Chickenman

Deleted post.

Deleted because I posted this at 2:15 AM and wasn't thinking straight.

Either one will work fine. As far as Hypoid gear lubrication they are identical. Buy the one that's cheaper....

Yes, they're definitely very deep and also too long ( circumference around the bore ). It just takes a slight bit of bore notching to un-shroud the Intake Valve and too provide clearance for high lift cams. Always do the minimum notching necessary in the bore. Excessive bore notching reduces CR ( can be as much as half a point ), reduces combustion quench ( not a good thing ) and creates a " Dead Zone " pocket for unburned combustion gases to collect. Bad spot to get carbon buildup and possibly cause detonation. And you never want the notch extending into the ring seat area. If that happens, go to a bigger over bore and hope you can salvage the block.

^ NOS Nissan rings would be a Moly faced top rings. Kind of a lighter grey in clor than the actual ring material. Pretty sure the second ring on OEM Nissan rings is a Napier. They usually have an ID mark on the top of the ring so that you don't put them in upside down.

I've used Grant or Hastings rings on everything from Small Block Chevies to Datsun A12 engines. Decent quality ring. You just have to decide on the bore finish. As stated above, Moly faced rings should always be finished on an automated honing machine like a Sunnen. Regular cast iron rings with no face coating can be used with a backyard ball hone. Moly's can't. BTW, the actual ring material can be cast iron, ductile iron or even Stainless Steel. Each has different characteristics designed for specific applications. Ductile Iron and SS are more durable and are used in High performance applications. IE: High RPM, Forced induction, Nitrous and Diesels. The face material, Moly or Chrome, is usually Plasma sprayed on separately and is very thin.

I don't think your Nissan source is correct. I was a Nissan partsman for over 17 years and still have connections to Nissan Canada. All GENUINE Nissan rings for the L-series are Moly top rings. With usually a regular iron second ring. 12033-A8620 is no different. Grant is NOT the OEM manufacturer of rings for Nissan. When your parts guy Google the Nissan part number I think he missed the fact that 12033-A8620 is used as a CROSS REFERENCE by Grant ONLY as a fitment guide. Genuine Nissan rings ordered from Nissan are going to be Moly faced top rings. Edit: I just checked with one of my " Trusted " Nissan partsmen just for curiosity. 12033-A8620 is still a good number, no stock in Canada, but still available out of Japan. He hasn't ordered any in a while, but as far as he knows Nissan still has the same ring suppliers from Japan as they've always used. I've done some searching online, and 12033-A8620 is available as a GENUINE Nissan part ( supposedly) from several online sources. Probably NOS.

Jock Rhoades at Bill's Datsun Shoppe near Portland Oregon built my new L28. He used regular Cast Iron rings. Makes sense. He's been building Datsun engines for over 37 years. He uses Moly or regular Iron rings depending on whether or not engine is re-bored and honed or just needs a quick de-glaze of the cylinder walls.. Moly faced rings require a very fine bore finish to seat properly. Final hone must be done on a Sunnen honing machine. You cannot get a proper finish using a DIY Ball Hone. Very good sealing and very long life with proper bore finish. OEM by all engine manufacturers since the early 1970's. Regular Cast iron rings will seat on a much rougher bore finish. What you would get with a DIY ball hone. Relatively fast seating miles and will last nearly as long as Moly rings. Actual " Chrome " rings are seldom used on Automobiles with the exception of Dirt Track racers or Baja Racers. The exceptionally hard wear surface of " Hard Chrome Faced " rings is required to resist the grinding effects of minute sand particles that invariably get injested by the engine. Even the best Air filters allow some extremely fine dust through. Dirt bikes also use " Hard Chrome " faced rings. They are not required nor desired on street cars or Pavement race cars. I've had lots of engines built over the years. I have specific machine shops that I trust with my engine building. They've all said that Moly rings MUST be finish honed on a Sunnen or similar automated honing machine. The piston ring Manufacturers also have Tech sites online that will confirm these facts.

Errr...that's not good. You shouldn't be messing with the AFM gear to adjust idle mixture. That;s what the idle air bypass screw in the AFM is for ) It may be hidden by an aluminium plug.. but it's there. It's really easy to screw up the AFM settings by changing spring settings and " messing " with the gear. You've really got to be careful there...... Best to have a 4 gas analyser or Wide Band AF meter hooked up when you play with the AFM inner guts. And mark the original settings so you have a baseline to go back to.

