bjhines

I have to disagree with the issues of pad material transfer. This is made out to be more of a problem than it is. I have run damn near every combination of brake parts ever used on S-30s. ON TRACK and on the street. Willwoods with a balance bar are on the current track buildup and the only combo I have not run to the breaking point yet. Gimme a few months... The most common causes of brake shudder are dirty mounting surfaces and warped rotors. Many rotors come out of the box WARPED!!! Another common problem is dirty/rusted mounting surfaces... clean them well and the rotors will be less problematic. The aluminum spacers used to mount the 300ZX rotors are prone to corrosion and may even speed up the process between the dissimilar metals. The aluminum spacers seem to exacerbate the "warped/wobbling" rotors symptoms. The answer to this issue is to mount the rotors on the hub and turn the entire hub assembly with the rotors bolted to it on a brake lathe. This is a "cure all" for those annoying shuddering brakes. I always do this with new rotors. I keep a second set of hubs with turned rotors mounted and ready to swap. As far as overheating rotors... I have had them split radially through the entire radius before they warped. I get thousands of stress cracks in the first 30 minutes of track duty.. they last for many events beyond that initial crack-in time. Overheating is not as much of an issue as it is made out to be. Street driving simply will not stress brakes as hard as track use. I don't have warpage problems on track so there is not a correlation between overheating and warpage. I am willing to bet that there is a problem with getting the brakes WET while hot. That is a much more plausible cause for warpage than simply overheating the rotors. It may turn out that spirited street driving and then running through a river will cause warpage of the rotors.

The factory fuel rail has a restricted bypass that was there to aid in purging the vapors out of the lines during hot starts.

there are guys gettting 250HP out of mildly built L-28s with good indution and exhaust systems. This should be close.

The electrical system has 2 sub-harnesses(passenger kick panel) that power the pump only when the key is in the run position and the engine is NOT running. The original harness only operated the pump to PRIME the system. This is very helpful when the car has been sitting for several days or on hot climates where heat has caused the fuel in the lines to vaporize, vapor-lock. This means that you must still use the mechanical pump to feed the carbys on a car with a stock electrical system. If you are looking for fuel pipe routing then: One is a LARGE feed tube(right frame rail to filter area) one is a SMALL return line(right frame rail to filter area) one is a SMALL vent line(left frame rail to vacume flow control valve)

The fact that the light comes on when the pedal is applied and goes off when released means that the switch is working. There is no reason whatsoever to suspect failure of the switch. The pressure warning switch has absolutely NOTHING whatsoever to do with the brake proprtioning valve. The brake booster has NOTHING to do with the warning light system. That light comes on to tell you that either the front or rear brake system has failed to hold line pressure when the pedal is depressed. The pressure warning switch is the block with multiple lines, sitting near the framerail under the master cylinders. There is a front/rear pressure bias due to a leak or a significant amount of air in the system. Recheck your bleeding and assembly work.

Nice info there Carl. Those are the harnesses. It was my understanding that the add on kit was available to retrofit all the earlier models but was a factory installed piece on the 1973 models. I have never seen those harnesses in an earlier car. I have seen them in both the 1973s I have owned... and a few other 1973s. Recheck the service procedures. I have checked the series relays operation and they are there to CUT OFF the electric fuel pump. There is no way you could test the operation of the electric fuel pump with the engine running... unless you disconnect the voltage regulator terminal.

I am providing pics just to clear up continuing confusion on the 1973 240Z fuel-cut harness. The harness has a terminal from the voltage regulator, a terminal from the starter solenoid. It also contains a FUSE for pump power(many people neglect this in their mods). Here is the harness, it is actually 2 different harnesses Fuel-CUT relay harness Part number Fuel pump POWER harness part number Here is the passenger relay bracket with the fuel cut relays removed. It also has the EGR relay and the stone-cold temp switch removed. I sincerely hope this clears up the misnomers that continuously float around on the web.

It is true that many previous owners have changed the wiring configuration... But I have owned 2 1973 240Zs that had unadulterated wiring with the relay system I have described. I also have a 1972 that has all of the wiring in the dash harness minus the add-on relay harness for the fuel pump. This car needed to have the fuel pump connections completed in order to provide power to the fuel pump at all. Another point about a kill system.. That might work fine on a farm tractor(or a drag race car).. But regardless of oil pressure... a sudden loss of engine torque while cornering at the limits is a sure way to go OFF-Road. I would much rather loose an engine than loose the entire chassis because my fail-safe kicked in at the WRONG TIME. I see a lot of bright ideas like this as an instructor and tech inspector. I will fail the cars with these systems in place. The worst is the IGNITION kill systems guys come up with. There is a good chance that oil pressure may drop in a high-G turn. The sudden loss of ignition(engine power) under hard cornering will kill you fast. this is an ABSOLUTE NO- NO on track!!! GOTO Radio Shack and pick up a piezo buzzer and wire it up to buzz when your oil pressure drops. Then YOU can decide when to get out of the throttle instead of your fail safe sending you OFF-course. I have 2 different buzzers that buzz when the oil accumulator valve operates and another when system pressure drops significantly. They have different tones so I know what is going on at all times.

The original mechanical pump crosses over to many other vehicles. It was originally made by Kyosan-Denki(sp). They are still available through a variety of sources including E-Bay for less than $50. I don't doubt that full mark up on these pumps can be over $100 but that is lining someone's pockets with your money.

I have to chime in here on some misinformation on the operation of the ELECTRIC FUEL PUMP WIRING. The 1973 240Z uses ONLY THE MECHANICAL PUMP during normal operation. The electric fuel pump is for priming the system ONLY!!!!! It will not operate once the engine is running. None of this is detailed in the electrical diagrams. There are hundreds of things not shown in any of the wiring diagrams. There are a bank of relays on the passenger kick panel for the 1973 240Zs. There are 2 relays associated with the electric fuel pump. Relay 1) cuts the fuel pump OFF once the alternator produces 12v(engine running). Relay 2) cuts the fuel pump OFF when the starter is engaged(start pos on the key). The operation of the electric fuel pump is only to PRIME or REPRIME(vapor lock) the fuel system. It will operate when you turn the key to the RUN position. The relays cause it to shut off once the car is running or the starter is engaged. The electric fuel pump has a filter on the bottom that is often neglected. Check it or change it. There are many other components on the passenger kick panel that operate flashers, wiper delay, wiper auto run for the washer pump, EGR relay and temp switch, accessory relay, etc. The electrical diagrams only brush over the most basic systems in your car. There are hundreds of wires that are simply not shown in ANY of the available diagrams. This is especially true for the bastard 1973 model 240Zs.

The air horns are there for several reasons. They smooth out the airflow entering the venturis. They also contribute to the overall runner length which is determined by the build specs of your motor and the dimensions of your carbys and intake tract. I considered shorter full-radius stacks but the expense is high for somewhat limited gains.

I love the Webers. These pics might give you some more ideas. BTW. I used the stock fuel rail with return line, stock mechanical pump, stock vacuum control valve and PCV system. I added an electric pump in the rear and rewired to keep the pump on while the engine is running. The car runs flawlessly. I get it to 130MPH at tracks all over the South East US. I love the tunability of the Webers. I have a tackle box full of jets and venturis and all of the Weber tools. I use 3 fuel/air ratio meters with O2 sensor bungs welded into all 6 primary tubes(I occasionally swap them to check the other siamesed cylinder ports).

It is just a doubler. It reinforces a kink prone area in the chassis rails. Your rust issues look minor to me. I have been into quite a few S-30s for rust repairs. Yours looks pretty good in that area. 1. Drilll out the spot welds and remove it. 2. Clean up the rust underneath. There WILL BE RUST under it. There was probably rust under it the day it came off the container ship. 3. Cut a slightly larger piece similar in shape(to ensure contact with clean unrusted metal). Form it to fit the compound angles in that section. 4. Weld the new piece securely in place. Use a combination of perimeter and plug welds. 5. Treat for rust and seam seal the entire area including the pinch seam of the frame rail all the way to the front.

That comparison to the drawing on the wall is way off.... The Ford drawing has very little similarity to the Z car drawing... Give me a break... That is totally reaching for Ford Worship... The author is comming off like someone who thinks Japaneese people are "little"... That should not be republished as fact... but as an example of small thinking on the part of many Americans post WW2... understandable for the times.. but a relic today...

I am most impressed with nearly everything that TWM produces... I guarantee that the TWM airbox is worth every penny... PLUS!!!! the TWM airbox can be ordered with the mounting panel precut to fit the Weber triples on the 240Z... I will get you some measurements of my aluminum box if you would like... but I would reccomend running far far away from the idea of an Aluminum box...