Jgalland09 Posted January 1, 2015 Report Share Posted January 1, 2015 Hey everyone, am just new to the forum as I just bought myself a180b wagon. Love the car and want to keep it generally original as poss but I HAVE to take it down a few inches. I am still kinda learning all the tech stuff when it comes to suspension but any info at all would be much appreciated. Im guessing ill probably just put 2" blocks in the back, but the front has me a tad confused. Ive read different ideas about it eg cut springs, coilovers etc but not sure what to do. This will br a family car as well and ideally dont want to cut springs if poss. HELP haha Quote Link to comment
datzenmike Posted January 1, 2015 Report Share Posted January 1, 2015 Cutting springs is the worst way to lower. It can work but cutting also increases the spring rate making it stiffer. Stiffness is alright within reason but the chances of getting the height and not too stiff is unlikely. Well if money is no object then get coil overs. If coil overs weren't so expensive I would run them also but once the ride height is set what use are they? How many times a day or week do you need to adjust your ride height, really? They are simply money going along for a ride. But if money is a concern and or you like going things yourself, and if you like the same results as coil overs for about $25 then here is how I did it... Remove the strut, compress and remove the spring carefully. Loosen and remove the gland nut. Use a dental pick to remove the inner O ring. This must be removed in order to remove the damper inside. Save and clean/reuse the O ring. This will allow you to remove the factory oil bath hydraulic dampers. If they have already been replaced with incerts, well too bad, just keep or replace if worn. If you have the factory ones you are in luck because you can replace the thin watery hydraulic fluid with thicker 20W weight motorcycle fork oil to firm them up. Oil bath dampers... There is about 300ml of fluid and it's messy so be ready for this. With the internals out of the way, (for now) use a 6" angle grinder and trim carefully around the lower pring perch just above the weld. Just deep enough to trim it off. You can use a hacksaw. Grind away the weld. This will allow the spring perch to now be able to slide up or down past this position. When assembled the bottom spring perch will be supported and held in place by a 2" split collar that can be raised or lowered to set the ride height. Mine were about $25 a pair and when tightened will support 6,000 each! that 2 1/2 610 per strut, more actually. When I finished fiddling with my ride height by trial and error I MIG welded a small spot on the strut just below the collar... you know, just in case. They have never moved. But before that, the spring rate should be dealt with. A lowered ride height puts the vehicle under side at risk from bottoming out on the 'soft' factory springs. A firmer set will not only improve handling but resist suspension travel, which is a good thing. My 610 FSM rates the front springs at 96 pounds per inch. My 710 is about 100 lb/in. so very similar. I worked out the spring constant by using a simple mathematical formula and by trimming a little over one coil off increased the rate by about 50% which according to everyone is rather conservative. However better too little amount rather than too much as you can't put it back. I won't get into what's the best rate only that it can be worked out, it's easy to do and you can adjust to what YOU like. Now we have the means to adjust the ride height and the means to adjust the spring rate. Next is replacing the hydraulic damper oil. I bought a liter (enough for three struts) of 20w Bellray motorcycle strut oil for under $20. Filled the dampers and bled the air out and I love the ride. All this for under $50 and the satisfaction of doing it myself. My other 710 I just used ATF auto trans fluid. It's around 12w I think and my wife drives this car, didn't want complaints. Quote Link to comment
datzenmike Posted January 1, 2015 Report Share Posted January 1, 2015 Before After 1 Quote Link to comment
Jgalland09 Posted January 1, 2015 Author Report Share Posted January 1, 2015 Cheers for the accept and appreciate such a quick and detailed reply!! As far as I know all suspension is stock. Ideally I'd like to spend less on this so it can be put into other parts of the car. I've read somewhere you can put in 240zx struts in as they're shorter, better brakes too? Then could I either trim springs or purchase some new ones to suit? And quick q, blocks or reset leaves what's your opinion? Thanks heaps! Quote Link to comment
Seansm10 Posted January 1, 2015 Report Share Posted January 1, 2015 Hey mike as far as your spring rate goes from chopping, do you feel like you could chop more off and still have a somewhat comfortable ride? I'm looking to get a fairly snug fitment on some 14s that came with the car without sacrificing too much drivability (considering aftermarket springs). I plan to roadtrip the wagon this summer and am trying to balance back stiffness with kickass pictures to acquire short lived internet fame. Lol. Sean Quote Link to comment
danfiveten Posted January 1, 2015 Report Share Posted January 1, 2015 Hey you need to share pics of the 610 for us to help ;) Quote Link to comment
datzenmike Posted January 1, 2015 Report Share Posted January 1, 2015 Cheers for the accept and appreciate such a quick and detailed reply!! As far as I know all suspension is stock. Ideally I'd like to spend less on this so it can be put into other parts of the car. I've read somewhere you can put in 240zx struts in as they're shorter, better brakes too? Then could I either trim springs or purchase some new ones to suit? And quick q, blocks or reset leaves what's your opinion? Thanks heaps! On a leaf spring rear suspension, blocks are easy to make (or buy) and install needing only longer U bolts. Just like the front, any lowering endangers the underside from bottoming out on dips or bump in the road, especially at speed. Like the front the rear spring rate should be increased to limit suspension travel. Additionally the stock handling has now been compromised by firming the front. Cars are designed with a small amount of understeer as this is considered the easiest for the average driver to recover from ..