Oddmanout84

I was just about to order some jets. Damn, now I don't know if I have the heart to. I remember a couple of years ago calling him up and navigating through the minefield of questions he threw at me (determining what jets he should sell me based on the engine I was getting ready to build). Went over my displacement, compression ratio, what Mikuni size I had, etc. When he asked what cam I was using, I blurted out that I was thinking about using "an Isky Stage III 490 grind.", since I hadn't really decided yet and it was the only one I could conjure up. "I don't know what the hell that means!!!", was the annoyed reply from the other end of the line. Racking my brain for the approximate duration & lift numbers got me back into the green zone. Todd had plenty of knowledge to dispense regarding the subject of Mikuni carbs, but you had to pass some of the checkpoints yourself. It was refreshing to have someone yank the info out of you to sell you the right thing, rather than what you thought you needed or wanted at the time.

I used a very thin layer of RTV (the oil resistant type that looks about the same color as molybdenum disulfide grease and comes in a pressurized can) on both sides of the felpro gasket used, spread with my finger, and left to tack for about ~10-15 minutes before installing. Getting the bolts in is the worst, do as many of them as you can *lightly* with your fingers to prevent cross threading. It's cast iron, but it still happens alarmingly easy. For the tight ones you can't fit your hands in to turn, use a long socket extension and turn by hand. Don't use the wrench for anything but final torque, and even that's only 10-12lbs if I recall correctly.

Madcaw, Yes, I'm leaving the runners the way they are (for now) for that exact reason. Maybe I'll hit them with 80 grit to smooth out some of the casting, but that's about it. I hadn't mocked up the thermostat housing yet, so thanks for the warning. I certainly have had a problem with finding the right mounting bolt/stud that actually fits the manifold, however. They certainly made things tight on the upper side!

Wow. It's been some time. Long hiatus, time to get back into it. Turbo motor is being canned (for now) and work continues on the NA Mikuni project (aka Project DF). Not fully decided on which head I'm using (N42 vs. P90 thread), but at this point I think I'm leaning P90. Specs: -Rebuilt L28 N42 Block, 280zx flat top pistons (STD) -P90 head, swapped valve train & cam from 280z N47 (working, may change) -Triple Mikuni 40phh on Mikuni short-runner manifold, small ~1 1/4" velocity stacks -Hooker "Super-Comp" header -2.5" Thrush resonator -Ansa glass-pack tips -280zx NA distributor (no recurve yet, running vacuum advance w/carbs) Essentially, a build using the parts I have on hand as much as possible. Just need to purchase pipes to fabricate and assemble the exhaust. Pics later, maybe. This build won't be a monster, but it will hopefully run in time for a move.

When I started work on my 280, I wanted to remove my oil pan for the stupidest reasons: to paint it orange. I told myself it was a good idea because I'd be able to see oil leaks better and because I was curious about what I'd find in the pan (there actually ended up being quite a bit of grit and half of a 3M sanding disc from god-knows-when). Back then I had no engine hoist, so I made do. The short of it is that yes, you can remove it whilst installed. It will be an absolute pain though to get some of those bolts out. It was a tight fit, but I don't think I even had to remove the sway bar, or the engine mounts. Getting the thing back in carefully with gasket was a bit more challenging, but not impossible. Clean the surfaces well before you do, and it shouldn't leak. But at least when it's leaking, you know that it's not empty, right?

NewZed, Yes, I might just have been a bit hyperbolic with that one. I guess its not terrible when you consider it being only around a point of difference. Regarding the redesign of the chamber though, my understanding was that with the lower compression ratio comes lower emissions, which would be right about in line with what they were trying to do at the time: Power sacrifices in the interest of fuel economy and lower pollution. Adding a better working/flowing design retained performance. HUD, When I first started with my zed, I got it running on the stock N47/N42 dished setup for about as long as it took me to source an L28ET. I was lucky enough to find a new friend with a decently rebuilt one sitting in his garage with a Haltech E6K managing it. That motor was incredibly fun, until it broke due to the builder putting a wanky bolt stackup on the crank pulley and a low oil pressure issue. My fault for not looking at things hard enough. Bang for the buck, and the general consensus on Hybridz, tips the hat toward the turbo motor (if you're sticking with the L6) in most cases. Depending on how rusty/gunky yours is, maybe you won't need to re-ring it. It seems like when people crack open the bottom ends of these motors to "refresh" things, it opens up to more problems in the long run.

