BRAAP

The answer to your question is a nice warmed over budget Chevy V-8 swap. (I know most of you think I’m strictly an L-series guy with all the custom L-series heads we build here, but deep down, if it goes fast, I really don’t’ care what’s under the hood, and bang for he buck, the SBC swap is pretty hard to beat). For example, for my personal daily driver back in the late ‘90’s, I personally built a 280 Z that ran very consistent 12.3 @ 113 MPH at Woodburn drag strip in northern Oregon, using a VERY mild Chev 355, (cast pistons, Edlebrock performer intake, hooker shorty headers, 041 casting iron heads with 1.94/1.50 valves, cam was a s 216/228 @.050” on 112 LC, 468/480 lift). Running on some real cheesy 195 60 HR 14” all season tires, Yokohama Y-388 to be exact. Trans was a Borg Warner W/C T-5 five speed trans from a ’91 Firebird. The engine idled glass smooth at 750 RPM,, no lope whatsoever, got 20 MPG on the freeway with a Holley 650 double pumper, and if the throttle was used judiciously, the car was as docile to drive around town as a stock L-28 powered Z car. My wife regularly drove the car around the greater Portland area with no problems of it being a beast. Good luck

Pete, Thanks for the update. Looking forward to your next… Moby, Also looking forward to your EDIS-8 update as well. If we can help out in any way, let us know.

WOOPS!! My bad. You are absolutely correct. I wasn’t paying attention to the details within this thread, (I just lightly skimmed through it), and I just assumed he was asking about how/why just the act of shaving a head would need to have the valve springs shimmed…. DOH!!! Sorry fellas. Please forget my previous post. Paul

Shaving the head has no affect on valve springs, (unless you shave into the vale spring pockets which would be impossible). You can shave the head as much as you want and the valve spring pressure with the valve on its seat and over the nose of the cam wont change, so there is no need to “shim” the spring just because of surfacing. You shim the springs for other reasons such as sinking the valves deeper into the head, etc. or for any other reason that the installed spring height isn’t where it is supposed to be for that particular spring. Now you will need to shim the cam towers if you shave al to of material off of the head to keep cam timing within the range of the factory adjustments on the cam sprocket. Spring shims and cam tower shims were mentioned and pictures shown as well in this thread about what is involved in building a custom L-series cylinder head. http://forums.hybridz.org/showthread.php?t=108398

I’m assuming you are talking about the N-42 chamber that wasn’t welded. The sanding wrap marks are just for removing the “as cast” finish during the process of polishing, going to finer and finer sanding wraps to a polished finish for that head. We had no intention of removing material other than to get a polished surface. As for what tools we use, For Aluminum heads like the L-series, We use cutters for non ferrous metal in a die grinder, (no Dremel tools here. I ported my very first head for myself using a Dremel and will NEVER do that EVER AGAIN! Dremels are for modeling, not porting.) These non ferrous cutters are more aggressive than ferrous metal bits and don’t clog as easily when carving on metals such as Aluminum because of the angles ground into and on the flutes of the cutters themselves. For porting Iron heads, such as OE Chevy heads, we use the ferrous cutters. We only use the sanding wraps to remove the high spot of the divots left behind from the cutters. The picture below represents only a small portion of all the porting tools we use to port heads. The cheapo fat die grinder on the right is for hogging and the long skinny Dotco grinder is for finish work. The cutters along the top left are for aluminum, (non ferrous), and the cutters in the middle are for porting Iron heads. The dead valve on the top are my sacrificial L-series valves. They are nothing more than a pair of sacrificial valves which will help protect the valve seats from runaway die grinding efforts, and trust me, it WILL happen no matter if you have only 30 minutes experience or 2000 hours behind a die grinder, it still happens once in great while and those sacrificial valves will protect the seats from having to replace them because of an uh-oh. Speaking of run away cutters, “when” that cutter does grab and takes off across the head, if you position yourself and the cutter in such as way that “when” the cutter does take off across the head, it will do as little damage as possible, i.e. divot tracks across the deck surface, big gouges in the spark plug threaded hole, removal of to much material causing the head gasket fire ring to over hang the chamber requiring rewelding, etc. The more damage you cause, the more machining and material removal needed to clean up those uh-ohs. Tricks like positioning the cutter in such way that “when” it does grab and take off across the head, it only goes across the open chamber and not the deck surface. This requires repositioning yourself and the head in several positions for each and every chamber. Porting is very time consuming, patience demanding, job that requires experience to get it right. If you have never done this before and are dead set on trying it yourself, try using a scrap head for practice. I don’t mean just doing one chamber and then moving on to your good head, I mean complete the head to its entirety, as mistakes will be made, and a scrap head is the best place to make the biggee mistakes. Making these mistakes on scrap head will help point out where your weak points are in regards to keeping the cutter from getting away from you. Using a scrap head in this manner allows you to mess up as much as needed so that you can establish little tricks that help you and your technique in keeping those inevitable uh-ohs to a minimum. Hope that helps.

