jmortensen

I'm sure that is it. 4mm of toe in on one side is a lot. That's almost 3/16". I'm interested in how you slotted your rear crossmember. Was it anything like this? http://forums.hybridz.org/showthread.php?t=89111 If so you might be able to mod it a bit more with a turnbuckle and get rid of those eccentric bushings, or put a screw through them so that they can't rotate anymore.

Just in case you haven't seen me post it before: http://www.jrdemers.com/280ZX/distributor/distributor.html has a good bit on checking the bushings, rebuilding this distributor, etc. The breaker plate is pretty smooth. You'll need to rough it up for the JB weld to stick.

Steering rack is not likely, I think a problem there would be really obvious. I'd be looking at a toe change or a caster change or something like that. The aluminum bushings have a reputation for rotating by themselves, that might throw toe off pretty significantly in the rear, which could explain your problem.

A bigger cam will get you a lower compression reading and that is totally normal. That's why you hear people saying that cams "bleed" compression and you lose low end power. It's true that they lower static compression, but they do so to increase efficiency higher in the rev range. I don't know enough to say that your new compression readings are "normal" with a big cam. I think the common consensus is that the reading you get on a compression tester shouldn't be used for anything other than to compare the readings to the other cylinders.

Who is sitting in the car? You need to sit in the car when you set corner weights (with the swaybars disconnected preferably) and then you need to have the preload removed with you in the driver's seat. That doesn't sound like preload, but what it could be is a bit of a mystery. You're sure your alignment didn't change? What kind of bushings?

Swaybar mounts are going to affect the car turning either direction, just as adjusting an adjustable bar on one side only affects the car's response in either direction. The bar attaches to the suspension on both sides, so it shouldn't react differently in one direction or the other, unless it has some preload. Preloading the swaybar makes it act differently in one direction than the other. That's why I kept bringing it up. You did mention removing preload when corner-weighting and I missed it. How are you removing the preload? Shims? Heims jointed end links?

Use the specs that cam with the cam. I believe mine suggested setting .002" tighter than stock...

You don't time an aftermarket cam with the factory marks. Here is a writeup on timing a cam: http://forums.hybridz.org/showthread.php?t=111523 Even if you have the cam timed correctly, you can expect crappy results with factory EFI, because factory EFI is crappy and can't self-adjust to a large cam, so everything gets thrown out of whack. You might check with the ITS racers who are running 280Z's (if you can find one). I think a couple years ago they were given the ability to chip the computers, and so there might be somewhere that you could send the computer to have it chipped if you were really keen on keeping the EFI. If that doesn't work, then to properly utilize a larger cam you will really need aftermarket EFI of some kind or carbs.

Sway bar preload eliminated?

I think you misunderstood what he wants to do. He wants to JB weld the WASHERS to the breaker plate and they will trap the ball bearings. I think it's a good idea, even if I'd just JB weld the breaker plate and run without vacuum advance.

Sway bar preload eliminated?

5 lbs lighter each as I recall. Panasport = HEAVY.

P30 denotes a 30mm piston. I just bought the 30mm piston VW GTi struts mentioned in the Hybrid Z thread last year and had them revalved. So yes, parts are available and never should have been unavailable.

More than you ever wanted to know about Bilsteins: http://forums.hybridz.org/showthread.php?t=138601 http://farnorthracing.com/autocross_secrets6.html I'd run em. As Carl says they can be rebuilt by Bilstein if necessary, but it might not be. if you push them through their full stroke a couple times then you can feel for dead spots where there is no damping. If there are any, send them back to Bilstein. If not, run them as is. Not sure what the valving is on the old units designed for the 240z. Not sure if there are any mods necessary to run them with stock isolators. I think you'll have to open up the hole in the middle, and I'm pretty sure you'll have to use an impact to tighten the nuts on top down since there will be no D shaped cutout left there. No biggee, and I think those are well worth the effort to use. Bilsteins kick arse.

Thanks for the correction. I'm obviously not a muscle car guy...

How differentials work: http://auto.howstuffworks.com/differential2.htm Yours is an open differential, unless you've put a limited slip in there. Both axles are engaged all the time. The reason you thought they weren't is because solid axle cars load the right tire with the torque from the engine, so they tend to spin the left. IRS cars like the Z don't do that, so if you take off in a straight line you'll likely spin both. If you get into a corner and punch the gas you'll likely spin the inside. A limited slip will fix that inside spin. All of this has nothing to do with your vibration. Not sure what your vibration is from, but it is doubtful that it has anything to do with the gears in the diff. I'd suspect a U-joint somewhere, maybe on the left side if you haven't changed those yet.

