Royce

All good advise but I have one more thing to add to 2manyZs and Daniels suggestions. You say this started just after installing a new exhaust system!? The worse kinds of backfires are through the carbs, lean condition. Sounds like you may have an exhaust leak that is allowing some air to get in the system and help unburnt fuel to burn. You might want to start at the exhaust manifold and work your way back making sure everything is tight and that there is no leaks or cracks. I would look closely at any unions or welds but there could be a crack along the pipe someplace too. If you have a leak over time you would see black carbon build up in that area.

FYI... I don't remember what year Z car Alfadog has but in the US only pre '72 model year cars required cutting the console or trans tunnel to fit the 5-speed. The shifter possition of the '72+ model 4-speed is the same as the 5-speed. Have fun!

Okay one correction to make on my last post! In regards to the rear bumper, on the 240 you can reach the bolts inside the quarter panel from underneath the car. When you adapt to a late 260 or early 280Z (still don't have a '77 or '78 to check!) you will need go in through the interior to get to that same bolt. That means removing the interior quarters like I described above because although the hole is in the same location the late 260 and early 280Z has deep pockets on the inside quarter panels. Also, it looks like you could not use the 240 rubber spacer, that goes between the quarter panel mount on the bumper and the body. On mine a thin piece of rubber was cut into a square. That's all folks!

Howdy 2manyZ, Actually the rear quarter panel bumper mounts are different on the 240 than the late 260 through '76 280Z (haven't checked a '77 or '78). I went out and checked the cars before answering this time. I'm learning! The 240 bumpers wrap further forward on the quarter panels. Your '75 280 will have a bolt that is installed from the outside through the rubber side bumper and into a nut that is welded to the quarter below the side marker light. The 240 is held by a bolt that goes through a hole, you have to take off the interior quarter panels and hold a wrench on one end from inside the car, about 3 inches in front of the rear marker light on the rear quarter. Good tips on the large bumper struts! Have a good one!

Lesson 1 - No 5-speeds in US Zs until 1977 model year 280Z. It has been changed. It is a very easy swap! Lesson 2- What 5-speed is it? If 5th gear only drops engine revs about 400 revs on the freeway, around 70MPH, then it is probably a 280Z 5-speed. If it drops close to 1000 revs than it is probably a 280ZX 5-speed. Nothing wrong with having a 5-speed in a 240Z. End of class! Now go take your Z for a drive! Have fun!

Oh, almost forgot! You should buy the CD too! May not be big help for this project but always and handle tool for reference! Have fun!

My late 260 (12/74) originally came with 280Z style bumpers and was converted to '73 240 bumpers by the previous owner. They looked very good on the car! The front bumper looked like it was an easy swap, although I believe the '73 bumper requires early, pre-'72 mounting brackets. If you have that braket it looks like it will bolt into existing holes. The back is a little more difficult. The big issue is the shocks from the big bumpers. From what I hear you need to drop the gas tank to get them out. Once they are out you have a large hole that is visible from behind. The holes probably extend 1" below the 240 bumpers. I don't know about a '77 - '78 280Z but the 260 and up to '76 280Z still have and use the 240 style mounting location. In other words the 240 bumpers mount up to the rear valance just like on a 240. The difference is on the quarter panels where you will have to drill a small hole for the bolt for the side bumper mounts. Hope that makes sense! Corrections, comments, questions are welcome!

Congratulations! Enjoy the ride! I drove my Z to work today!

Since my Z only has the stock AM radio I would have to say L6 by Nissan. But if I had tunes it would be "kashmir" by Led Zepplin. Best played while flying down a long stretch of road at night! Otherwise any guitar based rock from Lynard Skynard to Dream Theater Yes, I had long hair and played guitar in a band for many years in my younger days. I'll tell you what, nothing worse then swapping out a Z diff and getting your hair stuck in a creaper wheel and then ending up with gear oil in your hair. I just had a flashback!!! Have fun!

SORRY FOLKS, MY '73 240Z (BUILT 10/72) DOES NOT HAVE THE MOUNTS FOR A REAR SWAYBAR!!! DOOH! I hate it when that happens! I just went out to measure it and there wasn't one and I don't even see the mounts for one! Looks like I have been under too many different Z's these days. I did check my 260 & 280 and although I cannot say for sure that they are the original bars they are the same diameter, approx. 21MM. Regarding whether to run a rear sway bar or not on a Z, I really don't have any info on that. The only Z that I have really driven hard enough to cause understeer or oversteer is my '71 and it doesn't have a rear bar. For the $$$ to get the custom rear swaybar setup I would rather get the strut tower bars to stiffen up my chassis. One of the potential problems with a rear bar is that if your suspension and chassis is too soft and you corner hard it could actually pick up a tire. If you don't have a limited slip diff. you will be sitting until that tire comes back down. Of course if I have the mounts for one I would probably try it just to see what happens. Have fun!