Hmmm Looking for unshrouding info eh… Does this help? Maxima N-47 roughed in… Custom polished exterior N-42 in the rough in stage… These next few are of a custom Welded chamber N42 at various stages.. And a P-90 that we just shipped out this week. Does that help?

Silent has first hand experience with the Schneider cams, (he is currently tearing down his current engine to clean out all the metal flakes that used to be cam lobes), and as such, his new cam is a fairly radical cam that we had Rebello grind for his P-79. I’m sure Silent would be glad to tell all about his Schneider cam woes…

Very nice Pete. Looking forward to when it get it up and running on EDIS…

The ’82 short block, if it has the OE pistons, will be flat tops and with the P-79 head will make for a great combination. As for porting. The How to modify your Nissan engine book written by Frank Honsowetz is a great book. He doesn’t come right out and give away any porting secrets, but if you read and reread the heads section, some things will pop out from between the lines and will point to the L-series weak sports, (hint hint… valve shrouding). Also, if you peruse the threads I linked earlier in this thread and study the pictures “carefully”, that should be enough to get you DIY head porters going. We are actually building a P-79 right now for Hybrid member that is getting the full port treatment, Rebello cam and possibly N2O. If he is reading this thread, he may be nice enough to allow pics of his head and the port work we have done thus far to be posted, though that is his call.

Dave, Thanks for the head ups. I’m actually using the Intrepid Coil pack for the DIS ign on our L-28 powered F-prepared 240’Z. http://www.msefi.com/viewtopic.php?t=15436 I never thought to look very closely at the Intrepid intake while pulling the coil packs. Are the twin cammers the 3.5L or the single cammers? We have both at our local U-pull-it yard currently By chance are you contemplating a similar intake design for a V-8? Sorry for hijacking Silent... ..

The MN-47 would be cool, but I don’t feel it will give you any substantial power gain over what the P-79 were building for you, other than the slight bump from in power form compression ratio and as you noted, race fuel will be your guys main diet. If it were me, and being as I’ve been down the N/A L-series AND the SBC avenue for my personal Z cars, the SBC is hard to beat. Reliable 350 HP and completely docile around town from an engine that cost less the build than the L-series is pretty hard to beat… My measly little 330 HP Chev 350 running anemic Edelbrock Performer intake, OE Iron heads, (that I reworked of course), 1.94” 1.50” valves, and World Class T-5, in my 2700 lb 280 Z ran 12.3 @ 113 MPH on some real cheesy 195 60 HR 14” all season tires and way wrong gearing for the drag strip. Engine idled glass smooth at 750 RPM with NO lope, got 20+ MPG with Holley 650. Here is a link with a real crappy picture of the V-8 install just after I installed it, (plug wires were a mess etc), and there is a pic of my EFI L-28, and of the car drifting… http://www.datsuns.com/projects/paulrproject.htm Here is the 12 second time slip http://www.datsuns.com/timeslips/paulr101098best.jpg FWIW, by the end of the is summer, (have to get caught up on customer projects first), I will get started on putting together another V-8 Z for my daily driver. This one should be strong in the 11’s. I already have the ’75 shell that is straight and virtually rust free and also already have the complete assembled SBC 355 short block that came from an ’85 Vette complete with ARP hardware throughout, brand new Kenny Duttweiler Trickflow aluminum heads with CNC chambers, T-56 trans, Aluminum driveshaft already shortened for the T-56 V-8 Z with new U-joints and R-200 adaptor, all motor mounts, aluminum water pump, gear reduction starter, Fluid damper, etc. The only parts I’m missing are headers and an intake manifold. I’m seriously considering scratch building an EFI Intake that resembles the Dodge Viper in design and running WOLF 3d EMS with COP ign. Sorry for the tangent, but V-8Z just plain ROCK!!!

