jmortensen

Again I would suggest a leak down test. Pay a shop if you don't have the tester. It's well worth KNOWING that you need rings rather than trying to use the numbers from a compression gauge, especially if you don't have one cylinder that is way down from the rest. The mileage issue is a not necessarily a function of bad rings, it could be a problem with the carburetors, bad tune, ignition timing, etc. Doing the leakdown test will tell you what is going on with the engine's ability to pump air efficiently. You can worry about the mileage after you get the engine mechanicals sorted. http://www.carcraft.com/techarticles/116_0406_cylinder_leakdown_tester/index.html

Could also be a 200SX trans IIRC. Don't they have 1st gear down and to the left?

Retarding the cam timing makes more top end power and will show lower compression numbers most of the time. Advancing it makes more low end power, less high end, and shows higher compression numbers. Also compression gauges are really not that accurate and generally shouldn't be used against one another. A leakdown tester is a much better test of the engine. Just FYI. If you put oil in the cylinders and the compression jumped, then rings is your culprit. The best test is a leakdown test, but with the jump you can pretty much assume that if it jumps 15 psi with the oil, there is something going on there. Nissan bottom ends are pretty strong, so you could probably get away with new rings and honing the block if there is nothing really obviously wrong. As to how much benefit that gets you, it's tough to say. You've got it right. Cam tower shims usually come in .015" heights, and you add them underneath the towers to restore the distance between the cam and crank sprockets. An adjustable timing gear would allow you to fix the cam timing but wouldn't fix the loose chain issue. If the head really had "a couple thou" taken off, it probably doesn't matter, but if they had to take more than .015" I'd say get the cam tower shims because the loose chains tend to make noise. Cutting the head .015" actually adds .030" slack to the chain, because you lose length on both sides of the pulley. This makes the effect on timing more drastic and also the effect on slack in the chain more drastic. I don't know if by adding one shim you would need to look at the lash pads, but keep in mind when you start changing things in the valvetrain you are potentially messing with the geometry there and it doesn't take too much to throw everything off kilter and then you start having problems that are more difficult to fix. The other option is to get a Kameari chain tensioner and an adjustable cam gear. With these two you can cut the head a good amount, take up the slack in the chain with the new tensioner, and correct the cam timing with the gear. That's probably $800 in parts, but it is a SWEET setup in that it allows a lot of flexibility. You could mill the crap out of the head to change the compression ratio, slap it back on and adjust the cam timing with the gear and take the slop out with the tensioner and you're good to go. http://www.zccjdm.com/catalog.php?ref=azcarbum&recview=11&dt=43033&disp=name

That's a pretty wide open course. Looks like a great one for a Z. I bet the FWD guys are pissed! Hehehe...

I never tried that guy's suggestion of going to the shorter manifold, and it never made sense to me why that would help. My understanding of what is going on is that when the throttle is snapped open you have a loss of velocity in the runner. If you use a smaller choke, the velocity is higher, so that minimizes the problems. If you use a shorter manifold of similar runner diameter I don't think the velocity issue changes too much, but like I said I never tried it. On the issue with the pumps, I have convinced myself of the following (not saying I'm right, there are many different opinions on this stuff): 1. The pilot affects a lot more than the manual says it does. It will be contributing to the overall mix pretty high up in the rpm range, 4-5000 rpm easy. I like the "How to Modify" suggestion of 1.5 turns out on the pilot screws. If you need more, get a bigger pilot, less get a smaller one. 2. The pumps squirt a big pee stream of gas into the runner. Take the carbs off the car and open the throttle and you'll see what I mean. If there is little velocity, that pee stream of gas isn't going to atomize as well and that is where I believe the stumble comes from. 3. A richer pilot will help to fill the gap that the pumps don't fill well. 4. If you could get different jet blocks, that would be the way to solve the problem. I was planning on trying some of the OB or 8 blocks to see if they helped but never got around to it. Webers have tons of different emulsion tubes to choose from, Mikuni owners don't. Is it possible that a longer stroke could help? Sure, if I'm wrong about the velocity in the runners thing or if it could be thin enough to atomize properly and fix the lack of fuel in that one rpm range. Here's a post from another forum about getting the mains to come in earlier. Looks like that's a function of the emulsion tubes, so at least according to this forum I may have been onto something with the jet block thing. It does seem like getting the mains to come on earlier would negate the need for a larger pilot. The fat pilot is definitely a crutch: http://www.innovatemotorsports.com/forums/showthread.php?t=2309 Play with the pilots and I think you'll find that I'm right that they do a lot more than what the manual says. I was tipped off to that fact by Dennis Hale and I found him to be correct on that one when I played around with it. YMMV. I used a narrow band with a $6 Harbor Freight voltmeter and shot for .8V at WOT. I had it set up on the console and used it constantly. The refresh rate is a problem, but I couldn't find an analog gauge for 0-1 volt. I've had several friends buy the Autometer gauge and need to replace the crap O2 sensor that comes with it immediately. The gauge would just be full rich or full lean, no middle ground at all. I used a Bosch one wire for a 90's Chevy on my car, but friends have used the heated O2 as well with the gauge with good results. The gauge (with Bosch sensor) was given the seal of approval by a friend who had his car on a dyno with a wideband in the tailpipe. His story was that the dyno operator was laughing about what a POS the gauge was until he saw for himself that it was right on with what the wideband showed. Interesting. It was a long time ago, probably coming on 10 years, so I could just be remembering his advice incorrectly. I'm sorry he's not around to ask. I know I was told to go from 34's to 37 choke tubes and I tried the larger pump nozzles and then was told to go back down on those. It ran great at higher rpms but had the stumble so the next thing I was going to try was smaller chokes to fix the stumble, but I was autoxing so the stumble was more of a problem than the hit to the top end would be. I had reduced the stumble A LOT from when I started. I'd say it was probably 85% fixed compared to day one.

