jmortensen

It's easy to find pistons in 1mm overbore, which is .040". I think you'll have to eyebrow (notch) the block for valve head clearance if you run the N42 on the L24 block. If you're mixing and matching anyway and aren't worried about staying original, why not find an L28 and use the N42 on that? Should be worth about a 15% jump in power due to displacement alone. Knife edging the crank is overkill for your usage. It's expensive and is really about removing rotating weight, which based on your flywheel comment you aren't too concerned about. Cast pistons would do fine if you aren't really upping the compression or revs a lot. The L series has enough low end torque that the 10 lb flywheel is really pretty easy to deal with. Stop and go is no problem at all. The one thing I'll say about it is that it's tougher to keep a totally steady pace on the freeway, the car instead always seems to be accelerating or decelerating. You will get used to it and learn some finesse with the right foot, but it does take a little time. 16 lbs would be a big improvement over stock as well and you can have your stock flywheel turned down to that weight for about 1/3 to 1/4 the cost of a lightweight replacement. My clutch recommendation is ACT with a stock clutch disk or their CF clutch disk. A puck clutch is unnecessary for your likely power levels and will make the car uncomfortable to drive daily due to chatter and harsh engagement. If the bore of your engine isn't badly worn (and they usually aren't) you will most likely be able to just hone the block, swap rings and bearings, and reuse the old pistons. No problems with that and it really keeps the cost down.

No info on the possibility of camber plates yet, but you should section the struts just like you would 240 struts, because they're going in a 240. The reason the 280 struts are different is because the rear strut towers are higher inside the car, and so the top hat and the strut have to be taller to get all the way up there. DO NOT use the 280 isolators in the rear. Use 240 parts, because the 280 stuff is an inch taller. The fronts are the same as I recall, so no problems there. You can check on the hubs and brakes in the front, but I think you may need to use the 280 hubs, discs, and calipers, even though they're heavier. I don't have too much experience here, so double check that. I believe the rear hub offset is the same, so you can use the 280 brake parts with 240 stub axles, but the 280 stub axles are again theoretically stronger so you might want to go that way.

Camber plates or stock rubber isolators?

Oh man, there's a can of worms... The 280 stub axles are 27 spline, the 240s are 25 spline. This means that the 240 stub is theoretically weaker. Either stub fits in either housing, and the bearings are the same. You MUST use the correct spacer between the bearings, that part is critical. Every single strut I've had apart has had a "B" spacer, but supposedly there is an "A" and a "C" as well. The 240 and 280 rear brakes are slightly different, I don't think this will be much of a problem for you, except when ordering replacement parts. If you're swapping in the front struts from a 240 the hubs are different than your 280. The bearings are the same, but the 280 hub has a different offset, so 240 and 280 rotors are different, and I think the calipers are different as well. What's more, the size of the strut tubes themselves is different, so the coilover parts need to be ordered for a 240 or a 280. If you aren't going to camber plates, then the top hats on the struts are also different (the 280 has an inch taller rear top hat). Can you give us a list of what exactly you are changing? If you're going to camber plates for instance, you'll lose those rear strut tops, and then you would probably want to section the rears less than the fronts. If you're going to an aftermarket front brake kit, a lot of them require 280 front hubs and won't work with 240 hubs because they need the extra offset.

99.9% sure it should be 3" for a 280Z. Stick a tape measure into the strut tubes and measure the lengths. Subtract the difference, there is your answer. When you section you'll want to have at least the same difference in length, if not have the fronts even shorter in relation to the rears, again because of the tendency for most people to run the front end lower than the rear. The idea is that when you're done you want the front and rear struts running in the middle part of the travel. Maybe this will clear things up a bit. Sectioning the struts lowers the car. You might say it lowers the maximum ride height. So you can still extend the strut all the way, but it is now shorter, so to put the body on the strut the body comes down. Make sense? So if you sectioned the rear to fit the housing as you had originally stated you would lower the back end 4.5" (3" to match the front, then the 1.5" spacer) and the front not at all. The arse end would drag on the ground and the front would be close to stock.