We have saying in the engine building business. “Always build as much displacement as you can afford”. Going from 2.6 liters to 2.8 liters will deliver more gains in of itself than even the most ideal head swap, (unless the head has been extensively massaged of course). If he can find a complete ‘81+ ZX L-28, (flat top pistons with the P-79 or P-90 head), he’d be way better off from the get go, then it is just a matter of getting the carbs dialed in “properly”. I can’t emphasize how important proper tuning is. We could spend 10 hours hashing out which untouched stock cylinder head would be ideal for your fathers L-26, and this theoretical “ideal” cylinder head may perform just a tad better. That tad better performance being a few maybe 10 Horse power tops, due to the head swap alone, is something that most of us wont feel in the seat of the pants. Here is one little story of just how important proper tuning of the “complete” engine package, mainly fuel and ignition, really is. Years ago I ran across a gentleman who thought his triple Webber L-28 powered 240Z was the fastest Z in the USA. How do I know this you ask? Well, he told me so himself so it must true, right? Any how, he rattled off big camshaft specs, massive port work, huge exhaust, radical hot ignition parts, and the list went on and on. Listening to this gentleman spew just how special his L-28 powered 240 Z was with the list of go fast goodies and mods performed to it, there is no doubt in anyone’s mind that the car should be fast be any standard. Well he want ed to prove it by running me and my lowly mostly stock 280 Z. I turned him down time and again knowing my car was no match for this monster Z. I finally reluctantly accepted his challenge and all along I knew for sure his car would out run my lowly little 280 Z even if he short shifted. My car was a ’75 280 Z street car and the engine consisted of a completely bone stock ‘78 L-28 short block with the OE dished pistons, N-47 head that I personally did some valve unshrouding on, nothing else. OE stock ’78 cam, original Nissan Hitachi EFI, header, lightened flywheel, recurved ign advance, and countless hours of dialing in the ignition curve and tinkering with the EFI. Pretty much I was running a nothing special L-28. We ran heads up and I whooped him at approx ¼ mile by several car lengths. He was pretty hot under the collar to say the least and couldn’t believe his super hot rod L-28 powered 240 Z just got whooped by an obese mostly stock 280 Z with the lowly Nissan EFI and stock ’78 smog camshaft. So we ran again, same outcome. Never saw that gentleman again. FWIW, my car at the drag strip ran a measly 14.4 @ 97 MPH, not a remarkably fast Z, but also not to shabby for stocker. If his car had all the goods he claimed it had, it was easily capable of 12 second time slips in the ¼ mile, but apparently, his poor super hot L-28 powered 240Z was in a very sad state of tune. Moral to the story, you could have the best most optimum combo in the world, but if it isn’t “TUNED” properly, all the best parts in the world wont do you squat. That same car received a very mild Small block Chevy 350 a few years after that. The V-8 engine had a mild cam and idled at a glass smooth 750 RPM, no lope whatsoever. Induction consisted of just a basic Edelbrock performer intake and Holley carb, heads were stock Iron heads with 1.94”/1.50” valves, though with a little porting work from yours truly, again nothing special, just a mild average garden variety Chevy 350, but with lots of time invested in tuning the ignition and fuel. With that engine, my 2700 lb 280 Z ran 12.3 @ 113 MPH at the imports drag races with completely wrong gearing and some really cheesy 195 60 HR 14” all season tires. Based on what I’ve gleaned from your posts, your father wants snappy quick performance and you guys are hoping that a cylinder head swap will achieve jsut that. I think his time and money at this point would be best spent on tuning what he currently has and/or possibly swapping in a late model L-28 with flat tops and either the P-79 or P-90 head and of course dialing that package in. All else begin equal, you could run a dished piston E-88 combo, or a flat top P-79 combo and sure there should be a few horse power difference between the two different engine combo’s on the dyno, (the power nod going to the flat top P-79 combo), but I truly feel the small difference in hp would not be felt seat of the pants. Again, I truly believe at this point that if he just had his current set up truly “dialed in” properly, it should perform very respectably and most likely put that grin of yesteryear back on his face, that is if the valves and rings in the current power plant are sealing properly. Just swapping on a head that might be a little more ideal than his current head, even if this new head is the most ideal head for his pistons, the head swap itself won’t deliver all the goods. The “goods”, is in the state tune… I have a feeling that what I just wrote, isn’t what you really wanted to hear and if so I apologize, but I truly and honestly feel that tuning is where most performance lies. He already has good foundation of go fast parts. If it were my car, I would definitely try to dial in what is already there, or swap in a late model L-28 long block under the current induction system and dial in that set up.

Muha hahaha… Wahtcya got in mind there Bryan?!?!? LOL BTW, are you planning to use Head studs on this Nawwwzz monster?

