Xnke

Might call Clark's Z Cars, he was in the Nashville area last I heard. Don't know if he does anything but stock cars, worth a call. You will pay a LOT of money for someone else to be doing the work on one of these...What's your budget? Have you ever ridden in a stock Z? How about a 450HP Z car, which that LS3 would EASILY do. You may find you are completely satisfied with something less than you expect...remember...the Z is VERY light compared to your other vehicles!

If you're trying to keep this cheap and easy, you've missed the mark by a mile. Stock Z31T driver's center bar gets swapped to the passenger side. You've already got this if you have the Z31T axles. Stock 1990-92 OR 1993 WD21 Pathfinder 4x4 front driver's center bar gets fitted in the driver's side. This is a 10$ part in the U-pull yard. Using the 1993 center bar, you run a larger spacer, about 1.25" thick on the driver's side. 1990-1992 will need a thinner spacer, as the axle is STILL shorter than you need it to be, but not AS short. Spacer thickness for the 1990-1992 axle will be less. The spacer thickness depends on if you have bolt-through companion flanges or the threaded companion flanges, as they are going to be different thicknesses. Not a huge deal to measure out, either. Done. No binding, no problems.

That exhaust looks killer. I wouldn't worry about the drop-thru that much, it's usually not more than the wall thickness of the pipe or it REALLY drops through and looks like crap on the outside too. (I mean to say that the drop-thru is not usually more than wall thickness X2) The air near the outer walls of the pipe doesn't move nearly as fast as the air in the middle, so you are very likely just fine on the welding bit. A few years of carbon inside, and a few good hot highway blasts will burn off all the little whiskers and burrs inside, leaving a reasonably smooth bead.

Valve stem seals, at a minimum. Probably time for a fresh head, the guides and valves may be worn too.

Absolutely. The camshaft will wear in at a MUCH lower rate than a newly cut valve will recede into the cylinder head. The lifecycle of a valve seat dictates that the valve will show a period of rapid recession, followed by a levelling off of this recession to a low, steady rate, after the valve and the valve seat have pounded themselves into a closely fitted, well sealed situation. Also, the valve stems will stretch, the keeper grooves wear, etc. All of this happens at a much faster rate than the cam base circle wears. The rocker arm wears only very slightly faster, and the lash adjuster pivot not very fast at all; but the predominate wear locations are at the valve end of the valvetrain.

That's how my car was done. Nearly 3/4" of bondo in some spots, it's now down to 1/8" in the thickest areas. That's the best that could be done and keep it reasonably decent looking.

I have full coverage insurance on my Z. It WILL NOT cover the cost of replicating the car, unless you get collector car or specialty car insurance from a company like Hagerty or a stated value policy from another insurer. Full coverage is nice, but the insurance company doesn't give a damn how much money you've spent on the car...they only care about what the car "books" at. The replacement cost is not considered, it's the "we're going to give you this much for your car because this is what we think it's worth" cost. Without a stated value policy and a current appraisal, you're not going to cover the replacement cost of the car with simple "full coverage" insurance.

Got the fuel rail complete and pressure tested this evening. Complete failure...the reamer used to finish the injector bores cut a perfectly consistant 11.25mm bore...which is NOT enough of a crush fit to seal the injectors. The rail will be bored and have sleeves pressed into place to save it, since I have an integrated fuel pressure regulator on the rail. It's either that, or trade this set of six DSM 450CC injectors for some 42lb 14mm injectors.

It's off. Valve lash is a minimum clearance required. As the valvetrain wears, this lash closes up, and as it closes up, the valves do not close fully and leak. Your valve lash will become zero before it starts to open up.

That dimension doesn't fit my car...my 240Z spacers were much closer to 5/8". 16mm, actually. Actually, there are a lot of folks in that thread that are wrong...the spacers go on the BACK of the hub, not over the wheel lugs, and from a quick reference against the difference in brake rotor heights, I'd say that you're looking at a 10 or 11mm spacer thickness.

Those plugs look really oily. Does that thing smoke at all? I am thinking you might want some valve stem seals. (Or a head rebuild, pending a leakdown test.) As others here have said, I've pounded a set of stock pistons and rings through rusty bores and the rings came out without a scratch on them...and after honing all the rust out, the bores were within spec save for the rust pits! Not surprising that these engines last forever as long as you keep oil in them. (Or if you don't, but the bearings don't care for that, much).

The C stamp cam is tiny. It won't have much, if any lope, nor will you notice any difference in the butt-dyno. But that thing sure does sound good! I second the motion for good suspension components, you need'em.

Why not just measure them? It only takes me about an hour and fifteen to machine one of these from solid. You need to start with a 4.75" round, 1.125" thick.

The PCD for the holes is 103mm, and the holes are 10.5mm diameter. The center bore is 80.9mm, through bore is 78mm, and the pilot is 80.9mm diameter and 4mm deep. The thickness depends on if you have 280Z hubs or 240Z hubs. I don't know the thickness required for the 280Z hubs.

You should know that using launch control will destroy those 50$ wideband O2 sensors in a major hurry. Gets expensive when you forget to take it out of the pipe! Retard timing to 3 degrees at 2600, spark cut at 3200, cut 3 of 5. Snaps footlong flames out of the back of a straight-piped turbo ZX with a .63 housing.

