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new guy with a couple questions


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Hey everybody,

 

I'm new here and new to datsuns. I have a '79 "510" wagon that I bought at the beginning of last year. I've just been driving it as my point A to point B car. I have to replace all of the bushings in the suspension here in the next couple of weeks along with springs front and back, as my suspension is shot. I figured that while I was at it i would lower the car. I have been reading the forums for the past few months and will probably be going with the shaft collar method in the front and a mix of blocks and a bastard spring pack for the rear. But, i still had a couple of questions that i didn't find answers for.

 

I would like to drop the car 3 1/2 to 4 inches but was not sure how involved it was to go that low. I'll try to keep this short as possible since i'm putting my thoughts in with the questions.

 

1. How low can I realistically go using 280zx inserts in the stock housing. I read that 2" is the max safe drop for stock struts if you take it easy. I figured with the 280zx inserts I could go 3.5" and still be safe going off a stock setup. I couldn't seem to find how low peoople were dropping their cars with just the 280 insert.

 

2. My front coils are toast so I need to get new ones. I plan on using coils from a circle track supplier but I could not find any info on what length to use when lowering. I know I need a stiffer spring but I don't know how to determime length.

 

3. Does anyone know where to find leaf spring bushings for the '79 cars. I've looked online and found whatlooks kinda like leaf spring bushings but thet are listed as rear lower control arm bushings.

 

Any input will be greatly appreciated. I do know my way around a car but it has been limited to older offroad trucks and GM metric chassis dirt cars. I just wanted a little input before I tear into this car and mess things up.

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1/  A shorter insert does not lower the car. The strut tube needs to be shortened to match a shorter insert. OR replace the strut with one that is already shorter like from a 280zx. Just measure the difference between the strut length and the shorter insert... say 2". Make two cuts 2" apart on your strut tube, remove the 2" section and weld the tube back together. Need I say that these cuts must be straight and the welds strong???

 

Two inches is conservative and probably sensible if using the stock spring rate. If running much stiffer this will resist suspension travel an 3" is probably safe. I've lowered about 3" on my 710 but the spring is 50% stiffer. I've run over the local RR track and that's quite the ski jump. The front end was fine. This is way way more than you would find on the average road.

 

2/  The springs don't wear out. You can easily calculate and shorten yours by trimming one, or a fraction of a coil, to get the spring rate you want without buying new ones. Stiffness is measured in pounds per inch, or lb/in. 200 lb/in means that 200 pounds will compress the spring one inch. Now that's the numbers but what you actually 'feel' is very subjective. Some will like 300 lb/in and say that perfect, others will say 175 is perfect. There is no way to tell in advance what YOU will be comfortable with so when shortening to set your spring rate be conservative as once cut you can't put it back if too stiff.

 

If buying springs where do you start??? Maybe trim your stock springs until you get where you want, work out the rate and order new ones.... or just keep what you have!!! 

 

3/  Here are the Nissan Pt. numbers... You may be able to cross reference these to  some other maker

 

55046-U8600 upper rear shackle, also upper and lower front spring. Six per leaf spring. 2 back 4 front

55047-22900 lower rear shackle. Two needed per spring

 

55045-22900 center front spring. two per spring

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my car is on 280zx struts with zx inserts with A10 top hat and lower perches with 2 coils cut out (using the shaft collar method)

 

Note about the front: you can NOT go lower than me if your rims are 6.5" or wider with 0 offset

 

its lowered 2- 2 1/2 inches and this is how it sits currently

 

IMG_0339_zpsb287bde9.jpg

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Thanks guys, that info helps a lot. Datzenmike, I was going to use the stock springs but my passenger side sags a good 2" lower than the driver's side unless new struts will fix that issue I'm pretty sure that I need new springs. Fat510, I'll have to do some measuring for clearance as I have stock 13's on my wagon. Love the car though. Mine is just like yours, even the same blue. Again thanks for the info. I'll definately be using it.

