Kirkster Posted September 23, 2015 Share Posted September 23, 2015 (edited) Well my 75 N42/N42 lost compression in cylinder #4 so it is time to pull it and do a rebuild. Unfortunately since I am racing this car in SCCA Solo B Street Prepared there is not a whole lot I can do to it. The cam has to stay factory. I can bore the block .0472 over which is basically the 1mm oversized pistons and they have to be the dished variety to keep it legal I can also deck the head to factory specified limits or .010 if there is nothing in the 75 factory workshop manual about limits on the decking of the head. Finally I can port match the intake and exhaust 1 inch into the head. And that is it per the rules. Now I have two ways I can do this. One is by finding a machine shop to do the work on the block and head and I put it all back together with the 1mm oversized pistons. The other is buy a motor built to these specs or send mine in to have the work done. I have looked at Rebello for a new motor, and I also engaged Datsunspirit and will see how they each price out. Any suggestions on where I can get reliable machine work done in the Mid Atlantic? Or should I just go with Rebello or Datsunspirit? Why am I doing all this work on a stock motor? For two reasons. One to prove to the Solo Rules committee that the car is underpowered for the class (I don't expect to see much over 170whp with a fully built to the rules motor and my competitors are all 250hp+ cars even though I am 600 pounds lighter than the 300whp 350Z and only 100 pounds lighter than the 240whp Mazda Speed Miata that spanked the entire class this year). The second is to support my bid to get all of the Z cars from 1970 ~ 83 on the same line so I can put a L28et motor in the car which would be much more competitive with the class (and probably still underpowered since I would have to use the factory turbo). You have much more credence to get rules changed when you build the car which I have already done. Edited September 23, 2015 by Kirkster Quote Link to comment Share on other sites More sharing options...
Ben280 Posted September 23, 2015 Share Posted September 23, 2015 Looking forward to seeing your progress! I think we might have met this year at Nationals, (Orange Z right?) Hopefully you can sway the SEB, but they don't seem to give much thought to the older cars! Quote Link to comment Share on other sites More sharing options...
johnc Posted September 24, 2015 Share Posted September 24, 2015 There is a lot you can do to build a BSP engine. The internal engine build limitations are the same as for SCCA ITS. Way back when Keith Thomas' L24 made 208hp running SUs. You can legally get .5 more on the compression ratio by using projector tip plugs and have the machine shop set the valve seats proud into the combustion chamber (max limit spec'd by Nissan). There are other machining tolerances that a good machine shop can take advantage of. You can run a light flywheel and pressure plate. Intake is open. Exhaust is open'. Ignition is open. 200hp is easily within reach. Quote Link to comment Share on other sites More sharing options...
johnc Posted September 24, 2015 Share Posted September 24, 2015 Weight is another place to look. My BSP legal 240z weighed in at 2,105 running 15 x 8 wheels and 2,165 with 16 x 10 wheels. Quote Link to comment Share on other sites More sharing options...
clarkspeed Posted September 25, 2015 Share Posted September 25, 2015 LNA in Greensboro. Sam will build you some power. Quote Link to comment Share on other sites More sharing options...
gogriz91 Posted September 25, 2015 Share Posted September 25, 2015 I know the former shop manager from Sunbelt in Atlanta who may be able to do the build or recommend a shop, PM me if you want his contact info. Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted September 25, 2015 Share Posted September 25, 2015 Yeah I was up against s2000 and such in bsp and on the stock engine it was just laughable trying to keep up. Moving up to SM this next season with an engine swap. Quote Link to comment Share on other sites More sharing options...
Kirkster Posted September 28, 2015 Author Share Posted September 28, 2015 My 240 BSP car weighed in at 2303 with the gas tank filled to 3/4 full and 18X10 CCWs with 285 hoosiers. Not a lot left to take out that I can see right away... I am already running a light flywheel and pressure plate. Running headers, and the group buy intake (which is going to get swapped out for something with longer runners). I will see what I can get done for a reasonable price from Rebello's and DatsunSpirit and pull the trigger on that soon. Quote Link to comment Share on other sites More sharing options...
johnc Posted September 29, 2015 Share Posted September 29, 2015 There are a lot of ounces that can be removed from the car. You should be able to run your fuel tank at 1/8 (2.5 gallons) and be fine for 3 runs. The early 30 amp alternators save 5 lbs. No radio or speakers or related wiring. Two row radiator, one horn, no choke cables, etc. Quote Link to comment Share on other sites More sharing options...
Kirkster Posted September 29, 2015 Author Share Posted September 29, 2015 (edited) I usually run the fuel tank at half tank and sometimes a bit lower. I have run into starvation at local events when I went to 1/4 tank. Already running no speakers. Have not felt like taking out the old push button radio yet (I kind of like the power antenna ) and you can't remove the OE wiring for the radio but the non OE wiring to the radio is gone. The radiator dry weight can't be less than the factory radiator so I have not bothered with that as I don't have any cooling issues. I know the seat belt retraction units are pretty heavy but I need to put in a harness bar before I get rid of those... I still have 2 horns... But most of the easy stuff is gone... The undercoating on this car is really thick so I could loose 20 pounds or more of that stuff... But the motor is my first priority now. Edited September 29, 2015 by Kirkster Quote Link to comment Share on other sites More sharing options...
johnc Posted September 29, 2015 Share Posted September 29, 2015 Your car is a '73 as I just now noticed. You're about 120 lbs. heavier in the basic chassis them my early 1970. Mostly for DOT required safety reinforcements. If you can get the car down to 2200 you're about a good as you can get. Factory radiator is a two row so use that weight. You can also go with a fuel cell and with a clever installation (bolt-in aluminum framing, removing the filler hose, etc.) you can save a few pounds and run much less fuel. Quote Link to comment Share on other sites More sharing options...
Kirkster Posted October 6, 2015 Author Share Posted October 6, 2015 Johnc, Any advice on an intake for fuel injection? Is the later model webbed intake going to do well or is there an obvious better choice for a Fuel Injected L28? K Quote Link to comment Share on other sites More sharing options...
johnc Posted October 6, 2015 Share Posted October 6, 2015 Everything from the head out is open IIRC. ITBs or a custom plenum intake. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 6, 2015 Share Posted October 6, 2015 Everything from the head out is open IIRC. ITBs or a custom plenum intake. I think he's somewhat leery of the latter given our recent experiences... Quote Link to comment Share on other sites More sharing options...
Kirkster Posted October 7, 2015 Author Share Posted October 7, 2015 Tony, I actually got a good intake manifold from the group buy. It will probably be great for a turbo application but for NA it is less than optimal. I am currently looking at a factory FI webbed intake unless I can get something better. I have a webbed intake right now that I am going to have to do a bunch of welding on before I can use it. Just looking to see if there is anything else out there that would work better for a NA application. Not sure I am ready for ITBs though. I will probably be spending enough on a motor this winter, as well as Aero and other things for the car itself this winter. Quote Link to comment Share on other sites More sharing options...
Tony D Posted October 8, 2015 Share Posted October 8, 2015 You would be amazed at what shows up cheaply overseas on some auction sites... Quote Link to comment Share on other sites More sharing options...
Kirkster Posted November 3, 2015 Author Share Posted November 3, 2015 So plans have changed. Wife's Job gets eliminated Jan 1. The motor has been dropped off at a local shop for boring and honing... Still taking things .040 over and getting the head rebuilt and everything decked to the FSM max specs. Also have a webbed factory intake that I will be putting a 65mm 240SX type throttle body on the end of it and sealing up all the silly emissions holes in the intake. Only really need the brake booster, IAC, and MAP sensor connections. Will keep you all updated. Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted November 3, 2015 Share Posted November 3, 2015 Are you limited to a metal hood and hatch? lightweight battery possible? Quote Link to comment Share on other sites More sharing options...
Kirkster Posted November 6, 2015 Author Share Posted November 6, 2015 I need to find some pistons. I am looking for dished pistons. The Nissan part number is 12010-Y4116 which was superseded by 12010-Y4133. The nissan dealers are telling me that they can't get them. What are my alternatives out there? ITM? Just checking to see... K Quote Link to comment Share on other sites More sharing options...
tube80z Posted November 6, 2015 Share Posted November 6, 2015 One area to lose some weight is the clutch. Go to a 7.25 or 5.5 multi-plate clutch either use a flex plate with flywheel or integrated unit. That will get you 15 pounds or a tad more of rotating weight. These aren't as expensive as they used to be and you can find good used ones on ebay from the nascar cast offs. Lithium battery is another easy upgrade. Good luck getting the cars all on the same line. That would be very cool. Cary Quote Link to comment Share on other sites More sharing options...
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