N-47, MN-47 and P-79 have round exhaust ports. E-31, E-88, N-42, and P-90 have square exhaust ports. HTH

Hmmm.. His triple carbs won’t hurt him one bit, in fact, his induction system is ideal from a pure “performance only” stand point when it comes to carbs. The trick is getting them dialed in properly. There are a lot of guys out there that claim to be good at tuning those carbs, but in all reality, there are only a handful of real super tuners in this country that can actually extract their maximum potential on an engine. Once tuned properly, they will hands down, out perform the OE EFI, all else being equal. Even the early SU carbs will out perform the OE EFI when set up properly. Stormin Norms 12 second N/A Z car is testament to that as there are NO naturally aspirated Z cars running 12’s with the OE EFI system, let alone many in the 13’s, if any. There are plenty of carbed and aftermarket EFI Z’s in the 13’s and a few in the 12’s. Hope that helped… Paul Ruschman

Where in Portland did you reside? What in particular are you interested in learning about regarding L-series cylinder heads?

Read these two threads completely through. They should help guide your decision as to which head best fits your Z car budget. Heads… http://forums.hybridz.org/showthread.php?t=105653 Big and Nasty head work… http://forums.hybridz.org/showthread.php?t=104420 As for hands down Carbed power, money no object, as Stormin Norm mentioned, either the E-88 or N-42 with welded chambers like the on in this thread… http://forums.hybridz.org/showthread.php?t=108398

Stoker L-series with flat tops and MN-47, sure, it would be a Race or Av gas engine only. If you wanted a pump gas stroker L-series with the MN-47 you will need custom pistons manufactured with a dish CNC’d directly under the chamber for a streetable compression ratio friendly with pump gas. This is totally do-able, the question then becomes, how large is the budget for your stroker MN-47 engine build?….

I live in Sandy Oregon, just east of Portland. We live pretty much right in between Portland and Mt. Hood. Where about in Cali do you reside?

Ok guys, This in regards to cylinder heads… The Z car N-42 and Z car N-47 heads share the exact same combustion chamber shape and volume. N-42 was available in ’75 and ’76, the N-47 from ’77-’80, for the domestic market. The ’76 N-42 heads did receive the steel intake seats as did all L-series heads from that time on, where as the ’75 N-42 heads had those soft bronze intake seats, unless they have been replaced in the past. The port differences themselves has already been covered so I wont rehash that. Now as for the Maxima N-47, it has the same ports as the Z car N-47, but the chamber is completely different than any of the other L-series head and is the smallest of the L-6 combustion chambers in volume. The Maxima N-47 also uses a smaller intake valve. If any of you want some “real good” detailed info regarding any of these heads and which heads work and don’t work on the various short blocks, I strongly recommend reading these threads… Both of these threads are VERY VERY informative in regards to the details of the L-6 cylinder heads…. http://forums.hybridz.org/showthread.php?t=104420 http://forums.hybridz.org/showthread.php?t=105653 If I get the time, I should just take pics of the chambers and ports of all the L-series 6 cylinder heads that Nissan manufactured for the domestic market as we have at least one copy of all of them, E-31, E-88, N-42, N-47, P-79, P-90, P-90-A, and the Maxima N-47.

We are considering MS-II for one of our customers N/A L-28 powered ’73 Z for similar reasons. He won’t need any of those extra goodies yet he does want EDIS, and I’m sure the higher resolution of control that MS-II brings to the table vs MS-1, won’t hurt drivability….

YES!!!!!! V-3.0 on MS-1 will run EDIS! You will need Mega Squirt & Spark Extra programming and Mega Tune to take advantage of the EIDS. Even V-2.2 runs EDIS. We are currently setting up TWO MS-1 systems running EDIS on Datsuns. One is a MS1 V2.2 which is currently running EDIS in “spark only” config with Dual SU’s for induction in a Datsun 510, (WOW what a difference EDIS made over the OE Electronic Dizzy). The other project is myF-prepared SCCA Solo-II Z car running MS1 V. 3.0 and EDIS. Here are two threads that you should go over concerning the EDIS and Z cars… http://forums.hybridz.org/showthread.php?t=103781 This thread has some good info and pics of the EDIS Test bench in operation... http://www.msefi.com/viewtopic.php?t=14920

