DAW

Mike, I'm talking about a hood from about '73-74 that was associated with the vapor-lock problems in those cars. It may have been a dealer-installed remedy or it might have been called a "sport hood", others may know the history of the hood. I've seen other photos of it before on this site (rarely) but I couldn't find them using search. The elongated opening in the hood is offset and located above the left side of the head, above the carburetor fuel lines, and is about 16"x5" in size. The "scoop"/riser unit canopies this opening but is centered on the hood, similar in shape to the stock center elevated portion, but larger, taller, and extending farther forward. The openings in this "scoop"/riser are in the vertical sides of the riser and not in the front or rear (not cowl-induction). I'll try to get a pic posted but if anyone recognizes this and has a pic, go ahead and post it. I had a nice surprise when I drove the G-nose car home...it's a 5spd. I had just assumed it to be a 4spd. DAW

Why don't you pull the engine, but instead of throwing $2,000 at some body shop to try and resurect a lost cause: find a good body/chassis? You are not going to patch something up and end up with a better situation or condition than a well-preserved original. DAW

Great thread! DAW

Does anyone know where I can find some or where I should look? Thanks. DAW

Thanks guys, I thought I was doing well especially with the G-nose car and the rare hood. The autocross wheels/tires will go on my PL510. The reassurance on the good deal was well appreciated by my wife! DAW

For $2300 I just bought: one 5/72 240Z CA car was in dry storage for 7yrs, runs, no rust, G-nose, NISMO rear spoiler, nicely redone seats & door panels, all stock L24, 4spd, one small dent L quarter panel. 4 polished slotted alloys with like-new Yokohama A032Rs, 195/60-14s. an L24 with dual downdraft Webers, header, remote oil filter and cooler, Nissan Turbo valve cover, E88 with unknown mods/cam, 5spd trans. '73 240Z with stock L24 and square-top Hitachis, factory vented/riser hood (rare), good doors, fenders, hatch, typical R frame rail rust-through and early floor rust, not through. I only have to move this package about 1/2 mile to my house. I hope I got a good deal and I think I probably did but I haven't bought any older Zs for a while. What do you think? DAW

A couple of readers got it. How many thought "This is Spinal Tap" or "Best in Show" were documentaries? I was suggesting we take a look at ourselves as a group and NOT get into splitting hairs or creating double standards on what we define as Hybrid Z material. I personally feel that a Hybrid Z car can be a '70s Z that has been transformed with state-of-the-art fuel delivery and ignition, turbocharging that wasn't offered back then, hybridized L6 engines with alternate heads, blocks, cranks, induction, etc. I feel that a 240Z with a stock L24 and a Jaguar rear end is a Hybrid Z and is equivilant to a stock 240Z chassis with a stock 350 Chevy engine. I propose an Inline 6 forum which includes BMW, Mercedes, Volvo, GM, and any other non-Nissan transplant engine (stock or modified), as well as any significantly modified Nissan L6 engine or a later-year (stock or modified) L6 engine, and any stock or modified RB engine. My point of the post was that ingenuity, art of fabrication, and engineering are the essence of a Hybrid Z car, not the configuration of the powerplant. What does not belong here are those trying to tap the experience, generosity, and resourcefulness of other members just to fix their broken car. Perhaps membership should be contingent on passing a written test with definitions and terms such as: LSD, VLSD, R200, R190, R180, wheel offset, crank angle sensor, TPS, Lambda sensor, stoichiometry, compressor bypass valve, rod/stroke, detonation, 4 bolt mains, piston speed & stroke, etc., etc. If the potential member can't pass the entrance exam then they can hang out as an observer on this site and on other sites, e.g., ZCar.com and study up so that they are a more active participant and contributor rather than a leach or PITA. I was being FACETIOUS with my post. I now am posting here because the initial forum is locked. I would not have let it go on with the responses flowing that did not recognize my black sense of humor, but I left town right after I posted and just got back. Lighten up, I was pointing out the irony in moving towards excluding Nissan L6 engines as not Hybrid Z material when some constitute a huge performance vein (e.g., turbocharged engines) on the site. I feel the L6 belongs and Hybrid Z should include engine hybridization as valid criteria. Whatever the source of the powerplant, if the horsepower is more than doubled from the stock Z car hp; it should be considered a Hybrid Z. It is worthy. DAW

