DAW

Step back and think about what you need and what you don't, in order to achieve your goal. "More" can be less...a P79 head on a L26 is good only if you're turbocharging it as the compression will be abysmally low. If you've got the P79, can we assume your car is f.i.? I'll cut to the chase, the best performing head for your application (and already set up for unleaded gas and f.i.) is the Maxima L24, N47 head (NOT the 280Z, N47 as it is totally different). Use it as-is or swap in the cam from your P79 (and matching rockers/lash pads) and swap the intake valve springs from your P79. If you do this you will have the strongest, otherwise stock, L26 you can put together for very little money (Maxima heads are cheap and abundant in JYs). An N42/N47 (L28) head will yield a stock L26 c.r. P79 is way too low a c.r. Maxima N47 (L24) head will put you at about 10.2:1 with less tendency to ping than an E88, E31,or N42 would at the same c.r. If you want to drop the c.r. by .5 or so, you could run 2 head gaskets (I've never done this but 12 sec SU Norm says he often does this). DAW

Oh, BTW your 260 block should have "eyebrows" cut horizontally into the tops of the cyl bores to provide clearance for 38mm ex valves (vs 35mm). Confirm that these are there or your ex valves will be "machining" their own block reliefs. They should be there unless it's a home-grown L26 (L24 block + L28 crank) vs factory L26. DAW P.S. If they're not there you can grind them in and more smoothly, better-flowing than the factory placed recesses.

Use the 260 block gasket for your 83mm bore, not the N42 gasket from the 86mm bore source. Your bore hasn't changed, it's still 83mm. DAW

Make sure your vapor canister hoses are intact and hooked up right. This is how the fuel tank is vented while engine is running..if the diaphram in the lid of the canister were cracked I think you'd have an occluded tank vent which could cause the type of fuel delivery problems you have. Is your injector/fuel rail cooling fan operating correctly? Sounds like your AC vacuum pump isn't hooked up right or you switched one of the small vacuum lines to a check valve, etc. If you don't have a factory service manual, and Haynes/Chilton is not detailed enough, your city library may have the Mitchell Manual series for reference and these are very thorough. Does the fuel pressure monitor you hooked up show erratic when the car acts erratic? DAW P.S. Confirm that your fuel return line is not crossed with the fuel supply line under the hood if you haven't already done so.

I agree with Greimann, the tire repair kit and 12 volt mini-compressor are invaluable. I've repaired a flat on the roadside without even removing the wheel from the car with this setup. I'd forget the fix-a-flat can. I've heard and seen evidence that the material in those cans is corrosive to the inside of alloy wheels and that clumping can unbalance the wheel. A cross-lug wrench is nice because it's fast and can also be used with its 17mm and 19mm ends for other bolts (brake calipers, etc) while serving as its own breaker bar, and some aftermarket wheels have a different lugnut hex size than those for the stock steel spare. If you're running larger aftermarket alloys with lots of offset and spacers, consider using the spare from an RX-7, the 4x4.5" bolt circle, aluminum spoked version (early 2nd gen??). It's light and the generous offset should match-up better than the stock spare to your other three for your limp home. DAW

Lots of diatribe in this thread. RE: the original post re best head for high performance na L6...I didn't see any comments or response to my selection of the L6 Maxima N47 head as perhaps the highest potential na L6 head with some slight modifications (nothing as extensive as shaving 0.80"). The L6 is basically a "plus 2 cyl" version of the L4 (the LD28 is a "plus 2 cyl" version of the L4B) and the US market L20B U67 head represents the L28 N42/N47 head; there is a closed chamber head for L20B truck engines (W53 sq port, W58 rnd port) that is a smaller volume chamber than the U67 and provides better performance with less tendency to ping than does the U67 at the same c.r. The W heads can run a smaller chamber than the P79/P90 heads because there is less displacement per cylinder (smaller bore, deeper dished pistons) than the P79 L28E/ P90 L28ET, and there is no corresponding L4 head to the P79/P90 (shorter-valved/raised roof) head. The biggest oversight in L6 performance head selection is the Maxima L24 head. It is the equivelent of the W58 L20B head and this configuration is not otherwise available for the L6 (but would be on a factory 10.5:1 L6). DAW

What if you could take a P79 head and lower the roof to decrease the combustion chamber volume? Let's say, lower it by the distance equal to the difference in length between a P79 valve and an N42, E88, E31, N47, etc, valve...now would that be a great L6 head or what? The quench configuration of a P79/P90 and the high compression volume of the E31... There is such a head and it's abundant in JYs, it just needs upgraded intake valves, springs, and L28 cam. DAW P.S. N47 from Maxima, not 280Z.

My LD28/L28E hybrid runs very cool using a 180 degree thermostat and the LD28 oil/water cooler/heat exchanger. The overall temp of the engine (both water and oil) seems to be lower running this setup than a high compression L28 without it. RE oil pumps, the L28ET has a higher flow pump than the na, and the L28ET with an AT comes stock with an oil/air cooler and it has an even higher flow/volume pump than the MT car. I haven't seen specs on the LD28 pump but it likely has a high flow/volume pump because it uses the oil/water cooler and it provides oil flow to an alternator-driven vacuum pump (has a drain tube back to the pan, just like a turbo). Anyone have the specs? DAW

The valves in the E88 are too small for 2800cc, and the seats aren't designed to handle unleaded gas. By the time you put in updated seats with larger valves, you could have bought a used P90 head, or N42 depending on what pistons/cr you want. DAW

Thanks Les, I think you're right that I ought to pick it up. I'm thinking that this was a low mileage car, A/T, in the G20 Infinity and I'll bet it is pristine on the inside. I've been looking at CA16DE engines in Pulsars and CA18ETs in 200SXTs and I'm curious as to interchangeability and valve/port size on these heads and the SR20DE head. I wish the SR20DE had a rear sump, for use in an early Zcar, but I'm wonderring if any one has tried changing out crossmembers between 280ZX (or other source) and early Zcar, in order to put the rack & pinion BEHIND the crossmember, in order to run a front-sump pan??

For $650 I can get an LSD unit; no, a complete LSD diff,...but I think I'll but a dashboard instead...DAW

Can't hurt; might help. DAW

I've had my eye on an SR20 engine out of an early '90s Infinity G20 (front impact, low miles) for a few yrs now. It's at my favorite JY, sitting in a dark corner with a broken cyl head/camshaft from the accident. I can get it for $150 (maybe talk down to $125) as a "core" engine. It has manifolds and injectors, TB, etc., but no computer or harness. I saw another broken (block) SR20DE with intact head at another JY for $100 recently...so, $250 for an SR20DE; is it worth it? BTW, I have a PL510 if it doesn't work in the 240Z. DAW

Thanks Peter! I'm a Sweden fan, I picked my 940Turbo up at the factory in Goetenburg (sp?) and shipped it to the states later on from Bremerhaven. I'm going to look into your suggestions. I've been impressed by the simplicity of the 2.3 and the performance, and it seems to me that the hp ratings are very conservative. My turbo wagon just hauled ***. Actually, for a simple, effective swap into an early Z, I think a B230FT with the stock engine mgmt system would be a great start, then upgrade from there as needed. DAW

I've been toying with several alternative inline 4/6 engine swap ideas. I'd like to find a donor with an advanced engine mgmt system (stock), RWD, reasonable wt, rear sump, and abundant parts access. If anyone out there has experience with Volvos you may be able to help with this question: can the B234F become a B234FT? Or can a B23FT become a B234FT with the head swap? I'm assuming the use of European market turbo exhaust manifold onto the 4-valve head. I know there's a European B204FT, I drove one in Italy, and in keeping with their practice of staying under 2 liter displacement (tax laws) and fewer emission laws, they really tune their smaller engines. I remember the car being about as strong as my B23FT in the states. So, I know the 4-valve head has a turbo manifold as in Europe, and the 4-valve head was used on the 2.3 liter na engine here on the 740GLE for a year or two..so what kind of performance (with the right pistons) would a larger displacement Volvo turbo 16-valve 4-cyl provide? Anyone know the wt of the Volvo 4cyl? Has anyone considered the Volvo I-6 B6304F for a swap (10.7:1 cr, 24 valve, 2922cc, 204hp@6000, 197 ft.lbs. @4300, Motronic system, rear sump)?

The wastegate actuator diaphram is mounted using a curved two-bolt flange that acts like the other retainer flanges holding the compressor housing to its baseplate. Using a curved plate (like a spare retainer plate) under the actuator mounting plate would reposition it slightly ("shim" it) in the direction of its opening action on an L28ET...which would weaken its closing tension and allow it to crack open at lower boost; not higher. Since there's no way to shim it in the beneficial direction, the external mod needed would be to add a supplemental extension spring between the wastegate lever and the actuator bracket, along the axis of the rod. This is best done incorporating an "S" hook/link in the attachment so that longer or shorter of this link can manipulated to get the desired additional preload. There may be other car mfgs that afix the actuator to their turbo which allows shimming of the actuator such that it displaces the diaphram further from the wastgate lever pivot and in this case shimming could be used...but not in the L28ET. DAW

Some very creative and impressive work into this tailight thread. I'm seeking a nuts & bolts type solution that I can accomplish with speed snf reasonable cost. For a 240Z without a lot of body kit mods, i.e., with stock chrome bumpers I like the stock 240Z tailights, with Euro amber turn lenses. However, I don't like the 280Z lenses and would prefer a customized tailight panel instead. I've retro fit '72 bumpers onto my 280Z and I want to keep some sort of chrome trim on the panel to make it look period-appropriate with the bumpers. Presently I'm fitting early '80s Toyota (Corona, I think) tailights. The chrome trim ring looks a lot like a '67-'68 Camaro in shape & size and the lenses are long horizontal, amber top/red bottom. I'm pretty sure this will look much better than stock 280Z...but at a JY yesterday I found a '70 Cougar with intact horizontal uni-tailight ($50). I searched this forum because I think I've seen mention of this swap, but nothing. Does the tailight have to be narrowed? (I didn't have a tape measure but it appears to be in the ballpark). Any info? DAW

BTW, when you have a significant bog/miss/lag with a triple set-up, the problem could be coming from one or two of the carbs and not all three. e.g., if the linkage arm from the main throttle shaft to one of the carbs slips (like from all that crazy throttle action in an autocross)...the car will drive but runs very strange. If you haven't already done this, drive your car briefly without the air cleaners and noting the bog, confirm it's there. Then pull over and check for accelerator pump volume at each carb. You can check only one carb at a time if it's going to be an accurate comparison since the fuel bowl supply is changing, unless you have an electric pump refilling the carbs. You may need a mirror and flashlight to observe the spray but often you can hear and feel the spray discharge and its duration. You're looking for uniformity of function first, then for absolute observation of the pump spray. Hopefully, you'll find one of the carbs has a weaker accelerator pump function than the other two, and problem solved. DAW

BTW, what size valves (int. and ex.) do you have in the E88? If you're not sure, what yr 240Z is the E88 cyl head from? (This is related to your triple weber question). I think this post could have gone into carburetors forum, but there are a lot of L6 na performance engines with triple sidedrafts..more than any other specific engine type..so why not? DAW

At 300-400 rpm, cranking, throttle blocked open: std = 178psi min = 164psi DAW

It sounds more like an accelerator pump problem. It may not be the pump jet sizing but more a problem with the pump system itself; stroke, spring, check ball/seal, etc. I'd double check this system. The bog is happenning when part-throttle is opened rapidly to WOT. It is up to the accelerator pump to cover this transition until the sudden airflow change has mains fuel matched to it. DAW

Too eratic. Matching the cyl head/water temp input modification to modification of the temp sensor for the AFM can increase richness through out the rpm range if it's needed, but this technique is for small amounts of extra fuel and not for load-based (turbo) tuning. DAW

Use a water temp sensor as the '79 (and earlier L28s) had. It's located in the thermostat housing on these earlier heads. Just splice it into the harness for the cyl head temp (your '81 connector won't reach to the thermostat hsg). The thermistors are the same, you'll be inputing very similar values (water temp vs cyl head temp) and the ECU probably won't know the difference. Don't put the sensor in the intake manifold! DAW

I put mine in the spare wheel well and grounded to the frame (and use a ground strap up front, engine block to frame), but at times I think that I should run a ground cable direct to the block. One of the best setups I've seen is the type I have in my Starion. I bought it from TEP and it's a battery box steel frame incorporated into the rear strut brace...it's really well made and a great design. I put a marine plastic box lid over the orbital battery and secured it hold-downs and stainless steel acorn nuts. I don't know if it's available for the Zcar or not but it's "two birds with one stone"...(whatever). If not available...design engineers?? DAW

Jim, that was amazing! I think the non-A/C cars use far fewer vacuum hoses/diaphrams/devices. I've gone to the JY before in search of a non-A/C 280Z heater and controls assy in order to clean up and simplify things (I don't want the A/C anyhow), and I've found the factory non-A/C cars to be scarce. DAW