Chickenman

You need some space to work. Like it or not you're going to have to take the manifolds off. Get some REALLY good penetrating spray. PB -Blaster or Kano Kroil is very good. ( WD-40 is Meh ) Interestingly a home brew of 50% ATF and 50% Acetone keeps coming up to the top of the penetrating list preferred by Machinists. Let it soak in for at least 24 hours. Another very good bolt removing spray is CRC Shock Spray. This cools the bolt down to -30c and shrinks it. This breaks the rust crystals and allows the penetrating fluid to wick in between the threads. Used a lot in heavy industry, Turbo applications and Marine applications. I'd use a combo of the two. Then use a brand new left hand drill bit ( Cobalt steel ) to remove the old stud. Once you drill out the center, that will relieve the wall tension and it should come right out. Pilot hole with 3/32" right hand drill bit. Then switch to LH 1/8" drill bit and move up to LH 3/16" as necessary. You don't have to drill all the way through. Just enough to release the wall tension. You can also use a center punch to " tap " the stud out by turning it. Edit: After a good penetrating oil soak and maybe the CRC Shock Spray, try the old " center punch " tapping technique. Sometimes you get lucky and don't have to drill. Nissan did come up with a field fix with 9mm studs... not 10mm. The important thing is that the hole in the manifold should be at least 1 to 2 mm greater in diameter than the actual stud. This is to allow for expansion of the long 6 cylinder exhaust manifold. Later 260z and 280z exhaust manifolds used larger " clearance" holes than the 240z, at the ends of the manifold. That's because the ends move more than the center of the manifold. Use 260Z or 280Z 9mm studs if you have to enlarge the thread holes. To tight of a stud clearance hole on 240Z exhaust manifolds is what caused the original bolt shearing. It's not a fastener strength issue, but rather a problem with the cast iron manifold getting longer when it gets really hot. The manifold grows in length, puts a sideways load on the stud and shears it off. Some Big Block Chevies have the same problem. If you can get the 8mm stud out with the threads in the head intact, you can still use 8mm studs. Buy the factory Nissan studs or high grade 10.9 or 12.9 grade Metric studs. Next enlarge the clearance holes in the cast iron 240z exhaust manifold by 1 to 2 mm on cylinders #1,#2, #5 and #6. That should solve the problem permanently. BTW,headers usually do not have an issue with the 8mm studs getting sheared off, as the header flange does not grow as much with heat.

The switch is a simple grounding switch. It's under the red plastic wiring conduit in post #36

Yes, that's an entirely different deal. Projector lamp housings are made for HID as Daniel Stern ( and other sites ) mention and that's the way to go. RCMP are really cracking down on the aftermarket HID " bulb only " conversions in BC. Too many drivers being blinded by glare on dangerous highways like the Sea to Sky and Coquihalla. " Proper " HID's with projector housings are fantastic. It's the cheap H4 to HID conversions in Parabolic housing that are just horrible for light scatter and glare. I've been driving the Sea to Sky and Coquihalla for 20 years as a professional driver. Retired now and not missing either Highway. Beautiful roads in Spring and Summer. A nightmare in Fall and Winter. Especially at night. One of my favorite shows... but glad I'm not driving in Winter anymore: https://www.youtube.com/watch?v=S82Ed2XJXB8

If they are those cheap aftermarket H4 to HID conversion kits please don't. They scatter light everywhere and blind oncoming drivers. Plus if you get pulled over by the RCMP, you may get a ticket. ( HID conversion kits are illegal in most provinces of Canada ). And the reality is that aftermarket HID bulb conversions are usually a downgrade from Halogen or H4 lamps in actual lighting capability. Buy a good set of H4 lamps like some Cibies from Daniel Stern lighting, put in your relay kit and enjoy amazing lighting with crisp cut offs that don't blind every body else. HID bulbs require an entirely different reflector geometry than Halogen bulbs. You should never use an HID bulb in a lamp designed for Halogen bulbs. Tech article from Daniel Stern Lighting consultants. http://www.danielsternlighting.com/tech/bulbs/Hid/conversions/conversions.html

Tom Petty's " Runnin' Down a Dream " is pretty darned good too.... and FreeBird by Lynyrd Skynyrd... and... LS Oakland 1977 Live. Enjoy!! https://www.youtube.com/watch?v=QxIWDmmqZzY

In the event of a " Catastrophic " brake failure on one of the circuits ( say a blown brake hose ), the shuttle valve will switch over and isolate that circuit. That enables you to " pump up " the brakes without losing all of your fluid and pressure. Pedal travel goes very long, but you will still have " some " brakes. Once tripped, it locks in place and has to be reset by applying reverse hydraulic pressure. This can be done by following a special procedure when bleeding as ZH mentioned.

