blueovalz

I've had one on my first Z, and if I remember correctly, the instructions were to attach the cover with some kind of adhesive. I believe silicone is used most widely. It was never meant to be "sitting" on the dash. You may also want to sand the cracks smooth as the crack walls are usually raised by such an amount that it keeps the dash cover from making good contact throughout. Clean (using a solvent of some sort to remove any oils or silicone based preservative) the dash thoroughly before applying the adhesive. I used heavy metal plates to keep the dash positioned correctly until the silicon "set".

My guess is that the extra support is to provide lateral support to the rear suspension uprights at the control arm pickups. The drop bracket is, again a supposition, to raise the roll center on the rear suspension.

You could, but it would be less than desirable. First of all the control arms will be pulled/pushed fore and aft when the bar is in use. Also, this arrangement will cause unequal force on the body depending on how much the bar will twist (it would work much like the Ackerman principle, but on the body attachment points instead (one side's attachment point will experience a "push" of unequal force - opposite, but not equal - than the other side's "pull").

Thanks John. I hear the Zcar.com explosions already.

I've looked hard at doing this as well (not through the frame rails though). I talked to their machinist and he said he would build a custom length shorter than there "canned" size for an additional $25. The most challenging parts are the arms. My intention was to modify them (lighten them up), and then link them to the strut tubes instead of to the control arms.

Hopefully the below can be added to JohnC's wonderfull FAQ. It does not provide specific dimensions, but hopefully will provide the reader a conceptual idea of what all is involved with sectioning struts. If done correctly, is not something you do by measuring with a mic, marking with chauk, and cutting with an ax. It takes some preparation, time, and consideration of a lot of variables before it can be done right. Deciding on the strut length (where the top of the strut housing, or the gland nut location) as well as the placement of the threaded tube can only be successfully determined after you know where you want your ride height to be in relationship to where it was prior to the sectioning. For example, if your suspension was set up at a 7” ride height, and the current struts were positioned exactly half-way in their travel window when the car is at rest, you have a reference point to work from in deciding how much to section and where to place the threaded sleeve. Let’s suppose you wish to lower the car to a new ride height of 5”, and you wish to use the same exact springs previously used on the car. To do this correctly you’ve got to reduce the height (top of, or the position of the gland nut) of the strut tube by the same amount that you’ve lowered the car (2”). Doing this allows the suspension to once again sit at the midpoint of the strut’s travel window. The only way to do this though is with a shorter strut insert because the OEM insert will be too long to fit into the shortened tube. So what you need to know now is “how long is the body of the new shorter strut insert?” If it is at least 2” shorter than the OEM insert, you’re in luck because you can use a spacer to make up the difference at the bottom of the tube. If the new insert body is less than 2” shorter than the OEM insert body, than you must increase the strut tube length to at least match the new strut insert’s body length. This may mean that you cannot cut the full 2” off the tube, and must instead settle with a longer than desired tube (strut length), but one that will still work within the parameters of the suspension travel. All of the above is only a starting point though. What if the new strut insert has a shorter stroke than the OEM strut had. If the OEM strut had an 8” stroke (just for the sake of this explanation) and the new insert has a 6” stroke, this means that the center of the travel window must be moved up 1” (1/2 the difference between the two strokes). This means that instead of cutting 2” off my strut tube in preparation for lowering the car, you only need to cut 1” off the strut tube, because now you must raise the strut up 1” to compensate for the shorter stroke of the new insert. So now you’ve added another factor to consider before you cut. One note I would like to add is that it is always better to error on the side of a too long a strut tube. If you cut the strut tube even .200” too short in relationship to the new insert’s body length, you will not have enough thread engagement in the gland nut to secure the insert. In fact, I will go so far as to say even .100” too short can present a problem. With that said, .100” too long will allow the use of a washer or shim to tighten the new insert with proper gland nut engagement. You can always add a shim, but to lengthen a too short a strut tube will take a lot more work. Guess what, you’re not finished yet. If you install camber plates, or any part that changes the strut rod mounting point’s relationship with the top of the strut tower, then you’ll need to find out what this change is. Will the installation of camber plates allow the strut to sit higher in the tower, or will it push it down lower in the tower? This change will impact where the car sits in relationship to the strut’s stroke window (the desired midpoint of strut movement). A camber plate with no rubber spacer will allow the strut rod to be over-extended at the new ride height if this factor is not considered. Thus in this situation, you’d need to lengthen the strut tube additionally for this situation. How long are your bump stops? Will you use bump stops? Will the upper assembly reduce the available stroke on the new insert, and if so, by how much? All of this needs to be considered because it will dictate where the gland nut is positioned (the length of the strut tube) Threaded Tube Placement Now let’s look at the location of the threaded tube. Nearly 100% of all coil-over conversions involve a change in springs. Your planned ride height change of 2” must take into consideration the spring rate change as well. For example, lets assume the reference ride height (original pre-work ride height) used 100 lb/in springs (again, a value used only for this discussion) on the struts, and you wish to use 150 lb/in springs with the coil-over set-up. This means that the springs will not compress as much as the OEM springs did. At rest, if your corner weight (un-sprung weight) is 600 lbs, then the new spring will only compress 4” as compared to the OEM spring which compressed 6”. If these two springs were the same length (OEM and new), this means the bottom of the new spring must be raised 2” (again, ½ the difference between the two rates) to keep the same ride height. But rarely are these springs the same length, so now the spring length (more specifically, the spring compressed length) then becomes a factor as well. I only mention all of the above to cause you to think about all that goes into this project. In simple terms, if you know the spring rate, and you know the corner un-sprung weight (not total car corner weight), the you can determine the length of the new compressed spring. Then take this “compressed length” value and measure down from the upper spring perch, mark the strut tube at this length (this is with the suspension assembled and installed on the car, and the car sitting at you intended ride height), and then use this location as a good estimate on where the center (midpoint) of the threaded tube should be (actually, this is where the spring perch would be located midway on the threaded tube). Then once you know where the threaded tube should be positioned, the location of where you wish to weld the tube seat is a no-brainer. Lastly, you need to consider what the use of the car will be. If the car is to be used on the street, but occasionally used on the track, then you may wish to lower the threaded tube so that you can raise the car a small amount for the street, and the lower is a good bit for the track. Regardless, take into consideration whether the car will be occasionally raised or lowered depending upon future use, and then place the threaded tube accordingly. Usually, if the threaded tube is place correctly, and the lower spring perch is used midway up the tube, you should have plenty of room to move the perch for varying ride heights (provide your threaded tube is of sufficient length).

