Bruggles Posted July 24, 2018 Share Posted July 24, 2018 Alright, first a bit of introduction. I bought my z around 4 years ago, it was in okay shape but hadn't been run for 16 years. It is the late 72 model, so some of it is early 240z and some is starting to get to 260z stuff depending on the part. When I got the car it had a "rebuilt" engine with a 280z (n42 block) and an E88 head. Not a great combo in their stock forms - anything above like 5000 RPM just didn't happen. The floors were rusted out along with some other random parts of the car. I replaced the floor pans, cleaned up the dirt, mouse poop, etc. I replaced the rubber brake lines with stainless lines and any of the steel ones that were rusted along with the calipers, rear cylinders, master cylinder, etc. I put in poly bushings all around with ST swaybars and Vogtland springs with stagg shocks. I put on some Azenis RT615K+ (195/60 R14) tires, got it running and started autocrossing it. At this point I was into the whole thing around $3500 including the purchase price of the car - not bad. Quote Link to comment Share on other sites More sharing options...
Bruggles Posted July 25, 2018 Author Share Posted July 25, 2018 pic of the car After reading some aero stuff I covered some of the radiator opening with cardboard and made a plexiglass rear spoiler. This stuff actually helped hold me down on the track a little better with the side benefit of less exhaust smell. Since the cardboard worked it has since been replaced by a plastic piece that does the same thing but adds some stiffness to the air dam and doesn't look like a piece of cardboard. With the new suspension the car felt much closer to what I was looking for, but the engine wasn't quite up to par so I took the head off to see if there were issues with the engine. It looked a little worn, and had the dished pistons which means low compression ratio so it was time for a rebuild. Some details and conversation on the build are here The basics are: - N42 Block bored out 1mm - Flat top ITM pistons with balanced rods and ARP rod bolts - Casting imperfections smoothed - Turbo oil pump - Stock 280z valve sizes with SI valves and bronze seats - Late E88 head - L490 regrind - Aluminum sprayer bar - Light port and polish on the head and matched the header and intake to the head - ARP head studs - Fidanza flywheel and new clutch - MSA ceramic coated header - New seals all around - New harmonic balancer - New aluminum radiator, water pump, hoses, etc. - Cold air intake from stock air box with Norm's child toy modification (you can see it in the background of the engine block pic) - All new hardware mix of SS and higher strength steel bolts depending on location Including all machine work and parts the rebuild came out to around $3500 The engine runs great now, quick response and great acceleration. Quote Link to comment Share on other sites More sharing options...
Bruggles Posted July 25, 2018 Author Share Posted July 25, 2018 With the "new" engine in place and running there have been a few other issues that needed sorting out. On my first track day the fuel started boiling in the float bowls while running so it was time for a better heat shield between the headers and the carbs - yes these are ceramic coated headers and a better heat shield is still needed(not just a nice to have especially for track days). I built a new heat shield from scratch, it is hard to see in the pic but basically it looks like a park bench from the side without legs and covers the whole length but largely follows the style of the original with the addition of the flat bottom part. The place that is normally cut out is a bump in this version instead and the whole thing was covered with adhesive heat reflective/insulating sheet. This now keeps the carbs much cooler, so during driving there are zero issues. With this solved, I thought I was good to go but when driving on a hot day and letting the car sit for a while it starts perfectly but then it will die or become extremely sluggish. It died on the freeway which was a pretty scary experience. After looking around it looked like vapor lock so I searched around and found that insulating the fuel rail was a good way to fix this so I insulated and isolated the fuel rail. I first slit rubber fuel lines and put them over the original steel lines. I then drilled all of the mounting holes to .420 so I could put o-rings around the studs/bolts to prevent it from touching any metal. I then wrapped it with header wrap 2x. In retrospect the adhesive stuff that I used for the heat shield might have been better to not have exposed fiberglass around the lines, but either way after testing yesterday it looks like this problem is solved. It was attached with nylon washers on both sides so it is isolated from metal all around. Here it is completed and installed. After sitting for a while it is now a little harder to start, but once it starts it runs/idles great and doesn't die 1 mile down the road. I think what was happening is that the fuel would evaporate from the bowls first and then the fuel line would heat up and it would push fuel back to the bowls but leave the lines empty. So I am going to try isolating the fuel bowls from the heat even better, maybe add another layer to the heat shield or wrap the bowls. Either way it shouldn't leave me stranded in the middle of a freeway until it cools enough to drive. Yes I am still using the mechanical fuel pump and belt driven fan. Quote Link to comment Share on other sites More sharing options...
