Mike

Shortening Struts Submitted by, John Coffey Moss Micro, Inc. jcoffey@mossmicro.com http://www.mossmicro.com As a result of my parts for sale post I've received a few questions about shortening struts. The best description of he "why's and how's" was sent to me back in 1996 by Wayne Burstein: ---------------------------------------- Let's start by defining the task at hand. We want to lower the car in order to lower the center of gravity. I'll skip all the analysis on why we want to do this because there are lots of good books on the subject, and confine my comments to what you might run into in performing this on a Z. First I need to define a couple of terms: Bump -- suspension travel in the compression direction (i.e. the result of hitting a high spot in the road). Rebound -- suspension travel in the opposite direction (i.e. the result of going over a hill and the wheels leaving the ground). The first problem we run into is that when we shorten the springs, we are reducing the available bump travel in the strut cartridges by the same amount we lowered the car. With all the travel available in a stock Z, this is not too much of an issue when we lower the car only an inch or so. For those of us who are racing our cars, we often lower them much more; for instance, in the SCCA's IT class, we are allowed to lower the car until the rockers are no lower than 5" above the ground. This causes a problem because the suspension is almost fully compressed when the car is sitting at rest. When you hit a bump, the suspension quickly bottoms out (hopefully on a bump stop of resilient material). This is a real problem because in effect, the spring rate increases very dramatically and negates all of our efforts to drive the car smoothly. When driving at or near the limit, this often is the beginning of a very impressive crash. Well, we now have the car at the desired ride height, but need to increase the travel in bump. The way to do that is to shorten the struts. Now things get pretty messy. This is dependent on the length of the struts but the struts need to be long enough to insert the cartridges of choice. For racing, the ones that I would recommend are Carerra, Koni, or Tokico, in that order ( this should cause a bit of discussion on its own). If we automatically shorten the strut to exactly fit the cartridge, we might actually shorten it too much. This leaves us without adequate rebound travel. Just in case this does not scare you, it should. I learned my lesson the hard way when I had the rear wheels pick off the ground while cresting a hill that had a slight turn to it. That made for a looooong full lock slide at 100 MPH! Ok, now we need to decide just how much we want to shorten the strut housing. The desired end result is to have about equal bump and rebound travel. In other words, when the car is sitting at rest, we want the struts half way compressed. On a street car, this is fairly easy to do, because we generally set the car up once and never play with it. Race cars are another situation entirely. First of all, different tires require different ride heights -- for instance, switching from 60 series to 50 series tires lowered my car by .75", causing me to have to raise the car by the same amount. We also play with spring rates, and assuming that we are using coil overs, need to keep the spring collar low enough on the strut housing to avoid it interfering with suspension travel. The bottom line is that before cutting anything off your struts, you should carefully think about what you anticipate doing to the car over the next few years as far as tire/wheel, strut, spring or ride height changes, and then come up with a compromise that works for you. FWIW, most people shorten struts 1-2". If you figure out that you want to go more than this, recheck everything before cutting. Yes, you can add a section, but speaking from experience, it is much easier to remove than to add. I almost forgot to mention this, but if your strut housing is longer than the cartridge, you need to put a spacer below the cartridge inside the housing -- typically, these are just pieces of tubing that is slightly smaller in diameter than the inside dimension of the housing. Just a couple of tips to consider: 1) The best way I have figured out to cut the struts is to use a large pipe cutter. This gives a fairly straight cut with minimal cleanup -- you need to grind the burr off the inside of the housing and bevel the outside edge before welding them together. Be careful not to make the cut so high on the strut that you hit the threads for the gland nut! 2) To remove the original spring perch, the quickest way I have found is to cut through it just above the housing with a grinder or cut-off tool, and then grind the remaining metal off. I found it much easier to do this before cutting the strut because even though I was not cutting the section with the perch off, it did interfere with the cutter. 3) After lowering the car, you need to align the suspension because you have added negative camber at both the front and rear wheels. Of course, you should probably do this any time you remove suspension components anyway. Finally, Carerra was of invaluable help to me in figuring out what to do and how to accomplish these modifications, as well as supplying many of the parts I used. You can reach them at: 770-451-8811 Sorry to be so long winded, but this is a fairly complicated task to plan and implement without too much trial and error.