It should do fine even on a normal bottom end and I daily drove my car with a similar cam for years, but yes, a stroker makes it even better. Here is a video of my 8.5:1 engine with brand new Mikunis (read: not tuned) and a very similar cam. http://videos.streetfire.net/video/2000-autox-indisde-and-outside-I-think-my_8051.htm

The back side bushing does nothing but allow the front side to move. The front is the part that takes the load when you go over bumps or step on the brakes. Rubber in the back is a good idea. With poly you can also run the rubber in the back and cut down the stress on the rod.

They usually fail right at the step where the rod is machined down for the bushings from what I've seen. It's a square step, a perfect stress riser. The rods are close enough to 5/8" that you can run a 5/8" die down one, and they're failing in bending where the stress riser is, not in tension as the stats you're referencing are given. I agree with you about the suspension travel. The stiffer the better in this situation, as less travel means less movement on the rod.

We're starting to hijack this thread, but adjustable front control arms is a tough way to adjust camber. If you only want to set it once, that's great and it's probably all you need, but if you want to go to an autox and change it and then change it back after, camber plates are much better. The problem is when you change the camber with the front control arm the toe changes. Jeff was asking how much change he could make to the length of the control arm before the tie rod was too short. That's a really good question and I think it's pretty likely that you can adjust TTT's LCA farther than you can SAFELY adjust the tie rod to match it. It might be a good idea to mark the inner, remove it, measure how much thread you have to play with, and then adjust the LCA accordingly. I think their rear control arm design is particularly bad. No triangulation, the outer part is a flat plate, the thing looks built to flex. I much prefer the A arm with a toe link to any attempt to make a different H arm to replace the stock unit. At first glance the TTT front control arm looks pretty good.

Think he's still looking? It's only been 5 years...

The rule of thumb is 1.5x the thread diameter should be engaged. I think the prudent thing to do is to check and see where you're at, but I would guess that 6mm shouldn't be a problem. When I raised mine I just slotted the hole and then measured with a bump steer gauge as I kept moving the pivots up until I had minimized the bump steer. I think I ended up about 1/2" higher than stock. I know JTR has their 3/4" up recommendation and others say 13/16", but measuring is really the way to dial it in and I came in well under the usual recommendations.

Did you read any of the stuff about poly bushings snapping the TC rod? The reason you had to take the rod off and not tighten the rear nut is because doing so would flex the bushings. Every time the suspension goes up and down it is now forced to flex those bushings, putting a good amount of side load on the TC rod at the end where that turned shoulder is.

I don't see the difference really. If you think of the front as essentially an A arm with the control arm and TC combo, they're pretty similar. I was also running on big slick tires, so putting more lateral load on the control arm than most would, easily over 1g. Plus there hasn't been a single person on Hybrid Z stating that their toe adjuster moved, and their slots were horizontal at the bottom, not vertical, which one would think would be more likely to move. The paint is not a bad idea, I'm just saying that I think the parts are not likely to move in my estimation.

Congrats on getting it so dialed in side to side. That worked out really well. FWIW I doubt you'll have trouble with the slotted parts moving. Just keep the bolts torqued. I slotted my front crossmember to adjust bumpsteer, set it and then drove my car daily and autoxed every month and did some track days and it never budged one bit, and the control arm only has one bolt.

