Mack

As I've saidin other forums, thats HOT! love the colors and the shiny polished bits! Cant wait to see a dynochart! I bet it will lay down more than you are expecting...... Thumper>>>> obviously you do not know of 1 fast Z's distaste for break-in periods, lol! He told me he never breaks an engine in, and thats how he did his last one. Ran just fine until it died an unnatural death. Ill let him share the details if he wants, HA ha! as far as the fram oil filters...... where the hell did this come from?? I NEVER heard about Fram being bad until I moved down to Phoenix. I run Fram on EVERYTHNG and Ive never roasted an engine due to an oil problem. well, o.k. just once. But it was a KA24E, and it had broken the timing chain guides, allowing the tensioner to pop out and create a massive internal oil pressure leak. quite common problem on the eearly ones. EDIT: a fram filter matches the color scheme!! lol actually, a factory nissan blue unit would as well.

NIssans TB48DE one of these would be fun if you threw a turbo on it. Hell, even without the turbo, it would move a Z car.

also, Ive seen some T4 (t04?) turbos on some old *** Volvo and Mercedes turbo deisel egines. Didnt ford turbocoupes and SVO's with manual transmissions come with T3 super 60's? wouldnt that be an upgrade for the stock 280ZX t3? interesting info on the holsets. Im a BIG fan of junkyard engineering, lol!

a high quench head in and of itself is not less prone to detonation, but a high quench head and motor designed to take advantage of it IS less prone to detonation, and not just because of the timing factor/flame travel factor. A motor that is designed for it has .035" or less clearance between the top of the piston and the quench pad on the head. HERE is a good article on Quench. jsut a small exerpt EDIT: hoov100, are you running a Maxima N47 or just a regular Z/ZX N47 head? they are NOT the same! nor are they even close! lol

BlackBeaut>>>> for valve releifs on a piston, i would figure no more than 2cc's. 5cc's is a little excessive, i would think. Sounds like the motor you have in mind would be a screamer! ITBs are DEFINATELY the way to go. Ive had a ride in 1 fast Z's car, and it is bloody fast. HA ha!!! no way man!! those 40's are going on my 71 240Z with the original L24 and E31. its gonna be a nice old school, era correct build. I also have an old, big gold electromotive ignition box and mallory coil to go on it. Although, those 40's would probably flow a little more than the stock crappy 30MM EFI intake runners. GOLLUM>>> i would also be interested to see an emissions chart on my car. It does not concern me tho, because my car is registered in North Dakota, HA ha!! What does a high CR produce more of? is it HC's? or is it NOx? I always thought that a higher CR had a more complete burn than lower CR engine. but, I can never remember emissions laws, theories and what not. How much of a C/R does the S2000 have? I know the 350Z's run about 10.25:1, and the pass just fine.

Actually, I moved back to MN now, and there is 93 octane as far as the eye can see, so its not bad at all!! But, when I was in AZ, if you hunted you could find 92, but most places were 91. It ran fine on 91, even in 110+ heat. As long as I didnt mash it and take it to redline. On the E31 note, It really is a crap shoot. The E31 has a different comustion chamber design than an MN47 (you win 1 fast Z). While the E31 is high quench, its not as much of a quench design as an MN47 (ugh, it hurts everytime I type it, J/K), its just basically a small chamber. Or at least this is what I remember My E31 head looking like before I sold it. I still have on, but its on a car right now. bone stock early early 71. I have a fairly decent understanding of DCR and what not, and I do realize that by lowering the DCR, you get to a point where a high C/R motor will not ping as much because the intake and exhaust are open at the same time and it allows some compression to "bleed off" at lower RPM's. Thats why Im saying the MN47 is an awesome head. Im running 11.4:1 on pump gas and I don't need to lower my DCR to not ping at low RPM's. I'm guessing a LOT of Briann510's power lies in the headwork. I mean, it IS a rebello motor afterall, and he has made NO secret of how much he spent on it, HA ha! now, THAT would be an interesting motor to do side by side comparisons on in regards to HP vs. compression!! trouble would be getting the same amount of head work on 2 different heads. I COMPLETELY agree with you on the fact that the L series intake manifolds are the kiss of death. Luckily Spork is starting to make aftermarket EFI manifolds that are actually affordable!! as in ~$500!!! not bad! One of those would do WONDERS on a megasquirted engine!!! You know, every now and then I get bad ideas of throwing my 40pph mikunis on this engine, but I cant bring myself to have a carb'd 280ZX, lol! I dont have a reluctance to get a big cam, I just have a reluctance to get a big cam RIGHT NOW, with the stock EFI. If I did that, it would exacerbate the problem. I need programmable EFI FIRST, then I go for the big cam!! I hope when someone searches this thread, they can get something useful out of it other than you and I just responding to eachothers posts!! HA ha!!! Of course, there has been some good info come to light in this post, so all is not lost! BTW, when I put this head on my flat top block, I put on a 60MM TB and did the port match thing as well as removing the intake bumps all at once. The difference was night and day over a P79. the extra almost 3 points of compression made it a lot snappier. Like I said, I dynoed it ONCE, with a faulty IC unit and it made 141 RWHP @ 4100RPM's. Most L28E's (runnig similar mods, but stock heads) are lucky to break 100rwhp at that point in the powerband. I would LOVE to get MS, a cam, tune it and go back!!!!