Edit: The two ports on the bottom of the TB are " Ported " vacuum as mentioned. Normally you will see no vacuum at idle with a Ported connection as the vacuum port is located ahead of the Throttle butterfly valve on the AFM side. Only when the throttle is opened will you see vacuum, and it will rise as more air is drawn pats the port. Perfectly normal. Manifold vacuum ports on the other hand, are located behind the throttle butterfly, so they will see high vacuum at idle. Regarding low vacuum readings at brake nipple. You should be seeing 19 to 21 hg/in with a well tuned STOCK motor in good condition. Check all these areas: 1: Does the car have a stock cam? A hi perf cam will reduce vacuum readings at low rpm's due to overlap 2: Check your ignition timing, you want about 10 - 12 BTDC with the vacuum advance disconnected. Note: Timing light sometimes go wacky. If you have the slightest doubt about your timing light, try a different one. Late ignition timing will produce low vacuum. 3: Make sure that the distributor advance is working properly and that it returns properly to zero advance at idle. Twist the rotor to check mechanical advance mechanism. It should " snap " back to the zero position. Often the mechanical advance gets gummed up and sticks. If the Timing mark is hunting back and forth at idle that usually means that the springs have stretched or that you don't have enough tension on them. Timing should not start to advance until approximately 1,000 to 1,1000 rpm. 4: Triple check for vacuum leaks. A mighty vac is a good tool to have. Check the small accessory hoses and one way check valves as well. Often the small hoses to the cruise control or AC FIC valves will crack and leak. Obviously check the brake booster hose and check valve for any laeks. . Makes sure that the PCV hose is not cracked. 5: Less obvious areas for leaks are the fuel injector bosses. Check the phenolic spacers for cracks. I use a spray bottle of water with the engine running. Spray any suspect areas and if the engine rpm stumbles, you have found a leak. Often you can see the water getting sucked in. Much better than the old Propane trick, as you can't see where the propane is going. 6: A rich idle will lower vacuum reading... but it has to be Pig rich. Have you adjsuted the idle air bypass screw in the AFM. It's sometimes hidden with a plug. Properly tuned with no vacuum leaks you should be seeing. 19 to 21 hg/in at idle. One more thing...try a different vacuum gauge. They do fail occasionally and read low. Post back with results and GL.

ARP Rod bolts are a good idea, especially if you have 8mm rods. ARP head studs are a bit of over kill and make removal of head a PITA if you ever need to pull it. New factory Nissan head bolts are excellent quality and all you will ever require, unless you plan on Turbo charging over 15 lbs. The Later Turbo bolts are even stronger. ARP main studs. Won't hurt, but not really necessary. New factory Nissan main bolts are fine to 7,500 rpm. Have the Rod big ends checked for roundness. Usually good ( Z Rods are forged as is crank ), but check them and resize if necessary. Balance the COMPLETE rotating assembly. Including Crank, Rods, Pistons, Flywheel and front damper. Straight 6 engines can produce nasty secondary harmonics. Factory balance is usually pretty good, but can be made even better. And if you change pistons, or do any Rod work, you should re-balance a straight 6. Have the clutch Pressure Plate zero balanced separately from the flywheel.

When I first looked at them I was going to say that they looked like Mikuni Solex. Have a look on main emulsion tube. Look for an " A " , " B " or " O " stamping. If you find those, then it confirms that they are OEM Mikuni Solex emulsion tubes. The lettering denotes early or late models. I've got a few extra sets in my carb spare parts boxes. I'll have a look later and snap some pictures of my Mikuni emulsion tubes. Early SK and Mikuni emulsion tubes are almost identical in appearance, although hole sizes, positioning and number of holes may vary

May as well add to the confusion. I owned an original 1971 240Z, production date 10/70. This was a Canadian market car and came with a splash pan that was definitely spary painted from the factory. Still had the manufacturing stickers over a thin coat of what looked to be a matte finish black paint. My 1968 Canadian spec 510 had the same style of splash pan and it was painted the same color. Funny thing was... I was a Datsun/Nissan Partsman for 17 1/2 years from the mid 1970's to the early 1990's, and I can't remember ever selling a splash pan for the early Z's and 510's. Everyone just seemed to throw them away... Of course, it could also mean that I'm just getting Senile and can't remember Isht !! In later years, particularity the later 70's and all through the 80's and 90's, Parts specifications for Canadian and USA production markets were often different. Electrical wiring connectors on exterior Lamps and body harnesses were of a different configuration than USA cars. IE: Canada would get a type of sealed terminal ( similar to Weatherpak ), where a California car would get a non-sealed terminal or one of a different configuration. Engine components were different, even as far as Pistons and camshaft specifications. Some of the weirdest things were different, such as Windshield wiper blade assemblies and even drive-shaft U-Joints on the 720 series of trucks. California models got a smaller U-Joint than Canadian models. Generally Canada got HD everything and usually Japanese or Euro spec on motors through to the mid 1990's.