Continued Article -- by John Coffey > For those that are interested, here's the answer: > > Car 1 was the fastest with a time of 60.322 when driven by the driving > instructor! > > But, Car 3 was second with a time of 60.389 and Car 2 was third with a > time of 60.411 with the same guy driving them! Even in autocross > those time differences are fairly small. The person who drove all > three cars owns Car 2 so we can assume he got everything out of that > car that he could. I own Car 1 and my best time of the day was a > 61.312. I also drove Car 2 and my best time in that car was a 63.4xx. > The owner of Car 3 had a best time of 59.7xx and he was the fastest of > all the Z drivers. He didn't drive any of the other cars and was > stuck in the 60.5xx range until he made a heroic last run of the day. > > What were the guesses from the two lists: > > Car 1 - 5 people > Car 2 - 2 people > Car 3 - No guesses > > Sorry, no prizes for the correct guesses. > > What do we learn from this? Probably that there is no one correct way > to setup a suspension for autocross. A good driver can adapt to the > capabilities and foibles of any car and quickly get the most out of > it. There might be more ultimate potential in any one particular car, > but it takes some time and practice to wring it out. > > Thanks for playing. We have some lovely parting gifts at the door...

3-Car Comparison Submitted by John Coffey > I was at a 2 day autocross driving school over the weekend and I had > chance to ride in and drive a number of Solo street prepared 240Zs. > What surprised me was how each one drove differently based on how the > owners had the cars setup. Here's what I observed: > > Car 1 > Springs: High rate springs, 25lb difference between front and rear > with the rears stiffer. > Shocks: Tokico Illumina 5 way, set for stiffer rear compression. > Sway bars: Low rate both front and rear. > Tires: 225/50-15 Yoko RS2s. > Differential: LSD with very high breakaway torque. > > Car 2 > Springs: Low rate springs, 100lb difference between front and rear > with fronts stiffer. > Shocks: Tokico Illumina 5 way, set for stiffer front compression. > Sway bars: High rate both front and rear. > Tires: 225/50-15 Yoko RS2s > Differential: LSD with very low breakaway torque. > > Car 3 > Springs: High rate springs, 75lb difference between front and rear > with the rears stiffer. > Shocks: Tokico Illumina 5 way, set for stiffer rear compression. > Sway bars: Medium rate both front and rear. > Tires: 225/50-15 Yoko RS2s > Differential: Open. > > Car 1 was very balanced while under power and could be easily steered > with the throttle. Very responsive to throttle inputs up to a point, > too much throttle for too long would induce a spin. It did not like > trail braking into a corner (the way Bondurant teaches it) and would > respond with lots of understeer. Turning and braking would also > induce a lot of understeer. Corner entrances would either be perfect > or completely screwed up. The understeer could be fixed with a quick > blip of the throttle and (rarely) with the brakes. Corner exits were > the fastest of the 3 cars (if you did the entrance right) because you > could get the power down early. This car wanted to be driven with the > throttle. > > Car 2 was also very balanced while under power but was more difficult > to steer with the throttle. Preferred to be steered with the brakes. > It liked trail braking into a corner which was the most effective way > to get the back end around. Understeer was prevalent but could easily > be fixed with the brakes or a lot of throttle. Easy to get a good > corner entrance. Corner exits were fast but had to be controlled a > bit with the brake and throttle at the same time. Not too responsive > to the throttle, you had to put your foot into it to get a reaction. > This car seemed to have the typical 240Z handling traits. Overall > balance but you needed to left foot brake to control the understeer. > > Car 3 was biased more towards oversteer especially under power in a > corner. Responsive to gentle throttle inputs but with the open rear > if you went to far, you were gone. Car had a razor edge between power > oversteer and spinning. Understeer was common but could be controlled > with trail braking or throttle. Car was responsive to trail braking > but less so than Car 2. Corner entrances were fast and the car could > be balanced through he corner pretty well. Corner exits were almost > as fast as the other two cars but it was a result of carrying more > speed through the corner. You had to wait a bit before putting the > power down. > > Now... the question is, which of these cars had the fastest time of > the day with the same driver? Let's hear the pundit's guesses... > Next post has the answer........

