Chickenman

Yes..I meant to include a sentence about dragging a finger nail across the line to " feel " it. I've edited the previous post accordingly. Problem is that sensitivity to feel varies between people. Some people can feel a .001" dip.. Some ( like my Ham fisted buddy ) can't feel .010". Most people can however, see the line, and if a line is visible it's the start of the wear cycle and more checking is required. The two rockers in that particular picture are quite severely worn. Picture came from a thread in which noisy rockers were the issue, and these turned out to be the culprit. Bottom line. If you can see a wear line on the Rocker... check it closer. Particularly if you're having trouble with a noisy valve train. My .02c FWIW.

Try and find a Machine shop that uses a Steam cabinet. This does a much better job than media blasting as it gets into every nook and cranny, including the INSIDES of water passages. Parts are blasted in an enclosed cabinet with high temperature ( 500+ degrees depending on model ) steam from every angle at high pressure. No damage to finely machined surfaces, so you can clean things like pistons with out having to mask off ring lands etc. And of course there is no media to dig out of little nooks and crannies. Parts come out looking like brand new..inside and out.

One thing that has been mentioned but bears repeating. Carefully examine the wiping area on the rocker arm. Worn rockers will show a distinct line ( or dip ) across the wiping face at about mid point. Edit: If you have a visible line, the rocker should be checked closer for wear. Drag a finger nail across the line and if you can feel any dip or drag the rocker is worn. Replacement or resurfacing may be required. A rocker arm with a wear dip will never be quiet. The wear line appears at the high point of the Cam lobe at max lift. This is also the maximum pressure point during the cycle. It is often an indication of inadequate lubrication. Here is a picture of two rocker arms that are worn. Note the distinct wear lines. They will never be quiet unless re-surfaced:

Nope... skip straight to fully warmed up engine and check valves hot. Cold setting as per FSM, and as others have noted, is only an INITIAL setting. Just to get you in the ball park. Final setting is to be done HOT.

I agree 100%...however, some machinists will still grind Valve stems regardless.

If, after thoroughly going over the valve train, and the engine is still noisy, it could be excessive Piston to wall clearance which cause Piston slap. As engine was rebuilt previously, it may have been bored or honed and the Machinist may have gotten the clearances too big. It doesn't take much. Datsun engines had Hyper-eutectic Cast pistons ( High Silicon percentage ) way back in the 70's. That enabled very tight bore clearances with minimal Piston expansion. Machinists who are used to working on older Domestic engines may not be aware of that. Domestic engines of the day had regular Cast pistons ( Lower Silicon percentage ) that expand more than Hyper-eutectic. My old engine ( which bit the dust ) was apparently rebuilt by some hacker and had huge Piston to wall clearances. The end result was a very noisy engine that sounded very much like the one in your video. The thing is, piston slap can sound almost the same as a noisy Valve-train. my engine had both problems and it sounded like a Mack Truck!! Hopefully that is not the case with your engine... but something to be aware of. Concentrate on the valve train first.

That definitely sound like noisy valves to me. The cold setting is ( .008" Int/ .010" Exhaust ) just a preliminary step to fire up the engine. According to the FSM a final valve setting should be done with the engine Hot. Hot setting is .010" Int and .012" exhaust,. measured between the Cam lobe Heel and the wiping pad of the Rocker arm. Couple of questions. Stock camshaft correct? Re-ground cams sometimes have slightly tighter clearances required due to profile. All new valves? If you re-adjust the Valve clearances when Hot, and it doesn't quiet down check the end of the Valve stems. Some machinist's will regrind them to get the installed height correct after replacing valve seats or over sized valves. On my old engine, the Machinist ( not mine ) had ground the Valve tips with what looked to be a Bench grinder. The tips were not even remotely close to being flat. Lash pads would tilt and mess up the measurement That's something to check as a last resort if valve train won't quiet down. A quality Machinist should never make a mistake like that, but isht happens. Never trust anyone is my Motto...

Just an FYI for those who want to Insulate their Fuel Injectors and Fuel Rails from heat. Wire Care makes a variety of Thermal Tubing, Firesleeves and Thermal wraps. A really handy product is the T6 Thermal wrap. This comes in various diameters ( from 1/4" to 2" nominal ) and is split so that it can easily be wrapped around lines and injectors. Has a self sealing Hi Temp adhesive on sealing edge to provide a clean and durable installation. https://www.wirecare.com/products.asp?prodline=t6f Wire Care has some other really interesting products.

I don't recall there being the selection of manual Transmission oils back then, compared to what we have now. Most of the time 75w-90 was a pretty standard spec. That is molasses compared to what is run these days in some Transmissions. As fuel efficiency became more and more important, friction reduction by using thinner and thinner oils in both the engine and drive-train became more important. The development of Synthetics, Synthetic Blends and special additive packages revolutionized both Engine and Drive-train lubrication. You could run much thinner oils ( which helps Synchro engagement ) without sacrificing gear protection with the newer Technology oils Fresh brand new Synchros ( Brass ) do make a difference though. You can slice your finger open on the grooves they are so sharp. Old synchros, while they looked fine to the naked eye, often had dull edges. That adversely affects shift quality. I suspect some transmission fluids were better than others in the 70's and early 80's, but the Oil Technology wasn't nearly as good as it now is. Probably more " Hit and Miss " back in those days. Just my .02c

This question is often asked. Is the GM FMSM fluid GL-4? The answer technically is NO. It is GLS... which stands for " Gear Lubricant Special ". This designation is reserved for special formulation oils, generally only available from Car Manufactures. GM appears to keep the information proprietary on this fluid...which is fine. But it is fully Yellow metal compatible being specified for their Synchromesh manual transmissions ( including Gertrag ) that contain Yellow metals. Some reports indicate that this oil is manufactured by Shell. I have no way of confirming that. GLS is apparently not an API standard, as it is can vary from Manufacturer and is a proprietary formulation. IE: BMW has there own GLS spec manual transmission oil. As does Audi, Mercedes, Honda, Volvo, VW, GM and Chrysler, What all these transmissions using GLS formulations have in common though, is that they do contain " Yellow " metals, so any oil formulated for them has to be Yellow metal compatible. Honda forums are one of the most active with the Honda factory GLS factory oil being replaced with the GM GLS spec oil ( Friction Modified ). It seems to solve the majority of Honda synchro problems. Hope this helps a bit.

Those Ford Inertia switches are a good idea on any Race Car ( or Vintage car ) with an Electric fuel pump. Summit Racing sells them as does any Ford dealer: http://www.summitracing.com/int/parts/sum-890145/overview/

Ron... I have a question about the clock in my 1976 280Z. When I got the car last year it was losing about 15 minutes in a week. I took the clock out and adjusted the screw that makes it run faster. At first this didn't seem to make a lot of difference and I hand to keep advancing the clock hands manually. Now however, it seems to be keeping pretty close time. Question is: As you manually adjust hands to correct time, does this somehow add or subtract a " compensation amount " ?

Personally I've been using it for over 80,000 km in my 1998 Audi A4. It had a " crunchy " 2nd gear Synchro due to a clutch issue. Was formally using Amsoil manual Trans fluid. Switched to the GM fluid at 164,000 km. Within 100 km transmission started to shift smoother. Within a week all notchy shifting in 2nd gear ( and all gears ) was gone. Car now has 245,000 km on it and shifts like butter. I have actually tried switching to Redline MTL at various points. Shift quality always deteriorated. Soon as I put the GM FMSM fluid back in, the tranny shifted smooth as butter. Same on my 280z and I've had the GM fluid in it for over a year. A friend of mine switched to the GM FMSM fluid in his G35 and it's never shifted so smooth... even with new factory Nissan fluid in it. He's got over 30,000 km on it now and it literally " falls " into gear. Nothing but good reports from anyone who's tried it. This stuff is danged good!!

Yes..100%. You've got GM's guarantee on that. And all the empirical data from use in Honda's, Nissan's Toyota's, BMW's, Audi etc. This stuff isn't something new. It's been around for over 10 years and used in the field on manual transmissions with brass synchros for literally millions of miles. . Actually all Fluids specified for Manual transmissions are safe for yellow metals if you think about it, since all manual transmissions usually contain Bronze or other Yellow metals as Thrust washers, Synchros or fork shifter pads. Only GL5 Differential oils have the high Sulfur content that is required for Hypoid cut gears. Hypoid cut is in a Salisbury type differential where the Pinion center line offset from the crown gear center line. This creates a lot of shear forces and requires a GL5 oil with extreme pressure additives ( Mainly high Sulfur and Phosphorous compounds ) FWD Transmissions use bevel gears, not Hypoid cut, so that is why FWD diffs can get away with using a ( edit ) GL-4 fluid as Dual duty for both the transmission gear lubrication and diff gear lubrication. GL-4 has some pressure additives, but not nearly as much as GL-5.

I'm sorry but I don't believe that is correct. Larger reservoir is always for front brakes ( Primary ) as the front caliper pistons will displace more fluid as the pads wear, as compared to the rear brake cylinders ( Drum ) or rear pistons ( Disc rear ). That is universal. Also confirmed by FSM that larger reservoir is closest to the Firewall and is indeed for the Primary side. Primary piston is front brakes. Secondary piston is rear brakes. OP what year of ZX cylinder do you have? Later reservoirs are a " Divided " one piece plastic Reservoir , but larger Tank is Primary or Front brakes and is closer to Firewall. Scan of 1980 FSM S130 Brake Master Cylinder:

Of course check the rear diff mount to see if it is broken. It won't cause actual rough shifting... but it will make a big BUMP noise if it's broken. Report back with what you find please. Good Luck.

An oil and filter change is good advice. Automatic Transmission fluid is often over looked as a Maintenance item. But it has to be changed just like engine oil. Once every 24,000 miles should be sufficient. Change the filter as well of course. Rock Auto carries the Filter and Gasket and will ship Internationally. You may be able to get the parts from your local Auto Parts stockist as the Transmission is more common than people normally think. Use Dexron III fluid. One other thing to check is the piping or vacuum hose to the Vacuum modulator. This is a Vacuum valve on the side of the transmission that sense load on the engine according to Intake Vacuum. High load = Low or Zero Intake vacuum, like at WOT. The vacuum modulator then increases line pressure to the clutches and discs to prevent slippage. There is a Vacuum fitting on the Intake manifold that connects to the Vacuum modulator. I think it comes off the brake booster Tee fitting. If the hose or piping is damaged ( or not connected ) the transmission will think you're at Wide Open Throttle all the time and shifts will be very harsh. Check the connection at the Transmission end as well. Usually the problem is a perished hose. The Vacuum Modulators themselves seldom fail.

Part numbers for GM and AC Delco " Friction Modified " Syncromseh Transmission Fluid. BTW. The GM Fluid and AC DELCO are the exact same part. Just different labels. Lordco seems to have one of the best prices. $12.75 CDN per liter wholesale. AC DELCO CDN part number : 10953509. For USA members the AC DELCO USA part number is: 88900399. GM USA part number is: 12377916 Edit: All of these part numbers are the same fluid. For some reason GM/AC Delco keeps changing the packaging and part numbers. I've just found out this morning that some Canadian GM dealers have this fluid under both the old numbers and the newer ones. Friction Modified Synchromesh Fluid on left ( The Magic Elixar ) . Regular GM Synchomesh Fluid on the right. Notice difference in Part numbers and Labeling. The good stuff always says " Friction Modified ": GM Packaging of the good stuff: AC Delco packaging of the good stuff. Can be White or Black bottle depending on alignment of Planets. Go by Part # and description. c

Could be negotiating for price. What did he say was " horrible " about it. Sloppy feeling, crunching gears between shifts. If he can't be specific it sound like a negotiating tactic. British cars are not exactly known for their precision gearboxes.. . Loose bushings in the shifter will make it sloppy. That is pretty " Normal " with the early Trannies and monkey motion gearboxes. The " Legs " on the bottom of the trans shift lever tend to spread apart with age. Heat the " Legs " and straighten them in a vice. Then throw away the old retaining pin and cir-clip and replace it with a Double nutted bolt. That prevents the " Legs " from spreading apart in the future. You may want to add a couple of thin washers on the inside to adjust final clearance. Edit: Just as an FYI, or if your car does have any slightly " notchy " shifting: One thing that will make an enormous difference to shift quality is brand of gear box oil. By far the best fluid in these boxes ( and others ) is the GM " Friction Modified " Syncromesh fluid. This is a Semi-Synthetic manual Transmission fluid that is absolutely incredible. Not to be confused with " Regular " GM Synchromesh fluid. You have to buy the stuff that says " Friction Modified". Available as both GM and AC Delco part. Same stuff. Part numbers swap around all the time so dealers may have mixed stock. Sometimes in a Black bottle, sometimes in a White bottle. I'll provide a link with the Various USA and Canadian Part numbers later... but I'm heading out for dinner right now. Our local Honda, BMW, Audi, Nissan and Toyota dealers use it as an " undocumented " Warranty fix for baulky shifting transmissions. The stuff is really amazing. Better than Redline MTL.

Got a Smart Phone? For a temporary Speedometer you can download a GPS App ( Free ) that uses GPS as a speedometer. They are very accurate. Apps available for I/phone, BB and Android. Search your App store for " Speedometer ". I use one from Gadget Box on my BB. I have a suction cup style Cell phone holder mounted to my W/S and it places my Cell phone at an ideal location. Large HUD on my BB Z10 makes it very handy. Handy for my GPS driving Maps as well. I've got the wrong speedo gear in my Tranny. ( Diff ratio change ). Just haven't had time to change to the correct gear. So the GPS App comes in very handy.

^ You are indeed correct. I forgot about the simplistic nature of the Factory AC routing only through the Vents. Bi-Level would give you the best mix of air currents with AC. Bypassing the thermostatic control should still be of benefit as the air drying effects of running the AC should lower the humidity levels in the cabin significantly. The small cabin area of the Z helps in that respect. Edit: Actually, the factory system allows you to do that already. The FSM on page AC-9 shows Bi-level selected with the Temp switch at about 40% with AC actuated. Heated air via Defroster ducts and Air Conditioned air flowing via center Vents is flowing through the system. Something is definitely wrong with my slider control. So the outcome of this, is that our discussion led me to the diagram in the FSM that shows that my Temp lever is not moving the full range. I believe it is a problem in the control lever system itself, as it is a " Hard " stop... not the typical soft or binding stop of a kinked control cable or a sticky control valve. Time to rip things apart...again!!

I'm beginning to think it's designed in. From what I can tell, the cable is running freely with no kinks. But it is a solid hard stop in the control mechanism itself. I did have it apart earlier this year, so I wonder if I assembled something wrong in the control head. Your comment on the short range of the Thermostatic control does raise questions though. I' guess I'm just gonna have to pull it all apart and examine things a bit more closely. Heater blower is a bit noisy and needs some lubrication. Maybe a Winter or Fall project. I can live with the slight whine from the blower motor and I've got the AC working freezy cold right now. FYI. Modifying the OEM system to give heated conditioned air to the defrosters like modern cars is very easy. Just add a jumper circuit in parallel to bypass the Thermostatic Control switch and the Micro switch on the Mode lever. Circuit is already relayed, so a simple Push On - Push Off switch will work. There;'s a spare switch plate cover on the center console that can accept a switch. You can probably find some factory AC switch to fit. Button = Off and AC system works as Factory design. Button = On and system AC will work in all modes and temperatures. Easy Peasy. Living in the PNW, I know how important heated air, that has been dried by the AC system is.

We'll see how the flattening goes. If that doesn't work I'll probably order the MSA cover. Thanks to all for suggestions. Just got back from a local car show. 1,200+ cars.. but got a bit too much Sun. I look and feel like a boiled Lobster....ugh.

1976 280Z with Factory AC. Anyone else have a 280Z with factory AC that can tell me if this is normal or not? Temperature control lever does not have full range of motion. Stops well short of Full cold position and Full hot position. I've checked the cable that connects to the Thermostat control. Cable is free and not binding and Thermostat lever seems to be traveling it's full range. I'm wondering if the extra travel is designed in for use on non-AC cars that use a manual style water temp valve, instead of the Vacuum controlled valve?

That's one idea I was also thinking about. I think I'll give that a go.