Sorry to hear about your crunched Z! This may in fact be a job for the pros, but I would check one more thing before spending any $$$. The four bolts, two on each side, that mount the hood to the hood hinges have a little room for adjustment. If you loosen them a little, so the hood can move freely, you should be able to press down gently on the hood and see if it is hitting something or if it will in fact go down all the way. If it looks like it could go down all the way than you can adjust it. You can either lift the hood and adjust it by trial which can take some time to get it right. Another way is to have someone gently hold the hood down while you tighten the bolts, works best if you don't have an airdam and you lie under the front of the car. If that doesn't work than take it to your local body shop. Hope it helps! Have fun!

Actually it was a little before the 260. Starting with the '72 model year the Z's had a rear swaybar, mine missed it by 2 months! I believe the stock diameter is the same even though the car got heavier over the years. I've got three of them from various cars (240, 260, 280) and I'll double check the diameters. The sway bar end links attach through holes in the rear control arms and you found the front mount points at the unibody frame rails. For the best performance many go to a totally different design that attaches to the rear suspension members instead of the unibody. This is also best option for early pre'72 240Z folks. For $20+ UPS ground shipping, probably less than $10, I could send you a good used complete stock setup with-bolts, nuts, hardware, bar and the best used bushings that I have. It will all bolt up to what you have. Send me a private message or email with your ZIP if interested. Also, probably best to replace bushings with poly bushings but this will get you started. Unless you upgrade your suspension and the front bar, like for series autocross or racing, you probably won't want much thicker than stock in the back. Adding a heavy rear sway bar gives you more rear wheel spin or oversteer. Hope it helps! Have fun!

Here is the source I have in my notes for the original simi-gloss metalic gray for the grill or rear finisher. Classic Datsun Motorsports 345 Olive Ave. Vista, CA 92083 E-Mail: Les@classicdatsun.com Web Site: http://www.classicdatsun.com/ Phone: 1-760-940-6365 NOTE: Just wanted to clarify that I would NOT blast or use solvents with the stainless trim still on, as EScanlon mentioned it is very thin and bendable!

If it hasn't been changed, the panels should be held on with the large plastic, rivet type fasteners. I have seen many replaced with screws or pop-rivets. You can remove the plastic rivets by pokeing the pin through the middle with a punch, or a nail works too. Most likely a few may not survive the process, remember they are probably 30+ years old. If they do come out okay be sure to find the little plastic pins so you can reuse them during assembly. First remove the license plate. Then remove the three finishers and the license plate light bar. Next, gently removed the stainless trim around the light holes. Then I just sanded the painted parts a bit to scuff up the old paint. I painted mine semi gloss black but that is not the "correct" original color. Then was able to reinstall the trim and put it all back on the car. I'll try sand blasting next time, since I have a spare. It should hold up fine to solvents or blasting. Mine could have been done better but it looks good from 20 feet away. I have done it twice in the last 14 years I have had the car. I know that there are sources for the original dark grey color, check www.zhome.com I am sure it is there somewhere. The dark grey should be used on the front grill as well. I'll try to find it and report back. Have fun!

I think out of the box the '72 240 makes the best daily driver. Reasons being: 1. Newer transmission design, used through the 280ZX. (This is why the console was redesigned and the fuse block was moved to the passenger kick panel, also makes for easy upgrade to 5-speed) 2. Rear sway bar. 3. Diff moved back about an inch (I am not sure if the wheel base is longer or if this is just supposed to correct a problem with the half shalf angle or something, anyone know???) 4. retractable seat belts. The '70 and '71 series I are probably the most collectable (hatch vents and 240 quarter emblems.) The '71 series II is very similar to the early cars but doesn't have the hatch vents and quarter emblems. I have fitted the later style trans in mine but it does require modifying the trans tunnel and center console a bit. The '73 with early carbs can be just as good although the bumpers where slightly redesigned and would be a little safer in low speed accidents. Bottom line is they can all be good daily drivers and many have been changed with the later improvements over the years so it may be best to go with a rust free (or as rust free as you can find) example of any year. I am sure I forgot a few things but this gives some general ideas. Corrections, comments and questions are welcomed. Have fun!

Umm... well... maybe not! (I say hiding in the corner of the room!) But I wouldn't mind going for a ride!

One more thing about the F54 block, there are two different pistons that came in them. The "turbo" motor came with dished pistons which leave you with a 8.?? compression ratio then there is the "non-turbo" motor that came with flat top pistons which would put the compression ratio up in the 10.?? range.