Happy to help. Good luck.

I'm guessing the spacers are probably for the rear. Front to be used with no spacers, and a hole drilled in the bottom of the strut housing. Really on a 280 the rears should be 3" longer than the fronts. Most people race 240s though, and then the rears should be 2" longer, so that would be an understandable error. I assume the first sentence was supposed to say that a "spacer is required". I think the hole in the front struts makes perfect sense. You'd still have to disconnect the steer knuckle to adjust the struts, but you don't have to adjust your struts every day... This tells me that the AD struts are 2" shorter than stock. That's about right, and so you should section the front struts to fit the housing without the spacers. Ask GC for a 3" spacer or make your own and assemble. So basically yes, you were reading me right.

You want the front struts to be about 3" shorter than the rears for the 280 struts. When you buy Tokicos, for example, you get the same basic struts front and rear but the rears have a 3" tube pressed onto the end of the strut to make it longer. 240Z's are the same way, but the rear struts are only 2" longer than the front on the 240. I'm not sure how long the AD strut is, but whatever you do to the front will determine how long the rears should be. The fronts need to be sectioned due to running out of travel more often than the rears do as a general rule because most people lower the front end more than the rear and end up with a little rake. I set up my sleeves so that the spring fits with no slop against the strut top and the spring perch at the same time. Wherever that locates the sleeve, that's where I put them on my car. That does not allow you to preload the spring, but I knew I was going to run the car low enough that preload wasn't an option anyway so I figured that didn't matter. I think this is the case for 99% of the people running coilovers on a Z.

That's a pretty good deal, congrats. Wondering what an "LS30" is though...

LSD is MUCH faster on a road course or at an autox because you can apply the power much earlier and get forward drive instead of just spinning the inside wheel. It's a night and day difference. I know no autoxer or track junky who doesn't have an LSD or welded diff. Spinning that inside tire is the slow way around.

The 115mm is the ID of the ring gear. I think the early R180s (pre 76) have a different size ring gear ID. If that is right, then the gearset would work if you got a 115mm open carrier or LSD. Otherwise no.

Hwy 23 all the way to the beach!!! Then again, I always used to get stuck behind a big arse truck going up Grimes Canyon. That and the margin for error on the latter half of 23 is pretty much nil... it can be a tough climb out from the bottom of some of those canyons when you make a mistake.

I'm not sure I understand this response. Are you saying that you believe the BRE spook and spoiler cannot be improved upon? You might actually look at the numbers over there. The tests measured drag AND downforce and a bunch of other parameters. The results were pretty clear. http://forums.hybridz.org/showthread.php?t=121877

Gordon's site is a GREAT resource, but all of the parts listed there are LSD specific pieces.

You could take a look at the aero testing that was done at Hybrid Z. The nice complete article was removed, but you can look at pictures of different configurations and compare them the the table of results. Spook and BRE adds 70's flavor and does improve things (it's config #11 in the testing). Actually everything tested worked as advertised. The last configuration fared the best in terms of downforce, but I'm guessing it wouldn't fare well with most of the classiczcars.com membership in terms of style.

Making it thicker is one way to make the part stiffer. Another would be incorporating a lip on the edge, like the piece you're competing with. A third would be to roll beads in the sheet, like a floorpan. What you have planned should work just fine, by the way, and I'm not trying to be a PITA...

Stainless would be a better material, as it doesn't conduct heat very well. It's more expensive as a raw material and harder to weld so it may drive the price up a bit. I don't think this shield needs to be nearly 1/8" thick either. You could probably use 22 gauge sheet.

