NewZed

There's a note in Honsowetz's "How to Modify" book about potential damage when installing that type of pin. You have a dilemma. Install and hope or take apart and be sure. Note - I'm only relaying what I've read in the two books I referenced. Never built an engine but understand the concepts. Were it mine, I might throw some heat on the pistons to get some expansion, and dowse the pins in oil to see if I could get some oil in there. To be sure. If they loosen up the odds are better that expansion when running will allow lubrication. Hopefully one of the engine builders will have some more experienced comments.

Don't forget that everything starts at the CAS with the ECCS system. The computer controls ignition.

Monroe says standard piston bore clearance is 0.0003". Not much but enough to allow oil penetration. He also says if they're not lubricated you can gall the surfaces at break-in and ruin the piston. He also describes letting oil soak in to the bores to make sure they're wet at start-up. Did you oil yours? Seems weird that ITM would sell pins with pistons but not size them, or at least add a note that they need sizing. Did you mix up the pins? They might have been matched sets. Just a guess.

It's pretty easy on the early 280Z's, I've done it on both sides of my 76 with glass in place. You can't see what you're doing, so memory of what you were just looking at is required. But 78 has the newer door style. Might be more cramped.

You might also measure pressure with the FPR not installed. Just to be sure there's not something blocking the ports. The FPR is just a pressure relief valve. If you don't have some monster fuel pump pushing so much fuel it can't bleed off pressure, it should work if the flow paths are clear.

Don't forget to check the gauge.

Read BRAAP's EFI tips here, along with the other threads - http://forums.hybridz.org/forum/90-l-series/ You won't get much bang for the buck with what you're planning for the engine. The ZX transmission with the 3.9 will have a better gear spread than what the 78 has. If ti started and ran fine, it probably was fine. Might be best to just get a new HG and put it back together. The stock Datsun parts are of high quality, even used, compared to much of the "rebuild" parts you'll find. A bore means all new pistons and rings, for no real benefit. A hone means new rings, for what, if it ran fine? The first three things, and the exhaust system will add some pep, the rest, not much. You can do those with the stock EFI system. Many would say that getting a modern EFI system, like Megasquirt, and keeping the the stock engine, would be more worthwhile than the engine mods you describe.

There's a check valve in the pump. They fail sometimes. Crimp the supply line before it leaks down and see what happens. You didn't say anything about what the pressure was before you replaced the FPR but the fact that fuel dribbles from the FPR instead of flowing could mean that the FPR is blocked or defective. If you knew what it was before it would give a pretty clue about blockage versus FPR. Some aftermarket FPR's can be connected backwards and will give full fuel pump pressure in the rail if that's done. I'm not familiar with the Z31 fuel system in general beyond the basics, besides the fact there are 6 years worth of them. There may be differences. Give some details on yours. Think in terms of pressure instead of flow direction. Pressure works backward too.

Compare the distance from the mounting surface to the rod contact surface between the two cylinders when you do the replacement.

It flowed backward, from whence it came, when the fuel pump stopped spinning.

The fuel probably went back the way it came.

That has happened to others. You can use a screwdriver if you're handy, to press the valve down and slip the rocker arm back in. Make sure the piston is down and the cam lobe is on the base circle. It's described on page 86 of Monroe's "How to Modify" book, if you have it. Or you can search around the internet, there's probably a video somewhere. The L4's (510's) have the same rocker arms.

It can be caused by an exhaust leak and extra fuel. The missing ignition (if you're lucky, it's an ignition problem, could be a cam lobe) on one cylinder is probably passing unburned fuel, the exhaust leak supplies oxygen. The P79 exhaust liners are designed to burn any fuel that exits the cylinder. One possibility. Is it still EFI? P79 on N42 is not stock. What else has been modified? Best to just get it running on all six first. You can pull injector connectors to find the dead cylinder.

I read the diagram and explanation as 27% of the base pulse is added on top of the other correction factors. So by getting coolant correction back in to the equation, you lose fuel enrichment as the engine warms up compared to no coolant correction. If the diagram is approximately to scale, that's a lot of fuel.

If the CTS was disconnected it was richer everywhere. Now it is leaner everywhere. That's just how the system works. Your nose may not know but it's happening. Unless you tweaked the AFM back and are working off AFR gauge numbers. It's a crude system you've got there, good luck with it.

Warning - do not watch this video right after watching zredbaron's video - https://www.youtube.com/watch?v=-Dj6LUXdn4E&feature=youtu.be&t=2m10s from here - http://forums.hybridz.org/topic/24798-na-31lhead-camshaft-questions-no-shortcuts-max/page-12 It will hurt your brain. How long have you had the car? Could be several things, in addition to what bjhines said, causing backfiring. I think some people call what yours did, "after fire". Fuel in the exhaust system lighting off.

In your other thread the guys were implying that you had ring damage due to detonation. Detonation is much more likely now that you've removed the super rich condition.

A typical page in the FSM will show the simple diagram then a drawing of the wiring with connectors. Shapes and everything. Another sample. Included a page number. Can't go wrong at least taking one quick look at it. You might get hooked. It might be liberating. You can also use a meter to see which wire ends are connected to each other. Beware relays though.

Bunblebee's writeup is not really a tutorial, it's more of a primer to get you started. You need to get in to the stock wiring and control system diagrams, and test the circuits to be sure that things are connected as you think they should be. Attached an example of the ignition circuit.

Could be a bad PCV valve. Here's the basic concept.

Glad ti worked. The two missing bolts threw me. And I haven't looked at many so don't really know what's good and what's not. Carry on!

You didn't say you've only been chasing the clunk since yesterday. That's not very long. You also said that you tried to tighten the gland nut but didn't have the right spanner. But you're asking about the gland nut. Plus, you're asking if that nut in the picture needs to be tight. Sorry, it just seems like you haven't really thought through how the strut/shock assembly works. Could be that the shaft slid up when you jacked up the car. The gas-charged shocks keep the shaft extended. The nut itself looks cocked in the picture, like it's cross-threaded or too big for the shaft. Two bolts and not much meat around the strut mount looks like someone's home-made adjustable camber setup. Overall, it looks problem-prone. In the meantime though, that nut needs to be tight, to lock the top of the shaft to the strut mount. It could be your clunk. You might start a thread asking for opinions on that camber adjuster job, and how you can make it better. Might be fine, but it does look iffy.

It tightened itself? That's the nut that holds the shock shaft. It needs to be tight. Search "gland nut" on your favorite search engine and you can learn what one is.

As Pac_Man says, if you can connect the hard drive to a working computer with a newer operating system, it will probably let you copy the data. Search "bridge cable computer" on the internet, if you don't have a spot to install the hard drive in whatever other computer you have available. You can buy a cable that will power the drive and let it communicate.

Here's a link that has some good pictures. Not so sure of the method, but the pictures are good. Be careful with the lubricants. 3/4 down is the adjuster, click on them and they blow up. http://www.hammondsplains.com/newtechtips/brakes/77drum/