This plate is located at the bottom of the hatch. It is part of the car and is spot welded to the tail-light panel. It's flat and has a hole in it to allow the hatch to lock into the frame. My panel was rusted underneath. I had to replace it. Upon shopping every resource I could find..... I found out that Nissan re-released this part just for this reason. Here is the part number: Part Number = 999M1 - M0000 Your local Nissan dealer will sell this to you for around $100.00, but, Courtesy Nissan has this panel for around $75.00. Courtesy Nissan will give all 240z-club members a 25% discount!! This is VERY good information to have on hand. Also keep in mind that Courtesy Nissan will charge you shipping. But, they usually have the part *ON HAND* whilst most Nissan dealers must order it (which takes a week).

Original post by: Andrew Levy Many of us have heard the down side of these modules as being limited to 5000 rpm on an 8 cylinder eng. Actually these modules are not limited by the operating frequency but rather the original coils were the limiting factor. The original coils where mounted in the top of the distributor cap, where the temperature is quite high. Also as the frequency increases the amount of time for the primary winding to cool decreases, so the effect is as the temp of the coil rises so does the resistance in the coil, which decreases the output. This is why MSD claims that if you replace the coil in the cap with there Blaster coil it will increase the max rpm to 6000. This setup with a MSD blaster coil can work to 7500 rpm on a six cylinder engine. --------------- / \ / \ W\ ------------- /C G\/ \/B W= positive lead from the pickup C= negative side of the coil G= negative lead from the pickup B= positive side of the coil First, mount the mod to a piece of aluminum .060in - .125in thick. Make sure that you use the silicone grease that comes with the mod. I typically mount the mod to the bottom coil bracket bolt. The following wiring directions are for 240 z models. There are two black with white tracer wires. For convenience, I connect the short one to the + side of the coil. Now connect the longer black and white wire with the green and white wire to the mods terminal B. Then a wire is connected from the coils negative terminal to modules C terminal. Here are some tips for swapping the distributors. Before you remove the old dist turn the engine to 10 degrees before TDC, make sure it is on the compression stroke by observing the direction of the rotor, it should be pointing at the number one spark plug lead. When installing the new dist, turn the dist body so that the #1 spark plug lead is lined up with the rotor. In both cases you may want to mark the distributor bodies with the location of the number one spark lead, so that you don't have to keep installing the cap to check for its location. If this is done the timing should be set at approximately at 10 degrees BTDC, which should allow the engine to be started so a timing light can be used. ------------------------------- Here are the details on the HEI ignition system that I'm running. About three years ago I built a L28 for a friends 70. I intially set it up with a MSD 6A and a 76 dist. After a month or so the MSD failed. So in order to get the Z on the road again I went down to the local autoparts store and got an HEI module, it cost about $25 dollars. Went back to the hooked it up and realized that it worked every bit as good as the MSD. I have used HEI mods. in many applications before, but never compared them to other electronic ignitions. Here are some benefits to this system. First, the stock tachometer will work with out any extra devices. Second, they are sold everywhere and only cost $20 - $30 dollars. Third, they seem to be more reliable than the aftermarket ignitions. The installation is quite easy and should cost less then $100 dollars complete. The parts needed are a magnetic pickup \ reluctor type of distributor, and a four pin HEI module (Standard ignition pn # LX-101) or equivalent, no ballest resistor is needed. First you need to determin the polarity of the wires going to the distributors pickup. Some have a red and a green wire, the red is the positive. If you have one with two green wires or you can't tell what color they are you will need to test them. This can be done by rotating the dist. shaft the same direction as it would be turned by the engine and use a volt meter to establish the polarity. This system generaters AC current so look for a positive reading when the raised portion is approaching the pick up and negative when it departs. You could try to establish the polarity by starting the engine and use a timinglight to check each combination, the one that gives you the most retarded timing should be correct. Below is a drawing of a average HEI module, the letters refer to the pins. I mounted the HEI mod. on a piece of aluminum , sheet .o6o" thick which bolts to the fender via. the bottom coil bracket bolt. Remove the factory ballest res. and locate the two black-white wires, short and long and the green-white wire. The longer black-white wire will connect to the positive side of the coil. The short black-white wire will be connected to the green-white wire. A piece of 14-16 gauge wire will need to be run from the positive side of the coil to pin B on the module. Another piece of wire will need to be run from the coils negative to pin C on the module. The positive wire from the distributors pickup connects to pin W and the neg. from the dists. pu. connects to pin G. I connected a ground wire from a dist. hold down bolt to the HEI bracket. Make sure you use the silicone sealer that comes with the module between the bracket and the mod. If the the module is not grounded well it will fail. /-------------------\ HEI module -> / \ / W C \ /\ G / - - - - - - \ B /\ dist. + /\/ \ /\ - batt. - + This setup will not work with all coils. It works best with a MSD blaster coil. You can mail order these coils from Summit and Jegs for about $25. I have gotten distributors from wrecking yards for $25-$40 dollars. The distributors where used in datsun 810's and Zs. These dist. are very reliable electrically, but not so mechanically. There is a plastic cage that holds three, 3mm ball bearings half of the time it is broken or the balls have pitted the the thin spring steel races. This only effects the operation of the vaccum advance. I don't run vac. adv. with S.U. carbs. So in this case you could solve this problem with epoxy. Another solution is to replace the bearing and cage with bushings made of brass bronze or teflon PTFE. I have also modified these dist. to use torrington bearings.