If you use a newer R180 the axles don't bolt in. There are several workarounds for that. You can buy modified stubs from www.betamotorsports.com or you can disassemble the carrier and install the threaded "button" that the stub axles bolt to. Obviously the modified stubs is the easier way to go, but the other really isn't difficult and I'm sure your racer friend could do that with his eyes closed. More details on that procedure here (where the pictures start): http://forums.hybridz.org/showthread.php?t=114798

I used to sell parts for Randy's and have been through that .pdf booklet many many times. I've driven the 3.36 with ZX trans and it is painfully slow off the line and 5th is useless for anything but flat ground in my opinion. The 3.7 is better for sure, but a 3.9 is what was used from the factory on the ZXs with the 5 speeds and a 4.11 would be a small step up from there. Have you used the transmission calculator? You can input your tire size and figure out your revs at a given speed. Might help your decision: http://www.geocities.com/z_design_studio/

That may be the exception to the rule, but the general rule is that it is far easier to swap in a diff that already has the correct ratio than to install a ring and pinion. The FSM shows special tools and complicated procedures for setting pinion depth. As with any diff it can be done just by looking at the wipe pattern of the gears, but adjusting things will require shims that probably aren't on the shelf of your local dealer. It may be possible to use shims from a different vehicle, but it does take some skill to get things set up correctly so that the diff doesn't whine. This gear installation manual has some pretty good wipe pattern do's and dont's at the end and may be helpful: http://www.ringpinion.com/Content/HowTo/TechnicalInstructions/Yukon_Installation_Kit.pdf I'd suggest the 3.9 diff, or a 4.11. I was autocrossing and daily driving my Z for years with the ZX trans and 3.7 diff, and I felt that the 3.7 was a bit tall when I ran that combination.

One difference is that sand can get into the frame rails and turn your car into a giant maraca. Baking soda won't turn your car into a percussion instrument if it gets into a frame rail or other enclosed space...

SK's are still available and they have a mix of Weber and Solex or Mikuni jets. Jets should remain available, and if the carbs live up to the hype they should be better than either the Mikunis or Webers. 45s would be better, I wouldn't waste your time with 40s.

There are 2 different rear sway bars. One attaches in front of the diff and uses the brackets that are built into the frame on later Z's. I'm thinking my old 72 did not have these brackets, but that car met it's end 10+ years ago, so I might not be remembering accurately. If yours doesn't have the brackets on the frame, you might have to weld an appropriate bracket on. The other style mounts behind the diff and uses new uprights in back to attach the brackets to. Suspension Techniques sells that kind of bar, but I don't know whether it is possible to just buy the uprights and the straps to hold the bushings. You'd also need the bushings for the center of the bar to get everything finished up, and to get those bushings you'll need to know the diameter of the bar.

3.90 R180's are like hen's teeth. I'd find a 4.11, they're much easier to come by as they were used for the front diff in the mid 80's Nissan 4x4s. For cams I was running something very close to the Schneider Stage IV and thought it was great with my stock compression L28. When I added triple carbs it became obvious that the cam was too small, but it worked nicely with the SU's. I wouldn't buy the Schneider cam though, I'd have your stock cam reground. If you search around the internet you'll find that the Schneiders are usually closely accompanied by posts about oil no longer containing as much zinc and phosphate, and they'll say how hard it is to get a cam to hold up without those additives. But those threads really seem to follow the Schneider cams around if you know what I mean. The bigger your cam is the LESS octane you'll need, and since you're only running 9:1 you might be able to run your motor with a ~.490/290ish cam at 89 octane, maybe even 87. But now that I think about it, shouldn't a flat top piston and N42 combo put you at more like 10.5:1? Even so, I think you'll have no problem with 92 if you have that kind of compression with the larger cam. Also if you search for octane boost you'll find out how little of a boost you get from the can you buy at the auto parts store. You can buy the components from the hardware store by the gallon, much better bang for the buck. I don't think you'll need it for your planned build.

That gloves not long enough shouldn't be a deal breaker. It's a minor inconvenience at worst.