LanceM

Oils come in many types and uses, cutting oils are usually 5-10W oils without additives. Something needs to be used to keep the stones from loading, a light oil does this by floating the cut particles away from the cut and the stone. I wouldn't recommend using a solvent as it is much more flammable than a light oil and there is the possibility of sparking when using the tool and the drill driving it. Ideally a steady stream of water would probably be best but standing in a puddle of water using an electric drill just doesn't sound like a real smart thing to do I like WD-40 because it comes in a can and is handy for spraying out the cylinder to see how things are progressing.

I use a 3 stone hone but the process should be the same. My best results are gotten by using a 1/2" drill with a speed control to get the speed around 60 rpm or so and moving the hone rapidly through the cylinder to get a good crosshatch pattern. I've found that higer rpms make it hard to achive a good pattern as it tends to be very horizontal instead of X pattern. I also try to keep the hone well flooded with something like WD-40 to keep the stones from loading and to keep the debris out of the cylinder. Hone only until the glaze is gone and a good pattern is achieved, doing more and you risk taking the cylinder out of round or exaggerating any taper in the bore.

Fair enough!

You miss my point, the inexperienced won't do the math, "I did it on my Z I can do it on the wife's car" will be their thought. Maybe the wrong decision and bam injury... I just wanted to point out that you have to be careful on forums like this, some take the replies here as gospel and apply it everywhere, whether it is good advice or not. I do things all of the time that are not "safe" but it is my decision, my level of acceptable risk, and I would never recommend someone else doing it because my level of acceptable risk might be much higher than theirs or my equipment different changing the risk level. Just as an example, you say zip it off, with an air impact? What if some poor soul does it with a box end wrench?? There's a lot less steel and a lot more hand in the way of that spring that weighs?? and is moving forward how fast?? And to answer your question, no I didn't do the math but after doing mine with a compressor, which was a PIA, and now knowing the compressed strenght of the spring I would probably tie them up as compressed and zip them off with an impact but I would never recommend it, someone else's injury following my advice is beyond my acceptable risk level

Since many of the people here on the site are having some of their first experiances working on cars in general it is probably best to go with the safety first attitude. Compressed springs are a danger, how much may depend on it's particular application, but still a danger in anycase. Personally anyone that jumps from a perfectly good airplane is a moron IMHO even though it isn't "terribly dangerous" with proper training and a good parachute The right way is the best way to do things safety wise, even if it take special equipment and more time. No flaming intended just my $.02...

I thought I'd post this as here in Northern Indiana any Z in a junkyard is rare, a 75 is unbelieveable. Blue w/white interior, cracked dash, rusty, 4 speed. The car is complete, minus the few small items I liberated. Bad news is this yard does not sell cars, only parts. Anyone that is interested in it's location PM me and I'll give you directions, it is close to Syracuse, IN.

Doubt that it is timing, sounds fuel related. Don't know EFI very well but I would check fuel pressure, TPS, and the AFM. You can check the TPS with an ohm meter, don't know about the AFM.

I'd go with option 6. Unless the head is a rare one it is usually cheaper in the long run to replace it with a known good one that hope that a repair holds. If it was a steel head I would have more faith in the repair than I would with aluminum, JMO. Going with the E31 with bigger valves would cost more than a reworked N42 head, plus depending on which E31 could you take the extra compression? Life is full of options, just most of the time none of them seem like "great" options

Check the fuseable link coming from the starter, that probably would have gone first when things started blowing, it would keep everything from working if it was blown.

Since the ignition was off I'd bet the only thing you cooked was the alternator/regulator, I'd hook it up right and start it up and see what happens, if the alternator is gone it won't be charging.

I've seen this done several times, but not on a Z, but with most everything unibody now I don't see that it would be different. The halves are cut and jigged before welding together. For sure nothing I would try at home! Nothing special was done during the cutting that I saw, mostly a case of getting things apart in a way that they could be put back together.

I bought a control cable from McMaster Carr and adapted it to the original choke lever. The original cables can be made to work but they look and are jerry rigged to say the least. The cable I bought was longer than I needed so I was able to cut to fit. Needless to say this is a mod as you go type of thing and you have to be able and prepaired to make things work.

No problem Gary, Weld through primer was new to me before I took the ICAR welding course and reading the word primer and spray can in the same paragraph brings the thought of "don't do it" first to mind!

Use something like a toothpick, maybe even shaved a bit. There is no way that you will be able to fill the scratch flush, surface tension will cause it to be higher than the surface if nothing else. That is why you will need to buff it out afterwards to level the paint in the scratch with the surface surrounding it.