The ZX distributor might be marginally more reliable because of it's stator and reluctor design where the stator and reluctor cannot change their distance from each other (unless the vacuum advance mechanism breaks), vs the Z distributor has a pickup which can move out of alignment and cause trouble and has a specified gap to be set. I've seen this gap cause problems on a friend's 510 with the 4 cylinder version of this distributor--pickup moved into the reluctor and the car died at an autocross. It took a while for my friend to figure out the problem, but the gap between the reluctor and sensor was fixed and it fired right back up and ran for the rest of the day. Soon after a DIS crankfire ignition was installed. The big difference is the amount of advance built into the distributors. I don't have the specs handy on the 260Z distributor, but I think I'm right in saying that it has something like 22+ degrees of mechanical advance built in. That's a lot. More on why you want less and how vacuum advance plays a roll here: http://www.classiczcars.com/forums/showthread.php?t=34073

I know the original thread is old, but I would suggest using the diagram on p11 of the instructions, using the two wires connected to the pickup coil in the distributor and connecting them to the violet/green wire pigtail coming off the MSD. This enables you to get rid of the E12-80 module which is one more source of potential failure. As far as what to get, I'd go with any NA 280ZX distributor, disable the vacuum advance so that it can't move at all, run the MSD as described and set timing at idle to around 18 degrees BTDC.

Because when the vacuum advance works, that's what you want. You'll have high vacuum just off idle where the port vacuum works, so you'll be probably somewhere near 20 degrees, and you'll have quite a bit of advance while driving in town. You'll have buttloads of advance when you're cruising on the freeway where you have high vacuum and you're over 2800 rpm; might be well into the 40s. And that's the point. That should be OK since the load is relatively low, and when the load increases the vacuum decreases so you get less total advance. Vacuum advance is all about trying to absolutely maximize advance to get a little better mileage. There are two reasons I don't like it. 1. They usually don't work right or are outright broken. 2. If you're on the freeway and need to pass someone so you downshift and punch it, you've now just eliminated (or nearly eliminated) vacuum advance, so your back to your base timing of 7 degrees plus the 17 from the distributor, so you have 24 total, which is NOT ENOUGH FOR PEAK HP. If you set the distributor to get 35 total without it, then the vacuum advance will add way too much advance at low load cruise. It might be possible to tweak it so that it only adds 5 degrees of advance or something, but that's a lot of work for very little gain in my opinion.

Paul, your vacuum advance isn't working. Don't know much about how to fix, because I always take the vacuum advance apart and lock them down so they can't move as a matter of course. Just for laughs, try keeping the vacuum advance disconnected and setting the timing at ~18 degrees BTDC and see how that feels. That's the way I ran mine. I think you'll see a nice improvement. 8.5 is 17 at the crank. The mechanical advance should be in by 2800 rpm. Vacuum advance can work at any rpm, so long as there is vacuum. If you want to measure total advance at x rpm, you should be measuring without the vacuum advance connected. If your mechanical advance is still working up to 4000 rpm, I'd say you probably need to clean up the mechanism and relube it.

Has anyone here ever bothered to figure out how much tension 240Z springs are under? I used to just point the strut away from me and hit the nut on top with an impact. I've never used a spring compressor on a Z. On other cars the springs can be under an extremely large load, but Z's have such weak springs to start, and then stock springs are usually sagged out anyway... Of course I'm not recommending that YOU try it that way.

In fact, 1982 FSM p EL-34 shows: (that's distributor rpm, double for crank rpm) 17 degrees all in at 2800 is a good amount at a good rpm. I'd say it's about perfect.

I used to have a chart of the different applications and their advance curves based on the distributor model number, but I can't seem to find it anymore. Regardless, I think you're mixing up 280Z and ZX distributors, or some other L series distributor. There are a TON of different mech advance units out there. The 280ZX distributors only have the two options, and as I recall the automatics had the one with more advance. I'm pretty dang sure I'm right on this one...

Disconnecting and disabling the vacuum advance entirely will let it run on just mechanical advance. The different T bars are for 17 and 18 degrees, so if you start with an advance of about 18 that puts you square in the mid 30's at total advance. That is JUST MECHANICAL ADVANCE. The vacuum advance is IN ADDITION TO the mechanical. I know a lot of people think that this hurts mileage or that it makes the car hard to drive at part throttle, that was not my experience. I got pretty good mileage, even with triple carbs I was pulling down low mid 20s on the highway. With SU's I once got over 30 mpg going to the track which was a long drive and I was hauling 4 tires, tools, etc, so basically it was probably like having a passenger along. This was with a .490/280 cam, MSA header and 2.5" exhaust and MSD. Another safe bet on the ZX distributor is that if you have one and it hasn't been rebuilt there is a very high likelihood that the vacuum advance mechanism is busted. I've only seen one that wasn't. Rebuild tips: http://www.jrdemers.com/280ZX/distributor/distributor.html I'd rather have a ZX distributor with the vacuum advance disabled than a 240Z distributor with pertronix or points. YMMV.

You do. You really do... ;-)