in front - rotors were in good shape. Old calipers leaked. New master cylinder)

Wires, plugs, cap were new via previous owner.

Fuel pump new via previous owner.

New lug nuts (it was an adventure getting the old locking lug nuts off without a key - broke lots of craftsman sockets).

New fuel filter

Lots of other misc small stuff.

Plan on checking valve clearance and timing next. Then back to the trouble shooting section of the EFI manual.

Quick update - I have the header and the EFI on. Now trying to figure out how to hook up everything. I am getting most figured out and the previous owner did mark many of the leads. Its taking some patience though...