BRAAP

Now seeing it in picture, it is the common after-market OE replacement gear, have a few old ones in my parts bins as well, seem to wear just fine, no issues. That style typically has an undercut groove in the perimeter, back side, (I incorrectly labeled it on the front side in this picture), with a couple/few holes drilled out of those grooves tot eh region between the two rows of chain, centrifugal chain lubrication. Little pin hole oiling port in the front of the #1 cam tower feeds that groove as well as the oil run-out from the front of the cam journal/tower. Never thought to weigh one though, interesting to see the stock Nissan gear weighs 1/2 again more than after-market version. (Thin flashing line in the 4 slots makes me think it might a casting vs a forging.) Thanks for the pics David.

Stravi, Sounds good. Side note, please stop using IM when posting here. We do not allow it in the forums. This thread explains why.. http://forums.hybridz.org/showthread.php?t=115824

Fuel flow? A clogged filter will cause the engine to fall off. As it clogs more, it will fall off at lower and lower RPM's

For Mr Coffey;

WTB, used Datsun L-series rocker arms! Looking for used L-series rocker arms, must be decent condition, no appreciable wear or divot in the middle that can be felt sliding a sensitive finger across the surface. Need at least 12 right now, (will take how ever many you have even if only 2 or 3 good ones). Looking for enough to do 3-4 L-6 heads, 36-48 rockers total. If you have rockers that you want to get rid of but are unsure if they are useable cores, PM some good pics of the wiping surface for the cam lobe. (Good lighting and a regular camera, macro mode, helps for those shots). This is an example of an unusable rocker. If the rocker has the small divot across the middle, (in GREEN) but cannot be felt when sliding a finger across it, it still may be useable. If you can feel it, it is no good. If it has the wear depicted in PINK, it is no good. Contact me via PM or E-mail braapZ350@hotmail.com

Too funny...

I'll pitch in $20. Have to video the burning for you-tube.

Not if I get it first!

Click ME!

$119 is already less than half of retail! Good luck!

If you search, you will find TONS of info, dedicated threads to what can and cannot be removed and still retain all the functionality Nissan originally intended. Here are a few examples. Customer car, N-47 intake, EGR removed, stock EFI, functions 100% OE. My personal daily driver, N-42 intake, stock EFI. Only comprise made here was the elimination of the air flow regulator. Higher warm idle speed for a decent cold idle speed. My personal Race car, N-42 intake, Mega Squirt EFI and distributor-less ignition. Another customer, N-42 intake, stock EFI. Another customer, N-42 intake, WOLF V4 EFI. Another customer, ZX manifold, WOLF V4 EFI. Another customers intake I did next to a virgin intake showing various bosses removed, holes plugged etc. As I mentioned, if you search, you will find all these and others documented and even dedicated threads covering what can and cannot be removed and what affects on performance, drivability, those modification will have etc. Good luck, Paul

YEAH! Induction is tough one for these engines. For a dedicated track car, seems to be 3 schools and all 3 work AWESOME! 1) Single 4bbl carb! 2) OE style EFI, such as the FAST manifold, (light weight) 3) ITB. Personally, the ITB route brings so much exoticness to the table visually and aurally!

The parts that require break-in to seat themselves are the piston rings to the cylinder walls and the cam lobes to the lifters/rockers. All the other parts should be good to go from the initial start up!

If the block is F54, (cast on the the side, driver side), you have a 99.9 % chance of having flat tops. If the head is a P-79, and the short block hasn't been swapped out, again, yes it will have flat tops.

Gear ratios will NOT increase torque, they will however trade shaft RPM for torque. Or, (depending on what you meant by your question), different "ratios" are not necessarily required if your engine is producing "added torque". Your driving habits, the engines power curve, intended usage, vehicle weight etc, will have a significant influence on what the "ideal" ratio or ratios would be for your application. Your initial question is just to vague. Added hook up? Tires with better traction will provide more hook up regardless if you “added torque” or not!

The first picture is modified chamber, extensive unshrouding performed. The second picture is an untouched virgin chamber, no work has been performed in that chamber, just highlighting the areas to be worked over. As for the spark plug boss, I have played with reshaping it a few different ways over the years. My current approach for the early heads leave the intake side alone, and blend the exhaust side into the chamber wall, mostly just increasing the radius of the bump on that side to smooth blend. On the P-79 and P90 heads, I just make sure there are no protrusions and all radius are smooth and gentle. I'm sure there is spark plug boss shape that lend itself to superior turbulence in the chamber during the compression stroke or one that allows clean efficient flow in and out of the chamber, etc,. MONZTER's approach in relocating the spark plug and angling it as he did seems to be the ideal approach, though not an easy or inexpensive modification.

http://forum.ebaumsworld.com/showthread.php?t=230929 This extreme Guido style is... uh... I pray this is none of our members.

Best MPG, freeway-only driving trying to achieve good MPG, filling up at freeway gas stations, measured with freeway mile markers, (I do NOT trust the Datsun ODO to be accurate). With my mild N/A L28 powered 75 280Z early 280 5 speed, 3.54 diff gears, stock cam and stock EFI, (this set up ran a best of 14.4 secs @97 MPH, 0-60 MPH in 5.7), I saw a best of 30 MPG freeway only driving with the dual 1 3/4" exhaust, dropped to a best of 28 MPG freeway when I went to dual 2" exhaust. Performance did not change going to the larger exhaust, just louder! The SBC 350 V-8 in the same car, holley 650 double pumper, World Class T-5 5 speed trans, 3.90 diff gears, (this set up ran 12.3 @ 113 MPH, 0-60 in 4.2 secs), 20 MPG, (measured on the way to the drg strip!)

Yeup! How'd you know that? Nigel, You are on the right track. This thread talks a little about the techniques and approach to valve unshrouding as applied to the L-series heads; http://forums.hybridz.org/showthread.php?t=110269 When I started learning performance cylinder head work, it was Vizards work that I studied most. His approach makes the most sense to me and after many years building custom cylinder heads, one of which Rebello Racing flowed on their flow bench, (that head was documented here in the L-6 section), and then ran on their dyno matching the power level of one of their custom heads, to me just confirmed what I gleaned from Mr. Vizard seems to be on the right track, (regardless of the actual power numbers Rebello claims from their Dyno, their engines are reknowned for being some of the most powerful and successful L-series at the track, as such I have a great deal of respect for their work). Last year I had the opportunity to speak with Mr. Vizard on the phone, what an honor it was to pick his brain on other aspects of engine design and thank him for sharing his knowledge. Back to your questions; 1) Radius from the seat itself to the chamber wall. Lay the chamber wall back to just shy of the fire ring of the head gasket. With the L-series, I will undercut the chamber wall where the valve head is closest to the chamber wall, yellow and baby blue lines in your pics. 2) Sometimes, depending on the casting, that region in red will have a lip just like your intake side does depicted in green. In that case, yes, blend it to be a smooth transition from the chamber roof to the valve seat itself. 3) Referring back to #1, remove material out to just shy of the gasket fire ring. Using the gasket you intend to run, place the block deck dowels in the cylinder head and lay the gasket on the head, (the deck dowels positively locate the head gasket for accurately locating the fire ring in relation to the combustion chambers). Now lightly trace the fire ring of each cylinder with a scribe of very fine point felt pen onto the deck surface. The unshrouding process will be a multi step process starting out with a very aggressive cutter to rough shape the chamber, then a fine cutter to blend the rough cut, then coarse sanding wraps to blend the fine cutting, then a fine sanding wrap to blend the coarse sanding wrap and even finer wrap or Scotch-Brite style buffer for polishing in some instances. Keep in mind that each step is a process of material removal, so don’t take the valve unshrouding out the to the fire ring in the first rough cut phase. Leave enough material so that by the time you get to the final chamber prep/blending/polishing, the chamber wall will be "just shy" of the fire ring so as not to compromise the fire-rings sealing ability. 4) Yes. Helpful thoughts… As you are unshrouding the chambers, keep a scrap intake and exhaust valve in the chamber you are working on. Those scrap valves are your sacrifice valves protecting the valve seats, allowing you to hog in the chambers without fear of cutting into the valve seats themselves. For the final shaping, you will have to remove those valves to be able to blend the chamber into the seat, just be very careful and take your time, don't rush it. Run-away cutters happen to even the most experienced porters. Also, try to visualize the air flow as it flows around the valve head. Lift the sacrifice valve off its seat slowly up to approx max valve lift for the cam you are using as you rough shape the chamber, taking note of the proximity of the valve head to the chamber walls. Keep in mind how air flows, boundary layers, how and why boundary layers separate, turbulence and its ill effects, etc. Ideally you want a flow bench to not only measure your gains, (not just maximum flow, but gains from strategic shaping), but also to replicate your efforts in the other ports. The flow bench numbers should never be used to compare one head to another. Static flow number are not equal to HP potential, only rough guidelines. The flow bench is a tool for the person porting the head, not a measurement of power potential. Here are some pics that may help illustrate that a bit more… Z car N-47 chamber, virgin with the fire ring in red felt pen, and after extreme rough shaping, prior to final smoothing. Material removal areas, for valve unshrouding here; (P90 head shown) Good visual of the “unshrouding”! A very closed chamber that was unshrouded, coarse sanding wrap finish, (Welded N-42, similar to E30). Pretty P90, ready for assembly; Hope that helps, Paul

The letter "E" in L28E is a designation primarily used mostly in parts books at auto parts stores, it will NOT be found on the engine anywhere. The "E" helps to differentiate early, ('75-'80) vs late, (81-'83) for the parts store counter people as that is the point, (’81 model year), when most of the "parts" changes took place on the engine itself, even though there were a couple internal changes in head casting and cam oiling for the '77 model year. Being as this L-28 was swapped into an early chassis, the E designation becomes not as important, but more importantly for sourcing parts is the knowledge if it is later 3 bolt thermostat housing or the earlier 2 bolt style. By definition, ALL US market L28’s are L28E, E meaning Electronic Fuel injection. All US L-28's from 1975 to 1983, will have L28 stamped in the block, passenger side, rear of the block under the heater outlet of the head. So long as the block is stamped L-28, it is an L28-L28E. If your plans are to leave the engine stock, there really is no need to concern yourself with early vs late L-28 as they all have similar performance, similar reliability, and either respond similarly to the same mild mods such as fine tuning, header and free flowing exhaust etc. Of more importance is the condition of the engine, how was it maintained, etc. For what it’s worth, the early L28 were dished piston and small chamber heads, 2 different casting of heads, N42 and N47. The N-47 casting was used on the last 2 years of the 280-Z and first 3 years of the 280-ZX. Later L-28’s were flat top pistons with a larger chamber head, casting number P79. If the head is casting number P90, chances are the engine is a Turbo engine, L28ET with dished pistons, unless someone swapped heads, which at the age of these cars/engines and so many people tinkering with them, is quite possible. If building a hot L-28 from a clean slate, the decision to start from an early or late L-28, each has its own merits and demerits. If you plan to build a radical L-28, don’t get to worked over which L-28 it is as you are going to change most of if not all the bits and pieces that made them different anyhow. In short, they are different, but from a performance standpoint or the standpoint of OE, they are all L-28E’s, all have the same potential. Hope that helps, Paul

Yeup, makes sense. The cam with the tighter LSA, (Lobe Seperation Angle), of 107 degrees has more valve overlap. They call the other cam an EFI cam as it is more friendly for "FACTORY EFI", (less overlap for more idle vacuum and comparable VE curve which the factory EFI is tuned to) That and it might be the internal oiled cam vs the external. With aftermarket EFI or carbs, choose the cam specs that best fit your performance needs, not necessarily whether the cam is labeled as EFI or Carb. This should help when choosing a cam. Tight LSA is generally more peak power and more peak torque, peakier power bands at the sacrifice of low RPM drivability, smoothness, mileage, emissions. Wider LSA for a given lobe profile will generally be smoother, more street friendly, have a broader power band with a flatter torque curve, but not as much over all peak torque as the tighter lobe separation variant. 104-110 degrees LSA is more performance oriented, the 104-108 range is generally race oriented. 112-118 is generally moderate performance, and modern 2 valve OE LSA's are in the 115-118 range. There is a LOT more to it than just this. Cam design and valve event timing as applied to 2 valve internal combustion engines could be a 2 year degree program in itself! This is just generalizations of how LSA affects power production and drivability. Depending on the lobe profile, mild vs radical, differing LSA figures can exaggerate those tendencies, or vice versa. Like most everything performance related, it's all a compromise. Finding the least compromise for that particular application is what separates the ho-hum power plants from the magical torque producing monsters. Ps. I've said this a thousand times and will probably say it again. I don't care what the cam manufactures claim, NO aftermarket cam that specs at any appreciable more lift/duration than stock, will play well with the factory DATSUN EFI, period! So for you guys reading this that are contemplating a cam swap and using the stock EFI, "leave the stock cam in your engine", until you are ready to install aftermarket EFI or carbs! Trust me on this! Seen and dealt with that scenario in the past far too often. This applies the old L-jet EFI as used on the S-30 and S-130 cars.

:lmao: Every generation has its Ricers, or "wanna-be's", "Posers" as we called them. Nothing new, been around for generations, it just seems more and more prolific as time goes on.

My BMW Piston-to-combustion chamber clearance issues were 100% resolved by installing an "additional" cylinder head! http://forums.hybridz.org/showthread.php?t=150253

I see a signature quote in this..