In keeping with the philosophy of the site, I for one, would like to see discussions of turbos on L6 engines taken to some site that exists elsewhere on the web, e.g., ZCAR.com, rather than crowding out the turbocharged/supercharged V8 discussions from that forum. It appears that there are very few V8s discussed in that forum so perhaps it should be eliminated altogether as it is not a pertinent performance topic re Hybrid Z objectives. A gray area is whether the turbocharged V6 topics should be banned or just the inline 6 topics. Maybe the limitation should be set at OHV discussions and restrict OHC engine discussions, most of which are re Nissan engines anyway, as they do not meet the Hybrid Z ideal. Who's ever seen an L6 powered 240Z go faster than a SBC powered Z anyway? It just doesn't happen. I'm calling Bravo Sierra. DAW

If you don't have an intercooler, get one. Detonation sounds like a dose of ball-bearings is being dispensed into your cylinders when you are accelerating under load. DAW

I gutted the front OEM 5mph shock cylinders on my 280Z and used a stock '72 bumper with brackets which I inserted into the empty cylinders using "J" bolts to retain the early brackets by tensioning these J bolts (exiting the rear of the cylinders) by tightenning locknuts fitted to them. When the early bumper was fitting well to the car I spot welded the '72 bracket where it inserted into the bumper shock cylinders of the 280Z. On the rear bumper, as I recall, I used '72 bumper and brackets and drilled the rear valance to match the odd holes (some of the 280Z pre-existng holes line up with the '72 brackets and others need to be created). Essentially you recreate what the '72 240 Z had there. DAW

Increase your static compression ratio and get an efficient intercooler. Ultimately you'll have to limit your maximum boost if you do this. DAW

I definitely would forget about the triple carbs for a daily driver and would recommend fuel injection. I'm not sure what shortblock you're using but if you go with a flat-top piston L26 or L28 you could take the entire top portion of an N42 or N47 L28 and bolt it on. That is, the entire intact assembly of head, manifold/injectors and f.i. harness, sensors, etc. There are better exhaust manifold choices, if not using headers, than the N42/N47 cast manifolds (P79 for example). A few tweeks to the f.i. system to manage the increase in c.r. due to the head swap, and you'll have a reliable, efficient, and reasonably quick daily driver Z. DAW

Thanks Bob. I wasn't expecting the overbore to exceed what could be had with the maximum overbore of an L28. I figured any increase in bore over 84.5mm is golden when you're working with an 1.8 plus rod/stroke. I'd trade 87.5mm bore for 89mm bore any day to have a 1.8 rod/stroke over a 1.65 rod/stroke. DAW

Why don't you just use an LD28 block? You won't need custom pistons or rods, as there are many combinations of Nissan rods (LD28, L20B(=LZ20S), LZ20E, LZ22S, LZ22E), and myriad Nissan pistons with 21mm pins to combine with these pistons depending on which bore and rod length you choose. The stock LD28 rod(140mm) and piston(46.5mm c.ht., 84.5mm bore, huge floating pin) can be used for a budget shortblock. With an adapted N42 head with f.i. it makes 10:1 c.r. and pulls harder than a stock L28E; with a turbo and P90 head it provides a stout bottom end capable of routinely handling 21:1 c.r. stock. Anyway, if you do the math, you can put together many combos to suit your rod/stroke of choice and bore. I don't know the maximum LD28 overbore but the cylinder walls feel (through water passages) thicker than L28s, which would stand to reason for the higher demands of the 21:1 c.r. The question is going to come down to whether you want a 3.1L with a 1.65:1 rod/stroke or a 2.95L with a 1.8 rod/stroke. If you're insistant on the L28 block, look into the LD28 rods...same length as FJ20 rods but with larger pin bores which could be rebushed. DAW