I have been accused of over-analysis of a subject, but in this case I'd look hard at the many strings on this issue before you start because the problem of having the threaded tube too high or too low has come up too many times to ignored. There are a lot of things to consider (ride height, spring rate, corner weight, strut insert length, and are other components being added at the same time such as caster adjusters. I'm sure I've missed other issues as well.

I will add a dissenting opinion on glass-to-glass bonding. Many of my panels are multiple parts bonded together after they were individually formed. I roughed up the bonding surfaces (36-40 grit paper), and then sandwiched a layer of resin soaked mat (thick enough to ensure full contact) between these two surfaces. I've never had glass-to-glass parts crack or separate.

Should not make any difference as long as the u-joint angles stay small (Pete's site I thinks has the recommended max on this). You probably already have that much in the vertical plane and not even know it. On another note, is there any evidence that different sized u-joints cause vibration? This would surprise me if so. My thoughts are that size makes no differnece as angles will not change regardless of the size of the joint.

I've had a lot of success with using 4 layers of 2 oz mat, which comes out to about 1/8" thick. For added rigidity around the edges, I fold it over to make a 90º angle (and trim later). If this reinforcement is in the middle of a larger part, then you can either bond over a foam rib, or you can bond a narrrow strip (usually I use 1" wide 1/8" thick strip) bonded perpendicular to the surface. I use the later were space does not allow a wider reinforcement. One thing to remember is that this reinforcement may (and most likely will) distort the panel slightly and become slightly noticable when viewed from the external side, due to the new glass reinforcement hardening and shrinking slightly. This then will need only a little sanding of the panel to get the shape back to the original form.