naw, there is no hard feelings, its just the internet, after all!! HA ha! I still think you guys are looking at this whole detonation/ping issue the wrong way tho. USUALLY, people run big cams to "bleed off" dynamic compression at lower RPM's when you are running too much compression for street gas, correct? well, I dont have ping at low RPM's. I have ping at high RPM, when and only when the AFM maxes out. My ping is NOT a compression issue, it is a fuel delivery issue. You can make ANY compression ratio detonate if you lean it out enough. It could aslo be the fact that my whole set-up (might) breathe better at higher RPM, with the semi ported head, port matched intake manifold, removed injector screw bumps (some of those were BIG), and the 60MM TB, and i also have a high flow air filter. If the engine flows more at high rpm, there is no way for the AFM or ECU to know about it, since even in a stock engine the AFM and ECU just "guess" at how much air is going into the engine beyond 3500RPM. so, since teh ECU thinks its a stock engine, its gonna feed it stock fuel requirements, which is not enough, even with a mild cam (which I kind of have, 256* vs. 248*) The more airflow beyond 3500RPM, the more the problem compounds itself. well, to say that my PING is not a compression issue is not TOTALLY fair. It does ping at an A/F that a stock compression car would not ping at. But, with proper tuning and a better A/F, it would not ping. and I bet I wouldnt have to go below 13:1 on the A/F to get it to stop, which is completely acceptible under WOT for a street engine. catch my drift?

o.k. Jmortensen I see some of your points. I do always state that I get ping because of the crappy stock EFI. If i were running carbs that I coudl tune, I could get rid of it. This guy (original poster) is runnig carbs, so he could tune it out if he has the time and know how. I agree with a few of your points, but disagrree with others. A big nasty cam would HURT me, not help me. At least with stock EFI. A big nasty cam would let even more air into my engine, without the EFI being able to account for it from its crappy RPM/fuel tables. so, my engine would run even leaner. I was just stating that I could unleash a whole new tide of HP with a cam AFTER I got the proper fuel management. will probably need bigger injectors too. 180CC's would not cut it with a cam. Nice video, reminds me of MSA last year. I ran a 68.1 on thier course, with really crappy front tires, roasting my rears through multiple gears. next closest 280ZX was 75 seconds, i think. oh, and the only suspension upgrades I have is KYB GR-2's and gas adjusts, that are 10 yrs old, so its all motor and driver, baby!! LOL! No offense, but I still have a hard time beleiving a 250RWHP 8.3:1 motor. hell, lots of people on here struggle just to get 250RWHP, let alone on pump gas. Bastaads car and his freinds.... we do NOT know the condition of either of the engines.. his freind could have had scorred cylinder walls, needed a valve job, any multitude of factors. only way to REALLY test would be to run different heads on the same block, with same carbueration, within the same day. the quench thing..... Gollum, by running a thicker head gasket, you are putting clearance inbetween the flat spot on the head (the part that is NOT part of the combustion chamber) and the piston. anything more than about .035" and it starts to get bad. Its a place for gasses and liquid gas to become trapped and detonate all on their own. thats why if you used a thicker headgasket to drop the compression raito, you would negate the quench effect and end up worse off than where you started. EDIT: just saw BRAAPS post. that about sums it up. Another way you could lower compression raito, but keep quench woudl be to unshroud the valves, and/or take some metal out of the combustion chamber. The P47 thing, HA ha!! ACTUALLY if you look at it, it truely is a bastard child of heads. It shares spark plug bosses, valve lengths, and intake port design with N series, but it has all the coolant holes, combustion chamber design, and production run dates of the P series heads. 6 of one, half a dozen of the other. I just got sick of typing Maxima N47, and if you look at it, it does look like a P series at a glance, without breaking out the micrometers and getting all technical on its ***, lol. and yeah, what do I know? Ive just put 20K on this motor and drive it day in and day out, lol!!! I knwo ping is bad and I will invest in megasquirt before spring. but by then, hopefully 1 fast Z and I needent worry ourselves with the mere mortal heads currently available for L series motors.....