If I remember correctly my wife's old '82 RX7 had a 12A and my sisters '82 GL had the 13B, or was it only starting with the second generation cars. I believe they are both a 2 rotor motor at between 1.1 and 1.3 liters respectively and are not bad but unless you go with turbos I don't think it will be an improvement. I am sure they would be a lot lighter than the Z motor. It is fun to spin to 8k RPM but neither of them could keep up with my Z. It would be interesting in a 510! By the way, when selecting an engine look for signs of oil leaking between the rotor sections. Once those seals go the oil spews everywhere and you pretty much trash it and buy another one. Just my opinion! Have fun!

I have had a lot of gas left over from my parts cars, about 15 gallons. I have been mixing 1 gallon of old gas with a full tank of good gas in my 240, so far without problems(knocking on wood!). I don't have enough lawn to use it up in the next 5 years mowing. Running it through a strainer first is a very good idea! I would not recommend doing this with a fuel injected car, but carbs should be okay. Mileage may vary! Have fun!

I have a good tank, it's either '72 or '73. I haven't compared to my '71 but it may be similar. Why don't you email me or send me a private message with your cars build date and your ZIP. I'll check the microfiche and give you an idea what shipping and price might be. For the rest of the gang, I am still inventoring my parts but I know I have a very good 260 tank, drove the car 6 months ago, and a not cosmetically perfect but clean inside '76 280 tank. Let me know if interested!

Ed, You don't mention, or I didn't see it, what car you have or more importantly what block you have. If you have a N42 L28 block under the N42 head, going to a P79 or P90 head will drop your compression to below 8 which would be low even for a turbo application. Also, the P79 or P90 take a lot of modification, or you would have to change your pistons, to get that much a good compression ratio with those heads. If you modify your N42 head now and decide you want to go faster in the future just find a good F54 block and put it under that N42 head and you will be close the the max compression that allows you to still be able to use pump gas, close to 10.5. I think anything you do to your existing head will be good use of $$$ because it could be used in either setup. I wouldn't bother with the E31, you really can do a lot for your $$ with a N42. If you decide to change heads I would be happy to take the N42 off your hands! Good things to do to the head: - going to hardened steel valve seats (just to eliminate needing lead in the gas). - porting (and port matching the intake manifold). - upgrading cam. Also, keep in mind that if you do decide to race or autocross having a modified setup can put you in a "faster" catagory. But again this depends on the club. Have fun!

Without listening it is hard to tell, it could be in the head(like a bent vavle) or bottom end (like a piston getting friendly with the head). Something may have worn or broke like the timing chain tensioner or a piston pin. But before I freak you out first look for something easy and obvious. Lets see... I have had a smog pump pulley crack(sounded like valve train problem), rod end crack (that was more of a thunk, thunk, thunk), I have heard of oil tubes breaking and rockers arms coming off. I think you are going to have to take the vavle cover off and see what is going on. Check timing chain condition and tension, valves, springs, rockers, cam. If something isn't obviously worn have someone turn the engine over manually with a wrench on the crank pulley and see if you can tell what is going wrong. Adjusting the valves could tell you a thing or to also. Next a leak down test may tell you if you have a problem with a particular cylinder. If everything passes visual inspection and you are sure it isn't something in the bottom end you could try a compression test to see if it reveals a problem cylinder. Anyone else with some other ideas? Hope it helps!

Sounds like there may be quite a few issues. I think I would start with a tune up(valve clearance, points, cap, rotor, plugs) and go from there. Or just go through properly setting up the carbs, either buy the ZTherapy video or grab a manual and go from start to finish. It is certainly possible to balance the carbs at 2000+ RPM without getting the idle right. It will be a challenge to set timing or the carbs if the other is out of spec. But if you get the carbs close you should be able to get the timing set. No quick fixes here.

The 1-4 ratios in all the Z & 280ZX gear boxes are very similar. The big deal about the ZX 5-speed is it gives you a much better overdrive so you can go with a higher ratio (or lower geared) diff. and still keep reasonable RPM on the freeway. The ZX trans also puts 1st and 2nd closer to 3rd to help decrease the large space between those gear ratios, but I digress. I haven't compared 0-60 times but I think it would help a lot more than it could hurt. What it does is makes the shift points closer together so that you don't loose as much momentum (engine revs) between gear changes. Is it better? It really depends on your driving style and what you want to get out of your car. In an autocross and racing environment (or just touring down a mountain road) it gives you more gear selection options and potentially will be quicker coming out of a corner. There is no perfect setup for all situations but with lower gearing in the diff you should be better off in performance driving situations. Of course if you are going to be autocrossing or racing first you have to find out what the club rules allow! Corrections, comments, and questions are welcomed! Have fun!

Oh and another thing is that the 3.5 R200 is very popular with the V8 Z crowd, since the 3.3 R200 seem to be just about extinct. If you wanted to you should be able to sell it without to much difficulty.