Just use multiple layers of paint, then buff it out. If you are only into the primer then the scratch is only as deep as the paint is thick.

No scratch remover is going to repair a scratch that deep. You will have to go the touch up paint method, do something soon since you are down to the primer it is the same as being down to the metal, rust will soon appear!

It is my understanding that in the high temp areas of the weld the zinc remains behind and is bonded to the metal, much like galvanizing which is a zinc coating I believe, which inhibits rust by coating the base metal. The unheated areas are protected by the paint itself. We've probably all have seen it but never recognized it, but heat up a section of metal red hot and then set it outside, the part that was heated rusts first and the most. I don't know why but it does, you can really see the affect at the pick and pull where there are cars that have burned, the closer you are to the hottest point of the fire the rustier the metal is. When you are welding temps probably hit 1200 or more, pretty hot! That is the point of using the weld through primer, it leaves a coating behind a the weld point to inhibit rust, rust that seems to start fastest and be worse at hot points.

Carl, I'm not familiar with POR other than what I have read here and on other boards so it looks like two edged sword time. Weld through primer may inhibit the bonding action of POR, POR will inhibit proper welding. Considering that the floor pans must add quite a bit to the structure of the car welding would be my foremost concern. A floor pan that is subject to rust in the future but securely integrated into the structure of the car would be more important to me than one that will never rust but has welds that may break over time because a weld contamination. Probably the best case would be to primer only the hidden weld area then after welding remove any visible excess primer, treat the metal and then POR. Where the welding is done on the visible side will need to be treated and POR applied after welding anyway since any POR at the weld site would be burned off and the welds themselves exposed. The primer in the hidden area should act as a quality rust preventive considering that these areas should be fairly well sealed "inside" the car. Using any method, my main concern would be that the structure integrity is not compromised, body flex will only cause problems whether it be in handling or paint cracking, with bad/weak welds flex will only increase as the poor welds break, causing more flex and more breaks. Considering that I'm sitting on that floor pan I'd like to be pretty sure it isn't going to fall off the bottom of the car one day

I have used it on heavier metals too being to lazy to change it out for a couple of welds and it works great. Penatration is very good and the puddle is easy to control for really great looking welds. I've found, for me at least, on thinner metals pull welding works best, for the thicker stuff pushing the puddle works best as would be expected.

Ah a perfect time for this, thanks Carl "I know you think you understand what you thought I said, but I'm not sure you realize that what you heard is not what I said!" In this case read not said The rattle can paint I ment was weld through primer, not the stuff you get at auto zone, you can't weld or at least shouldn't weld through POR or any paint for that matter. It contaminates the weld, weld through primer is meant to be welded through and has a high zinc content to both protect the metal at the weld point and conduct electricty to allow you to weld. No certified panel repair man would weld a panel on without using weld through primer, not unless he wants the job to come back because of rust through from the back side, insurance repairs, at least around here typically require it. Besides if the panel is fully coated with POR how are you going to weld it, no metal is showing? If you start your weld on the frame member which isn't coated and drag the puddle on to the floorboard you are hoping the heat will burn off the POR as you drag the puddle, loading the weld with POR slag and making a mess of the whole works weld wise, that's if you don't just burn through because you are going so slow trying to clean the metal with the weld heat. Again just my $.02, spray the weld area with weld through primer, then when done welding POR.

Just my $.02, clean metal welds best so I would POR after the job is done but I would coat all of the welding areas with a weld through primer (high zinc content) to help prevent rust starting at the weld points. This is a standard requirement for panel replacement and if isn't done more than likely rust through from the backside out. BTW, tests have shown no difference in results between spray on or brush on weld through primer so go with the rattle can as it is easier and quicker to use.

73 did not have a 5 speed available in the US so it has already been swapped with a later model, any of the later 5 speeds from the 280Z-280ZX will bolt in. There may or may not be issues with shifter hole location on a 71 but it isn't a big problem from what I have read.

I did the change on my 73 and had no problems with the 73 rod.

Though it is a lot of work there really isn't much else to do but put it back together and see. I would check what Carl mentioned about the timing cover, and I would check to see that the head is flat, use a new head gasket, and retorque after a heat cycle.

If the system has always had antifreeze in it should be OK, drain it down a bit and look in the radiator, if the tubes look clear you are probably ok, if there is a lot of gunk and build up then maybe not. Depending upon how old the hoses are they may be ok, if they are old or of unknown age they probably should be changed, better to do it now than on the side of the road in the dark!