I think you should check your cam timing and make sure it isn't retarded. A chipped/bent valve can produce those symptoms. Most likely you are dumping in too much fuel when the throttle closes suddenly and it detonates in the hot cylinder or exhaust system. Is this a high compression engine or stock c.r.? It sounds paradoxical that it would ping MORE when timing is dropped back. Are you setting back up the idle when it's retarded? (probably a retarded question) It may be increasing the temp of the cylinder with the retarded timing, contributing to ping. Have you tried a colder plug? Are you running too rich (floats too high, needle/seat leaking, suction piston/needle sticking, etc)? I put together a high compression, f.i. engine that backfired on deceleration but it stopped doing it before I troubleshooted it. In my case I think it might have been carbon build up in the headers glowing and igniting too rich a deceleration charge and possibly too high an idle speed. DAW BTW, I doubt the garage guy meant 40 degrees too advanced (i.e., 60-70 degrees); I bet he meant total advance was 40 degrees, or advance was 40 degrees in addition to the initial advance. DAW

Be aware that many dash light circuits are shared with the tailights. Check this out or you might get ticketed. Often the light switch connections or the switch itself (on the turn signal lever) will be corroded. DAW

I'm not positive of this, but pretty sure that the 9mm rod bolts/nuts use a 14mm socket to service and the 8mm a smaller socket (13 or 12mm). DAW

Why not go with the F54/N42 combo AND the triple sidedrafts? I've got this set-up on an autocross Z and it works well...very quick throttle response (nice feature for autocrossing). DAW

They sound just like stock '73 L24 pistons. The rods attached to those pistons probably have 3 times the value of the pistons if they are the 9mm bolt-type rods. The high compression in that engine would come from the type of cyl head that was on the engine (E31, early E88, late E88, etc). DAW

There is a night/day difference between those flat-top Hitachis and the earlier round-top SUs. Fuel distribution is going to be superior with the SUs than the 4bbl. I would use triple sidedrafts before a 4bbl. The SUs are highly tuneable and are simple and elegant in their design and function. Search for Norm's use of these carbs. DAW

They are calibrated differently. The max psi the na regulator delivers is calibrated to occur at zero manifold pressure, while the turbo is calibrated to a positive (zero + boost psi) manifold pressure when max fuel pressure is delivered. DAW

Assuming you're talking about dual TBs attached to a stock dual SU intake, take a look at Mitsubishi smaller 4cyl turbo cars (like 1.8L, etc), Tredias and such. You could also consider using two TBs with throttle plates removed (retain the injectors) on the SU manifold, piped into a common plenum with a single TB feeding them both in order to keep synchronization problems to a minimum. Maybe it's possible to pirate an entire engine mgmt system from the TB donor car and circuit-in a "shadow" duplicate TB/injector(s) to get the system going if you're budget is limited. DAW

It can definitely be done as a "low-pressure" turbo build up (an intercooler is vital here) but the maximum available horsepower will be less than an engine with lower static c.r. that can run a lot more boost. DAW

I see a few errors here that could lead to some miscalculated cr's. The stock early L28E had dished (10.9cc) top pistons and with it's N42/47 head made 8.3:1. The later F54 flat-top L28E was 8.8:1 with its P79 head. The L28ET uses dished pistons and P90 head (same chamber volume as P79). If you use the P90 head on an F54 shortblock, you will have 8.8:1 which is a bit high for a turbo engine. If you use an earlier L28E shortblock ('75-'78) and P90 head it would be the same c.r. as a stock L28ET (but it would have na pistons which aren't as strong as the turbo units. DAW

Avernet, your measures to restore the valvetrain geometry once the head was shaved were good but the lash pad problem now is due to the reground cam vs a new cam (base circle). I know that to drop the cam down would be putting slack back into the chain, but you could potentially use the stock lash pads with the longer valves you've already installed if you remove tower shims of the right amount. This suggestion is intended for if 16 new lash pads are too expensive. DAW