Bringing this back from the dead. I have gone through this thread a large number of times, and am working through figuring out the schematic and the PCB layout, which do not match each other. (Close, but there are parts on the board that are not in any of the schematics, and parts in the schematics that are not on the board) I do have the speedo working on the bench, though. The tach is quite straightforward, the Megasquirt Tacho Output circuit works like a charm. The speedometer doesn't care if it's a sine wave, or a square wave, as long as it's a bipolar signal. It only need about a 3V output to work, but that 3 volts MUST cross zero volts, so it's more like a minimum of +/- 1.5V. I solved this by referencing ground in an odd manner and that solved the issues with the speedo acting funny at low speeds. EDIT: I've figured out the "floats at low speeds problem, too...The differentiator capacitor was too small, and so the speedo would cut out at high speeds and would float at low speeds/nearly stopped/stopped. Upping it from 0.1uf to 0.22uf fixed both problems nicely.

Cracked L6 blocks aren't common, unless thrashed on pretty hard. The crack in that location appears to be an improperly installed headbolt, that has caused a tensile failure of the engine block. That block will eventually leak coolant, if it doesn't already, and will *probably* blow headgaskets near that area from lack of clamping force holding the head to the block. That crack, since the block is painted, and there is no paint in the crack, happened upon reassembly or shortly after.

Tony, you read my mind. I am thinking more and more that I want a black wrinkle baked-on paint finish, which is still paint but its as tough as powdercoat. I *think* I have enough of that stuff left.

"racecar tax" = The extra money shops and salespeople charge you for "premium" or "racing grade" parts that are really just off-the-shelf standard parts that happen to be popular or labeled as racing stuff. See also "ricer tax" for similar usage. Find the distributor that supplies the shops and salespeople, and you can usually avoid the 300% markups for "racecar" stuff...paying the same amount you would for "non-racecar" grade items.

Just call around town and ask. It's not like they are going to hunt you down for trying to evade the "racecar" tax...

The EP additives that are required in flat-tappet valvetrains have been removed from more modern oils because they aren't needed in a fully rollerized valvetrain. No sliding friction=no EP additives needed. That said, Valvoline VR-1 Synthetic is all I run in the car now, as it still has the flat-tappet additive package in it. I buy it from the local oil distributor for 3.46/qt, but I have to buy a case at a time. It's not expensive stuff guys, you just need to know who to buy from.

I looked at it two ways, the first was to treat it like ITB's...the plenum is so large as to be practically infinite from a pressure view. Then I looked at it as an industrial compressor setup, which also suggested a largeish plenum volume. The downside would be fill time, but that's not an issue at all with a positive displacement blower working at 95% VE. (M62 hits 80% by 4000 shaft RPM, 95% by 10,000RPM, and is back down to 80% by 16,000RPM.) The downside to these nice VE numbers is the temperature and thus density of the air...by volume, the roots blower is damned efficient, but by mass...not so much. When I take the manifold into the shop to get decked, I will probably have it bead blasted, then phosphoric acid etched prior to whatever coating I choose. I'm on a deadline, I want to make it to Branson Z Fest this year with the intake and the supercharger installed and tuned! That's a 10.5 hour drive, although I'll make the drive N/A and put the charge pipe and supercharger belt back on once I get there, if the gas milage just isn't there at cruise RPM.

The SR transmission is just another FS5W71C transmission as far as the speedo gears go. Just use the cable drive from the original 240Z transmission, knowing that you may have to rotate the cable drive to get the gears to mesh up...the shaft is offset depending on the rear end ratio, because the rear end ratio sets the size of the speedometer gear...NOT the transmission. Also, around 1981 the retaining clip bolt hole went from the bottom side of the cable drive/sending unit to the top side, 180* flip. DO NOT just flip the gear drive...it may not fit and then it'll break! You need to install the cable drive, then rotate it until the gears mesh up, then mark and file a new retaining clip slot into the original housing.

The plenum is a little under 6 liters, total. I sized it based on industrial roots blower plenums that feed reciprocating booster compressors, best I could figure. it just happened that the plenum material was very close in size to what the formula from one if my 1970s textbooks popped out, and I only had to trim the internal volume a little to match up convenience and the mathmatics.

Here's tonight's work, starting to get vacuum lines routed. Need to drill and tap this cylinder head for external cooling lines, and get them pretty close to the same locations as the ports on my currently installed cylinder head. I'll need to find another 240Z thermostat housing as well, or just machine a billet one. (I am very, VERY tempted...would mean no more weeping adaptors for coolant temp sensors!) The fuel pressure regulator housing is available as a stand-alone unit, if anyone is interested. 2.5, 3.0, 3.5, 3.8, 4.0, 4.5, 5.0 bar regulators are available, as well. They all fit the same housing, and can be changed out with the click of a snap ring. The Whole Shebang: 'Cept for these rubber lines, the fittings are all installed where I need them, except the MAP line for the Megasquirt. Here's where those lines that wrap around the back of the head go...compressor bypass actuator control lines.