coilovers / shortening housings / the usual ...

[EricB]

Hi guys,

i've been reading a variety of old posts here and on hybridz and feel pretty confident about what I am about to start on...

however i do want to think out loud to everyone here (John C, JMortensen, 2ManyZs, etc) to make sure that i've dotted my i's and crossed my t's

i am using advanced design struts with 280 housings.

for now, i am going to use the 1.5~2" piece of pipe GC supplied to space out the front struts inside the stock housing. I may turn something nicer on the lather somewhere down the line.

for the rear, we're looking at about a 4-5" difference between the AD strut and the stock strut - so there's some sectioning needed.

Instead of having the rear inserts sit all the way down in the housing (I do need some kind of spacer, or they will bottom out on the valve), I was thinking of using the same 1.5~2" piece of pipe on the rears as well.

I figure this will give me some flexibility down the line if I need it...

I think it's better to have not sectioned them enough, than sectioned them too much, right?

As far as locating exactly where the weld-on threaded coilover sleeve perch goes, I was thinking of positioning it such that the top of the coilover sleeve is flush with the underside of the gland nut. Does this sound good to everyone?

-e

[jmortensen]

You want the front struts to be about 3" shorter than the rears for the 280 struts. When you buy Tokicos, for example, you get the same basic struts front and rear but the rears have a 3" tube pressed onto the end of the strut to make it longer. 240Z's are the same way, but the rear struts are only 2" longer than the front on the 240.

I'm not sure how long the AD strut is, but whatever you do to the front will determine how long the rears should be. The fronts need to be sectioned due to running out of travel more often than the rears do as a general rule because most people lower the front end more than the rear and end up with a little rake.

I set up my sleeves so that the spring fits with no slop against the strut top and the spring perch at the same time. Wherever that locates the sleeve, that's where I put them on my car. That does not allow you to preload the spring, but I knew I was going to run the car low enough that preload wasn't an option anyway so I figured that didn't matter. I think this is the case for 99% of the people running coilovers on a Z.

[EricB]

Jon

the AD struts are also same length front and rear.

they sent along two small pieces of pipe (about 1.5~2" long) to act as spacers.

They did not send 4. Perhaps that was a mistake?

The valves at the bottom of the ADs extend beyond the bottom most part of the strut - so a spare is required otherwise they get mashed.

I found an old thread where someone drilled the bottom of the strut housing with a 1/2" hole to allow for the valve to sit in there...

if I put the spacers in front 280 housings, and then the AD struts, and then the gland nut, everything seems to fit perfect.

but you're saying I should still section the fronts (no spacers then?) and have the rears always be longer than the fronts? am I reading you right?

[jmortensen]

the AD struts are also same length front and rear.

they sent along two small pieces of pipe (about 1.5~2" long) to act as spacers.

They did not send 4. Perhaps that was a mistake?

I'm guessing the spacers are probably for the rear. Front to be used with no spacers, and a hole drilled in the bottom of the strut housing. Really on a 280 the rears should be 3" longer than the fronts. Most people race 240s though, and then the rears should be 2" longer, so that would be an understandable error.

The valves at the bottom of the ADs extend beyond the bottom most part of the strut - so a spare is required otherwise they get mashed.

I found an old thread where someone drilled the bottom of the strut housing with a 1/2" hole to allow for the valve to sit in there...

I assume the first sentence was supposed to say that a "spacer is required". I think the hole in the front struts makes perfect sense. You'd still have to disconnect the steer knuckle to adjust the struts, but you don't have to adjust your struts every day...

if I put the spacers in front 280 housings, and then the AD struts, and then the gland nut, everything seems to fit perfect.

This tells me that the AD struts are 2" shorter than stock. That's about right, and so you should section the front struts to fit the housing without the spacers. Ask GC for a 3" spacer or make your own and assemble. So basically yes, you were reading me right.

[EricB]

Ok thanks for clearing things up Jon.

I appreciate it.

-e

[jmortensen]

Happy to help. Good luck.