Tony, First off, thank you for the informational replies and to me at least, you came across with less attitude. As for the caps and italics for your post, that does help accentuate key aspects within your posts, but I’m not so sure that just adding caps or italics would take the attitude out of your original posts, though all your replies since, (to me any how), have had a much more friendly attitude which is greatly appreciated, thank you. You bring up valid points and seem to be well versed in “how” and “what” the OEM is bound to legally. Curious, what is your educational and practical background in regards to power-plant development, building, and tuning? In regards to the throttle valve pre-heat, in adding to your assessment of the anti-icing capabilities, I also believe it fulfills another function as well and that would be Emissions. By adding a consistent heat to the throttle valve, this helps to “stabilize” inlet air temps, by what little heat it does add to the air stream, thus helping keep tighter reigns on emissions control. As a Certified Aircraft technician, (acquired my A&P certs in ’91), and a private pilot as well, I’m quite aware of the effects of throttle icing and how it forms. On Fuel injected engines throttle icing is “almost” non existent and as such, the “carb heat” control found on all carbureted air craft was eliminated on injected aircraft, that is not say throttle icing doesn’t happen on injected engines, and I do believe when conditions are just right, temps, humidity, throttle position, etc, the temp drop at the butterfly, even without fuel atomizing at the butterflies, can be enough to ice. In a carb application, the heat being removed from the air stream due to the atomization of the fuel exaggerates the temp drop across the butterfly so icing DOES happen and it happens more often then most people realize. I’ve experienced this first hand a couple times while flying around Mt Hood here in the Pacific Northwest on cool humid days. Constant application of Carb heat at regular intervals helps keep the carb clear for optimum performance, i.e. able to remain ABOVE the terrain! As pilots, we are trained that Carb Icing can even happen at ambient temps as high as 70 Degrees F during high humidity etc, though the only times I’ve personally experienced carb ice while flying is when ambient temps were down in the mid to high 30’s at altitude. As for the divots/erosion/corrosion/pock marking found on the front cover behind the impeller, were you eluding to this being caused from cavitation alone? Cavitation, as you stated, is not good on many levels, as coolant flow will, for the most part, become non existent during cavitation, and that a reduction in impeller speed would improve cooling in that situation, which I agree with 100%. I am struggling with the concept that the forces present during cavitation within the Datsun water pump are strong enough to “mine” the aluminum from the front cover itself yet does no damage to the impeller blades, i.e. bent, broken, pockmarked etc. I realize the impellers are made of a harder material, typically mild steel, but most of them are just stamped sheet metal and as such, I would think they would also show some signs of damage as well. At any rate, I “used to be” fairly confident in saying those divots in the front cover under the impeller were caused from Electrolysis as a result of negligent cooling system maintenance, and usually those same engines that had this front cover problem also had the water jacket transfer ports on the deck surface of the cylinder head eaten away as well. Now I am VERY confident in saying the cylinder head coolant port erosion is caused from Electrolysis, but if those pock marks, (little round divots), in the front cover are from cavitation, please help me understand why that is and the physics taking place to cause this? If my original concept of Electrolysis causing those divots is incorrect, I need to know. As you stated, a coolant bypass is a MUST, and how that bypass is implemented is one of those things that not everyone will agree on. When most people eliminate the external water bypass on their engines, they will typically make provisions for a coolant bypass such as drilling the thermostat itself. The coolant bypass is a must for various reasons like Tony stated, such as to help prevent cavitation of the water pump while the thermostat is closed, to help “burp” the cooling system on an initial fill, and to a much greater degree, for the purpose of allowing the heated coolant to flow up to the thermostat itself so that the thermostat can “sense” the heat being generated by the engine and in turn modulate coolant flow accordingly. If no hot water/coolant makes its way to the thermostat, then it is surrounded only with cool water/coolant, i.e. the thermostat has no idea the engine is getting HOT. Being as the thermostat is remotely located in relation to the combustion chambers, i.e. not directly on top of the combustion chambers themselves, “if” there is NO coolant flow whatsoever, the only way the thermostat could sense the heat being generated by the engine is from conduction, which is a slow process. By the time enough heat has been “conducted” up to the thermostat to open it and let cool water to surround the cylinders and combustion chambers, it would be too late. So by allowing the coolant to flow up to, under, and/or thorough, the thermostat itself, the coolant that is being heated by the combustion process gets a chance to cycle up to the thermostat so it can “sense” the heat being produced and fulfill its duties of maintaining a consistent running engine temp. This is a major function of that external coolant bypass that most of us do eliminate, we just need to make sure an alternative bypass has been provided in its place.

Here is a thread highlighting the EDIS system with some great pics of the system in operation on our test bench. We currently have a Carbureted Datsun 510 with the L-16 (twin SU), running EDIS-4, using the Dodge Neon coil pack, and MSnS-E to control the timing, also covered towards the end this thread… http://www.msefi.com/viewtopic.php?t=14920