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Everything posted by johnc
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Find a 240Z that's been wrecked in front and cut off the rear 1/4 panels.
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On our L6 engines you "typically" want the NA header primaries to be 30 to 32" in length as measured from the back of the exhuast valve to the merge point in the collector.
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Cutting coils out of a spring increases its rate. You made the stock springs stiffer by cutting them.
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Find another roof skin. It sounds like a buttload of work, but finding a good roof, drilling out the spot welds and cutting it off at the C pillar is a lot quicker then spending decades trying to get a dented roof straight.
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Actually, comparing ITS spec L28s and L24s you'll find that the L24s make more horsepower but less torque. The L24s are typically spun to higher rpms which gives them a better horsepower number. There is a replacement for displacement, and that's rpm... Getting 50 more horsepower out of any NA L series engine through bolt ons is a pipe dream. You have to at least bump that came up to something around 280 duration, which requires intake and exhaust changes. And a good header (the Nissan Comp one) will burn up 50% of your $1,000 budget. Personally I wouldn't focus on a horsepower number. Take what you have and make it run perfectly - compression check, valve adjustment, carb tuning, ignition, etc. Then start your modifications with the exhaust system. A 2.5" mandrel bent exhaust with new head pipes up to a ported and opened up stock exhaust manifold will help. Add some ITG or K&N air filters along with some heat shielding between the carbs and the exhaust manifold. Swap in the N36 manifolds if you can find them easily, otherwise just clean up and port match the manifolds you have (do the same to the N36s if you get them).
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Front Suspension shock tube modification
johnc replied to Careless's topic in Brakes, Wheels, Suspension and Chassis
What a nutty statement! They will probably sell a million of 'em... And that reduction of clearance is a reduction of bump travel. A typical 240Z shock has about 6" of total travel. When the car is at its stock OEM static ride height you typically have 3" of bump travel and 3" of rebound travel. By lowering the car you are reducing the clearance between the strut tube and shock bump stop. This reduces available bump travel because; even though the shock might have 3" of travel availabe, the bump stop hitting the top of the strut tube effectively limits bump travel. To get it back, you have to raise the ride height or shorten the strut tube. -
Shot peening is a surface treatment that compresses the surface of a part and cold works it to increase fatigue resistance, reduce stress risers, and increase durability. I personally haven't seen any surface finish differnces between rods from a turbo F54 block and rods from a NA N42 block but that doesn't mean much. Depending on the shot peening process, it might be difficult or impossible to tell the difference between a peened part and a part that had be abrasively clenaed or polished. Also, its very common to polish a part after its shot peened.
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Front Suspension shock tube modification
johnc replied to Careless's topic in Brakes, Wheels, Suspension and Chassis
Not really. The shock shaft is the main load bearing element and its supported at the top of the shock/strut tube and at whatever point the shock piston is within the shock tube. At the point of greatest lateral load (outside of the car in a turn or under braking) the shock is significantly compressed so that the load is spread along a wide base in the shock/strut tube (top and the shock piston near the bottom of its travel). So, the load is spread through the whole shock tube and then transferred to the strut tube, not just the top of the strut tube. The shock/strut tubular combination structure is pretty dang strong. I've seen some very poorly welded strut tubes last for years of racing. -
You guys are making an assumption here that's not true, namely that all Lincoln, Miller, Termal Arc dealers pay the same price to the manufacturer for the machines they sell. That's absolutely not true. A dealer that moves 100 machines in a month will pay less for a machine then a dealer who moves 10 machines in a month. That's true for welders, washing machines, and most everything else except cars. So, in all your examples about dealers "foolishly" giving up business, maybe they don't want to or can't afford to lose money on a machine. I encounter this all the time with suppliers. If I want their good price I have to sign a contract and agree to buy $10,000 worth of merchandise over the next year. If I want their better price I have to spend $20,000 and if I want their best price I have to spend $50,000. I have to buy that much merchandise regardless of how much I sell or I'm in breach of the contract and I have to do it every year. That's why I can purchase some 240Z parts at Summit cheaper then I can purchase them directly from the manufacturer or distributor. That's why many welding suppliers can sell equipment over eBay or the Internet for less then most local welding supply shop can purchase them.
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The issue with L6 rods is not so much horsepower as it is rpm. If you keep the rpms down (under 7,000) on a 300 to 350 horsepower engine the rods and rod bearings should last just fine. That's assuming proper rod preparation, rotating assembly balancing, forged pistons, and ARP or the Nissan 9mm rod bolts.
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The camber plates at top really don't have much of an affect on track width. You would be better off pushing the LCA out and then adjust camber using the camber plate on top.
