coop

Nothing so fancy as that. All I did, is slightly slot the holes on the cross member and slide the entire cross member to the right. That at least gets the suspension back to where it should be. The e-bushings do the fine tuning, especially if I get them to stay where I want them. Sure, turnbuckles would work but they would also probably be determined to be illegal. I hate slotting stuff as I'd prefer to start with a straight car like my last one. The problem is, I was given this car by a friend and have tried to make it work. I will succeed but I will never again accept a dubious present such as this. Anyone out there reading.........don't start with a bent rust bucket. It will take years off your life.:sick:

I'm writing this from a hotel room on the road so I'll just wing it. Well, I don't know how I missed it but the forward, e-bushing on the left rear a-arm had indeed rotated about 30 degrees. This made for 4 mm of toe in at the rear. :stupid: In addition to that, there is some right thrust of the rear suspension. I went to considerable lengths to correct this when I built the car so I don't know, perhaps the thing is just bent some. The slotting of the rear cross member needs to be increased even more to remove the thrust. The down brackets appear solid and square. Could all of this have caused the car to turn poorly to the right? Time will tell as I left the car in pieces when I walked out the door today. I hope this is the smoking gun. We'll see.

Well, this is an area where I've compromised over the years. I sit in the car when I do the corner weighing but I don't when I remove the preload. Yeah, I know, not as accurate as it could be. I should get 165Lbs of weight and place it in the seat while I do all the adjusting and measuring. That way the preload would be guaranteed to be zero. I like it though, good idea. Now, where can I find that much dead weight around the house? Might have to take a trip by the ex wife's house. I use aluminum eccentric bushings all around. The left rear might be toeing in as trail braking ends and power is applied. I'll be checking that soon. Sounds too easy! Static toe looks good, however. Again, there may be a broken mount, etc. What about a problem in the steering rack?

To relieve the preload, I reach under the car while the suspension is fully settled on the scales. I loosen the adjustable slide that attaches to the bar just a little and only at one corner. Then I loosen the lock nut from the down rod at that same corner. I then turn the down rod bolt which is threaded into a heim joint. I turn the bolt back and forth until the slide starts to become real loose. At this point, there is no preload. I just tighten everything back up and I'm good to go. Any difference in preload that has been relieved can be measured on the scales. Any way, the weird thing about all this is that the car was perfect the last time it raced and I haven't made a single change since then. Something has to be broken. Also, the upper spring perch is in good shape as it was inspected when I replaced the shocks.

It's weird alright. Corner weights are perfect as I scaled the car again when I got back home and again after changing the shocks(I always remove preload when corner weighing). At the track, I even corner jacked the car to get it to change behavior in both directions and went to a full soft rain setup. No mater what I did, same result, a bad push in right turns. This even occurred at Fernley during testing. I've had people turn the steering wheel while I'm under the thing and no notable slop. Perhaps the rear end is taking some sort of toe change when the left rear is loaded? I also thought about the Quaife. Could it be acting up in only one direction and I can't feel it in the seat of my pants? It's only a set of gears since there are no clutches back there. Quaifes are supposed to be bullet proof. Also, I used to run a locker and that led to under steer only on slow corners. If the Quaife was locking up, the rear should be stepping out on fast corners just like my old locker and you think I'd feel it let go. Same result on multiple sets of tires with consistent tire pressures. Possibilities? -Crack in steering linkage/rack/coupler -ball joints -toe changing -bad spring -diff -cracked frame or TC rod/mount - then why does the car brake in a straight line? -sway bar failure Maybe I should move everything on the left that is transferable and move it to the right or just replace everything. I sure wish there was a smoking gun here. Do steering racks ever act up?

Yes, a Quaife.

:ermm:Recently ran the car in Vintage at Laguna Seca and the thing wouldn't turn right. It just wanted to push straight off the track. This happens under light throttle application just after turning into the corner. The race before, the car was perfect. I've tried tightening everything and have found nothing wrong. Sway bars are snug. The alignment looks good too. I even tried rebuilding all four shock absorbers and the car still pushes in right hand turns. The thing is, the car turns left great. Now don't tell me to start running NASCAR, as that joke is getting very old. Has anyone seen this behavior in a Z? I've been running a Z for over 20 years and have never come across this. Your thoughts? Thanks, Coop

The San Francisco Region of the SCCA is putting on a vintage race on 4 and 5 April. There should be several 240s running there including mine. Stop by and say hi if you're in the area. Coop