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Sorry I always forget that sarcasm projects poorly across the interwebs. I know struts won't fix the problem. That's why I said that I need new springs. That is why I asked about spring length. I have done a lot of reading on suspension and have a decent idea of what I need to do to lower it, such as a higher spring rate and normally a shorter spring. I just can't find the info on how to determine what length to get. I've seen the calculators for finding out spring rate increase if you cut coils and the ones that can tell you what the spring rate of a given spring is by it's dimensions, but nothing about how much shorter of a spring that you would need if buying a new spring. I don't want to go off and spend $100+ on a pair of springs just to find out that it's not even close to what I'm looking for and have to buy more springs. Again, I appreciate the input as I didn't realize that I would have to cut the the stock strut tube for the 280 inserts to actually go lower. I was under the impression that I just had to put a spacer under the insert to fill the gap and then I could just lower the spring perch.

 

Fat510, thanks for the reminder. I forgot about the wheel clearance issue with the 280zx struts.

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Sarcasm aside, you did say...

 

Hey everybody,

I'm new here and new to datsuns. I have a '79 "510" wagon that I bought at the beginning of last year. I've just been driving it as my point A to point B car. I have to replace all of the bushings in the suspension here in the next couple of weeks along with springs front and back, as my suspension is shot. I figured that while I was at it i would lower the car. I have been reading the forums for the past few months and will probably be going with the shaft collar method in the front and a mix of blocks and a bastard spring pack for the rear. But, i still had a couple of questions that i didn't find answers for.

I would like to drop the car 3 1/2 to 4 inches but was not sure how involved it was to go that low. I'll try to keep this short as possible since i'm putting my thoughts in with the questions.

1. How low can I realistically go using 280zx inserts in the stock housing. I read that 2" is the max safe drop for stock struts if you take it easy. I figured with the 280zx inserts I could go 3.5" and still be safe going off a stock setup. I couldn't seem to find how low peoople were dropping their cars with just the 280 insert.

2. My front coils are toast so I need to get new ones. I plan on using coils from a circle track supplier but I could not find any info on what length to use when lowering. I know I need a stiffer spring but I don't know how to determime length.

3. Does anyone know where to find leaf spring bushings for the '79 cars. I've looked online and found whatlooks kinda like leaf spring bushings but thet are listed as rear lower control arm bushings.

Any input will be greatly appreciated. I do know my way around a car but it has been limited to older offroad trucks and GM metric chassis dirt cars. I just wanted a little input before I tear into this car and mess things up.

 

Which doesn't really explain anything. It's been my experience that some owners don't have a clue (not you) and tend to generalize...  like "the motor blew up". But a few questions and it just turns out it's just water on the distributor cap. (a simple fix) In this case toast is just one broken spring and maybe the bushings?

 

Yes you can use any strut that will fit your strut, even shorter ones with a spacer below it. You are correct.

 

Spring length has nothing to do with the rate (or the ride height if planning to run split collars) but I agree you can have two coils with the same number of coils, same wire thickness, same coil diameter, same spring rate and yet one coil can be taller or shorter. I would say that if the coil is too short it will 'stack' sooner than a coil with more space between each coil. If replacing your coil get something near the stock length. An example... the 610 front coil is about 15.5" long unloaded. Installed on car it's 7.64" and with 6.5 coils so just over an inch between coils. At 96 lb/in it would require about 1200 pounds per side (2,400 total) of additional weight to bottom them out. If you replace with, say 200 lb/in that's 4,800 pounds... more than twice the weight of the car. 

 

Math at school wasn't my strong point so if anyone can see an error in thinking here ... please go ahead and say something.  

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Datzenmike, I just saw what you said about working out a spring rate based off the stock springs being cut. Didn't think of that. Thanks.

 

 

Yes! I'm betting you have a broken spring and it may not be usable. Maybe another HL510 spring can be found? Failing that another strut or pair of struts (for a matched set)could be cannibalized for the spring, and if it won't exactly fit your top hat and lower mount just cut those mounts off and use them and the other top hat.

 

With a measuring tape you can calculate the new doner spring rate in advance and see if it's close enough to shorten to get what you want.

 

610s are 96

710s are about 100

PL510s are 89

 

ZX and 810/Maxima are too wide.

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