Jmortensen>>>>>>Look, I dont know why you are getting into a pissing contest with me about this head. I run it, have been running it for quite some time and my engine survives to this day. Someone on this board asked if there was anyone out there running this, I said it was me. The ONLY bad thing about the car is the crappy EFI. Megasquirt.....That woudl take care of my problems. Putting the car in 5th and lugging it up a hill SHOULD produce tons of ping if it were a compression/poor chamber design related ping. but, since its an EFI/bad tuning related ping, it DOES NOT ping at low RPM's only when the ECU goes into its little AFM-maxed-out-tirade and goes lean. STOCK ENGINES go lean at this point, like in the 14's AFR's under WOT. thats not good. the reason they do not ping is because of 2 factors. the air flwo isnt there and the compression isnt high enough to ping on a 14:1 AFR. OPTIMUM AFR's for performance on an N/A engine are somewhere in the 12.5 ~ 13.0 range. So, J mortensen, you are telling me that you had a car that put down 250RWHP with 8.3:1 compression?!?! thats not even close to right, unless you have some MAJOR headwork. either that or you are running a 3.1 or 3.2L. Ive NEVER seen a dyno for an L28 that put down even CLOSE to 250rwhp with a 8.3:1: compression ratio. Me thinks your G-tech is fouled. How would a shaved P90 run any better than a maxima head? unless you are shaving it less than .080", but I ASSUME you are talking about "the mod"? It would run worse. less compression = less power. I bet if I put mikunis on my car it would scream too. However, I am running a stock L26 cam, stock intake manifold and stock exhaust manifold. put all these stck parts on your 8.3:1 motor and it would be in my rear view by the end of first gear. BOTTOM LINE.... you can slap a P47 () on an F54 flat top block and have a decent little screamer if you can live with a little ping under WOT. A better set up would be megasquirt to tune the ping out of it. an even better set up would be a cutsom intake manifold (cough*1 fast Z's* cough) and megasquirt. The stock EFI system and manifold both suck. oh yeah, a cam would be nice too. thts my next upgrade. somethign with more than .410" of lift and a lil more duration than 256*, lol!!

oh yeah, BLACKBEAUT... here is the pic you requested...... the maxima N47 is on the left, a regular 280Z/ZX N47 is on the right. the chamber CC's out to be right around the 39cc mark. very nice quench area.... hope this pic helps!

I should have clarified. I dont get ping UNLESS I am over 90% throttle. I can go 3/4 thorttle and take it to redline and its fine. I can shove it in 5th gear, go up a hill and mash the throttle and it wont let out a peep ntil the RPM's get to 3500. And the thing about the temperature,..... the temperature only affects what RPM it starts to ping at in the 3500 to 4000 range. Im thinking it has something to do with the density of the air and how much you need to move through the flapper door to get it wide open. oh, and I doubt your 8.3:1 engine would make a 1980ZX 2+2 run low 15's in the 1/4 mile. I do need to get some high octane gas, but that would be a bandaid. I NEED megasquirt. that would be the proper way to do it. It was stated in this guys original post that he was running webers (albeit DGV's, not DCOE's) that would probably run a little richer than the STOCK EFI. You can just slap a P47 on a flat top block and it will run, it will be quicker than a stock motor by far. you will deal with ping only under WOT (or close to it) unless you go megasquirt or 300ZX stuff. Hey, Ive been using my car for pizza delivery for about 20K miles, plus towing trailers, boats, motorcycles, cross country trips. My engine runs like a champ. nice and smooth. good oil pressure, seemingly good compression (havent checked it), when it cranks over, its very even. I have a 1978 for van with a 460 in it that is NOT so even tho, lol!! the point im trying to make is that I have not broken any ring lands or mashed any rod bearings from my pinging.