Right you are John. I'm not allowed to do that mod. Also, I've been told by folks behind me that I "throw the car into the turn" to establish my drift angle so I may be making up for weakness in the car's performance by driving it with less finesse than one might drive a really good handling car. I do feel that my car turns in quite well, maybe because I use the following technique on tight corners: I brake very hard right up to the turn in point, then quickly let off the brake and while the front end is still highly loaded, I make a sharp turn of the wheel to get the turn in and rotation I need. Then I use the throttle to adjust my track out. This was the only way I could get the welded rear end to work. I use a Quaife now so I presently can use a little more finesse. :laugh:

Hey John, I might dissagree with you a little bit on using that much caster. I experimented with adding more caster and found that the steering wheel forces became so great that the car was difficult to drive. You see, I was using so much arm strength to turn the wheel that finesse went out the window and I couldn't react fast enough to put the car where I wanted to. I suggest that caster be set close to stock. Then you can add or remove spacers/washers at the end of the TC rod to keep the car from pulling to one side and to get the feel you like. Back when I couldn't afford delrin TC bushings, I would grind down the stock rubber bushings and surround them with big washers and then torque them down real tight. This worked quite well if not great. I later graduated to delrin bushings and washers(which I now use as spares) and I now use spherical bushings which are very precise.

With the tires you are using, there is very little you can do to increase the turn in capability or crispness shall we say other than raising the tire pressures. Changing camber will have limited effect since your tires are so tall that the side walls are moving all over the place trying to keep the contact patch working. What I would do is go to a high performance low profile tire. Then run some negative camber on the front end and a little on the rear too. A larger sway bar up front also helps with turn in as the delay due to roll over is diminished. Also stiffer shocks can help. Here is what I run: 225/50/14 Hoosiers all around - great turn in and traction on the way out too but prone to flat spotting though so watch out. The Toyos of the same size are much more forgiving and come with more tread depth. They are a little less precise than the Hoosiers. Camber: -3 Degrees front, - 2.5 degrees rear Toe: Zero in front. Just as little as is measurable in the rear. Just don't let the rears toe out under any kind of load! About a 1" front sway bar ( don't remember off hand from this hotel room). A small adjustable one in the rear since I use some fairly stiff springs. Ground control dual adjustable shocks - don't go there. Go with the adjustable Tokico's for more general road and track use. Again, just try increasing the tire pressures to around 36 psi cold and see how that feels. Then try around 38psi. At least it's cheap. Hope this helps.

Hey Carl. I bet lots of folks would like to get their hands on those wheels. At least one of them can be seen on Frank Leary's FAR Performance car that is pictured somewhere on this web site. I met Frank at the Portland Rose Cup Trans-Am race where he was racing his turbo 280-ZX. I bought the wheels a few years after he died. :disappoin Been very busy with stuff like staying married, buying a new house and actually making the payments as well as slowly building the car. Did manage to run a couple of enduros in an RX-7. Fun but slow. I'm planning on running a vintage event in April at Laguna Seca. Thought I'd tone it down a bit since the last race really put a strain on the brakes. Lap times are so fast now that I don't know how much longer this old car can take it. :eek: Coop

I've just died laughing and hey ..... I only rolled three times - Doh! Actually, that is Bruce Frederick's car that I used to race against. It was always nicely prepared and had no problems that I can recall. It had a chrome-molly cage if I remember right. I offered to buy it at one time but it had already been sold. Coop

I built up a hanging paint/sand blasting booth with plastic, card board, duct tape, etc and used forced conditioned air to pressurize the thing and a large fan with filters to evacuate it. I can't paint well but I can sand and buff with the best of them. This car was actually a piece of junk that was given to me by a friend. It had to be straightened along with much rust removal and metal replacement and repair. I wouldn't do it this way ever again because it took 4 times as long to build as my last car. However, it would be a shame to use a perfect frame and trash it in a racing accident. Coop

Hi everyone. I just joined this group after having been away from all Z groups for a long time. It's nice to see all the intelligent chatter here. Just completed my three year project, a 1971 SCCA ITS/Vintage race car. On its first race at Laguna Seca in October, it scored a win and then two P2s the next day. The fastest lap it recorded was 1:43.9 which is two seconds under my old best time. Not bad for a 37 year old car. Stop by and see some of the pics of its construction that I've posted with my profile. Hope to talk to some of you soon. Coop :laugh: