Zed Head

I only have 280Z and 280ZX pulleys. I'll be keeping my eyes open in the wrecking yards in the future though.

There's a whole big thread on Hybridz about the LD pumps. Apparently, the original LD pumps pushed more coolant so people wanted them for their performance engines. But they don't make them anymore so the parts places are selling the gasoline pumps as LD pumps, or getting them mixed up. There are subtle differences in the pump body and blades. Some people ordered LD pumps and got gas pumps, some got LD pumps. And, for a while, the cast impeller pumps were hard to find,m apparently, only the stamped impellers were available. And they weren't very good. That's all I know. I'm always looking for easy part swaps though, so if a cheaper L4 pump will do the job with just a different pulley, that would be neat. The main reason I posted...

It would run like a turbo L28, off-boost. Probably okay. 17% more displacement, and bigger valves, might make up for the lower CR. There are general formulas out there that try to estimate the benefit of increasing CR. Here's one - http://www.wallaceracing.com/hp-cr-chg.php Doesn't look like much loss. This is one of the basics of the argument people make that optimized ignition timing is far more important than a few extra CR points. The added displacement might actually increase power. The engine will sound a little dull though. The exhaust won't have that rippy sound that high CR and a performance cam tends to give.

That narrows it down. The LD28 pump is typically used by people that want more coolant flow. The cast impeller pumps are commonly available though for the typical L28. The LD thing confused me. Still not totally clear though, to me. I think that you're saying that the height of the water pumps are different, putting the pulley mounting flange closer/farther from the front of the engine. You didn't say specifically but it looks like you're assuming that the L$ pump impeller will fit the L28 timing cover and bolt up correctly, and the only issue is the pulley mounting flange offset. Anyway, looks interesting. If you supplied some measurements people could check their pulleys. Short answer, for me, is no I have not tried this. I do have some L28 pumps that I could measure though. As I said.

There was a guy on the forum a while ago that put either a P79 or P90 head on a block with dished pistons. Said it ran fine, but it was his daughter's car and he was just getting it running so he could sell it. It was an EFI engine. Assuming the engine itself is in good shape, your biggest issue might be getting the SU's and intake mounted and the carbs tuned. I don't know if the P90 heads come with carb manifold mounting holes. I think that the other heads, N42, N47, for sure, and maybe P79, do, but they're designed for NA. The P90 is a turbo design, so no need for carb manifold holes. That's probably your decision-maker.

Not a big deal in the big scheme but the later 240SX's did get the reverse synchro. It's shown in the Motortopia link above (copied specific below), and in the FSM's (baulk rings for 5th and reverse, 1996). Of course, Nissan kept the 240SX name but changed the platform from S13 to S14, so that's different. The Z31 71C's had some improvements also, like double synchro rings for 2nd gear, some years even had double rings for 2nd and 3rd. The cases are the same though, so the swap procedure works on any of them. Don't know about the Z32 versus Z31 stuff. People tend to call this a bellhousing swap but it's actually a front case swap. If you're from GM world, a bellhousing is completely separate from anything that holds gears and bearings. It is essentially an adapter for the trans and engine, and covers the clutch, flywheel and input shaft, In the procedure being discussed here, the part being swapped is precisely machined and contains the bulk of the gears and bearings. The "T5"'s use a separate bellhousing, I believe, but that's a completely different transmission and manufacturer. http://www.motortopia.com/cars/1973-datsun-240z-11118/car-pictures/240sx-transmission-swap-14041/IMG_2766JPG_Thumbnail1.jpg-412263

Are you trying to find an LD28 analog or a stock gasoline-powered L28 analog? You have the L4 pump, don't you have an L28 pump? I have an L28 pump to take measurements from. Not really clear what you're asking.

The noise from the transmission in neutral, that goes away when you press the pedal, is very common. All of mine have it. jmortensen posted in the past about helping someone change a bearing because of the noise, I think it was the countershaft bearing or maybe the mainshaft, and having a quiet transmission for only a short while. The noise came back. If we asked everybody on the forum to listen for the noise, we'd probably create a run a on bearings or rebuild kits. Ssshhhhh..... Wow, my first attempt to find that old post and it popped right up - http://www.classiczcars.com/topic/35592-throwout-bearing-noise/

Since the wiring is non-stock, it's not clear where the blk/wh was originally. A schematic of your car's wiring as it is now would help.

If the resistor has failed you'll get infinite resistance. No current flow allowed. A quick check would be to run a jumper wire between the two On and Start posts, or just move the On wire over to the Start post. It won't hurt anything for a short while, the coil will just get hotter if you leave it. If it runs that way, then you'll know the resistor wire is broken. Edit - not sure, since my ballast is gone, but you could probably bridge those posts with a screwdriver for a really quick check, if you have a helper.

The old trick of spraying starter fluid around potential vacuum leaks works very well on the BCDD. Of course, it has to happen on the "right" side of the click. If you're sucking in unmetered air, the starter fluid will find it.

The pedal sinking to the floor is usually a sign of internal leakage in the master cylinder. But your second comment is a little bit confusing. If they feel good, what is the problem?

Woohoo, you get to use that funky connector with the rubber plug over it, up by the coil, that we've all wondered about. Could be the old corroded connections problem, or a partial-short across A and B at that connector if the rubber's gone. Or a gummed up solenoid. You might check the voltage at the single wire to the solenoid against ground while it's active to see what kind of voltage drop you're getting. I think a typical solenoid is about 1/3 volt. SteveJ probably knows for sure. Get as much easy information about the state-of-the-system as you can before tearing things apart.

Somebody (SteveJ maybe?) has pointed out in the past that LEDs are polarity sensitive. You only show one LED application, but maybe you replaced a bunch. Or maybe you tested the speedo with one polarity but got the opposite when you reinstalled.

I wonder if your problem isn't actually somewhere else, like maybe at the speedometer. As I understand the BCDD system, it's supposed to be inactive under something like 10 mph. You shouldn't be hearing the BCDD clicking, with engine speed changes, at idle. The AC idle-up solenoid might do that though. The way the BCDD works and a pretty detailed test procedure are described in the Emissions chapter of the FSM. If you just have a blown diaphragm, somebody (one of the Captain's, if I remember right), took theirs apart and replaced the diaphragm with a piece of thin rubber. It's on here somewhere, they described it. But your problem doesn't sound like that.

Probably won't make anyone feel better, but after I fixed all of the leaks in to my cabin and got the inside well-dried (a nice hot summer), my back window fogging problems are dramatically reduced. It just takes a small seep to allow enough moisture in to fog things up. I had leaks up front and in the back. For while though, I had an auto parts store heater/blower/defogger mounted on a board, pointed at the window. and wired in to the defrost grid power. The circuit handled the load easily. Noisy and took some work to keep it from sliding around but it did the job. The other "fog" problem though was outside condensation on the cold hatch glass. Who's got the rear wiper modification they want to share?

During manufacture, the spark plug ceramic portion is inserted in to the metal base then the lip of the metal is crimped over to hold the ceramic in and seal it. The hacksaw is used to cut off the crimped portion. Basically cutting off the top of the metal base, around the ceramic. Just place the blade in the corner at the base of the crimp and cut a thin ring of metal off. You have to work your way around bit by bit. You could probably also put the plug in a lathe or drill press and spin at low speed to cut a consistent cut. Don't let the saw get driven in to your gut though.

That's the assumption. I built a piston stop from an old spark plug. It was so easy, and easy to use that if I ever get another engine, checking the marks at TDC will be the first thing I do. Too much time spent wondering what's right otherwise. I checked my one spare engine and it was correct. Comforting to know the lump of metal taking space in the garage is correct. Here is the easy piston stop build method. I messed around once before, but the key is the hack saw. I think an 8mm tap was the right size for the bolt. A grinder helps to round the bolt corners. The plug I used wasn't even glued, the ceramic just fell out. The hardest part after that is carefully rotating the engine so that you don't doink a piston in to it. p.s. that's not me, I stopped wearing flannel many years ago. No offense.

Front tire. The whole car moves. If you use this method while adjusting valve lash you might crush your recycle bin by accident.

My method is to put the car in 5th gear and rotate the front tire until the damper mark is at Zero. That is TDC, assuming that the pulley and marker tab are correct. Then I put a wrench on the timing sprocket bolt and ease the sprocket backward to tighten the chain. The only reason to do that is to check the cam timing relative to the crankshaft and pistons, as rossiz described. Just saw your last post. Looks like the filament is glowing now...

I like this part. Doom looking in you in the face --- screw it, I'm getting one last ride in.

If I recall, you ported the other head that went to DP. That would probably give you more benefit than a slight bump in CR. If the top of the head was milled the measurement may not help you much since you don't how much was cut off of the bottom. The best way to calculate your CR is to fill a chamber with a known volume of fluid. I think that it's easier than it seems, the fancy plate is meant for super-precise work. Water with a little soap to remove the surface tension, fill a perfectly level chamber to the top. Should give a good number. Then do the math or plug it into a calculator. http://www.ozdat.com/ozdatonline/enginedesign/

It's a shame that DP is screwing up the good publicity opportunity. Rusty rocker arm pads, used bolts. Looks like a blend of rocker arms again also. Hope it checks out this time. Weird that he said he was rebuilding one for you but this one looks like it's been on a shelf for a little while. Maybe that big glob of goop is sealant from the core plug in the back of the head. It's all part of the challenge though. I can't be sure if I see one hole in the cam lobe for internal oiling. Check the back of the cam to be sure it's plugged. Maybe fill the passage with oil and make sure all of the holes are clear. It would be boring to just get parts that were perfect, and went on with no issues. Good luck with it.

So you're showing that the damper mark was off by 12 degrees. 34 - 22. Now you have to worry about the damper and if it's failing. Should last a while, but if the mark keeps moving that's a bad sign.

Your TDC location method is a little bit imprecise. There's play in the bearings and the piston barely moves at all as it goes over the top. The best way to locate it precisely is with a piston stop or a dial indicator with the head off. But it looks like the mark, and the crankshaft and the cam marks are all within a few degrees. Certainly not 20 degrees off. You can see by the distributor picture that the points of the reluctor are not close to aligned. When those two points pass each other that's when the spark happens. So your timing measure of 34 degrees seems in the ballpark. Still odd that so many parts are right but the timing is off. The one picture you don't have is of the #1 cam lobes, confirming that they're fully closed. It's a puzzle. You might put the sprocket back to number 1 hole, recheck everything and see how it runs then.