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costs to build an engine CORRECTLY
johnc replied to grumpyvette's topic in Gen I & II Chevy V8 Tech Board
Here's another example... I and at least 5 other racers I know have used one particular driveline shop for at least 10 years. The shop does great work and I and my racer friends have never had a problem with the 30 or so diffs we've had this shop build for us. They are more expensive then others and they sometimes take a little bit longer. Well, one of my customers asked me to recommend a driveline shop. I sent him to the only one I trust. My customer complained aobut the price and went to another shop. Guess what? The LSD was assembled with the wrong clutches and was basically locked solid (found this out when the diff was taken to the shop I recommended). Not only did my customer loose time and had to pay to rebuild the diff twice, he also trashed a set of 285/30-18 Kumho V710s at $1,200 when he flat spotted all 4 wheels at 100 mph after discovering a lot of understeer caused by the locked diff. Cheaper is rarely better. -
I bought my Precision TIG 275 from these guys off an eBay listing: http://www.weldingsuppliesfromioc.com Total price for the 275, including a bunch of extras, was 3,950.00. You'll need a 220V single phase 50 amp circuit for the welders you're looking at. I had to upgrade to a 100 amp circuit for the 275, kept blowing the breaker when welding aluminum over 200 amps. BTW... a water cooled torch is nice when welding aluminum.
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ARB - anti-roll bar CG - center of gravity RS - roll steer RC - roll center RCH - roll center height RA - roll axis DRC - dynamic roll center IC - instant center FT - full throttle PT - part throttle WOT - wide open throttle NRA - neutral roll axis NSP - neutral steer point LLT - lateral load transfer LLTD - lateral load transfer distribution SLA - short long arm suspension DR - damping ratio SR - tire slip ratio UO - understeer/oversteer
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Three succesful methods of welding aluminum to steel exist that I am aware of: Explosive Welding - as mentioned above. Friction Stir Welding - a tungsten probe is spun at some insane rpm and jambed into the joint, then driven forward, with the friction creating the heat and the spinning probe stirring the molten metal into a homogenouse weld. Cold Metal Transfer - a highly modified GMAW process that keeps the material at a considerably cooler temperature then a normal GMAW process.
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Front Suspension Swap question
johnc replied to Careless's topic in Brakes, Wheels, Suspension and Chassis
Not true if you are talking about dual coil setups. Both srpings compress, just at different linear rates. -
Whoo Hoo! Time to buy a Gulfstream 4!
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I was at the Lincoln Electric welding school for 6 months taking TIG, MIG, Alloy, Hardfacing, Oxy, Cutting, Pipe, and both Motorsports classes. The cost of the school is pretty cheap considering you're in class from 8am to 4pm and only the first hour is classroom instruction. I also stayed another few days and worked with Bill West on their motorsports 4130 tube welding certification (which never really came to fruition). I (along with a couple other guys) welded about 350 1.5" 4130 tube joints and then pulled each one apart to test the yield strength of the weldment. Learned a lot from that.
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Search the site. R200 strength has been discussed a lot.
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Buy them both. The price is cheap enough and you can always sell one or the other for at least what you paid for it.
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There's a thread about their products in the Vendor's forum.
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Maybe I got a little excited. I finished the cage in the Corolla yesterday and I set my own personal record by building a cage in 18 hours of work over two days. FYI... The cage I built is out of DOM tubing. And, come to find out, this car is a car magazine entry in the "24 Hours of LeMons" event I posted about in the Vendor's forum. I can't mention the car magazine because the entry is unofficial and there may never be a sticker on the car or an article written about the event. Back to the topic at hand: Given the material limits specified by the sanctioning bodies, material choice is the least of a cage builder's concerns when it comes to building a safety cage. Safety cage failure is much, much more often a function of design and manufacture then of material selection. CroMo tubing ultimately has less ductility then DOM but the material itself is not brittle. Ductility of 4130 is only 15% less then 1020 tubing (typical DOM) as bare material yet you are getting a 75% increase in yield strenght. Where problems crop up is when 4130 tubing is improperly welded. One anecdote: When I was at the Lincoln Electric Motorsports welding school they showed us a Joe Gibbs Racing Winston Cup car where a door bar failed in a side impact and a tube was sheared off, bent in and pointed at the driver's chest. Luckily there wasn't a second impact. Lincoln determiend that the door bar failed because of insufficient penetration on the weld. Gibbs racing inspected their other 45 cars and replaced all the door bars because the same problem was found in every car. Every person who did any welding at all at Joe Gibbs racing, was sent through two weeks of motorsports welding training at Lincoln.
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A roll cage is designed to maintain a safety cage around the occupant to prevent crushing injuries. A roll cage IS NOT an energy absorbing structure and should not be designed as such. It is an energy transferring structure and should transfer impact energy throughout its structure to other parts of the vehicle. BTW... If your brain impacts your skull at 45g that means the energy absobing safety systems (helmet, seat, HANS device, harnesses, crush zones) in the vehicle failed. If your mild steel roll cage deforms 600% it was improperly deisgned and you are dead. BS! Read my lips - a roll cage IS NOT en energy absording structure, it is an energy transferring structure. The crush zones on a vehicle are designed to absorb energy until these zones are crushed to the safety cage. New vehicles fail the NHTSA and DOT crash tests if there is damage to the safety cage around the occupants. We as cage builders are creating the exact same thing.