I appreciate the diversity of opinions. The P90 route is certainly the more practical one, and perhaps using the N47 cam and tweaking the mechanical/ignition timing might bring me close to what I'm looking for. I'm assuming it'll still be punchy even if I'm not milling it down? I should also mention that I have toyed with the idea of turning that combination into a higher comp turbo setup, but not for some time so that's really not on the table as a decision making point. Maybe if I win the lottery (in terms of finding, not the paying) and acquire one of those HKS units I can play with a carb turbo setup, but that's a when/if down the road. I also have an old E88 head, but I didn't bother mentioning it. According to the identification guides I've seen it appears to be one of the 240z versions with the different chamber design that's similar to the E31, and would solve the square exhaust port issue. It is however caked in 1970's grime, corroded in a couple exhaust ports, and all the brass seats are beat to hell. I'm just sort of using it as practice and a possible resurrection project someday. Uncle used to race Corvairs back in the day has a TIG, so maybe its worth trying for S&G. If nothing else, it's porting practice. The N47 w/ cam combo feels right to me, but perhaps I'm letting myself get caught up over compression ratios. Madcaw, I've been following your Mikuni thread ever since I grabbed my triple sets. I also have the same Mikuni manifold (came with the 40's), how does it work out for your build? I'm under the impression that its short runners are more suited to the upper RPM ranges, rather than lower end torque? That's another thing I had been factoring in to where I wanted this engine to be, but I'd appreciate knowing if my assumptions are baseless and shouldn't be weighing my decision.

Classic case of me speaking too soon, I suppose. I just found the "right" article to refresh my limited knowledge of cam specs and feel a little bit more enlightened about what I'd be needing. I'll have to do a bit more research, but it's looking like Web Cams' 391 grind is close to what I think I'm looking at. I'll have to see if the .050 duration of 238 is close enough to what I'd be needing at nearly 10:1 CR. I've only heard positive things about their cams, and the guy who runs the Datsun Z Garage website (who was in the local Z clued I once frequented) had one of their milder grinds in his motor. Of course, he was running a non-stroked flat-top L28 with a milled P90 combo, so his experience might not be congruent with my own if I'm going a slightly different path.

Thanks for the replies and the link, a good read. To a point, yes, that's the question. What do I gain with one head vs. the other in CR and chamber design, and which is currently the most economical. I do already know that the P90/F54 flat top is a decent combo already, as it is essentially what came stock in the NA ZX models (different number head, essentially same combustion chamber shape). But that was meant for the stock vehicle, and emissions concerns. I'm certainly not saying it's junk though, as it is widely regarded as the best designed and highest flowing of the bunch, and has that nice squish area, it's just not at the static CR I'd want it to be. And since I don't have access to the LD crank et al for a stroker, that may not be the best choice. Ryan, I do like the idea of the N47 the most, so I can agree with that. I should mention that I currently have a felpro gasket on hand, so that will probably bump the CR up a bit more unless I buy another Nissan gasket. I really need to research cams a bit more, especially for what constitutes a "big" one. I know with a higher CR I should be bumping up the duration, that's a given. I'm a bit less clear on the lift, though. I know more lift = greater quantity of air via increased flow, but most of the aftermarket cams I've glanced at seem to pair the duration I want with a greatly increased lift, to the point of requiring a set of springs. I'd like to avoid that, as long as it's not a bad idea. I'm admittedly ignorant of cam design, as I all but neglected the consideration for my previous turbo builds. I'll have to talk to the cam grinders if it's possible, or feasible, to get a high duration/low(er than .460) lift cam. I suppose I'll find out how stupid my questions are when/if it comes to that. Edit: And yes, I'm definitely using the refreshed 40's for at least a while. I'm not worried about them being tiny. Prettying up the 44's is a long term side project, especially given their worse shape. They were also bought piecemeal, not as a matched set like to 40's.

