Chickenman

That would do it. Still the tip wear is excessive for such low miles on your engine. I think the Royal Purple may have been responsible for that, Unless the Rockers tips were reground as well and went through the surface hardening too. Either way it adds to tales of woe that seem to go with Royal Purple....

^ Yeah... I was wondering about that tip wear too.

Lat picture really shows off the casting flaws in the old rockers. Look at the bad casting lines near the rocker pivot and the casting void shown at 1:00 by the pivot. Machining marks around mouse-trap spring groove and pivot ball oiling hole are also very irregular compared to new rockers Not up to normal Nissan quality, and I suspect those may have been reground aftermarket rockers??? IDK... Or maybe the new Genuine Nissan rockers ( 13257-W0300 ) were just made from a newer forging die? Abnormal tip wear on old rockers in Photo #2 as well. I think you dodged a bullet by catching this when you did.

You didn't answer this which we need to know. You mentioned that you can get a spark from coil wire when manually grounding Trigger wire... but do you get a good strong spark from the coil wire when cranking the engine on the starter. Yes or no?

That is my concern as well. If you place a reference mark on your monitor screen against the uprights ( at lower point ) you can see that the metal plates are flexing as you get on and off the power. Eventually this is going to cause metal fatigue and failure of the " L " shaped mounts. Likely at the top bend of the " L ". As JM mentioned, these thin metal upright plates may be OK for the Torque and Power of a stock L6, but they are no where near adequate for a stout SBC. I would highly consider building better and stronger versions of these plates. Perhaps with Gussets along the spines. Triangulating the Mounting plate uprights would also add immensely to their strength and would distribute the loads to the chassis. Adding Doubler plates to the Chassis at the mounting points of the original upright plates would be a good idea as well. All that Torque has to go somewhere... and eventually it all ends up at the Chassis mounts. The rubber pivot bushing can only dissipate a small amount of energy, and once they compress, all the energy is transmitted to the Chassis. The system is only as strong as the weakest link..... Edit: I'm not overly concerned about the movement of the diff. That's dissipating energy and really isn't affecting anything but Pinion angle. And I don't think the movement is excessive. If you took pictures of the IRS in a Corvette, you'd probably find a similar amount of movement. What is concerning me more is the flexing and movement of the LCA uprights that connect the rear LCA Crossmember to the Chassis. Those are flexing and that is not good. They will eventually fail from metal fatigue IMHO.

Stick to one thread please. Otherwise it gets very confusing. Check my replies in your other thread.

Regarding the rotor. Pull it off and check the bottom side in the Center. If you find burn marks, carbon tracking, or a lot of rust particles... that is a sign that the spark energy is arcing through the rotor. Rotor is toast. replace it. Common causes of rotor arc through or Cap center button erosion are: 1: Poor quality ignition leads or leads with too high of resistance. MSD spiral core leads are good. Taylor and Accel seem to be crappola. Check the resistance of each lead with a Ohm meter. One bad lead will eventually cause the rotor to burn through. 2: Do not run too big of a Spark gap. Yes an MSD can fire a .050" to .060" Spark gap. That also places a lot of strain on other components such as Caps, Rotors and HT Leads as the spark energy level rises to the plug " Arc over " point. Keep the spark gap below .045". .040" is a nice range on Normally Aspirated Chebies. Turbo cars are another matter. Please advise if you car is Forced Induction.

Also... 1: Check the center button on the distributor cap. Make sure it has not eroded away. Look for carbon tracking inside cap. Hairline :traces of carbon leading from plug terminals. Can look like hairline cracks. If you find either condition the cap is hooped. Replace it. 2: Check your rotor phasing. MSD has Tech articles on it. Can especially be a problem with a locked out Dizzy ( Mechanical advance locked out ) and Dizzy's that are used with Ignition Boxes or ECU's that have programmable timing curves. Just want to be clear on one point. If you pull the coil wire from the dizzy end, place it near the engien or chassis and crank engine over.... you get a good strong spark? Is that correct?