If you are searching for our Zcar CD support forums, click back and then find our dedicated section for the CD.

No 5-speed. I bought another 4-speed out of a Datsun truck. It had a little different gearing and operated a little lower. But, I plan on adding a 5-speed to it when the time comes. And, of course if I have money. It's still a long road ahead. [m]

I also tried this back in 1989. I cut the tunnel sheet metal and bent it back. Not a very nice job, but it did the trick. I also used contact cement to adhere a larger-flange rubber booty. This eliminated most of the road (and engine) noise. The stickshift also liked to pop out of first gear because it was rubbing against the plastic console. This was fixed by using channel-locks and a little muscle (snap). Again, not the best way to do it, but it worked. This whole thing is gone and the stock opening is in place. Since I am restoring this baby, I'll probably need to do something similar to your idea. Keep us posted! I'm sure I can use the information when I get to that point. [m]

I am unfamiliar with the flattops. I have the rounttop SU's. But, the mixture settings are controlled on my rounttops from the bottom. The mixture nuts are difficult to get to, but they are located where the small fuel tube enters the bottom of the carburetor. If you are looking up at the bottom of the carburetor screw... Tightening (righty-tighty -- lefty-loosen rule applies) it will send LESS fuel to the carb. I'm assuming you probably know that. But, hopefully my information about the location of the fuel mixture is correct. The adjustment screws on the top of the carbs control the airflow (balance and volume). [m] [This message has been edited by Mike (edited 02-28-2000).]

James, This question is more suitable for the Z-Car Operations area of the forums. I have moved it to that location. It's inside the Carburetion forum. [m]

This was posted to our old tips forum by Trevor: I chased gas fumes on my Z for quite awhile. When I had it all apart a year ago I replaced all the fuel vent hoses with the genuine Nissan ones and I kept getting fuel smell. Part of it was a leaking seal around the fuel level sender which I replaced several times and the last time I noticed that the tank built up pressure inside awfully fast while I was resealing it. I had never noticed any pressure build up when removing the gas cap though. I checked the valve in the engine compartment where the vent line hooks up. And although it wasn't hooked up exactly right, it basically hooked up to the air cleaner and the intake to vent the fumes it was also mostly plugged so the pressure was finding other places to escape like through the seal and around hose connections. Got the valve degummed and now I don't have the fumes or leaking problems anymore. -Trevor