great, now I get sucked into this thread...... How many guys are runnig a Maxima N47 (P47 ) with flat tops in a street motor on pump gas? ME. Been running it for over a year now, DELIVERING PIZZAS. probably have in excess of 20K on this set-up. I did do some mild porting. had the valves unshrouded out to the fire ring. blended the exhaust bowl area into the liner and took out some rough edged casting marks on the intake runner. I am running a 260Z "C" stamp camshaft (256 duration, same lift as other L engines) Im running STOCK 280ZX FI, and boy, does it suck. I took the injector bumps out of the intake manifold and put a 60MM TB and ported it to match. and I have a cat back 2.5" mandrel bent exhaust. I set my timing for about 12 to 15 degrees initial, i run pump gas all day long. I DO get ping, only AFTER about 3500 to 4000RPM which is when the poor flapper door AFM is maxed out and the computer swithces to an RPM/fuel curve. It hits like a switch every time, right at 3500 to 4000rpm, depending on ambient air temp. If you dig around the forum, you will find that the stock AFM's and therefore the a/f ratios go to crap at this point. Now, I can run mid-grade gas and it runs fine for highway cruising and around town. No ping unless its over about 75* ambient. no ping whatsoever on the highway, just flat out cruising. this is the ticket. I took it to a dyno for fun, again only having the mods listed in here..... I dont have the chart, but it put down a peak of 141rwhp.... at only 4100rpm. the reason I didnt go higher was because I had a bad igntion control unit. It wouldnt let me rev past about 4500RPM. it was screwing the tiing up past that point. Now, look around at dynos of stock L28's and you will find that they put down about 95rwhp at this point (4100RPM) so, clearly this set-up is worth something. If I had Megasquirt or even 300ZX EFI with a MAF, I almost garauntee you it wouldnt ping. Hell, if I even had an adj. fuel pressure regulator, I could probably cure it. edit: screw you. I still refuse to call it an MN47, its a P47 to me, lol!! j/k!

there have been advances made since "back in the day" Im not trying to be a dick, although I know I may be coming off as one here. There is a guy on Zcar.com, Briann510 not sure if he is here or not...... He had Rebello build him a motor for a street driven 240Z, He has put down 278rwhp, with more on tap. he is running MILD compression in comparison (I.E. I dont think he is running race gas) and he also has a streetable cam. He has been beting the piss out of it for a few months now, and it has shown no signs of slowing down. Of course, this is a 3.2L with head work. but its not an all out motor either. I shudder to think what this thing would put up on an engine dyno. I have heard reports of a drag racer somewhere in AZ that puts down 370rwhp on an NA L6, but have not confirmed it. running in excess of .750" lift. 250 at the crank is do-able in a daily driver for not ThAT much cash. I would say you could get by for under 3K if you spent it WISELY. hell, Im under 1K, car cost included and Ive shaved 3 seconds off of my 1/4 mile time, for a heavy 280ZX 2+2. yeah I know, i went from low 18's to low 15's, lol but you gotta admit, thats not bad.

there already has been some people out there who put LD28's in S30 cars. there was even one guy that put a turbo on it and made the damn thing run off of vegetable oil. Now, I dont know of anyone that has jammed 30 psi of boost down its throat, but you are going into completely uncharted territory here either. do a google search on "veggie van", but I think he sold his LD28t powered 240Z on Ebay some time ago. on a side note.. TONY>>> for a while Ive been fighting an urge to find a ZD30 and put it into a 240SX. 150HP and about 250lbs/ft of torque? That would be fun to turn it into a "drifter" burning deisel fuel, lol! I wonder what kind of mileage it would get, Im guesing low 40's to low 50's..... HA! Any ideas where I would go about picking up a ZD30 stateside? or time to just start Emailing random engine importers???

quick recipe for some easy HP. put flat top pistons in your block, get a Maxima N47 head (11.4:1 compression w/flattops), have it ported mildly, a camshaft in the 270 to 280 range with at least .450" of lift, header, 2.5" mandrel bent exhaust, and get an aftermarket intake manifold!!! the stock ones SUCK, or go carb'ed. There has been much talk on Zcar.com about an aftermarket intake that someone is selling for like $550. check it out. I think the posters name is spork. oh yeah, and ditch the stock FI crap, a Z31 system is VASTLY improved over the flapper door. Or say screw it and go MegaSquirt. all this should get you in near the 200rwhp range, if done properly. and that is probably 250 at the crank. Im pushing somewhere in the 160 to 170rwhp range and I dont have a FULL 2.5" exhaust, or a header or an aftermarket intake manifold or a cam, or a Z31 FI system. Ive got a 1980 280ZX 2+2 with everything still in it and its low 15 sec capable.

uhm, no you cannot. SOHC VG engines use 5 head bolts per cylinder, arranged in a star type pattern, DOHC VG's use more conventional 4 head bolts per cylinder, arranged in the more typical square pattern. So, you would need MAJOR modification to do it. just get a DOHC VG, they are plentiful enough. Just look for infiniti J30's or NA Z32 300zx's. Or if you want a single turbo VG, look at a japanses Cima. they came stock with a VG30DET, thats right, DOHC and 1 turbo. Plus, the heads outflow TT heads. on a side note, MARIO>>>>> yes you CAN put a DOHC KA head on a SOHC KA block. it takes ome timing gear modification, but it can be done. There is a guy over at NICO that did it. SOHC KA block + DOHC KA head = 12:1 compression. McAdam

the head is not welded yet, and I am not sure if we are even going to weld it, or if we will just be using gaskets with press fit pins inbetween the halves (thirds, I guess) to keep them aligned. As far as the cams, valve train and timing..... well, you'd be surprised to learn how many stock or very slightly modified nissan parts are used in this head.... Unfortunately, I moved back to Minnesota this year, so work has been temporarily suspended on this project, but rest assured, I wil get back to phoenix to visit 1 fast Z some time very soon, during which, a marathon of mechanical engineering, modifiying and machining will take place and we will get this project DONE. Mack.