Here's some Technical Data from Pegasus Racing on Micron sizing required for different systems ( Oil and fuel ) which confirms what 240Dan has been saying https://www.pegasusautoracing.com/document.asp?DocID=TECH00100 It is interesting that the fuel safe sock is rated at 31 Microns, which is pretty small. A lot of surface area though. https://www.pegasusautoracing.com/productdetails.asp?RecID=7297 After much research I managed to find some data on the Fram G3 Micron size. Apparently it filters down to 20 Microns. That size combined, with the small media surface area is what was probably causing the pump whine. 240Dan correctly pointed this out and I was wondering the same thing way back in Post # 6: Aeromotive #12304 is recommended to be used as a fuel pump pre-filter and filters down to 100 Microns. It also has 60 sq inches of filter materiel, which is very important. http://www.aeromotiveinc.com/fuel-filtration/ So that answers my question from Post #6. The Fram G3 used in front of a stock Nissan Roller vane pump, " probably " works OK as many people seem to have used it with no issue on Fuel Injected Z cars. But when you put a G3 in front of a High Performance Gerotor ( Walpro 255, Bosch 044 etc ) or Ceramic Vane pump it likely causes too much restriction and causes pump cavitation after a while. Atlantic Z Car was one of the sites originally recommending the Fram G3 to be used as a pre-filter ahead of the Fuel Pump. I'm switching mine out for an Aeromotive SS Mesh filter... http://atlanticz.ca/zclub/techtips/fuel/g3filter/index.htm

Integrated Engineering makes some nice Surge Tanks for both single and dual pumps. They are for Bosch 044 and AEM 380 pumps. Unfortunately I don't think they fit Walpro 255 pumps. I believe the Walpro 255 is a slightly smaller Diameter than the Bosch pumps. Edit: Having problems with direct link. Look under Products/Fueling Components/Surge Tanks http://www.performancebyie.com/

True... but he's running aftermarket LCA's which should have come with Poly bushings on the Inner pivots. The outers are Heim joints. . And as the inner LCA Poly bushings are fairly small, they shouldn't flex that much???

^ Agree 100%. My engine has a bit larger camshaft and pulls like a SOB to 7.000+ on the stock 188cc injectors. Quite surprising actually. It's been running so good, that I've a complete Haltech system that I've put off installing. Been too busy with other things, and I've just been enjoying driving the car. My normal DD ( Audi A4 ) has been down for over two months with a coolant leak issue, and frankly I don't care. Driving the Z has just been so much fun. Sometimes you can " Tinker " too much.... My bedroom is starting to look like a Parts Warehouse though. ( Coil over kits, Camber plates, Rear disc conversion, Speakers and Amps, ECU's, engine harness, W/strips, H/Lite covers )

Pull the plugs and post up some pictures of the firing end. Use a good Camera and turn off the flash. I'm suspecting that the plugs are fuel fouled. If they are, then throw in some fresh plugs. BPR6ES gapped at .032". The factory " Trignition " on these cars is notoriously weak. ( Matchbox module is light years better in technology ) . Breakup under load but OK under no load is usually Ignition related. BTW. What does " give out " at 2k mean. It won't rev at all above 2K????

I would be more concerned about the flexing of the LCA uprights than the Diff MB. Run the video and put your finger on the center of the LCA pivot bolt. That will provide a reference point. Watch towards the end of the video as he gets on and off the power. The centerline of the LCA bolt is moving a LOT!!. That is a separate issue from the Diff movement, but you're going to have to fix the LCA pivot movement as well. Diff movement seems to be just an issue of two soft of rear Poly mounts and possibly the front mounts are too soft as well. Or the front fabricated X-member is flexing. Either way the rear Poly mounts have too much flex. I'd try some Delrin mounts is there. Or you could try Trimming the ends of the Poly bushing flanges down and putting in metal spacers. That should reduce the Axial compression of the Poly bushing. Should help some, but I'm not sure if it will help with any Torsional compression.

Yes, thank you. You are of course correct. When I was looking at the OP video, he has custom made MB to mount the GM Holden differential. Initially it looked like the LCA uprights were attached to the MB as they were flexing at the same time the MB was flexing. That's what threw me. After looking closer it appears that it's just suspension loading that is bending the uprights. They need to be reinforced with a gusset of some sort. I've edited my previous post to correct my confusion...

Yes, the Maxima rocker arms are exactly the same part as any other L-Series motor. 4 or 6 cylinder. GL. Keep us posted. Edit: Regarding camshaft breakin. With new rockers follow the same procedures as breaking in a brand new cam and new rockers. 1: Get Isky to supply some of their breakin lube when they send the cam back. Coat the Cam and rockers liberally with the break-in lube. 2: Use a dedicated Break-In oil by Comp Cams, Joe Gibbs/driven , Edlbrock or what ever Isky recommends. Or use Delo 400 30 wt or Pennzoil 20/50wt Dino Oil . Do not switch to Synthetic oil for about 100 miles. 3: If possible, Prime the oil system before cranking. Take a old distributor drive shaft and machine the gear off it. Remove Dizzy and support collar. Chuck a 1/2" drill onto the priming shaft and run drill until you have oils coming out of the cam and or oil spary bar holes. 4: When starting engine, make sure it is ready to go at first touch of the key and make sure that it can keep running for at least 20 minutes. Have all your fluids topped up and Timing set properly ahead of time. 5: As soon as engine starts, raise rpm to a minimum of 2,000 rpm. Do NOT let the car idle. You want lots of oil spraying on the rocker and cam lobes. Vary engine speed between 2,000 and approx 3,000 RPM. You don't need to go any higher, but holding at a constant speed is not good. 6: Never EVER use an Energy Star motor oil on these engines. Particularly with higher pressure valves springs. Energy Star oils are usually thinner weights such 0w-xx, 5W-xx, 10w-30. Energy Star oils all have reduced amounts of ZDDP which is essentail for the longevity of high performance camshafts with higher lifts and higher valve spring pressures. I've given my recommendations on oil. I prefer an Ester based Synthetic ( once Camshaft, Rockers and rings are broken in ) such as Amsoil 10w-40, Joe Gibbs 10w-40, Redline or Motul. Dino oils such as Pennzoil 20w-50 are OK if you prefer Dino oils. ... the heavier weights are the ones to get as they are not Energy Star rated. The ES oils have reduced ZDDP too meet EPA standards. An interesting tidbit from my engine builder on Dino oils.... and I've heard this before on oil forums such as Bob Is The Oil Guy. And BITOG has engineers confirming this. Pennsylvania crude oils ( Pennzoil, Brad Penn etc ) are apparently a better crude oil than Western brands ( Quaker State, Havoline etc). Has to do with geological formations and the aging of the Dinosaur oil deposits. Oil deposits are apparently like fine Wines. The longer they age, the better they become. Since the oil deposits back East are Millions of years older than Western deposits, the better the base stocks become. I'd take this with a grain of salt... but it's an interesting observation.

Yes, that's why you have to make sure that if you stiffen the back bushings you also have to stiffen the front. You can't have solid aluminum bushing in the back and poly or rubber bushings in the front.

^ What JM said. Agree 100% Poly can be fairly flexible, especially when you have a larger diameter bushing with a thick wall. Poly comes in different durameters and you obviously need stiffer material. BTW, the Poly bushings that come in most aftermarket suspension kits are generally junk. Way too soft for suspension applications. Back to your diff mounting. Delrin would be a good choice as mentioned by JM, or even solid Aluminum bushings. Delrin is much stiffer than Poly. Stiiffen up the front bushings as well. They are probably a soft poly as well. Replace those with Delrin, Del-A-Lum or Solid aluminum. You'll get more road noise, but you can't have your cake and eat it too... Del-A-Lum bushings are a very good alternative. They use an aluminum outer casing, a thin liner of Delrin and then a steel inner collar. They are far superior to Poly in every respect. They will also transmit a bit less noise than solid aluminum bushings. Commonly used in suspension Control Arms of Pony cars and they work very well. You would have to get a custom set made, but any competent machine shop can easily do this. https://www.google.ca/search?q=Del-A-Lum+bushings+pictures&tbm=isch&tbo=u&source=univ&sa=X&ved=0ahUKEwj6vIaaoe7NAhVL8WMKHYF3An8QsAQIHA&biw=1232&bih=615

BTW, I have 4 re-built RC SL4-0440 ( 440cc Hi Impedance ) injectors that I'm willing to sell. Bought these for my Audi when I was planning a big Turbo upgrade. Then I bought my 76 280Z and decided to leave the Audi alone ( relatively) . I'd let them go for $150 CDN plus shipping to Canada. Then you'd only have to buy two more at $88.75 USD instaed of 6. PM me if you're interested. https://www.rceng.com/Saturated-Injector-SL4-0440-P30C6.aspx Picture of my injectors for sale: Edit: Where in Canada are you? I'm in Metro Vancouver, BC

