DAW

I think we're all not on the same page on this topic. BOV term was used but in the context of a CBV, so I assumed that's what was being discussed. A BOV was used on 280ZXT (it's that canister-looking thing on top of the intake manifold towards the rear cyls), it's a fail-safe if the wastegate fails so the engine doesn't blow; not present on Eclipse. A CBV (compressor bypass valve) was not used on the Datsun but was used on the Eclipse. It has a totally different purpose than a Blow Off Valve, it vents boost which is in the piping between throttle plate and turbo outlet when the throttle is closed quickly (like shifting) so that the built up pressure doesn't slow or try to stall the turbo impeller. It's a great feature to have and should be on any turbo'd car, especially manual trans. Nissan just left it off, along with the intercooler. DAW

Proper substitute, I don't know, but I've used that light brown lithium based chassis lube and it worked fine. Don't just put it on the cam, put a dab on either side of the rubbing block so it will always have a supply. Some auto parts stores sell Niehoff cam lube in a small tube. DAW

The Nissan valve is an Emergency Relief Valve, and the Mitsubishi valve is a Compressor Bypass Valve (according to them). DAW

/T when the convertor locks up. However, the shift point (under normal driving conditions) from 2 to 3 is to high. The engine seems to hunt and hover rather than shift. It will shift if the throttle is backed off to raise manifold vacuum to the modulator valve but that's a pain to drive that way. TheMy question is: Does anyone know if the modulators are the same in the gas vs diesel trans, or are the actuator rods different lengths? Next step and the engine has lots of low-end torque so the stall speed works out fine. Thanks in advance, DAW

I've gathered Volvo and Saab OEM pieces as I see them at the boneyards. They are larger dia. than most other intercooler hoses & tubing. When piping my intercooler, I have a selection of pipes to use and can come up with a combination that looks like it was designed to fit. One nice feature is that they have ridges already rolled into them for secure hose fits. I also used an Audi hose which was formed larger on one end (which fits onto the intercooler inlet) and smaller on the end which fits onto the Nissan turbo outlet pipe which I cut before the stock U-turn to the throttle body. I left just a slight amount of the larger U-turn segment so that it serves as a ridge for the Audi hose to fit over. DAW

The creative thinking is good on the BOV idea and I tried the same approach using an Air Pump regulator valve from the early Z. There was a problem in adapting it due to it blowing off at too low a vacuum signal, dumping boost you wanted to use. The Talon/Eclipse approach is good, although I didn't like the constriction of the short pipe segment which incorporates the base of the BOV. I took a larger diameter turbo pipe from a Volvo, cut a hole in it where I wanted the valve base to locate, then split the Eclipse pipe along its length opposite the valve. After shaping the eclipse piece around the larger dia. of the Volvo piece, I welded the perimeter of the Eclipse piece on and I had a BOV without restricted flow, and a mounting bracket (part of the Eclipse piece) DAW

looks good. I wonder how an alternate design with two "humps" starting at the front of the cap, one behind each seat, tapering down toward the tail end would be? DAW

Just curious, has anyone tried fitting the five-lug, vented rotor off the front of a '95-'96 240SX-SE onto the rear of an early Z? The rotor is a slide-on and the earlier four-lug 240SXs at least, have the correct sized pilot hole (68mm) for the Z axle fit. DAW

Sounds like a lean sag/throttle tip-in condition rather than something as gross as an accelerator pump volume mismatch. I think there are various power valve springs, jets, etc., for tuning this out of a Quadrajet. You've got to get the primary set up right before doing anything to the secondary. DAW

ljohnson has a good point about the venting system, all kinds of things can happen, including insects thinking a vent hose would be a great place for metamorphasis and leaving it blocked with a pupae or some such thing. I had an antique airplane for many years that I kept outside. One spring I took off and I was acutely aware that something had happened over the hibernation period because I had no airspeed indicator! Lots of potential for mishap without that gauge. Cause? The bug/metamorphasis thing going on in my pitot tube. Plus, they would constantly do that in the drain petcock of my fuel filter bowl so they don't mind gasoline fumes. Strange things can happen. DAW

It's tough to say where the problem lies exactly, but you know it's either fuel supply or ignition. I think I would make sure I topped it off with premium unleaded, including a can of injector cleaner/gas dryer. As your fuel evaporated, it left air in the metal tank. With temperature changes, condensation of water content of that air formed water droplets on the walls of the tank which streamed down, pulled by gravity, towards the tank bottom. Once those droplets hit the fuel level on their way down, their fate was determined. Since the aqueous phase (water droplets) is more dense than the organic phase (gasoline), there will be a growing pond of water at the bottom of your fuel tank that cannot and will not evaporate since it is topped by a layer of fuel. I would consider draining your tank (most have a drain plug) before refilling with fuel, and I would go ahead and change the fuel filter as it may be gummed up by now. Take a quick look inside the distributor cap and make sure there's not a lot of condensation and corrosion, and I'd recommend investing in one of those testers, such as sold by NAPA stores, which have a ground clip on one end and a spark plug connector on the other, and an adjustable gap in between which is set according to car type. If the ignition system is up to snuff, a spark will jump the gap. Good luck, and next year put a can of fuel stabilizer in the gas tank when you park it. I should heed my own advice, I have five untreated cars outside covered with snow and five cans of fuel stabilizer on the shelf in the garage. DAW

A good source for info on the Starion/Conquest, including actual cost of upgrades, is Top-End Performance. A weak link on the engine is the cylinder head with the emission control "jet valves" in it. They are very prone to cracking between the intake and exhaust valves, which means you can sometimes find a car for cheap and there are alternate heads available aftermarket. I've got a Starion ESI-R (intercooled turbo, factory box flare fenders). It makes a good road car and comes with 16" wheels, leather, LSD, and vented discs all around. These cars are grossly undertuned from the factory, with throttle body injectors and a restrictive exhaust, but even in that state of tune they are capable of impressive performance at highway speeds. DAW

That works out pretty well, what you've described. I like to work just from the crankpin, so, stock LD28 is a 140mm rod + 46.5mm compression ht = 186.5. Using Z20E rod = 152.4mm + 31.75 compression ht =184.15, or just over 2mm below deck. 84.5 to 88 is a big (3.5mm = .150") overbore, even on a diesel block. Also, watch the VG30E pistons, as they are rather narrow on the underside between bosses where the rod has to go. I have yet to check out a piston from a CA 20E (84.5mm), and I don't know what the compression ht is. How about an L28E piston, 86mm (0.60" overbore), 38.1mm compression ht, (186.5 - 38.1 = 148.4, and that's the rod you need. Z22E = 148.6.) Use flat-top L28s and an N42/47 head and it's a nice long-rod engine with over 10:1 compression. If you want more, then consider European flat-top L28 pistons in + 1mm (P8617 = 87mm) with the small pop-ups, combined with a P79 (or P90 turbo) head (both of which have the closed chambers), and you've got an engine with a high c.r., and a long rod/stroke. DAW

This may be the first time this question was posted. Thanks in advance, DAW

Is that why the aftermarket suppliers (eg MSA) state that the Weber big bore throttle body is not for turbocharged Zs? (because there's no provision for the fitting you've installed? DAW

A very noticable boost in performance will result from raising compression from 8.5 to 9.5:1. The E88 head has probably had L28 exhaust valves installed which is good to do, and the E88 exhaust valve seats can be machined to accommodate the larger valves. The Intakes, however, are a different story because the valve seats have to be changed to put in the larger L28 valves. With 2800cc, you're going to want the bigger intakes. That's where an L28 head starts looking good because it has the right valves to start with.By the way, the thickness of the cylinder head, from gasket surface (block) to gasket surface (valve cover) measurement is how you determine how much a head has been shaved. The specs for the stock head are available to compare. I've gone the route you're headed, with a shaved E31 with larger valves onto a L28 block with dished-top pistons...and I was underwhelmed with the result. Consider an L28 block with flat-tops and an N42 or N47 head, which makes almost 10:1 compression; or a set of NISMO European high compression pistons in an L28 block, with a P79 head, shaved a little. This combination has the benefit of a closed chamber configuration which promotes even fuel burn and less tendency to ping than the N42/47 head setups of the same c.r. There's one other configuration, and I run this on my daily driver. LD28 (diesel, 84.5mm bore, 83mm stroke) block, with it's stock flat-top pistons and 140mm beefy rods, and graft an N42 or N47 head (with the entire intake, exhaust, and EFI/ECU from a 280Z. This takes a bit of work and fabrication such as drilling cyl head bolt holes from 10mm to 12mm and using BMW head bolts, L20B timing cover, drilling dipstick hole in boss of block for your rear sump Z pan, etc. But it does make for a torquey engine and you'll have the only one on the block. Less tendency to ping than the same head on the larger bore, shorter stroke L28 block. Someone with an L24 might be interested in the E88 head with the larger exhaust valves (although they'd need to notch the top of the cylinder bores with the larger valves). By the way, there are two different E88 heads. The earlier one (fairly rare) has smaller combustion chambers, similar to E31s. DAW

Quick P.S., alternative to the Crane/Petronix/Allison optical trigger conversion into your distributor, you can take the entire electronic distributor from an '84 Maxima (or earlier, but with the black module box attached to the dist.). Simple bolt-in swap and less hassle than the other way. DAW

1) You have to ask yourself why the ignition timing is suddenly retarded once you changed the points. The point gap directly determines dwell, which directly affects ignition timing. In your case, you set the gap too narrow (lengthening dwell) and retarded the ignition timing. I know that adjusting the timing helped, but you need to go back and properly set the points, then proceed. Using a dwell meter is best. Make sure you've put a dab of distributor lube grease (comes with points)on the side of the points' rubbing block, so that there is a constant supply of lube to the dist. cam/rubbing block. Remember, as normal wear occurs, the rubbing block will wear and the gap will narrow. Anyway, set dwell (and not toward the higher limit of the specs), the reset your ignition timing. Bump up the timing a bit more than stock, as this will increase throttle response. If you get a ping (with good gas), pull off the road and slightly turn the distributor (in the same direction as the distributor rotor turns)then drive it and listen for ping. Once it's gone, stake mark the distributor base where the small index marks are, to indicate where you want it in case you have to remove it. 2) Before adjusting mixture, set dwell and timing. Then make sure the chokes are off, which means checking at the carbs also to make sure that the choke linkage doesn't have the jet base withdrawn any. You should push up with your finger on each of the tubes (they are in the center of the knurled nuts by which the mixture is set. You can really get lost with idle mixture adjustment, and remember that the adjustment you're making is affecting the entire rpm range re mixture. It's best to raise the jet fully (turn it clockwise seen looking up from the ground/counterclockwise looking down at the carb tops), until it stops back each off the same number of turns to a starting point. Try two turns of the knurled ring. Usually the is a small and large BB pressed in the ring which you can feel and keep track of your turns. Start the car, make sure carbs are synchronyzed (flowing the same air at part throttle and at idle, per Unisyn), set idle rpm screws, then adjust mixture. For performance, tend towards rich rather then lean, and keep track of where you are at re turns of both carbs. Don't get way out there with 3 total turns out on one carb, and 1 1/2 turns out on the other. Better to let it idle a little ragged at first, if that's what it means in order to keep the mixtures similar over the rest of the rpm range. If you still get a lean sag off idle acceleration, you could try lighter piston springs in the SUs, or richer needles. This gets a bit involved, but is well worth it. 3) Re points problems, if you get to the junkyard (on a budget) look for a Petronix type ignition points conversion from a Datsun 6cyl or any other 6cyl. Actually, you can just take the optical unit, wiring and module from any engine, then buy a 6cyl optical shutter from Crane.

the lengths in mm are: N42/47 Int: 115.2 Ex: 116.0 P79/P90 Int: 113.1 Ex: 113.9 So about 2mm . I don't believe this is going to help you with shaving the head, i.e. swapping in the longer valves. I'm assuming you're talking about shimming the cam towers to keep the timing chain length/geometry intact. I think you may make up more distance than you need. However, if you were to add a regrind high performance cam at the same time (using the added valve length instead of thicker lash pads that you would need otherwise), then both factors may justify the 2mm distance. If you were to go with the cam, and are on the ridiculous sort of budget I'm on, it looks to me like the Nissan 4cyl Z series head might provide a good alternative, plentiful, valve spring with more pressure than the L series springs. You'd have to check that out to confirm. DAW

What I'm suggesting is that you look at the rod/stroke ratio. Presently yours is 133/83 = 1.602, which is low. In the diesel block, if an overbore to 88mm were possible, the applicable rod length would be about that of a LZ22E, 148.6. This would yield a rod/stroke of 148.6/83 = 1.79, which is a significant increase. I'm going to try anLD28 hybrid overbored from 84.5 to 87mm.

Consider an N47 cyl head which on your flat-top piston short block would boost your compression from 8.8:1 to 10.0:1. That, with the suggestions others made re exhaust, etc., and your cam, would make a noticeable difference in performance, while allowing you to bolt onto your stock roundport exhaust manifold. By the way, the turbo torque convertors have a higher stall speed than the na cars. I was told by a trans shop that the torque convertors from the lockup convertor transes were different from the regular transes, that they had a different number of splines...I was in a trans warehouse a couple of days ago and slipped the torque convertor off a lock-up trans and onto a regular trans. There's no difference that I could see, does anyone know re interchangeability of torque convertors on JATCO transes?

I missed you, but think impact, inertia of rest. Put a 19mm or 3/4" boxend wrench on the cam bolt and whack it with a hammer. That will do it, not pulling on it. Don't forget to remove the 10mm head bolts (2) at the front of the head.

As above, 81-84. There is something to consider when obtaining an LD28 crank. Once you crunch the numbers, it becomes obvious that the LD28 crank transplant into an L28 presents a problem re rod to stroke ratio. The L28 is already all cramped up with no room for a decent length rod to use with the 79mm stroke, much less throw a 4mm longer stroke in there. That is why the LD28 engine has a block 19.7mm taller than the L28, to allow for a decent rod length (140mm). Anyway, I've converted an LD28 to an LD28E gasoline powered engine and I drive the car daily. It performs well (E42 cyl head)and yields about 9.5 or 10:1 compression and gets good gas mileage. I'm anticipating a great engine when I build a turbocharged one. Later, I'll go for an overbored LD28 block (I suspect a big overbore is possible), some rods in the 150's length, and a P series head. The point is, you may be able to get a diesel engine for the same price as a crank, and don't write off the block as it holds great potential. By the way, Nissan Comp told me it couldn't be done. It can; drill head bolt holes from 10mm to 12mm and use BMW headbolts, L20B front cover, reuse LD28 head gasket.

I agree. The L28ET was very undertuned from Nissan. Adapt an intercooler, run a rising rate fuel pressure regulator with a big pump, plug the manifold pop-off valve, install a compressor bypass valve, and increase the boost; and you've just picked up a lot of horsepower for a small investment.

It sounds likely to me that your water temperature circuit is open. Either the wires or connectors are bad or the sending unit is open. Computer thinks car is on Arctic Circle and is giving it full rich. Check to eliminate this, could also be cyl head temp sensor open, but water temp causes more dramatic effect. DAW