MacPherson Struts

[Jetaway]

Four months ago I bought a 1972 240Z. Never owned a 'Z' before and all I can say is: "Where have you been all my life, baby?" It's been modified by previous owners: 5 spd., electronic ignition, both presumably from a 280Z, cross-drilled front rotors, and the object of my question here.

The Z corners as if on rails and has somewhat of a rough ride. But I have no idea if the cornering and ride are unusual or typical for a 240Z. The only -- ah, anomaly, -- in it's handling is a tendency to get loose and a little floatly above 70 -- 75MPH, with even mild crosswinds increasing the looseness.

If I jack up the front end so that the wheels hang free, I can easily rotate the coil springs 360 degrees. This doesn't seem right to me as every repair manual that I've seen that deals with MacPherson struts includes wording to the effect of: "UNLESS YOU KNOW EXACTLY WHAT THE HECK YOU ARE DOING, WORKING ON MACPHERSON STRUTS IS A GOOD WAY TO TAKE YOUR FOOL HEAD CLEAN OFF," because the coil is compressed before installation on the car.

Another Z-car owner took a look at the springs for me and said they weren't stock, didn't look as if they had been cut or otherwise jury-rigged to fit and thus probably are for a Z, but didn't know what brand they are. I haven't pulled them, only inspected them while mounted on the car and I haven't been able to spot any markings whatsoever (which doesn't mean there aren't some right in front of my face). Physically, they are a deep blue that looks awfully close if not identical to the _color of_ the springs pictured here:

http://www.classiczcars.com/forums/showthread.php?t=31609

but they do not have the variable radius coils. Or, put differently, they look like 'normal' coils.

A couple of questions:

1) Any ideas on what brand or type (street, competition, etc.) of springs these are?

2A) Is the lack of pre-mounting compression on the springs a cause for worry on my part?

2B) Alternatively, are there some non-stock coils that don't require compression before installation?

Chris

[jmortensen]

A couple of questions:

1) Any ideas on what brand or type (street, competition, etc.) of springs these are?

2A) Is the lack of pre-mounting compression on the springs a cause for worry on my part?

2B) Alternatively, are there some non-stock coils that don't require compression before installation?

Most common springs are Tokicos and Eibachs which are both progressive on the 240, then there are the MSA and Suspension Techniques springs which are not progressive. There are/were many more manufacturers, but those are probably the most common.

2a) totally normal for aftermarket springs to not have any preload. In fact I bet if you search you'll find a bunch of questions from people installing asking if it is a problem.

2b) I don't think any of the aftermarket springs have enough preload that you couldn't get the strut top on by hand.

[Arne]

The only -- ah, anomaly, -- in it's handling is a tendency to get loose and a little floatly above 70 -- 75MPH, with even mild crosswinds increasing the looseness.

This too is normal, Chris. The stock 240Z has less-than-stellar aerodynamic qualities. A front air dam or spoiler will bring a very noticeable improvement.

[Jetaway]

2a) totally normal for aftermarket springs to not have any preload. In fact I bet if you search you'll find a bunch of questions from people installing asking if it is a problem.

2b) I don't think any of the aftermarket springs have enough preload that you couldn't get the strut top on by hand.

Thanks for the answers.

The problem with searching is that unless you know the magic word or phrase, you miss a lot of relevant posts. I did find a post from Carl Beck with 1972 spring specs which I'll use as a reference for my springs.

Chris

[Jetaway]

This too is normal, Chris. The stock 240Z has less-than-stellar aerodynamic qualities. A front air dam or spoiler will bring a very noticeable improvement.

Thanks, Arne and now that you mention it;)

Hopefully a photo:

Brutal, cheap and effective. Cost for the parts was under $15.00 (excluding the rubber sheathing which I had around -- figure another $5.00 if you want) and it nails the front end to the ground. Big improvement in crosswinds, even seems to cut down on exhaust odor. Hasn't cured my rhoomytism, though. and I'm sure its extracting a mileage penalty, but in all honesty, I haven't noticed one.

I didn't mention it in the original post because if it had turned out that the unloaded coils were a source of the floaty problem, the spoiler could have been covering up the problem.

[bigoak]

Holy Mecano set-up....

I suppose it isn't noticeable at speed...

Just don't slow down...

[oskidunker1]

I have been meaning to ask about this. My 72 Z was ok until I had Koni Shocks put on it. then it road so rough I had to get rid of it. If I buy another one, I do not want a stiff ride. can anyone tell me what kind of suspension/shocks I have should be looking for? IS an adjustable shock maybe the answer? Thanks