Found out that Nissan does NOT make gas tanks for the early Z-cars anymore. On discussion with some of the restoration specialists at the Z-Store, I found out a way to make my existing gas tank like new. It's a four step process: Boil the tank. Have it cleaned up inside and out. You can take it down to your local engine or radiator specialist to get this done. They will hot or cold dip it in acid to eat off all of the grime. Sandblast the tank. This can be done by the powder-coat specialist. Or, feel free to do it yourself if you have a sandblasting attachment for your air-equipment. Powder-coat the outside. Take the tank to your local (or maybe not so local) powder-coating specialist. Have them powder-coat the entire tank (outside only) in your favorite color. Also be sure to tell them that the thank has been dipped and stripped. Since the powder-coating process involves baking in an oven, some specialists get nervous about gas tanks. Gee, I wonder why?!!? :-) Seal the inside. Take the tank back to the radiator shop and have them seal the tank internally. This *MUST* be done after the powder-coat process. Since powder-coating involves high heat, a pre-sealed tank will be ruined from the heat. I guess the sealant bubbles on the inside. Now, I'm not sure if you can seal the outside of the tank after the powder coating has been applied or not. I wouldn't think it will hurt the powder coating to do this. Anyway, thanks to the anonymous donor for this information. I would publish the donors name, but, he probably doesn't want everyone calling him. I also saw a very nice article in the Z-Car Magazine about how to do this step by step. Check out their web site and get your own subscription for these kinds of tips. You can also order back-copies.

This is a link to Kyle's site: http://www.sonic.net/~kyle/su.html

You can read this, or visit the web page that I created at: http://scarab.240z.org/tips/tips_rack.htm The steering rack & pinion assembly unit is a pretty basic little setup. It consists of a small gear pushing a large bar left to right. The ends of the large bar are connected to your front wheels. This turning motion make the car turn left to right. Pretty simple explanation, eh? Well, that's how it works. Basics, get back to basics. If you figure this out, you'll be in for a nice life. Anyway, I wanted to share my experiences while looking at this little beauty. Why can't everyone benefit from my experience? It's also a nice way for me to look back at all the work I've done and say, "Whew! It's done!" The entire rack assembly mounts to the front mount bar. This is the same bar that the engine sits on top of. Therefore, engine removal is desirable, but, not required. Of course, I have all the correct tools to remove my engine in a few hours while the standard garage mechanic may not have this luxury. Well, I may not consider it a luxury. Anyway............. my apologies if some of this may be out of your field. The information isn't intended to be easy to perform. I did not perform a total rebuild on my rack assembly. I decided to cut it short of removing the gear mechanisms and tie rod knuckles. These suckers are $800 to rebuild for a reason! I cleaned the entire unit and tore just about everything else out of it. Okay, here we go. The parts that I used are: New steering rack boots. New polyurethane rack bushing mounts. New steering rack oil seal. Grease. New grease reservoir (from Nissan). With all of these parts in hand, and a previously removed steering rack assembly, I began my journey. Remove the old bushings. Use a screwdriver, knife, or whatever tool you need to pry the old bushings from the rack. Remove the old rack boots. You can probably do this with a knife or some scissors. Use a rag to clean up as much grease as you can. Clean up the outside of the rack assembly with a good degreaser. Remember, there is probably 20 years of grime on that thing! Just be careful not to get any chemicals into the rack internal components. Use a screwdriver and pry off the oil seal around the turning gear mount. This is the mount that the steering wheel arm connects to. Use extreme care not to bend the top of the seal. You might want to re-use it depending on its condition. Use a rag and clean out all of the grease you can inside the bearing housing. Now, take a some large pliers and loosen the locking nut (the large one) that sits around the slotted tension adjuster. Remove the locking nut. Remove the tension adjuster. SLOWLY remove the tension piston. Clean up the inside chamber and the piston workings. Be sure to keep the spring and washer positions noted. You can do this by just stacking them off to the side. You should be able to see the end of the zirk fitting and the bottom side of the rack inside the gear housing now. Clean it all up. Try to get a lot of the old grease out of there. Now take your grease gun and squirt some grease into the housing through the zirk. You should see the grease pumping in through the fitting. Be sure to fill the gear housing full of grease before you start the next step. Replace the tension piston by covering it with grease before you slide it into place. Make sure you put it all back together the way you found it. :-)

Please bear with me while I complete this page during my rear-suspension rebuild. It's not complete, but, I will be adding to it later. You can find the page here: http://scarab.240z.org/tips/tips_rear.htm [m]