^ thanks. That's what I was worried about. My door panels are in such good shape, that I just don't want to cut holes in them. And I have a 280Z.... so Kick panels don't fit. Grrrr

I've really put some hard miles some Automatic trannies with Autocross cars and Trailering. Two golden rules with Auto Transmissions. They like clean oil and they like cool oil. Change the ATF ASAP and the filter!!! Burnt ATF can destroy an Auto Tranny. It oxidizes and loses lubrication ability when over heated. Slight burnt smell and brownish tinge is a Red Flag. Black and stinking is too late!! Excess heat ( Towing, Competition or poor maintenance ) just kills regular ATF, and when your oil fails your Transmission fails as well. The factory oil coolers are seldom adequate. I always add a fairly large Hayden or Trans-Cool auxiliary cooler in front of the Radiator. That really extends the life of an Auto. PS Pumps also benefit from a small auxiliary cooler if you Autocross or Track day. Synthetic fluids can withstand a lot more heat before they break down. I use nothing but Synthetic fluid in any Auto Transmission, street or competition. Synthetic ATF has saved me a couple of transmissions that had been incorrectly assembled by " Professional " shops. I've since learned to build my own Auto Trannies for competition and they always get Synthetic now. Amsoil ATF ( available in GM Dexron formulation as well as Ford Mercon ) is VERY good. Not cheap. But really good stuff. It's worth the extra cost in the long run. Even on a used tranny.

^ Agreed

Has anyone ever tried putting 4" Mid-Ranges in the center console? On the sides towards the front? I was thinking of that. With some Dynamat it may work OK. Then 1" Tweeters in the vent eyeballs?

Mike... can you take some pictures of the Tweeters in the eyeball vents? I may have to try that. I have some Polk Audi DB-1001's that I'm trying to figure out a placing for.

July 1972 onwards has the proportioning valve on the Firewall. #6 in diagram. #21 is brake warning lamp on 7/72 and later models:

You are indeed correct. My bad. ( I've edited post #24 ). The Brake warning valve can probably be left in place. Up to June 1972 has the proportioning valve in the rear. This has to be removed and replaced with a straight union. Item #6 in picture:

Mount Panorama... you lucky Dawg!! The Bathurst 1000 is on my bucket list. Hopefully I can make it out next year. Lots of fans of Aussie V8 Super Cars in my area. The FR4's are actually less aggressive than the FR1's or FR2's, but they do come in sooner. For Track Days and Road racing it's not a problem, but for Hillclimbs it can be a bit of a balance issue as the fronts take longer to get up to temp. Hillclimbs are really difficult to get the brake balance right...

It's real easy to eliminate. Use a brass union ( Metric thread of course ) to couple the two rear lines together and a Brass Tee to join the three front lines together. The hardest part is finding a brass tee fitting with the proper Metric threads. But they are available. ,

What 6 piston calipers are you running Chris? If you can get the Mintex FR series race pads I would highly recommend those for a trailored race car. . From personal experience the FR series are incredible. Better than even the PFC full race compounds. We ran the FR1's on a GTO Corvette that had close to 900hp and ran 180 MPH at Portland International Raceway. Incredible stopping power, easy to modulate, NEVER EVER any fade, yet very easy on rotors. The really amazing thing is they would stop very well even when cold. We found the Mintex pads to be superior to the PFC 003' at the time. A lot of the Nascar boys were running Mintex FR pads at that time on short track and Road Race setups. ( Mid 2000's ) I ran the FR1's on my 425HP Hillclimb Camaro ( 3,270lbs ) . We were worried about lack of pad temp into the first corner, but it proved to be no problem. I ran them on Track days as well and I could brake side by side with Porsche GT3's with my setup..... lap after lap after lap. My friend has a 620 HP Trans-Am that weighed 3,900 freakin' lbs. He ran the Mintex FR's as well with no issues on Tack Days and Hillclimbs. Performance friction Race pads are very good as well. As are Ferodo. My 1986 Camaro setup. Front: WilWood Forged Superlites 4 piston with FR1 Mintex pads. Coleman 12.1" x 1.375" 48 vane rotors. Rear: GM 1LE 11.8" x 1" rotors with Forged Superlites 4 pot ( smaller pistons ) and FR2 pads. 1981 Trans-Am setup( 3,900 lbs ). Front: WilWood 6 Piston Gen3 calipers ( huge calipers ) with WilWood 13" x 1.25 " 72 vane rotors with FR2 pads. Rear: GM 11.8" a 1" rotors with WilWood 4 pistont Forged Superlites with FR4 pads. The FR1 was Mintex's extreme pad. FR2 to FR4 were for progressively lighter cars or less brake torque for rear brakes etc. If you can find stock on the Mintex I'd certainly give them a go on your 240Z. Probably FR2's up front and either FR2 or Fr4 out back depending on how much rear brake you like.

