johnc Posted September 2, 2003 Share Posted September 2, 2003 For Koni 8610 Inserts, other inserts (Tokico, etc.) require different lengths. FRONT From the dished bottom center of the strut to the top lip the overall length should be between 12.875†and 12.938â€. The perch height measured from the top of the spindle casting (opposite spindle) is 5.250†assuming a .250†thick spring perch. The strut tube is cut at 5†measured the same way as above. Approximately 2†is cut from the bottom of the top half of the strut tube but measure first to be sure of the exact length. REAR From the dished bottom center of the strut to the top lip the overall length should be between 14.938†and 15â€. The perch height measured from the top of the hub casting (opposite hub) is 7.250†assuming a .250†thick spring perch. The strut tube is cut at 7†measured the same way as above. 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. PROCESS 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. 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. 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. Slide the spring perch 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 perch. Make sure the perch is perpendicular to the strut tube. Tap the perch 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 perch. 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 2.250" tall and 1.5" in diameter out of .125 wall steel or aluminum (6061 T6) tube. Drop in and center these in the bottom of the rear strut tubes and install the inserts. Measure to make sure the inserts site 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. Quote Link to comment Share on other sites More sharing options...
zlalomz Posted September 2, 2003 Share Posted September 2, 2003 John, are the Koni 8610 inserts for use only with 280 strut tubes? Just in case someone was going to use these measurments for their 240 tubes thinking these inserts would fit. Quote Link to comment Share on other sites More sharing options...
jeromio Posted September 2, 2003 Share Posted September 2, 2003 In the spirit of ancient times, I dusted off the ol' FAQ and added this to the Susp.->Struts section: http://240z.jeromio.com/faqdraft/ Quote Link to comment Share on other sites More sharing options...
johnc Posted September 2, 2003 Author Share Posted September 2, 2003 The 8610s will work in any of the 240/260/280 struts. The 280 strut tubes have a larger OD and ID then the 240/260 struts. My instructions above were specific for the 240/260 struts. BTW... Amir discovered that the Ground Control threaded tubes won't slide over the supplied Koni 8610 gland nut. Slide those tubes onto the strut before installing the gland nut. BTW2... You'll have to source a different gland nut if you're going to use the Koni 8610s on 280 struts. The ones supplied by Koni only fit the 240/260 strut tubes. Koni may have an alternative gland nut for the 280 but I've never checked on that. Quote Link to comment Share on other sites More sharing options...
gramercyjam Posted September 3, 2003 Share Posted September 3, 2003 John, Very nice writeup. I have used a pipe/tubing cutter for this job and I didn't like the results as the cutting wheel tends to wander and produce a cut that requires lots of dressing to make it square. I think a good cut-off saw or mitre saw will probably yield better results than a tubing cutter. Quote Link to comment Share on other sites More sharing options...
johnc Posted September 3, 2003 Author Share Posted September 3, 2003 A cold saw works well but cutoff saws don't make square or perpendicular cuts. The vices are not accurate and the abrasive blade flexes as its going through the cut. I have used cutoff saws in the past but then I spend a good 20 minutes with a file and a machinist square getting the cut ends absolutely perpendicular to the tube centerline. The tubing cutters I have are pretty stout and I can buy blades that are good for stainless and CroMo. Ultimately I'm saving my pennies for a nice cold saw. KBC tools in Fullerton has one of their showroom floor for $1,750. I've been talking them down in price and, hopefully, they will get tired of me and let it go cheap. FYI... With the Tokico Illuminas or most other inserts you don't have to be as precise. Their OD is smaller then the OD on the Koni 8610s. Quote Link to comment Share on other sites More sharing options...
gramercyjam Posted September 3, 2003 Share Posted September 3, 2003 I know, but the cut will be way better than a pipe cutter. It will be "close enough" for welding if you cut slowly then put a tube inside the strut and clamp it in some angles. After all, you are going to get heat distortion when you start welding anyway, no matter how precise your cut. Quote Link to comment Share on other sites More sharing options...
Trevor Posted September 14, 2003 Share Posted September 14, 2003 Great writeup. Thanks John. Are the 8610s for both front and back or front or back only? Scott Bruning has addressed cutting strut tubes squarely - in the "Convertible Z Fabrication" video, he shows a fixture he made for the chop saw. It clamps to both ends of the strut to hold it square to the saw platform and the strut tube rigid on both sides of the blade. Made of 2"x2" angle iron IIRC. He also shows how to use an old strut cartridge for the alignment tool, inserted in the tube, while welding. The old cartridge was drilled out and drained of course. Quote Link to comment Share on other sites More sharing options...
demon Posted September 15, 2003 Share Posted September 15, 2003 BTW... Amir discovered that the Ground Control threaded tubes won't slide over the supplied Koni 8610 gland nut. Slide those tubes onto the strut before installing the gland nut. OR you could take a grinder to the gland nut while the assembly is in place and end up taking a chunk out of the shock shaft and having to buy a new shock... ...but John's way sounds a bit more intelligent Quote Link to comment Share on other sites More sharing options...
johnc Posted September 15, 2003 Author Share Posted September 15, 2003 The 8610s are for front and rear. That's why you need the spacer in the rear struts. And, as Amir learned, grinders are not good things to have near shock shafts... Quote Link to comment Share on other sites More sharing options...
Guest zline Posted October 15, 2003 Share Posted October 15, 2003 that would be this insert correct? http://www.modern-motorsports.com/catalog/product_info.php?products_id=51 Quote Link to comment Share on other sites More sharing options...
johnc Posted October 15, 2003 Author Share Posted October 15, 2003 Yup, that's it. Quote Link to comment Share on other sites More sharing options...
zlalomz Posted October 15, 2003 Share Posted October 15, 2003 Those are the ones I had in mind when I asked if yours, John are 280 strut tubes. According to that site they will not fit 240 tubes. Quote Link to comment Share on other sites More sharing options...
johnc Posted October 15, 2003 Author Share Posted October 15, 2003 According to that site they will not fit 240 tubes. I know at least a dozen 240Z ITS racers running the 8610s in 240Z strut tubes. Quote Link to comment Share on other sites More sharing options...
zlalomz Posted October 15, 2003 Share Posted October 15, 2003 Thanks John. I wasn't sure if 8610 reffered to a line of inserts or to a specific one. I went to Koni's website and got more info. Quote Link to comment Share on other sites More sharing options...
Guest zline Posted October 15, 2003 Share Posted October 15, 2003 Thanks for the info. I've been looking at these but I've been a bit weary of em. Anyone know of a site with a review of their performance? Quote Link to comment Share on other sites More sharing options...
silicone boy Posted October 16, 2003 Share Posted October 16, 2003 The giant tube cutter at harbor freight that costs about $15 is perfect for the job. It comes with a couple of extra cutting wheels and leaves a nice "V" for beldine it back together. Quote Link to comment Share on other sites More sharing options...
johnc Posted October 16, 2003 Author Share Posted October 16, 2003 Anyone know of a site with a review of their performance? The 8610s are not street shocks so you probably won't find anyone doing a review like they do for the Tokico Illuminas. The 8610s work with spring rates from 225 to 350. Anything out of that range and they are not as effective. The 8610s are a much better shock for racing then the Illuminas, but they are NOT a street shock. Quote Link to comment Share on other sites More sharing options...
Guest zline Posted October 16, 2003 Share Posted October 16, 2003 Anyone know of a site with a review of their performance? The 8610s are not street shocks so you probably won't find anyone doing a review like they do for the Tokico Illuminas. The 8610s work with spring rates from 225 to 350. Anything out of that range and they are not as effective. The 8610s are a much better shock for racing then the Illuminas' date=' but they are NOT a street shock.[/quote'] i meant on track reviews =) Quote Link to comment Share on other sites More sharing options...
74_5.0L_Z Posted July 14, 2004 Share Posted July 14, 2004 I am in the process of putting the Koni 8610 stuts up front. My ride height is about 6" at the bottom of the rocker panel. Will I have enough droop travel if I section the struts 2" as suggested by johnc? The write-up in this thread is well written. Can we make it sticky, or include its content in the FAQ? Quote Link to comment Share on other sites More sharing options...
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