Only about a Bazillion of the things. ( low impedance injectors ) RC Injection is just one source. They also carry Hi-impedance injectors. https://www.rceng.com/Peak-Hold-Fuel-Injectors-C5.aspx Motorman is a very good source for new and re-furbished Injectors. E-Mail them for a recommendation. http://www.fuelinjector.citymaker.com/web_page.html

larger cam shafts also require a LOT more static ignition timing. They will tolerate extra timing because the mixture density, and thus effective " Dynamic Compression Ratio "is very low at low throttle openings. Set your static timing to 15 degrees BTDC. Vacuum advance disconnected. Then connect the vacuum advance pot to a manifold vacuum port. The small fitting beside the brake booster fitting. This will add an additional 15 degrees of timing at or so at idle. So a total of about 30 degrees at idle. Don't worry, because of the low dynamic compression the engine will not be adversely affected. You should see your idle vacuum increase by at least 5 HG Idle should be noticeably smoother. Aim for an idle speed of about 1,000 rpm with your cam. Do NOT use the vacuum port on the TB . This is Ported vacuum and will be zero vacuum at idle. With a larger camshaft you need MANIFOLD or Full vacuum at idle for the vacuum pot. Note you may have to decrease the spring tension on the vacuum diaphragm to make sure the vacuum pot stays " pulled in " at idle. See Jason Grays distributor page to see a How to Do. All Nissan 280Z dizzy's have an adjustable vacuum pot. Both for spring tension and stroke length. While you are at it decrease the stroke length to 15 degrees instead of 20 ( Add 5 degrees of static timing and you should decrease vacuum timing by 5 degrees to bring cruise timing into spec ) Link to Jason Gray's distributor page: http://newprotest.org/projects/510/jasonGrayDistributor.pl

That's what I run. Where's your large Idle air adjustment screw? You have it blocked off with a bolt.That's no good and is part of your problem. Edit: Please post only current pictures. Other wise you confuse the issue.

Do make sure that your PCV hose is hooked up and operating properly. The hoses often split on the underside. Do NOT remove the PCV system and run Vent to Atmosphere from the block breather. That will adversely affect drive-ability and cause acids and other contaminants to build up rapidly in the oil. PCV " deletes" are one of the worst thing you can do to a street driven engine. The AFM also has an idle mixture adjustment hidden down low. It is sometimes blocked off with a removable plug. Even with 76 models, which the FSM says does not have an adjustable idle mixture. ( The FSM plugs the adjustment screw to meet EPA standards. And then states that the idle mixture is non adjustable. Not true. ) ) You can fine tune the idle AFR mixture with this air bypass screw. Really helps with big cam shafts.

Looks like he blocked off the Idle air adjustment with a bolt. That isn't going to help. I have my 280Z pulling 12 in with a 480 lift 280 degree cam. WOT should be zero inches of vacuum. Not 10 or 12. You should be measuring the manifold vacuum reading at the manifold port fitting beside the brake booster fitting. Not the " Ported Vacuum " fitting on the Throttle body.

As well as comparing the push rods on your old M/Cylinder and the new one, check out the Slave cylinders Compare the two Slave cylinders side by side. There are two different types. Your car is a 1973. The Slave Cylinder changes to a self adjusting style ( 30620-U7000 ) from 07/72 on-wards. The self adjusting Slave cylinders have a non-threaded rod and are different from the earlier style ( 30620-28502 used up to 06/72) that have a threaded adjusting rod and a ball nut. The clutch forks are also different and have to be matched to the appropriate Slave cylinder. The early and late slave cylinders are not interchangeable... although you can bolt them on... the clutch throw will not be right. If memory serves me correct, the later style self adjusting slave cylinder bodies are physically longer. Take some pictures of the old Slave cylinder and the new Slave cylinder and post them up. I've seen this before when parts vendors have supplied the incorrect clutch hydraulic parts. You should check everything side by side to make sure they are exactly the same. Of course if you have changed Transmissions, you may have a different clutch fork on the Transmission. Early style clutch forks have a hole in them that the threaded adjusting rod fits through. The Ball nut seats in the fork. The later Clutch forks for the self adjusting style clutch do not have a hole in the end of the clutch fork. The clutch slave cylinder push-rod is non-threaded and seats directly into the closed end cup of the clutch fork. As previously mentioned, these are very simple systems. Not much can go wrong, but there are subtle changes in parts that can mess you up. And a proper bleeding procedure is all important. You either need two people, or a pressure bleeder.