[John Coffey]

Instead of having the rear inserts sit all the way down in the housing (I do need some kind of spacer, or they will bottom out on the valve), I was thinking of using the same 1.5~2" piece of pipe on the rears as well.

The shocks in both the front and rear struts need to positioned at the top of the strut housing. You do this with spacers underneath the shock.

As far as locating exactly where the weld-on threaded coilover sleeve perch goes, I was thinking of positioning it such that the top of the coilover sleeve is flush with the underside of the gland nut. Does this sound good to everyone?

Where the threaded collar is positioned on the strut tube depends on the length of the threaded collar (typiccally 5"), shock travel, length of the strut tubes, spring length, spring rate, car corner weight, tire OD, and your intended static ride height. A 5" threaded collar positioned at the top of the strut is absolutely too high for 12" tall springs, probably too high for 10" tall springs and maybe OK with 8" tall springs.

[EricB]

john - thanks for the reply. I guess I'm looking for a ballpark location as to where to weld. I can always & probably will get different springs while I am fine tuning the rates.

You posted a pic of your coilovers with EMI camber plates & I thought I recognized the same AD struts as what I have. In that pic it seemed like yr threaded coilover sleeve was flush with the underside of the gland nut.

If they are in fact AD struts then you would have used the same 280z housings & would probably have sectioned them the same amount, no?

Did I not see things right?

[EricB]

jon - I measured the spacers GC included and they are definitely 1.5". Not 3" like you were saying. The dimension you gave is an approximate one (depending on rates/spring length/etc) or should it be exactly 3"?

Thanks guys

[John Coffey]

You posted a pic of your coilovers with EMI camber plates & I thought I recognized the same AD struts as what I have. In that pic it seemed like yr threaded coilover sleeve was flush with the underside of the gland nut.

If they are in fact AD struts then you would have used the same 280z housings & would probably have sectioned them the same amount, no?

I haven't installed a set of AD struts on a 240Z. Mostly Koni 8610s and 8611s and Tokico HPs, Illuminas, and HTSs. Sometimes I install the threaded sleeve up close to the gland nut and other times its as much as 2" below it. It all depends on the specific application.

Right now I'm building a suspension for a street 240Z running a LT1 and big wheels/tires. I'm using the stock upper spring isolators, coil overs, and 8" tall springs. In this particular case the 5" threaded collars are 1/2" below the gland nut. If the customer had provided 10" tall springs the threaded collar would be 1 to 1 1/4" below the gland nut.

There's no one set rule regarding where all this stuff get's positioned for a S30 car. I adjust things based on the customer, the intended use, budgets, and what will work given the above constraints.

[jmortensen]

jon - I measured the spacers GC included and they are definitely 1.5". Not 3" like you were saying. The dimension you gave is an approximate one (depending on rates/spring length/etc) or should it be exactly 3"?

99.9% sure it should be 3" for a 280Z. Stick a tape measure into the strut tubes and measure the lengths. Subtract the difference, there is your answer. When you section you'll want to have at least the same difference in length, if not have the fronts even shorter in relation to the rears, again because of the tendency for most people to run the front end lower than the rear. The idea is that when you're done you want the front and rear struts running in the middle part of the travel.

Maybe this will clear things up a bit. Sectioning the struts lowers the car. You might say it lowers the maximum ride height. So you can still extend the strut all the way, but it is now shorter, so to put the body on the strut the body comes down. Make sense?

So if you sectioned the rear to fit the housing as you had originally stated you would lower the back end 4.5" (3" to match the front, then the 1.5" spacer) and the front not at all. The arse end would drag on the ground and the front would be close to stock.

[EricB]

John & Jon

Thanks again for the extra details.

This stuff along with the strut sectioning FAQ on HybridZ is perfect.

Random question: while I am pretty sure that the front hub will be unaffected by changing from 240 to 280 housings (bearing part numbers don't change), it looks like there is a different rear stub axle for 280, so I can't re-use my 240 one right?

-e