(scroll down if you don't want to bother with words and backstory) So, after a long hiatus from the Datsun world (marriage, relocations, etc.), I'm back (sort of). Not much time for working on cars, so the orange 280z has sat like a lump in storage for 5 years. Luckily for me, my wife has forbidden me from selling off the car for a down payment, so I'm trying to blast away a quick build to get it running again enough to get it into a new garage home in New Hamster. Usually I hate asking Hybridz technical questions when I can get my enjoyment from browsing for a few hours, but this one is more of an opinion poll, I suppose, so I don't feel as bad. I'm trying to get a budget build together and I have a few options. Essentially I'd be fine if it just ran, but I don't want it to build a working slug either. This car is a toy, first and foremost, and I'll probably have home improvement projects that will put any major performance improvements on the backburner. I'd like to be able to have a little fun on the weekends with minor upgrades and tuning here and there. Now here are the important details: -Going for an NA build. I have a full out turbo L28 mothballed in the back corner, but it requires quite a bit more work & $$$ parts before it's good to go, and I want a break from it. -My base is a rebuilt L28 bottom end, with ARP studs & ZX flat-top pistons installed for a bump in compression. -N47 head, with a very mild home port (rough sanded intakes, polished chambers, very light unshrouding around the valves). It does however have a very slight warp to it, and would need to be bent/milled flat. Stock cam. This would bump my CR pretty high (near 10, according to the calc but I'd also CC before assembly to confirm), and I'd probably (definitely) need a bigger cam to run it on pump gas. Keep in mind though, that our New English pump gas is a bit "better" than the left coast stuff. or -P90 head. Pretty much stock, only hit the ports with sandpaper flappy wheels. Zero warp, stock turbo cam. Very clean, and as such I'd hate to mill it down for a bump in compression ratio, since that's an area I could potentially save some cash and use it as a spare turbo head down the road. I have a friend who ran a similar setup on Webbers for a while, but the lower CR seemed to make it a pig. It may have been dialed in since I last saw it, though, and his may have been running dished pistons as well (don't remember, never saw the inside). Triple Mikuni 40phh, and 44phh. The 40's are pretty minty, besides their gaskets, and have brand new rebuild kits ready to install. The 44's are in pieces and will require a lot more work, and matching outer venturis, but the rest is there minus additional jets. The choice for now is obvious, even though Todd (Wolfcreek) told me years ago in our conversations that the 44's are too big for an L28 and I should stick with the 40's... Even though everywhere else I read says the 40's leave the L28 a bit undercarbed. If Tony D is reading this, I know I COULD just press ctrl+shift right right up down, but I threw that one out with the bathwater. I know its not logical or as efficient, but I got both sets for a song years back and I like the idea of carbs. Various odds and ends for completing the project are available, including two sets of headers (both square port though). I just need a few sections of pipe to complete the exhaust from there back. The dilemma is the two heads. I know the N47 will give me the greatest bump in CR, which is "good" for NA power, but sacrifices ignition timing & has design efficiency issues. A few years ago another Datsun guy on the internets told me he was running a similar, higher CR setup with welded up combustion chambers just fine on pump gas and a better cam, but everything on Hybrid that I've read over the years says otherwise. With the P90 I probably have the more direct route, but a hideously low CR unless I put some work into it. I suppose I could swap in the cam from the N47 and make up for the loss with ignition advance, but I don't want a gutless slug that's impossible to dial in. It is, however, probably the most logical choice for getting the car on the road. I'll also add that I'm not entirely concerned with a specific HP number, but rather one that feels right, sounds nice, and is enjoyable to drive in the interim when there's mortgage, home improvement, and little demons running around monopolizing the remainder of free time. Ok, so that was a bit long-winded. I suppose, in summation, the question boils down to N47 vs P90 budget NA carburetor build. Wat do?

They are loud, and the sound gets old if you drive at constant speed on the highway for extended periods. Out of the box, don't expect to bolt them on and go, as you will have to invest a fair amount of time and effort attempting to get them to fit and aligned, which they likely won't. If I were to do it again, I would have welded the system together from the header back with only one clamping point, as the exhaust clamps failed me a couple occasions at the worst possible times prompting a roadside fix (probably my fault). Go into the purchase with these things in mind. With that, they get my full endorsement and 100% recommendation. One of my more memorable modifications.

As the title says, looking to get my hands on some late L28 N/A flat-top pistons and con rods, preferably still attached to each other and in working order (after I clean them up and put some rings on them).

Not sure if either of those will work, but I am pretty sure they're not Nismo/Nissan Comp extractors. I'd need a side view to see if they'd even work. Most headers seem to be designed to hug the side of the block until they're parallel with the oil sump. I need ones that either break away toward the trans tunnel before that or bump out to clear the bottom of the block by at least 3/4"-1" before heading back.

His response was something to the effect of "Yeah, they don't make those anymore," which I took as "I have none for sale." Same with the accel pump housings, he told me there were methods to fix the parts or to jerry rig something. That's why I figured I'd try making this wanted thread, since WCR was my best bet and it seems that's not going to pan out. For the accel pump, I'm going to try JB-Welding the brass stop back in over the spring and ball bearing, for the pump rod I'm going to try using the rod from a set of worn out 44phh's I found. It's not exactly the same as a 40phh pump rod, but the dimensions seem correct in the areas that count.

Current condition: