DAW

These are all good questions and I'm listenning with interest for the answers. I've got a VG30ET sitting around that I was going to put in an early Z but abandoned it because of interest in inline 6 experiments. I might put it in my 720 P/U though. I think your on the right track looking to P/U applications and I'd look there for exhaust manifolds as well. The oil pan configuration would be one of my main concerns re fitting this to your 240SX, but again, including P/U source, 300ZX, Infinity, and even fwd Maxima may provide effortless solutions. I was following this thread and didn't give my $.02, I've thought along the same lines, that the 240SX is well known to have a great chassis but anemic power source and could be great with a light, compact, and powerful engine. Some that come to mind are the aluminum block DOHC V6 Isuzu Trooper engine coupled to a 2wd 5spd, Mazda 929 DOHC V6 coupled to a P/U 5spd, a Volvo 2.3FT 4cyl (don't laugh, have you driven one?) M/T, etc. I don't think you're going to be able to convert the VG30ET to a VG30DET, start out with the DET if cost and clearance allow. DAW

I should add a few addendums: I am using a "mule" to do the work on this project, it's a Diesel Maxima that I bought specifically to do the diesel/gas conversion. It's also a lot less conspicuous during road testing than a Zcar. Once I'm satisfied that it's right, it is going in a '72 240Z a/t car (and hope the taller engine clears the hood). The Maxima is a front sump engine so I'll have to switch pan & pick-up. One thing nice about the turbocharging coming up is that the Maxima pan already has an oil drain (for the alternator-mounted vacuum pump) which I can use for the turbo oil drain. Presently, it has 240Z headers on it in the Maxima, and the Maxima has 280ZXT struts and sway bars and Infinity 15 x 6 1/2 wheels. I cut the springs a bit, the change from the diesel to gas cylinder head alone must be a 60-70lb wt loss. By the way, the LD28 block is 19.7mm taller than the L28, the same ht difference between an L20B and L18. So, you use L20B timing chain & front cover. As an aside, the diesel exhaust manifold is a nice unit, separate chambers, rectangular port, and alot like the early Z manifold but without air pump fittings. The intake manifold is also interesting, with long curved runners, the down side is that they have no injector mountings. I'd like to have the LD28 block sonic tested to see just how much of an overbore would be possible. I believe that there is a lot of metal there. The bare block itself is not much heavier than an L28 bare block, it's the head, diesel pump, and accessory brackets, etc that add so much weight to the diesel engine. The next step for this project is to change the L3N71B (3spd, lock-up torque convertor) for an L4N71B, and from a normally aspirated gas engine source. The stall speed on a turbo trans is too high; on a diesel, too low. Once squared away, I'll put the engine/trans into the 240Z and start again with diesel/gas hybrid #2: intercooled turbo. The internals in the LD28 are massive but as such won't want to spin high rpm, but a turbo doesn't need high rpm to make good power. DAW

BTW, 148.6/83 = 1.781 is a much-improved rod/stroke and something impossible with a L28 block stroker. DAW

In the spirit of Hybrid Z I'm offering some food for thought. The problem with putting the LD28 crank (stroke = 83mm) into the L28 block is that it's too cramped in that vertically-challenged block. The standard conversion uses Z24 or KA24 pistons (modified) with L24 rods (133mm). This gives a rod/stroke ratio of 133/83 = 1.6024, which sucks. I'm not going to go into rod/stroke and performance here, read-up on your own, but that's good for a truck, not a performance unit that could hit the track. OK...so here's the crux, I crunched the numbers prior to taking this project on and I decided it was worthwhile, I consulted NISMO and they said "forget it". So, take a LD28 engine and get rid of the cyl head, cast iron and it weighs a ton! Get rid of the diesel fuel pump and front cover (keep the water pump), keep the oil-to-water cooling unit on the oil filter assy. Massive alternator unit has an integral vacuum pump on its tail-end, could be useful if going turbo. Specs on internals: 84.5mm bore, 140mm rods, massive, with 1" floating wrist pins (not unlike a set of rods available from NISMO). Compression ht of pistons = 46.5mm and that's alot. Block ht. is the same as L20B and that's where the front cover is going to come from for our hybrid engine. So, the first phase of my experimentation was to put a N42/N47 series cyl head onto the LD28 block. This requires the aluminum head to be drilled for a 10mm headbolt to a 12mm headbolt. Nothing special here, most of it was done by hand. Headbolts were from BMW, some washered, 3.0 inline 6 cyl or 2.5 4 cyl (I think); but they were the right thread pitch and length, and 12mm dia. Reuse the diesel head gasket. Said head makes about 9.8:1 as I recall. L20B front cover and LD28 water pump will go together with a bit of grinding to the water pump. Anyway, it runs good. Presently it's coupled to an L3N71B A/T. One notable quirk is that the diesel A/T has a LOW stall speed. Luckily, with the good compression ratio, it's ready to jump off the line with good response and torque. So, rod/stroke @ 140/83 = 1.686, better already than the L28 block/LD28 crank hybrid, and that's with a HUGE compression ht of 46.5mm on those diesel pistons. Stage II is to fit a P90/P90A head to the LD28 shortblock and turbocharge. Stage III is to overbore the LD28 and fit with longer rods and pistons with more std compression hts; let's choose L28ET pistons (bore =86mm, dish = 10.9cc, comp. ht.= 38.1mm). So, with comp. ht. 46.5 - 38.1 = 8.4mm; then you can add 8.4 to the rod length of 140mm and that's = 148.4. Well, the closest Nissan rod is the 148.6mm rod from the Z22E engine (not to be confused with the Z22S truck engine with its 146mm rod), and there you have it. DAW