Why would they even bother with Winter fuel grades in California? It never gets cold enough there, except maybe in the Sierra's. Edit: Oh never mind...seems your Politicians got involved again: http://www.popularmechanics.com/cars/news/auto-blog/summer-blend-vs-winter-blend-gasoline-whats-the-difference-13747431

$600 bucks!! Damn..obviously I'm charging too little for Tuning carbs. I usually charge Lunch or Dinner for tuning Webers or Mikuni's..... Gonna have to up my prices from WhiteSpot

Just an FYI for everyone. My original reply was to purchase a 22301-P7901 Vacuum Canister was for the OP, who noted that he needed to buy a new one for his ZX dizzy. 22301-P7901is an excellent choice, being both a reasonable price and being a Canadian spec model with a single line. However, you do not need to buy one if you want a Vac Can that is adjustable. EVERY Datsun/Nissan electronic distributor that has the " Putty " blob on the end is fully adjustable for travel and spring tension. Both 6 cylinder dizzy's and 4 cylinder dizzy's. A really cool feature...

Don't know where you got that info from my friend, but it's incorrect. Info for 22301-P7901 came straight off Jason Gray's excellent Z/ZX distributor page, plus P79XX parts are ALL ZX ( Standard Nissan parts coding ).... and the factory Nissan Microfiche confirms it as linked in the above post. I may be getting senile in my old age..but I still remember my Nissan part numbers ( I was Nissan dealer Partsman for 18 years ).... although occasionally I do go to the supermarket in my Pajamas

22301-P7901 IS a ZX vacuum control. I edited my original post to make that clearer. http://www.xenons130.com/2H04.html

22301-P7901 Still available from Nissan and Courtesy Parts. About $28.00 USD This is a fully adjustable vacuum advance with both travel and tension spring pre-load being adjustable. Although a ZX part, it will fit retrofit onto most 280z distributors. Then visit the following thread learn how to Custom adjust these vacuum advances. GL: http://www.classiczcars.com/topic/31615-280zx-distributor-advance-curve-reference/page-2#entry459813

The more I think about it, the more I believe that emissions standards, with lean mixtures with retarded timing, forced some manufacturers to pull the spark plug tip out of the most efficient area for ignition and closer to the combustion chamber wall where the mixture burns cooler. Ground and center Electrode tip materials back in the day may not have been able to handle the heat. Pulling the electrode tip to a cooler location in the combustion chamber may have been a temporary solution in the transitional periods between Catalytic convertor development and the new Fuel injection systems. These weren't perfected over night by any means.

I can't figure it out myself, since even back in the mid-seventies Projected Tips were pretty much known to be superior in anti-fouling and combustion chamber position. Maybe Datsun got a smokin' deal on non-projected plugs from NGK? I'm only half kidding there. Nissan bought spark plugs from NGK by the Millions. You save a few pennies here and there and it all adds up for a manufacturer when you're talking those numbers. Datsun/Nissan has never used anything but NGK. The only reason for using a non-projected tip would be in engines with minimal piston to spark plug clearance. That means High Dome pistons, and that was not an issue on any Nissan motor. I wouldn't lose any sleep over it Edit: The only other thing that occurred to me is the Fuel crisis and EPA in the mid seventies. Mid seventies cars were terribly inefficient due to EPA emissions restrictions...then fuel prices went astronomic ( by 1970's standards ) . EPA standards were just getting into full swing and cars ran terribly lean back then with retarded ignition timing and lowered compression ratios. The retarded timing and lean mixtures would raise combustion temperatures dramatically and may have exceeded maximum temperature range for Projected tip plugs. A regular tip plug has a much shorter insulator, so it could handle more heat. I'm thinking that using non-projected tip plugs may have been a " Half Step " in plug heat range. So a BPR7ES would be too cold compared to a BPR6ES. So use a " half Step" like a BP6ES. Just my own theory.. no data ( Yet ) to back it up. Catalytic convertors first started appearing around 1977. Cats allowed the manufacturers to operate the engines much more efficiently, with more advanced Ignition Timing( IE: Normal ignition timing ) , fuel mixtures that weren't so lean that you risked melting pistons and exhasut valves. Compression ratios also went up, increasing the efficiency of the engines back to pre-EPA standards, but with lowered emissions. A think that's a plausible explanation...