In general terms I think you want to do less with the pumps and more with the pilots. I tried changing the lever and running huge pump nozzles to fix a stumble at about 2500 rpm and it just got worse. What made it better was running larger pilots, and after talking to Rebello and Malvern and Wolf Creek Racing I was left with the notion that the pump nozzles should be 40's and the stumble should be overcome with pilots or smaller chokes. I never measured or checked the throw on my pumps so I can't speak to the measurement question directly, although I did change the diaphragms thinking that was the cause of the stumble, to no avail.

Medium sized cams are nice for a hot street engine. You'll lose a little bit of low end but pick up a lot on top. Mild cams are nicer for daily drivers, more torque at low rpms but don't quite have the punch up top. "Big" cams are more for race only engines and have the added issues of increasing wear and requiring a lot more compression to make them work properly.

Suggestion--pick up a race car instead of modifying your car. Get an old ITS or better yet a GT2 car. Even if you just get a rolling chassis it will be well worth it. You'll get a cage, a fuel cell, probably a fire system, and a chassis that you don't have to be afraid to weld to or do what you have to do to pass the safety inspection.

I ran the GR2's in my first Z with cut stock springs for quite a while until I was rear ended and pushed into head on traffic. That was the end of that Z, but the struts never had a problem. I don't know what "extra work" the struts would incur by being in a different part of the travel. It's still a piston with a stack of shims being pushed through oil. The oil squeezes past the shims, and that's where the damping comes from. This is the same at the top of the travel as it is at the bottom. The thing to look out for is bottoming the struts without bumpstops. If you have bumpstops in place, there really shouldn't be anything wrong with running them in any part of the travel.

Motorsport sells the Schneider cams and their stage IV looks similar, but it doesn't have to be a Schneider. Layman's terms: It is a medium sized cam.

Really sounds like reaction disk based on that description. Could it be where the disk sits is somehow screwed up and not sealing? I'd try another booster if messing with the disk doesn't have any effect.

I have actually tried the zerks in the outer rear control arms. The bushings there are two parts and I put the zerk in between the two halves, so the grease did go all the way around the bushing. When I put my grease gun on it you could see grease coming out on both sides between the sleeve and the bushing in the center, right where you want it. I also had good luck on the sway bar bushings, even though they are one piece and I didn't provide a channel for the grease to move around the whole bar. Where it didn't work was on the inner rear control arm bushings. Those bushing caps are not sealed all the way around, so the grease just leaked out the corner. I think they would work for the front control arms too, but haven't tried as I have rod ends there so no need. I never actually ran the arms, I ended up cutting them up and modifying them for rod ends too, but I can say for sure that the grease on my arms came out in the right spot when I hit it with a grease gun, and you could feel the difference in greased vs non-greased bushings. I also called Energy Suspension and they said regular old moly chassis grease is fine, as are synthetics. If you wanted I think it would be pretty easy to put a groove in the bushing for grease. Haven't tried it, just thinking out loud, but a soldering iron might do the trick.

When I said "Poly is well known for squeaking" that meant Poly-urethane. So yes, lots of people have had problems with polyurethane bushings squeaking.

They look good to me. Only question I have after seeing them is: will the bottom of the arched part of the upright hit the link preventing you from using all of the adjustment in the slot?

I would suggest installing zerk fittings and drilling corresponding holes in the bushings so that you can lube them after install in as many places as possible. I know the front sway bar would work, think the front control arm might as well. Poly is well known for squeaking. I would suspect the swaybar bushings as the culprit for the noise you have now.

Sure thing, this is one of my favorite topics of conversation about Zs, though I have to say I'm still thinking about what you're going to do and not understanding how it will work. You still can't change location at the front of the control arm. So I'm thinking that changing the height of the back only would allow you a little adjustment of pro or anti-squat. I think you would get pro-squat by raising the rear link. I think anti-squat could be had by lowering the rear control arm attachment points. The camber will be affected by changing the angle of the control arm, but very minimally. I'd suggest camber bushings if you want to adjust camber and don't want camber plates. Just by way of comparison, the camber bushings have about 5/8" of movement front and back if memory serves, and they adjust camber by about a degree. I don't think you'll be able to move the control arm nearly as much by changing just one end which is why I think your adjustability will be minimal. Changing the height of the control arm on the back end will also introduce a twist into the arm, which is a bad thing. The stock arms are flexible enough that this probably won't be too much of an issue for you, but strictly speaking it's not the best idea. More on binding control arms and solutions to that problem: http://forums.hybridz.org/showthread.php?t=129154