This is an even better way to measure. From spindle pin center-line to actual spring seat point:

^ . Not quite what I was referring to Steve, but I know you were thinking the same thing. The dimension from the top of the strut tube to the bottom of the weld is not the critical measurement IE: Where your red line is drawn. If you measure from the top down on the strut housing, you could have a strut where the upper part of the tube is just longer, but the spring perch is in the same spot relative to the ground. Or different for that matter. Edit: In fact, that is the exact situation with a 240Z rear strut vs a 280Z rear strut. The actual strut housing tube on a 280Z is longer than on a 240Z. The spring perch height is different as well. You want the measurement from the bottom of the strut up to the spring perch. That is what determines ride height. Like this:

IMHO, the Internet is not always the best way of communicating. Biggest problem is expressing what we are " visualizing" in our heads. You can have two people " saying " essentially the same thing, but " visualizing " two different things in their heads. Sometimes an old fashioned phone call is better... Edit: PM sent.

Unfortunately that way of measuring does not tell the whole picture. You can have two strut casings that have the same overall length measurement with the exact same springs and top insulators but still have one side of the car dramatically higher than the other. How? It is the height positioning of the lower spring perch on the strut casing that affects ride height. And Late 260z and 280Z spring perches are NOT located in the same place as 240Z spring perches. Think of a Coil over. The spring perch is on a threaded sleeve. You can crank one side up or down and that raises or lowers that corresponding corner. You will only notice this when the suspension is LOADED with the weight of the car on the suspension. The " over-all " length of the strut housing may be them same, but depending on where the lower spring perch is adjusted that will affect ride height Measure both rear struts from the lower spindle pin center-line to the weld mark on the lower spring perch. That distance should be exactly the same. It does vary on different struts housing. I suspect that when you make this measurement, you may find that you have two different strut housings. You can have two strut housing that have the same " over-all length", and yet the lower spring perch is welded on at a different height. While you have things apart. Physically remove the top insulators and measure them for thickness. Also examine the inner structure and make sure that the rubber has not separated. I think people have already asked you to do this and it must be checked. Do not " assume " they are correct, even if they are brand new. Parts get mislabeled or can be defective even when brand new. And lets be clear on naming convention. Shock absorbers are not struts.... they are shocks. The shock absorber goes inside the strut or strut housing. This will avoid confusion. So, please measure both strut housings from the center of the spindle pin to the weld mark on the lower spring perch. post that dimension. Then measure from the center of the spindle pin to the top of the strut housing where the gland nut threads in. Post that dimension. Both strut housing should measure up exactly the same when you measure it that way. Report back with findings and we'll go from there... .

Edit: Yes, the proportioning valve is in the rear on a 1971. Edit: ( Original info incorrect ) The stock " Metering " valve is located under the Master Cylinder. It's often called a " Combo " valve as it is both a brake pressure metering and a brake failure warning valve. Here is a picture of the stock valve in the stock position. Note: Depending on year of car, front and rear reservoirs on Master Cylinder may be reversed. On this model, the reservoir closest to the Brake Booster is the front brakes and the reservoir farthest from the Brake Booster is for the rear brakes.

Here are universal Plug and Play kits that will work on any car, including 260z and 280z. Very nice product with Dual 40 Amp Hella relays. $149.95 http://www.ceautoelectricsupply.com/h4headlightrelaykits.html

^ Hey Bart. Thanks for trying to help. But unless you have been following all of George's posts, you may have missed some very important information. We've already covered that valves and rings are not the issue in this and other posts. Engine has very good compression. Within 175 to 180 average with a high of 185. Well within specs. Unfortunately, Georges mechanic, has got him chasing his tail around in circles. And George himself has got so many different about the same subjects threads on this and other forums that it is difficult for members to follow exactly what is going on.

One thing with using an aftermarket Proportioning valve that needs to be mentioned. You have to remove the factory metering/proportioning valve. You should not run both together. Doing so can result in a long, soft pedal and inadequate pressure to the rear brakes. So remove the factory valve completely, then connect the front brake lines together with a Brass tee. Plumb the WilWood Prop valve on the rear brake line in a convenient location.

Chris. I noticed that you live in Australia. You may have some brands of pads that are not readily available in North America. If you can access Mintex for the Superlites and Dynalites I would go with those over any of the WilWood pads. Ferodo also makes very good pads. Many people in the UK use DS2500 as a dual purpose pad. Mintex and Ferodo are very hard to get in North America though. Australia may be different. I've run WilWood calipers ( front and rear ) for many years on my DD Camaro, which I also ran in Autocross/ Hillclimbs and Track Days. Most of the WilWood pads just aren't that great.... and I've tried a lot of different pads The BP10's are OK for a street/Autocross combo pads, but Hawk HPS are better. Especially in the wet. I should note that I'm not a huge fan of Hawk race pads, but their street pad ( HPS ) seems to work very well with dual purpose cars. Note: HPS are not adequate for Track days on most cars. EBC just seem to have too many quality issues. Very hit and miss from what I've researched and heard from fellow racers/enthusiasts. Track days usually require a set of very good full race pads. I always ran a dedicated set of bedded brake rotors, matched to the Race pads I was running. Many full race pad compounds are incompatible with street compounds, and it takes a lot of bedding to get a proper " transfer layer " if you are swapping back and forth all the time.