Bruggles Posted July 25, 2018 Author Share Posted July 25, 2018 The tires are wearing on the outside edges more than in the middle, and the car doesn't grip around the corners as well as I would like so the car clearly needs more camber and likely caster. I did slot the shock towers but that only gave me maybe 1/2 degree of adjustment before the spring isolator hits the towers. The plan: - Get adjustable lower control arms front and rear. I thought about building these, but when I add up the part cost, the time, and the risk it just seemed like a better idea to buy the arms. I ordered them from Apex engineered and they should be here next week. I am guessing that these still won't give me the camber that I want but should get me much closer, and I ordered a pyrometer to be able to read the tire temps and get the car much more dialed in. - In the winter I will install coil overs with camber plates. Looking at TTT weld on with TTT weld on camber plates. Not sure what spring rates - part of the reason for doing this "backwards" is that I wanted to understand the difference that proper race alignment adds without changing anything else. It is vaguely possible that I will keep my current springs... for a softer ride when not racing assuming that I don't need coilovers to clear wider tires in the future. My hope is to learn as much as I can along the way and try to disentangle the benefits of different pieces. It seems like so many people get the correct geometry by doing coilovers so it is hard to say where most of the benefit comes from and since I was planning on doing both anyways I figured this could get me part of the benefit during the race season and the part that takes the longest can be done over the winter when I don't drive the car. Quote Link to comment Share on other sites More sharing options...
Bruggles Posted July 25, 2018 Author Share Posted July 25, 2018 Questions: - Camber vs Caster - How do you know whether you need more caster or camber in the front. I will start with the recommended settings that are found elsewhere in the forum, but anywhere I have searched all I can find is the info on how to use tire temps to adjust camber. The two are related, so any thoughts on how to know when to adjust which? - Tire size - I would like to get wider tires when these ones wear out and to do that while keeping sticky non-slick tires I will need bigger rims. Everywhere I look it says that bigger rims will slow acceleration and reduce the nimble feeling of small rims... Is it worth it to have the additional traction of wider tires? Is this really noticeable or is this just internet engineering? I am thinking of going from 195 to 245-255 wide tires so the tire in contact with the road will be much wider. The number of tires available in those widths goes up as the rim size increases, in 15" rim there is like 1 tire that wide, in 16" rim there are 5 or so and in 17" rim there are a bunch. What rim size would be ideal for all around performance (acceleration, deceleration, cornering g's, etc)? Quote Link to comment Share on other sites More sharing options...
hatepotholez Posted August 1, 2018 Share Posted August 1, 2018 kinda off topic, do you have a pic of the tire and wheel setup. Thx! Quote Link to comment Share on other sites More sharing options...
jhm Posted August 2, 2018 Share Posted August 2, 2018 Your questions regarding wheel and tire size really need to be prefaced with your intended application. Racing? What style of racing? A setup that works well for auto-x may be terrible on a road course. Off the top of my head, most people will probably steer you to a 16" wheel; but that may or may not be the best setup for your particular needs. And like in all aspects of life, your budget will likely be the biggest constraint, so you'll need to decide how much you plan to spend. Websites like TireRack.com are a good tool for determining what size and quality of tires are available. Quote Link to comment Share on other sites More sharing options...
Bruggles Posted August 6, 2018 Author Share Posted August 6, 2018 As far as intended use I would like to autocross, drive the car on road courses, and drive around town occasionally. My closes course is Utah Motorsports campus and I try to do events 1x per month. I haven't decided how much I can spend on wheels/tires yet and am just starting to look so I can set a realistic budget. For the wheel setup pic there is a pic in this thread a few posts ago that has a side shot where you can see the wheels. Quote Link to comment Share on other sites More sharing options...
jhm Posted August 8, 2018 Share Posted August 8, 2018 Sounds like a 15" or 16" wheel might be the best all-round solution; in either and 8" or 9" width. There's a decent selection of tires in those sizes (more in 16 than 15) for cheaper prices than you'll find for larger diameter wheels. If you're wanting new wheels at budget prices, check out XXR (or even Rota). Otherwise, keep an eye on the used ads for used wheels. Old Toyotas have the same lug size as S30's, so watch the 4AG forums, as well as Datsun forums.. Quote Link to comment Share on other sites More sharing options...
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