(lift off gas and apply brakes) A stiffer front and a softer rear will naturally add extra unwanted oversteer to the handling so increasing the rear rate brings this more into balance. What I did was take a shorter leaf from a spare pack of leaf springs and add to my leaf pack. This acts as an overload spring. Combined with a set of 2" lowering blocks I got the height reduction I wanted and the firmness needed. It was a longer thicker leaf that I shortened to fit in the second position. The 610 spring constant is 123lb/in and I expect the 710 is similar. You can also lower by having the springs de-arched also but extra stiffness is advised strongly. Now one important thing here no matter how you lower the rear. When the body is lowered this changes the angle of the driveshaft where it leaves the back of the transmission mostly and slightly at the differential. Because of the peculiarities of driveshaft mechanics they can only turn vibration free if the two angles are equal. One angle cancels out the other so if they are mismatched it WILL vibrate proportional to the amount difference. I found a low humming sound that was not there before. I wouldn't have called it a vibration and just put up with it. But upon reflection and some research I used a compass and a string with a washer on it to make a plumb bob and found them both out. The eventual fix was a small 1/8" shim between the upper part of the lowering block and the lower spring perch on the rear side of the differential. This tilted the front of the differential downward and restored the proper front and rear angles. The difference was nothing short of amazing. Hey mike as far as your spring rate goes from chopping, do you feel like you could chop more off and still have a somewhat comfortable ride? I'm looking to get a fairly snug fitment on some 14s that came with the car without sacrificing too much drivability (considering aftermarket springs). I plan to roadtrip the wagon this summer and am trying to balance back stiffness with kickass pictures to acquire short lived internet fame. Lol. Sean Right now my 710 wagon is on '84 Maxima wagon struts with slightly shortened 710 springs. The Maxima and the 280zx are built on the same platform and very similar. (large car, inline six engine, R180 sedans and H-190 wagon) The Maxima/zx coils are way too large so 710 springs used. The rotor is a few mm smaller than the zx and vented with a huge caliper. The 710 front spring is now at about 150 lb/in and it rides quite well. I do have an extra set of 710 springs and at some time in the future I plan to swap the struts side to side to place the calipers to the front to avoid clearance problems with the steering knuckle when the pads wear down. This is a long long way off in the future as I have new pads and rotors on it now . When I do, I may try a thicker fork oil and perhaps increase the spring rate to 200. I'm certainly in no hurry, and like I said, very happy with the drive ability and handling at 150. (racing 510 fronts are run at over 300lb/in!!!! can't imagine them being comfortable) I don't drive it every day, in fact mainly a few months in the summer to the Canby car show.... maybe a couple thousand miles, tops. I think a firmer spring rate would simply make the ride less comfortable on regular paved roads for minimal gain in handling. But this is just me and I realize everyone's different Quote Link to comment
Jgalland09 Posted January 2, 2015 Author Report Share Posted January 2, 2015 Hopefully that worked?! I have the car up North and the old man is driving it down next week for me so more pics then. Quote Link to comment
Jgalland09 Posted January 2, 2015 Author Report Share Posted January 2, 2015 My only other ATM... Quote Link to comment
Jgalland09 Posted January 2, 2015 Author Report Share Posted January 2, 2015 The pics are pretty poor but I'd just be happy to have tyres sitting just above the rims. Will need to get some lower profile ones but they are near new so will give them a good thrashing first. Quote Link to comment
Jgalland09 Posted January 3, 2015 Author Report Share Posted January 3, 2015 Lads, as I'll need this car on the road as often as poss I was thinking about getting my hands on a separate pair of front struts to work on them then chuck em straight in. As my car knowledge is average, does anyone have any tips on the struts? If I don't end up shortening the ones I have now, will 280zx ones be short enough? And are they more or less a straight swap? Any info would be great! Quote Link to comment
datzenmike Posted January 3, 2015 Report Share Posted January 3, 2015 The zx struts are at least an inch shorter and you can easily and safely drop a couple more. You will need to remove the bottom spring perch and use your 610 perches and spring as the zx springs are way too wide to fit up into your 610 strut towers. The calipers are much larger than the stock ones and will clear a 14" rim, not so much the stock 13s. The rotor is larger and vented and the zx strut hub is off set outward by an inch? more than the 610 hubs. The shorter strut tube and any lowering will cause a positive camber issue that can't be avoided. Take note that the 610 top hat is designed with an off set so that the three studs can be positioned to move the strut in or out slightly which can help. My 710 came with these period Moog camber plates. If you look at 710s and probably 610s also, you'll notice the front end is almost always too high compared to the back. I think Nissan screwed up on their suspension math and they are difficult to align, hence the camber plates added by alignment shops. You may need to get after market camber plates. ANY lowering will cause toe out but this is very easy for the home mechanic to adjust himself. The pics are pretty poor but I'd just be happy to have tyres sitting just above the rims. Will need to get some lower profile ones but they are near new so will give them a good thrashing first. Well to each their own but these old Datsuns don't really look right with newer inch thick tires on them. besides you would have to increase the rim size to 16s or 17s to keep near the same diameter to.. 1/ keep near stock overall gearing and.. 2/ an accurate speedometer. Larger 15" rims and thin tires just plain look weird on old Datsuns Quote Link to comment
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