the belt is driven directly off of the crankshaft, and it is a cogged gear. the gear teeht spacing looks almost exactly like an early to late 80's 200SX, you know the ones with the CA20E in them? also looks very similar to the VG30E timing belt, with regards to spacing and number of teeth, Ill count teeth on the crankshaft gear sometime this week to be sure. Mack

so, here I sit looking at all the pretty little bent valves in this RB25 head I have for parts, wondering how hard it would be to slap it on an L block, with external oil lines and maybe one or 2 external coolant lines. My mind begins to drift towards the semi complete LD28 short block with its BELT driven injection pump, I cannot help but wonder....... head bolt holes as well as bore spacing are DEAD ON as well as a lot of coolant holes around the cylinder bores. so, does anyone know where I can get a detailed coolant flow schematic for an RB25DET engine as well as an L series engine? I think I could pull it off if I could get my hands on some injection pump pulleys and just have them welded to the RB cam gears then find a suitable length belt and viola! well, besides putting some tensioners on teh outside of the timing cover and a few other hurdles. thoughts??

check out some industrial uses. I know the LD28 was used in some forklifts/tractors/generators. You might have better luck finding one in that type of market in Australia Mack

DAW>>>> no, I havent done any of the richening tricks yet. I tried (a) POT once, but that was when my ignition module was out. I really should go back and fiddle with it. I have a 5K POT so, it could be fun to toy around with that. On a side note, Z-YA, are you running a Z N47 or a Maxima N47? Im curious about the "quench" factor! not to start any wars or anything..... McAdam

yes, ping is bad. I have a P47 (maxima) on a flat top block ...........about 11.5:1 compression, higher than most racers on this board..... with a stock 260Z cam (256 duration) and I get pretty bad ping above 3500rpm, but I have determined this to be an FI problem. Around 3500rpm is when the stock airflow meter maxes out and the computer goes to a preprogrammed a/f ~ rpm curve. it is no longer measuring airflow, the fuel is injected based soley on RPM. the car only pings at lower RPM when I am running in excess of 15 degrees initial, otherwise its fine. in the summertime I can floor it in 5th gear @ 1500 RPM and it will not ping until 3500rpm. I drive my car every day in stop and go traffic (pizza delivery) and run 92 octane and I have not killed a piston yet. I CAN use 89 octane for driving around town, but I have to be light on the throttle (nothing more than about 3/4). The car uses some oil, but thats because it leaks from every seal under the hood! it does not smoke, nor does it run lumpy. I am, however, afraid to do a compression check, lol. A lot of my ping problems will go away when I switch fuel systems. Mack

sorry, man, I cannot find their website, but I do know the name of the shop, its fueled performance and their phone number is (602)-448-5620 they are based in Phoenix, and I talked to them about 6 months ago when they quoted me $800 for the RB30 block. I do have an RB25DET head with bent valves (same as VG30DE) that I may be willing to let go. also have most of the intake stuff too. and may be able to get a hold of an RB20/25 DET exhaust manifold, then all you'd need would be electronics..... mack

hey, have you considered an RB30DET? Venus auto USED to sell RB20DET and RB25DET heads only for $150 and I know a place that can get you an RB30E block that has been rebuilt for $800. then just get some custom intake and exhaust manifolds or get a hold of some RB25 stuff and run a standalone or MEgasquirt the bastard. Go to http://www.meggala.com and dig around on his site for the reciepe for the RB30DET. some of his freinds built on that pounded out 467whp @ 17.6psi. not too shabby. McAdam

lol@jon! I tried to get in your group, but Iwas a little late. funny you should mention stock 280ZX's, as I have one (2+2 to boot! N/A), well not stock. fastest time I turned was a 68.1, well that was when the clocks were working anyways. and that was pushing some VERY crappy front tires with some very not crappy rears, talk about plowing thru the corners.... but yeah, 1 fst Z's car was doing pretty good up until the motor blew. I think his best was 66.6 or something? only got in 4 runs. I need me an intake like that, lol! Mack