seattlejester

Whoops, it was in the calculations just not in the written equations. I guess in the end it doesn't matter in calculating ratio since they get canceled, but still bad book keeping. I am really sorry if this is trivial, but if you would mind entertaining me, to get the leverage arm then, you are using (roughly) the radius of the rotor minus the radius of the largest piston? I.E. for a front solid rotor aka Z rotor, 271mm - 27mm (for s30 front caliper), and 271mm - 21.5mm (for toyota 4x4 caliper)? Once again, I do thank you for taking the time. My curiosity does tend to be a nuisance to many.

Welcome to the forums, note this should really be in the troubleshoot section. Will the car run if you don't use reverse or the turn signals? If shifting into reverse or using the turn signal kills the engine, it sounds like an electrical problem. The lights that correspond to the wires should be on a separate fuse, so if they were grounding prematurely it should be blowing a fuse not killing the engine. Without a multi-meter this will be a difficult problem to address. If you could get readings of your battery that would be helpful in removing that as a problem source. If your battery is old or low on charge, the turn signal or putting it in reverse could drain enough power from the system to not charge the coil, killing the engine. I would suspect either the wiring for the turn signals, the turn signal switch itself having a burned contact, or the turn signal flashers, but throwing in the reverse lights makes me lean more towards a short causing the battery to drain. Additional information to the problem at hand would be beneficial as well. Such as the year of the car, any recent changes, basic electrical checks (alternator-load test/battery-voltage, fuse box condition).

Fascinating! Thanks! It has really been a while since I have taken physics, and sad to say I have lost some of the key elements working with biological systems the past few years. I really do miss clear equations and such. Thank you two for answering. Right, any clamping force (normal to the pad) would be multiplied by 1/2 of any diameter increase in the piston (squared) x pi. So when people upgrade the to the toyota 4-runner caliper with a significantly larger piston area they are drastically increasing the bias ratio. So looking at pad bite only (leaving tire compound, pad material, brake line pressure, etc in another category)... Just compiled for future reference: Stats: Fronts: Datsun 240z Front Caliper (~54mm) rotor 271mm Toyota 4x4 non-vented (~43mm, ~34mm) rotor 271mm Toyota 4-runner vented (~43mm, ~43mm) Rear: Nissan 280zx Rear Caliper (~43mm) rotor 285.115mm <- apparently my rears are bigger than my fronts! Nissan 240sx Rear Caliper (~38mm) Nissan Maxima Rear Caliper (~38mm) Setups: Toyota vented 4-runner and Nissan 240sx rear caliper setup Toyota 4-runner Front (43mm/43mm) = ((0.5*43)^2)*pi*2 = 2904mm^2 = 72% Nissan 240sx rear (38mm) = ((0.5*38*pi)^2) = 1134mm^2 = 28% Toyota vented 4-runner and Nissan 280zx rear caliper setup Toyota 4-runner Front (43mm/43mm) = ((0.5*43)^2)*pi*2 = 2904mm^2 = 66.7% Nissan 280zx rear (43mm) = ((0.5*43)^2)*pi = 1452mm^2 = 33.3% Toyota solid 4x4 and Nissan 240sx rear caliper setup Toyota 4x4r Front (43mm/34mm) = ((0.5*43)^2)*pi + ((0.5*34)^2)*pi = 2360mm^2 = 67.5% Nissan 240sx rear (38mm) = ((0.5*38)^2)*pi = 1134mm^2 = 32.5% Toyota solid 4x4 and Nissan 280zx rear caliper setup Toyota 4x4r Front (43mm/34mm) = ((0.5*43)^2)*pi + ((0.5*34)^2)*pi = 2360mm^2 = 62% Nissan 280zx rear (43mm) = ((0.5*43)^2)*pi = 1452mm^2 = 38% I am guessing from my numbers compared to yours that I need to factor in the leverage arm provided by the rotor diameter?

That makes quite a bit of sense, it would explain why there is some discrepancy between those that swear by either story. I hope this doesn't bother anybody if I ask this here, but would you mind if I bothered you for the numbers of the piston diameters for the fronts (of both types of Toyota calipers)? I know the rear piston has a negligible difference between the 240sx, maxima, 280zx pistons 38-43mm, I am curious about the fronts. So even though the Toyota S12 (solid rotor) calipers run a much wider pad compared to the stock S30 caliper, the effective piston area is what determines braking force? Is there no difference in the distribution of the force into 4 calipers versus 2, or is this one of the cases where we just look at the end result of the moving part and the contact that it can apply? Genuine curiosity here, I don't mean to berate at all, I know a string of questions can seem like that sometimes.

I'm running toyota front calipers (non vented disc) and maxima calipers out out back and I had to dial my proportioning valve to partially closed for the rear to keep the car from twitching in the rain under braking. I've seen the response above where some people whole heartedly state it does not work, and others swear the toyota 4x4 & 240sx caliper swap works great, even demonstrating lockup in the rear. Curious is this just a fallacy that this is an "upgrade"? I know the rear disc is not really an upgrade, just a convenience mod, but is doing the fronts actually harmful?

It looks like the w58 shifter assembly cover is thinner than the R154 one, which makes me think they are not interchangeable. The R154 with a 7mgte backed up to the firewall (leaving the stock hood latch mechanism) requires you to cut the transmission tunnel 2 inches forward and even with that a stock shifter might be out of the question (1, 3, and 5th, would be in your heater control). The w58 has the shifter located what I would guess is another inch or so back, so I would think using the stock center console is still going to be very difficult. The parts for extending the shifter cover and mechanism has skyrocketed, the toyota OEM parts for the two pieces needed to move the R154 back is roughly 200, there also is a service online that will extend both to your desired length and that costs approximately 250. I plan on extending the shifter itself back.

Psh, you have been trolling me too much lately. Can't tell when you are serious or not. Things left to do before the car undergoes surgery. LSD differential Replace ignition and door locks Adjust doors, windows, and locks Install hydraulic e-brake Trunk lock

That is unbelievable!

Good luck mate! Hopefully we will see this car up and running around soon .

Will do, I just feel bad about dragging you all the way from down south. When I'm finished, I may be able to give you a run for your money I was going to ask if the trans builder was any good since I want my trans cleaned up and looked at, but I guess that's a pass.

Let's set one up real soon, you can drive mine! So I have been on the fence lately. Sell the Datsun and move on, or spend a bunch of money and time and drive it until the wheels fall off. I am starting to make and save a little money, and before I head back to school I really wanted to reward myself with a new car. I love how the Datsun looks, but I have always wanted a 3rd gen RX-7 and I mean always. I had a savings plan and such and even listed the Datsun, but unfortunately the price of the FD3S has skyrocketed. A decent one fetches 15k easily, and that is a bit too much for a 20 year old car, I would not have enough to shop around till December. So I think that will be my reward after I graduate from grad school (when the car is importable), and for the time being it is time to make the Z hybrid-z worthy! Car will be going up on jack stands for a pretty size-able overhaul in the next month or two. A local member will be helping me to accomplish the work. Hopefully we will see a transformed car, worthy of the hybridz label . Plan is a super intense week (<-singular) of installs which means buying up all the parts ahead of time. I will try to do a better job of documentation, see you guys soon!

Warning this is going to be a fairly long post...scroll to bottom to see my question. So I had this idea in my head for a while, nothing new really just a push start, but I never had a reason to really look into it. Well the other day, I handed my keys to a friend to take my Z for a spin. He accidentally put the door lock key in the ignition and then managed to turn it pass the ignition lock. Long story short, we ended up braking the key to not make it look like the car had the keys left in it, and I have been essentially hot-wiring the car to drive it around. So I ordered a new ignition, but I figured since it was broken in the meantime, why don't I try playing with a budget push start. Note this is on a 1971 240z with an E12-80 meaning it no longer has the ballast resistor. Step one is to remove the ignition assembly by drilling out the two safety screws so I don't have to worry about the steering column lock. The portion that starts the car is the little solenoid/switch on the back of the ignition barrel. There will be two wires that will need to be grounded (formerly grounded through the steering column via attaching to the ignition barrel. The main issue people seem to run into is that you still need to turn the ignition of the car on, and then you can press the start button, this requires a smart switch or a simple board. My plan is even simpler than that, use two switches like race cars. One to turn on the ignition, and a momentary to run the starter. I've done a fair amount of searching and I've come up with the following wiring schematic. So my main question boils down to the starting. The stock switch has essentially two ignition wires. One to bypass the ballast resistor for when you start the car, and one employing the ballast resistor while the car is running, only one of these is active at each point, one is on in the on position, and the other is on when you are cranking. This is unique to me, but since I am not running the ballast resistor, will the wiring diagram above work? Mainly to have the ignition on (via the push button on/off), and then just run the starter motor (via the momentary)? My thought is that since the ignition is already on, it will be redundant, if not hazardous, to run two ignition signals to the coil. Or am I wrong and I need to run an additional signal with starter motor?

I think it may not be listed because a stock off the shelf replacement may not exist. My kit requires turned down Z31 300zx rear rotors. Quick google seach says specs are 11.417 inches with the 4 bolt pattern.

Sounds good looking forward to some early summer cruising

Yea both my friend and I are 200+ so that may have been the reason, car is still telling me to loose weight! I agree the 225's do not break traction at all, the falken's were just ridiculously skinny for what they were supposed to be.

^Looks like the welded diff may be a problem for autocross . On the flip side, a friend and I took it on some winding roads and on that the car behaved beautifully. It may be time to look for that all important LSD swap, as well as learning to drive a RWD car versus a FWD car. I did get some new rims and tires for the car and found something kind of surprising... Guess what the size difference is, as mentioned above I have falken 215/60/15 tires on the rim on top. The answer, the bottom ones are 225/50/15, supposedly a whole 10mm wider! Looks like falken just kind of stretched a 195 sidewall and relabeled them as 215 . Good thing is the smaller tire adds a little bit of gap in the back where I was almost tucking a bit before. The bad is that the width difference makes me rub when the car is loaded: me, passenger, tools, and big dips in the road. I think it looks ok though .

Wow doing work! Keep it up man, glad your ok.

I stand corrected, as long as you box the portion you cut out you can run whatever bracketry you want to your new core supports replacements.

This is a really old thread, I didn't know it was still open...but I just want to clear some things up now that I have some miles on it for posterity. I welded my diff for slightly better traction on corner exits (track) and general parking situations. If you take a turn and one of your wheels aren't quite loaded an open diff will spin quite a bit of the power away, I also have an open diff on my daily and I've been caught with one wheel spinning in loose gravel or coming off the ground (really bad driveways). I used to deliver where I would have to park in grass or off the side of the road on gravel so I wanted just a little bit of help. I had a friend at the same job who was stranded for 1/2 an hour in the rain at night without cell reception waiting for someone passing by to help push his car out onto tarmac. Car really isn't too difficult to push, just have to aim for really gradual turns . And it really is good for parking, if you are at enough of an angle your car doesn't even want to roll down hill...even if you want it to... Yes welded diffs do indeed chirp on turns, it even clunks if you are going real slow and there is a definite wear pattern on the rear tires. That's why you get tires with mileage warranties . At the time I really did not have much money, I paid $50 for the diff and welding it was preferable to being stranded on the side of the road some times. I do agree, it does wear on you, and after trying autocross, which I enjoy more than tracking, quick transitions are really destroyed when your rear wheels want to go straight. Keep in mind for long winding roads it is excellent price/performance. I am looking into an LSD, but if I was to wait for the LSD the car would never have been on the road (it has been for the past 5 months). And really a welded diff is not that bad in the rain. Granted it's not safer than the alternatives, but it is not like you have 0 traction. Only one wheel is slipping slightly so as long as you are aware it is not a problem. I do concede you do have to think a little more, but I think that adds to the experience, keeps you focused on driving. Conclusion: If I honestly really look at it, I did it because I kind of wanted to. I had a welder and I figured it was another skill I could add to my repertoire. I had spare diffs so if it was horrible I could swap them out fairly easily. The justifications for doing it is pretty weak (since I have yet to track the car on a course, nor have I taken deliveries with the car), but I haven't encountered much of the down fall other than annoyance. I may sing a different tune when I install the welded diff and find out it is much easier to turn the steering wheel, I blow a half shaft, or I spin out into a pole, but for me it has not been too bad. /thread

Did you end up using the stock mustache bar (differential mount)?

Wow sounds like a fair ordeal! Glad you nabbed the box . I used buds machine shop in tacoma for some machine work and they had me sorted out in a few days. It really is sad though, most of the shops around here are more oriented towards bolting things up.

Fiber reinforced plastic. There really isn't any load transferred across the radiator support. Once the strut tower to firewall to frame is braced/triangulated you can run whatever you want. All it is supporting is the hood hinges, grill, radiator, and in your case intercooler.

Whoops looks like I may have found the wrong link. I was using my phone at the time. BTW the seller is goodbrakes on ebay who carries the 10x1.0 female to 3/8-24 male adapters. They sell both the bubble and inverted flare style so be aware when you are ordering.

The rear split is used as a prop valve in most cars, i think there was a year when it was in the engine bay. but you can pull out the valve seat and regulating needle and spring and use it just as a straight tee. Check eBay, that's where I got my 3/8-24 male to 10x1.0mm female inverted adapters from (I can look up the seller when I get home). They were like 5$ a piece. The fed hill type lines are really good, the CuNiFer lines bend really easily and it's hard to link them unless you are shooting for a really right bend. Edit: I think John was pointing actually to this, not the brake lines. http://store.fedhillusa.com/tm183.aspx Sorry on phone no hyperlink

I had a really hard time finding that piece. If john has it I would definitely buy from him as it will save a lot of trouble. The options I came down to were A. cut out old proportioning valve and use as a split tee B. buy a 3/8-24 tee and run 3/8-24 to 10x1.0mm inverted male to female adapters C. buy a 3/8-24 tee and a flaring kit and change the fittings that meet at the tee and reflare the line I ended up going with C since that was what they had at my parts store. Just remember you have to bleed both sides if you change anything with the lines, simultaneously if possible.