For Koni 8610-1437RACE Inserts General Remove stock lower spring perch from all the struts and remove the brake line brackets from the front struts. Use a cutoff wheel to remove all the spring perches and brackets above the welds and then grind the welds off the strut tube. Get it smooth but be careful not to grind off too much of the tube itself and thin it. Front From the dished bottom center of the strut to the top lip the overall length should be between 12.875" and 12.938", measured from the inside using a tape measure. The threaded collar weld-on ring height (assuming 10" tall springs, 5" tall threaded collars, and 23" tall tires) measured from the top of the spindle casting (opposite spindle) is 5.250". The strut tube is cut at about 6.5" up from the top of the spindle casting to put the welded section under the threaded collar. From 1 to 2" is cut from the bottom of the top half of the strut tube but you must measure first to be sure of the exact overall strut length length as specified above. Rear From the dished bottom center of the strut to the top lip the overall length should be between 14.938" and 15", measured from the inside using a tape measure. The threaded collar weld-on ring height (assuming 10" tall springs, 5" tall threaded collars, and 23" tall tires) measured from the top of the hub casting (opposite hub) is 7.250". The strut tube is cut at 8.5" up from the top of the spindle casting to put the welded section under the threaded collar. From 1 to 2" is cut from the bottom of the top half of the strut tube but you must measure first to be sure of the exact overall strut length length as specified above. Process Preparation The Koni 8610 inserts are a very tight fit inside the strut tube. The inserts typically have an OD of 1.725 and the strut tubes typically have an ID of 1.730. All cuts must be precise and perpendicular to the strut tube centerline. Use a lathe or a tubing/pipe cutter. Bevel both cut edges at 45 to 60 degrees leaving a flat of .030 to .060 at the bottom of each bevel. This bevel is important to ensure proper weld penetration. Physically remove all paint and chemically clean (with Acetone) 3" to either side of the weld area. The strut tubes must be clamped into a large piece of angle and a tube (simulating the insert) of 1.720 diameter and 18" in length should be inserted into the assembly to help ensure straightness. Its critically important that the strut tubes are welded square. Welding the Strut Tubes Tack weld the assembly in at least 6 places making sure the inserted tube still slides in and out easily. After tack welding, alternate 1" beads back-stepping around the circumference. Make sure no weld bead extends inside the strut tube and frequently check to be sure the inserted tube moves easily. Be careful not to weld the inserted tube to the strut tube. You'll also need to lightly grind down he weld to allow the threaded collar to slide over it. Weld-on Rings Fabricate the lower threaded collar weld-on ring from 2" schedule 40 plumbing pipe (2" pipe nipple 6 or 12" long). Cut four .75" rings from the pipe and slide over the strut tube. They should fit over the tube but if not, cut a slot in the ring. A gap in the ring supporting the threaded collar is not an issue. Slide the threaded collar weld-on ring over the strut and tack weld it to the strut tube on the underside of the perch. This tack weld should be on the back of the strut with the top of the perch 5.250" from the top of the spindle casting on the fronts and 7.250" from the top of the hub casting for the rears. Measure down from the top of the strut tube to 3 places on the top of the weld-on ring. Make sure the ring is perpendicular to the strut tube. Tap the ring into position with a hammer before adding 3 more tack welds. After tack welding, alternate 1" beads back-stepping around the circumference on the underside of the ring. Insert Installation Try installing the inserts into each strut tube. They should slide all the way in with nothing more then a light push. Most likely they won't. Using any or all of the following, clean out and open up the ID of the strut tube: 36 grit 1.750" diameter flap sander 36 grit 1.5" diameter drum sander Christmas tree shaped carbide bit 1.735" diameter reamer 1.750" diameter wire wheel You can also sand the paint off the Koni insert and you will probably have to slightly grid down the weld at the bottom of the insert. When you can easily slide the insert into the strut all the way to the bottom, make two spacers for the rear struts that are approximately 1 to 2" tall and 1.5" in diameter out of .120 wall steel or aluminum (6061 T6) tube. The spacers put the insert at the top of the strut tube. Drop in and center these in the bottom of the rear strut tubes and install the inserts. Measure to make sure the inserts sit at the correct height. You'll probably have to shave a bit off the spacers. Once the spacers are correct, pour a little synthetic oil into the tube, install the spacers and the inserts, tighten the gland nut down, and torque to spec. Make sure the gland nut tightenes down on the Koni insert and doesn't bottom on the strut tube. The Koni gland nut for the 240Z strut tubes and 8610 inserts is part number 73.25.01.003.1 (M48 x 1.5p). For 280Z strut tubes (which are physically larger in OD and wall thickness) the Koni gland nut part nubmer is: 73.25.01.007.1 (M51 x 1.5p). You can get these from Truechoice but be sure to give them the part numbers. You will need a wrench for the Koni gland nut and spring perch. Both can be sourced from McMaster-Carr with the gland nut as part number 5480A13 (1.5" span, 7/32" pins, 5.5" long). The spring perch wrench style will depend on what type of adjustable lower spring perch you bought with your coil over kit. Tokico Ilumina BZ3099 and BZ3015 Inserts General >Basically all the steps are the same except for the measurements and the tightness of fit of the Tokico inserts in the 240Z strut tubes. The Tokicos are a little smaller OD then the Konis and slide in easy. Front From the dished bottom center of the strut to the top lip the overall length should be between 13.375" and 13.500", measured from the inside using a tape measure. The perch height (assuming 10" tall springs and 5" tall threaded collars) measured from the top of the spindle casting (opposite spindle) is 5.250". The strut tube is cut at about 6.5" up from the top of the spindle casting to put the welded section under the threaded collar. Approximately 2" is cut from the bottom of the top half of the strut tube but you must measure first to be sure of the exact length as specified above. Rear From the dished bottom center of the strut to the top lip the overall length should be between 14.938" and 15", measured from the inside using a tape measure. The perch height (assuming 10" tall springs and 5" tall threaded collars) measured from the top of the hub casting (opposite hub) is 7.250". The strut tube is cut at 8.5" up from the top of the spindle casting to put the welded section under the threaded collar. Approximately 2.250" is cut from the bottom of the top half of the strut tube but measure first to be sure of the exact length as specified above. The rest of the process is that same as for the Koni inserts and Tokico includes the gland nut for their shocks. They are hex shaped so a large adjustable wrench (or gland packing nut wrench) is needed for installation. | Back to Bench Racing |