Up to about 6 months ago I had all of my Nissan Partsman and Service Tech training tests and info. A lot of TSB's were included in that. Unfortunately, I did a massive clean-up and threw them all out. If I remember correctly, the reason for recommending Projected tip plugs in Canada, if regular tip Plugs were originally specified, was mainly to reduce cold weather fouling in our bitter cold winters. I don't know if USA had similar TSB's. Possibly in some of the more Northern States. The article that was previously discussed mentioned by Captain Obvious is correct. Improved flame propagation and reduced fouling are the Primary reasons for using Projected tip plugs.

You'd be better off getting the old arms refinished. The Nissan arms are extremely high quality. With aftermarket you never know what you are getting. If your old rocker arms are in good shape with no grooving or pitting it is safe to re-use them. Use lots of break-in cam lube and use a proper break-in oil like Joe Gibbs " Break In " oil. Contains extra ZDDP which is a high pressure ingredient for cams. Make sure that you do NOT use any energy star oils ( SM or SN rated ). That eliminates most off the shelf Synthetics below a 10w-40 rating. Never use ANY 0w-XX rated oil... Not enough ZDDP to protect cam surface with a HP cam and stiffer valve springs. Pennzoil 20w-50 ( non-Energy Star ) is also good. The 10w-30 is Energy Star rated...so don't use it. Then, after Camshaft break-in, switch to a good Synthetic oil with adequate amounts of ZDDP ( Zinc and Phosphorous high pressure additives ). That means most Amsoils ( Their 10w-40 is great, as are their Racing lines ) , Redline, Joe Gibbs Hot Rod Oil, Brad Penn Racing oils or Shell Rotella T6 5W-40 Synthetic for cold weather. The Rotella T6 is a well known oil in the Turbo and Motor Bike worlds. Excellent oil, and because it is rated as a HDEO ( Heavy Duty Engine Oil ) it does not have to be energy star rated. Racing oils, 4x4 Truck oils and Oils formulated for older cars are exempt from EPA Cafe rules and usually contain more ZDDP than formulations for new cars. Remember, if it's SM or SN rated and is Energy Star rated, don't use it in an engine with HP cam . Go for an SG or SH rated oil ( pre-2006 standards with higher levels of ZDDP ). BobIsTheOil Guy is an awesome site for researching Motor oils. No BS info, and actual Engineers for various Oil companies frequent the site. Search for articles on ZDDP if you are not familiar with the issues that reduction of this ingredient has created for Vintage car owners and Modified vehicle owners. http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=cfrm

I worked as a Nissan Partsman from the Mid 70 through the early 1990's. Datsun/Nissan had TSB's ( in Canada at least ) to always use the Projected tip plugs in place of the non projected tip. Places the spark kernel in a better position to promote flame propagation and also the projected style resists fouling better. As mentioned, BPR6ES-11 is what you want. You could also use their V-Power series. BPR6EY-11 The NGK NE61 plug wires are very high quality. Plus they smell like Bubble Gum...Yum!!

Yes... Total mechanical advance is initial timing + dizzy mechanical advance. In the example 15 + 17 = 32 32 degrees ( example ) is the figure that you check with your Dial Back timing light to get maximum power, with Vacuum advance disconnected. The additional Vacuum advance of approx 15 to 20 degrees is only required and supplied under light throttle, light load and high engine vacuum conditions. That is when the cylinder charge density ( VE ) is very low and the air/fuel mixture needs to be ignited earlier in the combustion cycle to ensure that the burn cycle is completed at the proper time ATDC. As soon as more load and more throttle opening occurs, the additional vacuum advance will drop off as the cylinder charge desnsity ( VE ) increases. Note: Do not confuse Air/Fuel mixture density ( Cylinder charge density or VE ) with Air/Fuel Ratio. They are two entirely separate things. IE: You could have a 14.7 to 1 AFR ( Stoich ) at 100% VE and a a 14.7 to 1 AFR ( Stoich ) at 50% VE. The 50 % mixture would have to be ignited earlier in the combustion cycle ( Vacuum advance ) because of the slower burning of the flame front. Lower charge density = longer flame front burn time ( given all other factors the same ).