Need more information about the part you're making.

And the more positive offset is on the order of ~ 3/4" for the Z31 hubs.

Good choice of color

I'm using a Griffin radiator (16 X 23) and it works marginally on a hot day. Probably better if I had some high rated fans.

I had everything correctly aligned and phased when I had my driveshaft shortened and installed, and I still had the type of vibration you describe. Obviously not everybody has this issue or it would come up more frequently. I think one reason I had this issue was the whole solid mounting thing on the transmission and differential. Eventually, I had a way to fix it which is not a method many folks will take on, and that was to move the differential 1" toward the driver's side. I had the vertical plane and angles correct, but the horizontal plane had the propeller shaft offset 1" toward the passenger side (which is normal in the Z and is somewhat an issue with a short driveshaft because it creates larger than desired U-joint angles). Since I was fabricating my own CV jointed half-shafts, I had the opportunity to shorten the driver's side, lengthen the passenger side, and move the whole differential 1" toward the driver. This cured the vibration issue completely. I still have a slight offset vertically, but wanted this to keep the U-joints moving a small amount.

I'm still of the opinion these should fit. I'd have to tactfully double check this with the mechanic.

I'd find out if the "rebuilder" actually rebuilt the axles, or ordered a set of rebuilt axles from another location. Everywhere I turned to find rebuilt axles only show one part number, which means there is no differentiation between left and right sides, which means you may or may not get a proper pair of axles. JohnC suggested this.

Cost and availablility would be my guess as well. One of the most awesome rides I ever had was in an old Falcon with a well built 460 using the 429 Super Cobra Jet heads. My god, you could drop a tennis ball down the intake ports on this monster!

It will be almost indistiquishable from the block you put in your Z with the exception of larger main caps (not visible unless oil pan is off), and the block being slightly wider and toller. It's just a puffed up version of a 302 basically (uses same type of timing cover, bellhousing, and heads.) The M blocks are puffed up Cleveland motors and will have a different timing cover and heads.

par·a·dox [par-uh-doks] :a statement or proposition that seems self-contradictory or absurd but in reality expresses a possible truth. Example: Sorry, couldn't help it. We had Blackstart practice (Blackout restoration simulation) exercises today, and it was a rough first day.

I'll verify what Jon said. Three locations on each side of the car.

I've got a helical LSD, but I don't know if it is Quaif, Nissan, or Gleason-Torsen (it's old and didn't have any visible markings while installed). Mine though does "lock in". Are you sure you have the correct shaft installed into the correct side? One very important thing I noticed with mine, and this this was a BIG surprise, was that the sides on my carrier are reversed. In other words my differential required that I have the normal passenger side stub inserted into the driver's side of the differential, and visa-versa. I couldn't believe what I was thinking I was seeing, so I measured into the splined area and sure enough found that the driver's side was deeper than the passenger's side where the stubs are inserted. What this meant was that I had to dissassemble my half-shafts and swap the differential side stubs to keep the shorter axle shaft on the driver's side of the car (where it must stay). This was more-or-less a PITA, but was well worth it. I had to get used to the difference in cornering on and off power, but I now love the way this differential works. What I would strongly consider, if this indeed is the case for you, is have your ZXT axles rebuilt by the guy in Johnc's recent posting (mentioned in another string) that is rebuilding these ZXT halfshafts, and clearly specify that during the rebuild he swap the inner CVs during the assembly. Here is the link: http://forums.hybridz.org/showthread.php?t=119863

That must be them because the old company (B&A) was in Fort Smith as well. Matt is correct on total performance now verses then, but I really liked the performance the 2 barrel heads gave, and those big A$$ heads and valve covers look intimidating in a show car. When I did my heads, I used nickle rod and welded a square piece of steel plate into the block-side water passage, and then drilled a new water passage hole on the manifold-side surface. A much simpler way to do this is have the square hole machined into a round hole and then simply put a freeze plug in it (which is what I think Bush does from what I see in the 3rd photo (arrow "b").

Great build-up. Keep the pictures coming as this monster progresses.

Interesting. Thanks for FYIing that to us.