steve91tt

I'll bet there are still lots out there. I've got one sitting under my bench right now from a stock L24. If you can't find one locally I'll sell it to you.

Be warned that replacing the foam can cause you to sit higher in the car. Not an issue unless you are over 6 foot. I replaced mine a while back and now my head hits the roof when I go over bumps. This was never an issue with the old foam. I bought my foam from MSA along with their leather seat covers. You may have different results with other vendors.

Agreed, I believe that the turbo and maybe the 2+2 had a larger clutch but I believe that the flywheels were the same. If you are getting a new clutch anyways then it should be simple enough to find a used flywheel from any L series engine and buy the clutch and colar to go with it.

We are planning on boxing in the top of the rear strut towers and bracing the main hoop there. He says that we should be able to get close to 45°. He will also run a bar between those rear braces for chassis rigidity. After that he will work on the harness bars and I believe he said that he was going to do more diagonal bracing for the rear hoop. The driver side door bar will also be removable using the following assembly... http://www.appliedracing.com/roll-bars-cages-and-components/swing-out-bar-kits-with-clevis-mount.html

Jeff, When comlete, the cage will include the upper door bar that you describe.

I guess I should have explained the bracket racing better. Every second Thursday at my local road course they have a 10 lap race that is open to any car/driver that will pass tech inspection. Each driver picks a brake out time and they stagger start the cars based on that time. If you go under your time for any lap you are assessed a 10 second penalty. First car across the line (plus penalty) wins. It's a fun race to watch. There are cars running 2:05's out on the track with cars running 1:30's. The fast drivers have to pass constantly. The slow cars have much more open track to play with. A few more bits of safety stuff and I get to go play.

Jeff, good catch on the 360° welding. This car will be used for road racing not drag racing so I'll follow up with the builder on this issue.

I dropped by the cage shop tonight to check on how things were progressing. Dash bar is in... The main hoop and roof structure is coming along nicely. And some great looking main hoop supports. It's a shame that you won't be able to see them when the seats get installed! If all goes well I can take delivery on Saturday.

Thanks John, that gives me some good discussion points to take the builder. Marty, I am putting the stock dash back on. The dash bar tucks up nicely to the firewall so I will only have to modify it slightly on the ends where the front hoop cuts through it. The dash has significant cracks so I don't feel so bad modifying it. You can see the masking tape mock up of the door bars in photo #8 in my original post. Hopefully that will keep the vipers out.

Agreed, my left knee is usually bleeding after a day at the track with stock seats.

I found this in the SCCA rule book... Improved Touring, Showroom Stock, Spec Miata, B-Spec AND Touring classes–The roll cage must attach to the vehicle structure (floor pan/ rocker boxes/ sills) within the passenger compartment in a minimum of 6 points and a maximum of 8 points as specified in these rules. I believe that means that cage mounts on the sills should be fine.

The accusump is a bit of a pain but not too bad. I may put a remote electric valve on it in the future. I thought about mounting it in the cabin but I'd rather keep it as close to the oil filter as possible. I installed a 85 dB buzzer in the cabin that goes off when the oil pressure drops below 20psi. I've never heard it go off so I guess the system is doing its job. I'll talk to my cage guy about the floor mounts. Thanks for the heads up.

The harness and dash bars are going in this week along with the rear hoop support. I went with the Cobra Monaco seat with Schroth harness. Hopefully that will keep my butt planted better than the 40 year old stock equipment has.

I've been doing 1 or 2 track days a month for the past year in my 1971 240Z. Starting next month I plan to start bracket racing at our local track so in order to pass the tech inspection I need a cage, racing seats, harnesses etc. The car started as non-running barn find last April. http://www.classiczcars.com/forums/showthread.php?42156-New-240Z-build&highlight=1971 Since then I've upgraded the suspension and added a Rebello L30 and an oil accumulator system. I stripped the interior and rolled the car into the cage builder 2 weeks ago. Lots of good progress so far. To my admittedly untrained eye, the bends look great and the bars are tucked up against the body nicely. The guy putting the cage together really has nice attention to detail. The floor mounts for the main supports are beautiful. There is still a bunch of work to do but with any luck it will be back on the track at Texas World Speedway on March 3rd. Fingers crossed!

The oil pan and pickup do not have to be changed to swap to a turbo pump. I don't remember if the pump spins cw or ccw but it will only pump in one direction. Running the pump with a power drill will allow you to see if the pump is working and if oil is moving as is should in the head.

The OEM pump will move lots of oil. If it were me I'd clean it up and put it back on. If you find you don't have good oil pressure then swap it for another. The pump is easy to change with the motor in the car. If you are worried about oiling I would remove the distributor/oil pump drive shaft and turn the pump with a power drill. You should get lots of oil through each of the holes in the spray bar in the head. When I did this with mine I was surprised to see that oil was leaking out around the spray bar fittings thus reducing the oil that made it to the cam. I made a tool to turn the pump by cutting the handle off of a long flat blade screw driver. I picked one up at sears for a few bucks. Works great.

Good point Bruce. I agree, if you put too much oil into the head then it may not be able to drain back fast enough. However, I believe the amount of oil that moves into the head is a function of pressure not volume. The turbo pump creates more pressure below the threshold of the relief valve because it pumps more oil. If both pumps have the same relief valve and thus the same maximum pressure then the same amount of oil will end up in the head. The turbo pump will just dump more through the pressure relief system when the RPMs are high enough to reach the maximum pressure. When the RPMs and pressure are lower than the set relief pressure then the turbo pump will deliver more pressure per RPM and that pressure is inversely proportional to the clearances in your bearings. In other words, I think that an older engine will benefit more from a high volume pump than a newer, tighter engine but if the pressure relief system is working correctly neither should have over oiling problems.

Yep, the hiss you hear is most likely a vacuum leak coming from the broken diaphragm causing extra air to be introduced into the intake. When mine failed my idle became unstable. Because yours went up you may be running a little rich and the extra air from the leak is bringing you closer to stoichiometry.

Depending where you get the oil pump it can have higher flow than stock or it can provide higher maximum pressure than stock. The high flow pumps came on the turbo Z's and other cars with similar motors. If you request an oil pump for a stock 240Z from your local autoparts store they will likely hand you a high flow pump. The only way to tell which one you have is to remove the bolts holding the two halves of the pump together and measure the rotor. If I remember correctly the high flow rotor is 40mm long. If you take the pump apart you will need a new gasket from MSA (<$1). I tried replacing the gasket with a thin coat of RTV when I took mine apart but the RTV was thinner than the stock paper gasket which caused interference issues internally in the pump. The maximum pressure for these pumps is controlled by a spring on the internal relief valve. MSA has higher pressure springs. Higher flow or higher pressure will cause more drag on the engine but I'm not sure it matters. I run turbo pumps on both of my 240's as I'd rather have a little more oil than a little more horsepower. If it were me I'd take it apart and make sure everything is in good shape while you have it off of the car.

Have you checked that the plug wires are hooked up in the right order? Mine will do what you describe if I get a wire in the wrong place. You might also put a timing light on each plug wire one at a time to check that you get a good even pulse from each cylinder. If you find one or more cylinders have an irratic rhythm then you might look at the rottor/cap/points/distributor.

You posted at the same time I did Zed Head. I didn't think of the ballast resistor.

The new coil should not have hurt the stability of your idle and you should not need a different distributor. We need more information to diagnose the problem. 1. Condition of plugs, wires, cap, rottor, distributor 2. Is your car stock or has anything been added or deleted? 3. Have you done anything to check the tune on the carbs? Float levels, vacuum leaks etc. 4. Other than being hard to start when cold was the car runnning well through the rev band before the addition of the coil? 5. Did you change anything else when you swapped the coils? Could the plug wires have gotten switched? With a little more information the folks on this forum should be able to help. Good luck.

On a 40 year old motor, leaky valve seals are as common as wet tires in the rain. If leaky seals could cause the symptoms you describe this wouldn't be 12 page long thread.

Sounds like it might be a mechanical issue inside the tach. Have you tired removing it from the dash to see if there are any mud dobber nests in the guts of the tach?

Watch out for RTV on the gasket around the intake ports. Gasoline can destroy RTV. In a wet, carbureted intake such as ours raw gas can find its way onto the edge of the gasket, eat away at the RTV and cause a leak. I caused a vacuum leak myself last year by putting RTV on my intake gasket. Lesson learned, now I always install them dry with only a little high temp RTV around the exhaust ports.