How in the world do you get that shock cartridge out of the strut assembly? Well, you need to have contacts, or a nice wrench will do! :-) Your main goal is to release that top nut. It's a pain. It's a big pain. It's not easy to remove with vice grips, a pipe wrench, or any other standard wrench around your house. If it's stuck.... you can give up now. Do this. Take it down to your local Nissan dealer. Go into the shop area and bring the strut with you. More than likely, someone will approach you and ask if they can help. Point to the nut and tell them that you need to have it removed. Hopefully they won't rush you out. If they don't, they'll probably walk you to a large tool chest, pull out a cool looking "special tool," mount your strut to a vice, and proceed to remove the nut with one swift motion. All this time you can pick the grease out of your swollen knuckles -- because your pipe wrench didn't work. :-) Yes, I'm speaking from experience. I couldn't get it out and my tire store friends couldn't do it, either. They probably won't charge you (especially if they know you), because it will take less than 2-3 minutes to complete the task. Tell 'em you heard it here! [m]

http://www.geocities.com/MotorCity/Track/6997/head.html

http://www.geocities.com/MotorCity/Track/6997/compression.html

http://www.geocities.com/MotorCity/Track/6997/engine.html

Not to mention that this BB system will notify you via Email when someone responds to your topic. And.... you get to use little smiley faces when you write messages!

One more thing.... I like these forums a lot better than the Email list because the information is permanent. One question answered by many can help out a lot of other people down the road. In other words, most messages about suspension upgrades will only need to be answered once. Future "upgraders" will only need to look in the forum and review a similar thread from someone else. [m]

Richard, These forums are still pretty new. They were put online around February 1, 2000. In our list, you will see a link at the bottom of every message to these forums. And, I plan to change the main web site to our new format. If you want to see our new format just visit http://scarab.240z.org Sorry, there is no spell checker (yet at least). To check topics, just click on the 240z-Logo and it will bring you back to the main Bulletin Board Forum page. From there, you can select the topics of discussion. If you aren't happy with the forums selections, send me your ideas and I will consider adding more. An ICQ number is part of a global-chat service. It's mainly a way of keeping a program running on your computer that will allow you to chat with people on demand. Visit their site at: http://www.icq.com I think you can change your own password. If not, let me know (don't post any passwords to this forum) and I will delete your account. After I delete it, you can re-create your account with a new password. I can't change passwords. As far as messages.... The Email list is completely separate from this Bulletin Board. So, if you want to stay in touch with the Email list... you'll still have to remain on our Majordomo mailing list. Maybe someday these forums will replace the Email list, but I doubt it. I'm sure there are people who will like to see both. [m]

Year 2000 International Z Car Expo in Las Vegas: http://scarab.240z.org/2000_Expo.htm Or go directly to their web site: http://www.playersexpress.com/zcar [m]

Back when I could drive my Z, I did the same thing. I replaced my stock header with a Motorsport 6-to-1 and 2.5" exhaust. My power increase was very dramatic. I could tell that the car was breathing a lot easier -- especially during acceleration. As far as noise... I could tell a difference. My car was louder, but it hummmed to a nice tune. Sounded strong and healthy instead of weak and choked. I can't give you scientific numbers, but headers are usually a lot better than stock (for the early Z's anyway) because they are tuned for the car. All the pipes are similar in length to create a balancing effect. Your other options include a 3-to-1 (6-to-2) header and a 2.25" exhaust. I have heard that the 2.25" exhaust gives you the same benefits, but it's not as noisy. IMHO: You can just buy a better muffler and use the 2.5" system. If you buy a header from the internet, make sure it has flange thicknesses that match your intake manifold. My Motorsport header had a thinner flange and it caused problems for me. The flange is used to bolt the header to the head. There are about 4 bolts that hold the intake and the exhaust header to the head (they share the same bolt). If one is thicker, the bolt doesn't fit right. Anyway, that's my $10 worth. I'd say go with a 2.5" exhaust and buy a good muffler. Definately go with the 6-to-1. [m]

Sorry, I don't know automatics. Otherwise I might have been of some help. [m]