Remove the cover from the AFM, mark the stock location and adjust it by one tooth only at a time and roadtest. You'll probably go only two teeth total...any more and think about enrichenning by increasing the resistance in the water temp circuit by adding a resistor in line rather than keep loosenning the tension on the AFM flap. By the way, switch to a 180 degree thermostat if your car has a 195 degree in it stock. I used a potentiometer inline in the water temp circuit in selecting the resistance value based on throttle response, etc on the road. DAW

By the way, I listed a few 5 lug, 5x4 1/2" bolt circle wheels/hubs with low to no offset set-ups which may do well on an early Zcar, but I left out one source: Jeep. I didn't mention it because the hubs don't apply due to the 4WD situation. However, the wheels might be useful. Grand Cherokee and Wrangler have low-offset 5 x 4 1/2" bolt wheels so aftermarket wheels for these applications could be good. DAW

Wheel bearings/spindle-sizing is one of the largest overlap areas of commonality between different makes of cars that there is. There's really only a few different wheel bearings and there are only a few manufacturers. I'm exagurating some. Use the grease seal on the donor hub, the inner diameter is shared and (common) bearing size dependent. If it has 12mm x 1.5 thread wheel studs (instead of Nissan's 12mm x 1.25), then use the donor's lug nuts. Theoretically, if you want to replicate the initial geometry, then a 5-lug hub would need to be from a vehicle with similar OEM offset wheel geometry. Considerations for the Zcar would be: Crown Victoria, Conquest/Starion, Mercury Marquis, SVO Mustang, Tbird Super Coupe, etc. All are 5 x 4 1/2" bolt circle. Go for the one with the best/lightest OEM alloys. It takes a trip to the junkyard, measuring with calipers, rulers, etc. The best junkyard is a large one with some of every kind of car so that you can pull a hub/rotor off one type of car, and carry it over to a Zcar where you install & measure for clearance/interference and caliper position. DAW

I'm wondering about that 5-lug front conversion and if there may be a more suitable source for hybrid hubs/rotors that more closely approximates the original Z front geometry (15mm offset). I'd like to know if setting the hub flange more outboard then running higher offset wheels preserves the geometry (roll center,etc) or not; engineers? I know that using higher offset rims than stock, without a hub change, makes the car have a mind of its own and it tracks off at random along any crease in the pavement it sees. DAW

The A/Ts have an OEM oil cooler air/oil and M/Ts do not. I assume the A/T pump is a higher volume pump and if you think you'll run an oil cooler the A/T would be the better choice. Just a side note, an interesting feature of the LD28 engine is a water/oil cooler unit incorporated into the oil filter base assy. DAW

Whoa...you're not going to make power without compression on a naturally aspirated engine. Your L28 has 8.3:1 compression ratio and that's not going to cut it. Here are some options: 1) You can swap your cyl head (N42) for an N47 from a Maxima L24 ('81-'84), as it has a smaller combustion chamber and will provide a modest increase in compression (I'd guess at about 8.9:1). Get the Maxima exhaust manifold too. 2) You can swap your piston/rod assemblies for those from a '81-'83 280ZX (flat tops) and retain your cyl head (N42) which will yield about 9.8:1. (you can swap pistons/rods with the engine in the car). 3) You can have your pistons removed from your rods and have the rim of that 10.9cc dish machined down until it's gone and you've created a flat top with less compression height than the 280ZX piston. This allows you to install L24 (Zcar not Maxima) rods which are 2.6mm longer than your L28 rods, and increases the rod/stroke ratio at the same time compression ratio is increased. Clearly, the Maxima head swap is the easiest. While not a dramatic change, there will be a noticeable difference in performance. With a change to 9.8:1 c.r. you'll notice a dramatic difference but you also have to increase mixture richness, run colder plugs, etc. You won't get much bang for your buck from a performance cam unless you've increased compression ratio. DAW

I remove the trim/bezel "Z" piece, cut out the "Z" center and finish the inner "ring" that you have left. Cut a piece of bright aluminum screen to fit between the bezel and the pillar, retained by the three bezel pins, and push the bezel into place. This modification looks outstanding. However, the drawback that I've found is that people, and not just children, are overwhelmingly compelled to push on the screen with their finger. It's like it's a finger MAGNET! Easily fixed though. DAW

"...Early L24 engines (up to L24-003606) have a six counterweight crankshaft and should be upgraded to an eight counterweight unit prior to any high-performance modifications." NISMO Catalog. DAW

Sorry guys, but I'm in the middle of moving and you would not believe the scope of the task! Five Zcars, one ZX, two PL510s, two Conquests, and a huge array of parts, engines, and drivelines. Photos later. I would have thought that X19 bumpers would be way narrow for a 280Z, but measure them and they are very close, almost perfect. The shape and appearance are very close to stock '77-'78 bumpers but they are MUCH lighter. As to strength, they definitely appear to be stronger than '70-'73 Zcars and, other than losing the 5mph impact feature of the stock '75-'78 bumpers, appear plenty beefy. A lot of European cars (Volvo, Audi, Saab, etc) had aluminum bumpers like these. Late model Hondas have plastic bumpers beneath those urethane covers.

It'll be a while before a can post pics of the intercooler & Fiat bumpers but I'll get to it eventually. Meanwhile, I should provide some further details on the bumper swap: use '77-'78 plastic endcaps (not '75-'76). They have a series of serrations/accordian-looking section in both fronts and rears. Fit the endcap to the Fiat bumper and note that because you've eliminated the extension that the bumper-shock caused, the endcap is now displaced several inches along with the bumper. This gives a much cleaner look to the car since you've lost those front & rear "workbenches" hanging off the car. Anyway, just cut out the required length of the accordian section so that the endcap mounting hole to the fender/quarterpanel lines up, and you're set. DAW

After trying to fit a wide variety of factory intercoolers to my 280Z, including Audi, Starion, Renault, and Volvo, I think I've finally found a viable choice. Saab 9000, 1987 (I think). It is a similar configuration to the Volvo rear-drive turbos, except it is wider and larger overall. The hose inlet/outlets line up with the Z vent holes in the radiator support when it is fitted in place. To fit, I notched the bumper shock mounts significantly to allow it to drop down into place. I have early ('72) bumpers adapted to this '75 Z and the modification to the '75 bumper mounts was no problem. Another solution to freeing up the bumper shock/mounts so that you can notch them for the intercooler is to: remove your front (heavy) bumper and discard. Remove the small screw at the leading edge of the bumper shock and release gas pressure. Cut off the piston/flange end sticking out of the cylinder. Remove the piston internals from the cylinder/mount assy by removing the nut at the rear. You'll probably need to remove the assy to do this step, and you may need to use a cutting torch to do away with the nut. Take a Fiat X19 front bumper (aluminum), the solid one not the twin bars, bolt your Z bumper/shock stubs to the Fiat bumper plates, and weld the Z stubs to the Z cylinders. You've just lost a bunch of weight from the front of your car, made it unique with an aluminum bumper, and freed up the rear aspect of the bumper-mount cylinders so that you can notch the for the intercooler fit. I'm not sure of the years for the X19 but you'll recognize the single square looking bumpers. By the way, get the rear (aluminum) bumper and the plastic grille also as they adapt easily to the '75-'78Z cars as well.

quote: Originally posted by Jason: I saw an older style (not the jellybean) Eclipse turbo at the junkyard today. It had everything but the air filter. I grabbed the intercooler to be used in a friend's non-intercooled 200sx turbo. Could the turbo, injectors (or anything else off the car) be worth taking for the 200sx or some other project? I'm not sure if a mitsu turbo would bolt on. The family has this older Pathfinder which I can tell is begging for a turbo or two. Somebody had already unbolted the pipe fitting for the compressed air side, and it looked like a little water had gotten in. It put a little surface rust on the inside (which I polished off with my fingertip), but nothing major. [This message has been edited by Jason (edited March 29, 2001).]