JMortensen

I really wanted to do this test but my bench that my vise is mounted to is flimsy enough that I tried to test a swaybars's spring rate and was WAY off. The itch to try again hit me and so I took one of my cherry pickers and welded a socket to the mast and tested both my Craftsman 1/2" clicker and my 3/8" Harbor Freight clicker. I was under the assumption that the HF wrench was a POS and was actually putting out a lot more torque than it showed. Turns out I was wrong. I tested the HF at 10, 15, and 20 lbs and it was within a lb on every setting. It goes up to 75 lbs or something, but I wouldn't use it for anything higher than about 25, so I didn't test it all the way up the scale. I tested the Craftsman (which has had about 15 years of abuse and has frequently been put away without being zeroed) and found that at set at 30 lbs it was actually giving about 28 lbs of torque and at set at 75 it was actually giving around 78 lbs. Pretty good on both counts!!! Thanks again Dave for the suggestion. This is something that I've thought about for a very long time and never managed to test.

Curious where you got the Power Brute from... I think most of the "drive lightly for 200 miles" stuff is carryover from ring and pinion break in. Ring and pinion sets work harden, so they need to be heat cycled a certain way. When I bought a Power Brute for my Toyota truck about 12 years ago I did some figure 8's just to get the LSD additive through the clutches so that it didn't chatter (I actually tried driving it without the additive and thought I had broken something, chattered BAD). Once the additive was in and made its way through all the clutches, I drove it the next day IIRC to an autox and flogged the crap out of it. That diff was in that truck for 150K+ miles and never had any problems.

You're running AZC brakes, right? If so, your vent should feed air into the center of the brake disk. I think the way you have it set up the vent blows on the inside rotor face, which can cause problems.

Yep, brand new pulley. I... uh... guess I could have just looked at the old one. Looks exactly the same, so I think I'm good to go. Thanks for the help Cable.

You've pretty much got it, it's a trade off between effort and quickness.

I get it now. That pulley is pressed on pretty hard, so hammering it on would not only be a PITA, it would take more than a few taps with a dead blow. I can definitely see damaging the thrust bearings by whaling on the front of the crank for an hour with a hammer... So I put the dual row chain on and pressed on the pulley with the tool and I have about 1/8" of the seal surface of the balancer protruding out of the front crank seal after I am pretty sure I bottomed the pulley on the crank. Does that sound right? Just wasn't sure if it should suck all the way in there, or if spacing everything else out means that the pulley will be spaced out too. The tool feels bottomed out.

Honestly, after looking at it I think the difference in terms of Ackerman would be next to nil. You could graph it out and not have to guess, but I tried making the arms longer and that didn't have much effect, and I think the quick steer knuckles are only 10mm shorter.

Try 3.25 and about 2-3 on the wirespeed for Datsun sheetmetal. You have to keep moving, but my Millermatic 135 doesn't blow through at that setting unless I do something wrong. If you're going around the top of the strut towers, there are two pieces of metal in there. There is a top piece of sheet which is very thin, and the strut top itself underneath which is probably .100" thick. If you're trying to weld to the thicker stuff you need to use a setting that will penetrate the thicker material. Without looking, my gut says put the heat on 6 and the wire speed on 5 (you can check the inside of the access panel to verify that). Then you'll blow through the thin stuff almost instantly and have to work your way back to the thin layer with the puddle.

Went and rented the tool. Of course the supplied bolt is about 3" too short. Will get the pulley and a bolt tomorrow.

I'll check out the tool. Maybe I'm underestimating the interference fit of the pulley, but I would think that the thrust bearings should be able to take a couple whacks with a dead blow. I would think that a couple smacks with a hammer isn't going to put anything like the kind of stress that my dual 7.25" clutch is going to put on them...

Interesting... I did finish the cam swap (EASY!!!), installed the dual roller chain/pushrods/springs, and my new setup did come with a new crank bolt so I'm good there. I need to get an LS1 balancer as I'm going to run LS1 accessory drive parts. I did hone the old balancer out to use it to locate the timing cover correctly, but I haven't even bought the new one yet. What does the tool do and where can I get one? Seems strange that a dead blow hammer wouldn't suffice here...

Have you sat in the car and looked over the dash. Looks tall to me, like you might have some trouble seeing over it, especially if you're short. Could just be the angle that the pics were taken from, but wanted to bring it to your attention just in case.

The cowl is a high pressure area, so by cutting holes in it you'd get air coming into it from the engine compartment, you'd probably just push outside air into the engine compartment. Sounds like coating or wrapping the pipes would be the best solution.

I don't know how I missed the word "hood". Sorry. Carry on.

They aren't small struts. That would not work. You're probably thinking of adjustable T/C rods which are used to change caster settings. Techno Toy Tuning and Arizona Z car and others make them.

Cam finally came in a couple days ago, went to pull the front cover off and couldn't get the crank bolt off. Drained the air compressor enough to where it popped back on and let it fill, tried again, still nothing. Turned up the regulator to 120 psi. Nothing. Gave up, rented a 3/4" impact, tried again, still nothing, aside from a chewed up a cheap ass Harbor Freight 15/16" impact socket, then finally found my Craftsman 24mm, drained the compressor again and let it fill, tried about 4 more times and FINALLY broke the damn crank bolt loose. I hope the rest of the installation doesn't go like this...

No problem. Go get another with the gear ratio you want, and swap the LSD into the new unit. I wrote a FAQ post on this. It's easy.

Don't rule out new Bilsteins. They're about $100 each, and all you need is a roughly cut spacer to run them. I used 1.625 x .060" tube for a spacer. You can get the 1.625 x .120 for about $7 per foot, I think you'd need about 6 inches to do both fronts if they're stock length. http://www.onlinemet...283&top_cat=197 Hope you sent the package via some sort of insured shipping method.

They are not the same book. Honsowetz's book (How to Modify) is about engines specifically. I haven't had one in my hands in 10 years, but I believe the other one is "How to Hotrod Your Datsun 510, 610, and 240Z". The How to Hotrod book has a lot more chassis stuff and I recall it having some pictures of some of the old BRE 510s. I think there is A LOT more info here for the Z car than you'll find in that book. I seem to remember it being pretty 510 specific.

If it doesn't come in contact with the ring gear, you can smooth it a little bit with a sanding disk and it should be OK. http://www.ringpinion.com/TipOfTheDay.aspx?TipID=9

I've learned a lesson again. Maybe it will stick this time. Never use extrapolated info like "the rack and tie rods are parallel to the LCA" when you haven't verified the measurements. As it turns out, the rack is set back a bit. I also was surprised to find that the tie rods are .5" shorter than the LCA. I went through and made measurements of my setup and graphed them out per .5" of rack movement. Did some more graphing, here's what I came up with. Stock (as close as I could figure, I've changed the LCA length so I guessed at 11" for the stock length from pivot to pivot, and I'm not sure that the control arm is directly perpendicular to the crossmember): 6.5, 6.5 12.5, 13 19, 20 26, 27 33, 36 With my current setup with the rack moved back 7/8": 6, 6 12.5, 13 20, 21 26, 28.5 33, 37 If add 1" of wheelbase to my setup: 6, 6.5 12, 13.5 19, 21 25, 29.5 31.5, 38 I also found that changing the tie rod length by +/- .5" has almost no effect. It appears that adding caster helps about as much as moving the rack back. With a 5 degree slip angle and my wider than stock track, the "right" steer angle on the front wheels would be: 5,6 10,12 27, 30 30, 49 40, 63 So you can see that I don't have enough Ackerman, but the difference probably isn't enough to justify Z bar steering or anything else when you're looking at the lower steering values where it is more likely that the car will be driven. I'm going to add as much caster as possible, and for autox I may just run a heavy static toe out setting, and then I could probably run close to 0 at an open track and do reasonably well.

That's a pretty good synopsis Dan. I would say that as far as "feel" goes, when a car goes from understeer to oversteer with one change, it doesn't take a lot of "feel" to recognize it. I asked my friend yesterday and he said he heated the knuckles with a torch and bent them so that the lines through the ball joint and tie rod intersected 1' in front of the rear axle. He then sent them out to be heat treated. So he also wasn't running "full" Ackerman. I've always been one to improve the end of the car that doesn't handle, rather than loosen up the one with traction. After he did this change he had to work on the rear to match the front, and when he got that done I was never quite able to catch up to him anymore, unless we went to the big track where I cleaned his clock with a big hp advantage. You can call that feel if you like, and while it wasn't a scientific, repeatable test, neither was the one that determined for me that getting slapped in the face doesn't feel good, but I still trust the results of both. I also went out to the garage and took actual measurements instead of extrapolating the figures that I had gotten from another thread, so I'm going to do more graphing and will post the results. Looks like a bit more Ackerman may be there than I previously thought, still not thinking that it will be very much. I'm also going to see what moving the front wheel forward an inch via lengthening the TC rod does.

I think you're still neglecting the other aspects of Ackerman other than optimizing the lateral grip in a steady state corner. Did you read the paper?

I'm going to trust that pointing the tire the right direction to go around the corner is more important. Why? Because I've personally felt the change it made. You're doing the same thing Leon is doing, focusing on the peak grip. That's fine if all you're worried about are large diameter, steady state corners. For an autocross car where the steer angles are sharp and steering wheel movements fast, I think the dynamic toe in and the negative effect it has is a much much much bigger deal. I think it also might be a pretty big deal on the road courses, and I think that can be proven out by looking at the clips I pointed out before and how many times the wheel passes 90 degrees. I did look and found a spec on steering ratio for the Z. 17.8:1, so that means at 90 degrees you've got ~5 degrees on the outside wheel. I came to realize that I was quoting the Ackerman specs in CCS, but that was for the particular racecar they were modeling, and a different wheelbase car might need more or less than that figure, but I think we can say that there probably should be "some" and there is none. I'm going to try and get to the second diagram exercise today.

So I'm guessing I may be the only person here who has tried the same car before and after Ackerman mods (friend's 510 where it really made a big difference). Why do I say that? Well, I just did the graph paper test, and found out some interesting things: The stock Z has very slight anti-Ackerman, moving the rack back where I have it gives perfect parallel steer on the graph paper all the way through the rack motion. Angling the steer knuckle out 10 degrees which is about 3/4" (I don't think there is room even if you wanted to) gives the following results: Rack movement vs steering angle outer and inner wheel: .5" = 7 degrees 1" = 13.5 , 14 1.5" = 20 , 22.333 I did this full scale, so I rand out of room here, but 1.5" of rack movement is almost a whole turn of the wheel, so going farther than that is kinda pointless, but you can see that the Ackermann effect is minimal. Lengthening the steer knuckle to 5" (about 5/8" longer than stock) gives the following: .5" = 6 1" = 12 1.5" = 17 2" = 23 outside, 24 inside 2.5" = 29, 31 Lengthening the steer knuckle to 5" and bending the steer knuckle 10 degrees: .5" = 6.25 degrees 1" = 11.5, 12.5 1.5" 17, 19 2" = 23, 26 2.5" = 29, 33.75 So the question is now what? Do I give up and let it go, or try to figure out how to make it better, I think that paper I uploaded really shows why it might be worthwhile to work on it. Couple of thoughts are to make a new crossmember, or try the Z bar steering, although that looks like you need a rear mount rack mounted up front and it would involve a lot of fabrication. Maybe a shorter steer knuckle could be angled out farther. If the knuckle was really short this might work I think, and then just rely on the ps and get a slower rack ratio to make it all work. Rear steer would allow a lot of options, but would no doubt have a lot of interference with the TC rods I worked so hard on. Not sure I would want to try steering off of the strut housing up higher, but that would also be an option. Dammit! Well, at least I figured it out before I ordered the new rack...