majik16106 Posted December 21, 2004 Share Posted December 21, 2004 need help on two basic problems, first is a caster problem in the front, my wheels are sitting too far forward, so i wasa wondering if anyone had used the msa caster kit? and secondly, any pics of the install? i think im going to need that and some body modification to keep em from rubbing the front end. second, i need some serious help with a coil over install. i have the kit, but im not really sure what is supposed to go where, and have no idea how to decide where to re weld the spring seats.. i have the modern kit. basically im an idiot with a pile of parts, i dont wanna pay someone to do this though, i wanna learn, so if someone could help me through it, id appreciate it, i can do this in private too. my e-mail is majik16106@yahoo.com Quote Link to comment Share on other sites More sharing options...
quicker240 Posted December 21, 2004 Share Posted December 21, 2004 Drive over to Birmingham and look at mine if you want.I could explain most of it but seeing it would help you the most I think.Bring your camera!! Quote Link to comment Share on other sites More sharing options...
Guest ON3GO Posted December 21, 2004 Share Posted December 21, 2004 there ya go my friend.. mike Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 21, 2004 Share Posted December 21, 2004 The main thing about the caster is that you can't be binding the front control arm bushings. Stock caster in a Z is about 3 degrees. Get too far over or under 3 degrees and you'll bind the bushings, which is not good. The more caster the better from a handling perspective. I'm running 5 degrees and I had to fix my fenders because my 250/45/15 slicks rubbed FWIW. With a taller tire you can't run as much. Running a smaller tire would help, or trim the fenders. You really want to keep the control arm bushings from binding though, so if the control arm bushings are looking good then trim the fenders would be my suggestion. Quote Link to comment Share on other sites More sharing options...
cabo Posted December 21, 2004 Share Posted December 21, 2004 there ya go my friend.. mike Are those struts sectioned? If they are how much? And finally which cartridges are you running? Thank you Quote Link to comment Share on other sites More sharing options...
majik16106 Posted December 22, 2004 Author Share Posted December 22, 2004 ok got it, thanks mike, my little helper. but still one major question.. how do you figure where to re weld the seats... i cant imagine your just welding and adjusting the coils to be in the same place, cuz that would mean one sits physically higher than the other, more lowered on one side. so. just pick a spot or what? and the lower seat is the only welded on part right? the rest of it just sits on the next piece correct? like up at the top, the plate on top of the spring rides up and down with the spring during adj. right? and the other pieces sit on top. on the caster, think your right, ive got a 225/45/17 on the front, im gonna have to take it out of the front end. was sort of my plan in the first place, but i figured it i could take it out with some caster adj. why not? you just confirmed what i sort of though anyway J, so thanks. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 22, 2004 Share Posted December 22, 2004 It's not too difficult to decide on where the threaded tube perch ring gets welded. You'll know the spring specs (rate and height), threaded tube length, strut dimensions, vehicle weight, and what difference, if any, you'll want in ride height. With these numbers in mind, one can get a pretty good guess on where the ring should be welded. Any difference can be easily taken up with the threaded tube. For example: I want to use 200lb/in springs that are 10" tall with a 6†long threaded tube. The strut insert casing is 1" shorter than the OEM strut, and the push-rod of the insert is 1" shorter than the OEM push-rod (for lack of a better term) at full extension, and I want to lower the car 1.5". Right off the bat, I know that I should shorten the strut housing 1" to gain the needed clearance for suspension compliance due to the new desired lowered vehicle height and the shorter insert length. So with this done, and the fact that the push-rod is also 1" shorter than the OEM rod, I know that the middle of travel for this new strut damper will be 1.5" (1" for housing + .5" for 1/2 of pushrod difference) shorter than the OEM damper. So I now know that with the proper spring location, my 1.5†lowering of the car can be handled by this new insert without any special parts or spacers (BTW, all lowering is done with the spring and not the damper, as obvious as this seems, I've seen some folks that don't recognize this immediately). I can estimate my 260z weighs about 2600lbs, which means the sprung weight will be about 2100lbs, which equates to about 525lbs/wheel. This means my springs will compress about 2.5". So now I have a spring that is ~7.5" long while compressed by the car's weight. This means that if the coil-over top spring perch is spaced the same as the OEM perch in reference to the strut tower height, then you can measure down from a point 1/2 the way down the push-rod (while it is fully extended) 10.5" for the location of where the top of your ring should be when welded to the housing (7.5" for spring height + 3†which is ½ the length of your threaded tube). This location should then place the lower spring perch roughly ½ the way up (or down) the threaded tube, and compress the strut damper ½ the way down, giving you lots of adjustment. If you want to bias the ride height a bit then you can modify the numbers to give you more or less room in the up/down adjustment window. The only significant variable not discussed here that should be taken into account is how the new coil-over upper perch (or the top of the strut push-rod) sits in relation to the strut tower height. In other words, if I go to the coil-over set-up, will I be eliminating the large rubber spacer that sits over the upper spring perch? If so, then this will change the ride height in itself. Quote Link to comment Share on other sites More sharing options...
Toysport Posted December 22, 2004 Share Posted December 22, 2004 Hey Terry, Can this method be done for the front and back? Thanks John Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 23, 2004 Share Posted December 23, 2004 I see no reason why not. As long as you have all the required information on the parts you are using, it's pretty straight-forward for all four corners. Just remember, this will get you close, but not perfect being the kingpin inclination (the strut's 13º slant) changes things slightly which compresses the spring just a tad bit more than if the strut was straight up and down. Also, vehicle weight is an estimate (F and R bias on top of this) as is the sprung weight (I subtract about 120lbs per corner off the "whole car" corner weight as another estimate). But this will get you pretty close. Just double and triple check everything before welding. Quote Link to comment Share on other sites More sharing options...
majik16106 Posted December 23, 2004 Author Share Posted December 23, 2004 damn, c thats y i post here. Quote Link to comment Share on other sites More sharing options...
majik16106 Posted December 26, 2004 Author Share Posted December 26, 2004 is everyone measuring everything like terry, or are some people just going up say an inch from the brake line bracket..? Quote Link to comment Share on other sites More sharing options...
Guest quadcamZ Posted December 29, 2004 Share Posted December 29, 2004 I have a 260Z 1975 and i am looking for a good kit what have you had good/bad experiences with? Quote Link to comment Share on other sites More sharing options...
johnc Posted December 29, 2004 Share Posted December 29, 2004 is everyone measuring everything like terry, or are some people just going up say an inch from the brake line bracket..? They certainly should be. Quote Link to comment Share on other sites More sharing options...
majik16106 Posted December 30, 2004 Author Share Posted December 30, 2004 sure, look, if thats how ill go through all that, but to be honest, im not really sure how much, my car isnt a fully fledged race car, and the lowering springs offered dont seem to lower the car enough for me, i mean, i know it seems stupid but basically i just need them to function, im not trying to win any hardcore road races, if i can get it to handle already and sit low enough, im cool. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 30, 2004 Share Posted December 30, 2004 if i can get it to handle already and sit low enough, im cool. But, getting a Z too low makes it handle poorly, regardless of springs, shocks, anti-roll bars, etc. Never lower a Z to the point that the front and rear lower control arms go beyond level, meaning: the LCAs must never point up (from the inside of the car tot he outside). Quote Link to comment Share on other sites More sharing options...
JMortensen Posted December 30, 2004 Share Posted December 30, 2004 Kinda hard NOT to lower it that far when you're trying to make it look good with 27" tall tires... Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 30, 2004 Share Posted December 30, 2004 So true! I struggled with the tire size I currently run. They are taller than the racing set-up I had, which now sets the car up some due largely in part to John's comments. I'm about as low as I can go with this tire combo. IMHO, the best look/performance balance (street) is a tire in the 24" tall range, and no taller. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 31, 2004 Share Posted December 31, 2004 I had a hell of a time getting my car to handle well with 25.2" tall tires. I was at a 6 to 6.5" ride height (measured at the rockers) with the 275/45-16 Hoosiers I was running. I can't imagine how you can get a 240Z to work with 27" tall tires. The chassis won't bite, it'll just skate. Quote Link to comment Share on other sites More sharing options...
majik16106 Posted December 31, 2004 Author Share Posted December 31, 2004 was afraid i'd hear that, been crossing my mind, i might have to just sell them off and buy some 16's. although, the guys with reaction research flares or the dude on his site anyway runs 18's and road races his? and bob's car with the old imsa flares uses 17's so something must be able to be done. Quote Link to comment Share on other sites More sharing options...
johnc Posted December 31, 2004 Share Posted December 31, 2004 You can run 17s or 18s but you'll need a really low profile tire. A 245/40-17 is about 24.7" in diameter while a 245/35-18 tire is about 24.8" in diameter. A 265/35-18 and a 265/40-17 tire will both be about 25.3" in diameter and can be made to work. The drawback to a tire profile under 45 for a Z is that you'll need good, multi-adjustable (or custom valved) shocks to make up for the tire compliance lost by the short sidewalls. Quote Link to comment Share on other sites More sharing options...
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