Zed Head

People spend a lot of time, effort, and money to get the valves to stay open longer, via camshaft changes, for power increases. Chevrolet's performance engines used to come with 2.02" intake valves, over the normal 1.94" valves. That's like a 51 mm over a 49 mm valve. The 2.02"s had problems with cracking between the seats but Chevy kept using them. They mattered. I only know that because I had a Chevy engine back in high school and 2.02s were a big deal. You'll find all kinds of combinations and rationale for all of them. The basics of creating power don't change though. But, I actually backed off some of my power increasing efforts, via advancing timing, just to get back to nice solid dependable engine. Messing around is a lot of fun though. Measure the valves on your E88. It's fairly common for people to put the L28 valves in those heads. I think that one of them is already at L28 size. The MN47 valve info is out there somewhere.

Looks nice. Not to pick, but your picture from tomorrow shows a rectangular side mirror while the one in the first post has a round one. Just wondering. And you have a blue one in your avatar. More wonder. Is it the same one, with new silver paint?

Nice car. Any reason you can't put more info in your ad? Not much there. Is it an automatic? Good luck.

I don't know why it bothered me but it did. Isn't your second ring on upside down? I tried to find some pictures but so far I've just found a video on the Hastings web site. What happened to good old line drawings, everything has to be a video. Who knows maybe she's putting it on upside down or you're not using Hastings. Anyway.... https://www.hastingspistonrings.com/tech-tips-faqs/installation-of-compression-rings

That damper has had known issues for yeeeeeeaaaarrrrrsssss. I think it's always been bad, somebody got their specs wrong from the start. Jim is either ignorant or lying. I'd guess that because the Z market is small, that he's just ignorant. Edit - This is the sad part. Suggesting he's a new guy, new school, not-my-problem school. Old school would get information and try to make it right. "We do not have any facilities for machine work here so there is nothing we can do. My suggestion is to have a machine shop hone it out until it fits." Edit 2 - Just realized that "we do not have any facilities" probably means that it's made in Asia, under contract. They probably don't even make parts any more. Somebody bought the Powerforce name and is milking it.

Don't overtorque. It's hard to find a good reference, and there are different types of "anti-seize" out there but this references implies that 2/3 of normal is a good rule of thumb. http://www.alliedsystems.com/pdf/Wagner/Forms/80/80-1057.pdf I spent extra time torquing mine to just right but when I detected a small leak I went right back to crank it down until stops mode.

Yes. On an N42 block with the normal dished pistons it raises the CR to about where a ZX engine would be. But with smaller valves, so not the same power level as a ZX engine. People use them with flat top pistons to get an even higher CR. Your engine is probably in fine shape, just not achieving its potential. Gasket height is 1.25, if you want to play around with a calculator. Just pick any head and plug in 39 for volume. Late pistons are flat-tops, early or turbo are dished. http://www.ozdat.com/ozdatonline/enginedesign/

Yes, the block type number is by the driver's side motor mount. It will be either F54 or N42. But, it's looking like you have the MN47 head, as people like to call it. A smaller combustion chamber, giving higher compression ratio. But also smaller valves. More endless discussion about pros and cons... The 280ZX heads with the CHTS are P79 or P90, not N47.

The Maxima L24E head also uses a CHTS, on a head ID'ed as N47. It can get confusing. Engine size should be stamped on that flat spot right there under the CHTS. The block type will be cast in, not stamped, somewhere around the driver's side motor mount. I always have a hard time finding the cast numbers.

With the Datsuns it's the oil pump and distributor drive quill that is out of adjustment. Once the oil pump is installed the drive quill, or shaft, is locked in to place on the crankshaft gear that turns both the oil pump and the distributor. (Never really put the whole picture together before). The oil pump is below and the distributor above, but they both get their energy from that long spindly shaft. So what you're really seeing is a function of how many teeth off the the drive quill is, to the crankshaft drive gear. That's why people use vise-grips or rubber bands to hold it in proper spot , before matching the oil pump to it, to get the distributor right. The oil pump doesn't care, but the distributor does. Also why there's no "180 off". We could count the teeth on the gears and come up with the various points of "off". I'm surprised we haven't done that yet.

You might be okay with moving the plug wires one over. Worth a try. That's pretty far off but it looks close to 60 degrees, which would be one wire spot rotation. How do I learn to braid my distributor wires like that?

Apparently, from the writings of the infamous Tony D, running on #2 or #3 with a new chain drops the powerband down in the RPM range. You get a torquier engine feel. So if you're not looking for high revs and max power it's a good option. I've always been a "short shifter" myself so if I built an engine I might try that. site, do you remember where the notch was, relative to the groove, with your #3 hole setup? Av8's doesn't look terrible, I brought it up more as evidence that things aren't right. If you get enough not rights collected, things don't work.

I think that they stopped in 1977. I have a numbers matching 1976 car, but the engine is in the garage, not in the car. It has the engine from a 1978 car that did not have the engine number on the ID plate. But the engine has a number stamped on it. Short - my 76 has an engine serial number on the ID plate, my 78 parts car did not.

This is your future Av8...

I saw the too big blob also and wondered. Notice though, and I've wondered about this in the past, how five holes in your picture are lined up, except the second one doesn't have a hole. The're not in the same spot on every lobe, relative to the ramp, they are in a line so that they can be drilled efficiently. The second one is on the ramp so they didn't drill it. So, if there was a hole in the #1 lobe I'd expect it to be on the other side so that the next three can be drilled, off the ramps. Your picture looks way too clean. It's unnatural. But there is a lot of oil, as there should be.

I'm not sure that all 1977 N47 heads have both a spray bar and holed cam lobes. My 1978 N47 head has only the holed cam lobes, no spray bar. The holes are easy to see though, so it will be apparent. I've spun a ZX engine with a gear reduction starter and got the bubbling crude through the holes. The early starters aren't gear reduction and I think that they might spin a little faster, depending on battery size and charge. With a spray bar you only have to worry about oil flinging from the spinning lobes, not squirting outward. Most of the oil spillage is over the edge of the head, down the side of the block.

I was imagining one of the old original 4Runners with the removable back half. I wouldn't try to put a complete engine in an SUV. Transmissions are easy, engines too bulky and heavy. Odds are in your favor on the engine that's in there. They are very durable, except for if the cam lobes run dry or they get overheated. You could build a table top to set on the $100 engine as a disguise. Picnic table maybe.

I've often used a come-along and the rafters in the garage. Not a single rafter though, place a 4x4 across 4 of 5 rafters to distribute the load. I bought a chain hoist to make it easier when I decided to swap engines. site was on target with "spare parts collection". I almost feel like we should be warning you...

I was going to suggest getting a used engine over a rebuilt one but assumed that they would be hard to find. Finding two right away is kind of unicornish. The CL engine looks very clean and original. The one downside I see is that it looks like cylinder 6 is at 125 and the others at 150. But testing pressure on a dry cold engine might be the cause for that. It will have lots of swappable parts like the oil pump, water pump, cam shaft and rocker arms (in case you find that yours are damaged), fuel rail (it's the one piece design, better than 75-77 three piece), injectors (they last a long time if they're fed good fuel), manifolds (although they are ZX parts and will take minor mods to work in a 280Z), etc. For $100 it's a nice solid package of parts at the worst. See if he has the flywheel, they're getting hard to find too. The distributor is out but he might have that too. For the costs and availability I'd consider getting them both. Look over the 75 engine and car. If the car is crashed but the engine maintained that's a clue. As is if the car is nice but the engine is trashed. You never know, I used to see both types around here but haven't seen a Z or ZX in the yards for about 2-3 years. There used to be 1-3 around at all times right after I got my car, 9 years ago. No more. Actually I'd do the $100 engine right away, then take your time on the wrecking yard engine. Edit - the transmission in the 75 car is probably a 4 speed. Don't take it, let them have it and see if they'll drop $50 to 100. It's not worth much and will just take up space. Unless you anticipate problems with yours. People can't give them away. If it's an automatic, there's no way you want to take it.

Maybe the rubber guy, nix240z, could look at making some. Make a mold, pour around some bracketry. It's a lot of rubber but there's not much to it. It just sits there. The're almost all rotten or sagging. Big market if they were priced right. @nix240z

Plus this. A valve might be bent or hanging in the guide, closing slowly. Or lash might be too tight, leaving it partly open. There's a time factor involved when you measure cylinder pressure, the speed of the piston generates the pressure. If it moved real slow all of the pressure leaks past the rings. And the pressure gauges have a valve on them to hold the highest pressure, so you can't tell how well the cylinder is really sealing. A good battery and a fast starter probably gives a higher number than a slow starter.

I built a piston stop from an old spark plug. Checked my mark once, for fun, the engine already ran fine. It was on. Considering all, and how close it seems to be, I'd spent some extra time with the valve cover off, setting lash, confirming cam timing, confirming TDC, cleaning up the spray bar, etc. It would be a shame to get it running then blow it up. It seems like the PO might have just thrown parts together, or tried to fix a few things, and didn't do the greatest job.

Lots of rounded bolt head edges on that head, and the cam lobes look painfully dry and crudded up. The valve seals and stems can't be better. wouldn't be a surprise if a valve was sticking a little, delayed closing maybe. Or a cam lobe is on its way out. A picture of the whole head would be interesting and some close ups of the other cam lobes.

I was thinking of that this morning but my brain was locking up on it. You're right, that could be the cam timing problem, why the notch and groove are off. The way to tighten the chain, to check, would be to put a wrench on the timing chain sprocket and turn it back (counterclockwise, standing in front of the car) until the chain is tight on the driver's side, but not far enough to move the timing mark on the pulley. Try to move the notch back under the groove. Don't worry about the bright marks on the chain, they are only for the first installation. The notch and groove are all that matter now. I would confirm that the chain is tight on the driver's side, and see where the marks are, before worrying about resetting the sprocket. Captain Obvious @Captain Obvious wrote up a simple way to get the pump and dist shaft right, using a method to hold the distributor drive shaft up in the hole so that you only have to match it with the oil pump. I think that there were rubber bands involved. I've used the small skinny nose Vise-Grips before. Your plug wires were set to match the oil pump being in the wrong spot. Seems like the PO might have mis-adjusted a lot of things. Since you're in there, and there's so much gunk under the valve cover, I would remove the spray bar and clean it out with carb cleaner. Make sure that all of the holes are clear. One for each lobe. Maybe turn the engine over and make sure oil comes out of the supply hole. Cover it with a rag first. With the plugs out and the motor spinning you should get plenty of oil. When you have the pump off to adjust the shaft, check condition of the pump parts. You don't want to ruin a cam lobe because of low oil flow. Sorry, if you're not a wrench now, you soon will be. Checking the cam timing, wiggling the rocker arms, cleaning the spray bar, and dropping the oil pump and resetting the distributor shaft aren't that hard. You have the right pictures of the tang. Notice how it's not 180 off? More like 115 or 120. Somebody goofed up when they reinstalled the oil pump.

Doesn't look you're getting much oil spray up there either. Things look kind of dry. I usually have enough oil on the edge that it starts leaking over the side. Oil everywhere.