Zed Head

I wrote a whole dissertation in reply, but realized that it all comes down to the fact that nobody has really shown that to be the case. No offense. I do appreciate your sharing your experience. I've done more straight comparisons between lubricants than any thing I've seen on the forums so far. I ended up at 75% Swepco/25% ATF. Is it better than 50/50? For my one situation and what I wanted, it was. Jon Coffy seems to know quite a bit, and he reported that the Swepco blend destroyed the synchros in his worn transmission. Who to believe? It's a problem. Plus it seems to me that a worn transmission is not the same as a new transmission. New transmissions have more texture on the baulk ring, sharper baulk ring and dog teeth, sharper splines and tighter clearances. It seems to me that these factors would be affected differently by the lubricant used. If new and old were the same, why doesn't plain old 75-90W keep working as the transmission ages? There are tons of opinions out there but little reason shown for the results. Most accounts are "I tried X and it worked - I'm happy and done". We haven't even mentioned Synchromesh yet. Without a good study on the subject, I can't say that one is better than another, for solving any distinct problem. The studies that can be found are all suspect in that they're done by companies selling a product. That's the essence of what I meant by voodoo. Who knows, the OP might have 85-140 wt in his transmission and sawdust to stop a leak? Anything might be better. Crap, I wrote another dissertation. Oh well.

http://forums.hybridz.org/index.php/forum/37-nissan-4-cyl-forum/

This is a little awkward. That's me over on Hybridz. I never planned to post on these forums so I have multiple identities. To clear up my situation - with my well-used 1978 5 speed, I had gear-grinding from 2nd to 3rd at high RPM using Valvoline 75-90W gear lube. I went to Redline MT-90 and the problem disappeared, and the low temperature notchiness also. It was like magic. Subsequently, I installed a well-used 1980 5 speed from the local wrecking yard and with MT-90 I had gear-grinding from 1st to 2nd and from 2md to 3rd. I never tried the Valvoline 75-90W in this transmission because the MT-90 had worked so well in the 1978 transmission. That's when I started the thread on Hybridz and, at Jon's suggestion, tried the Swepco 201, Swepco 201 50/50 with ATF, and finally Swepco 201 at 75/25 with ATF. That blend is working very well at this time. I should have added some detail, but based on your description of slight grinding when cold, the Royal Purple or Redline, along with the clutch adjustment seemed like the right path. But, in retrospect, since you don't know what's in there now, maybe going directly to a Swepco blend would be the way to go. I didn't want to complicate what seemed simple, but may have over-simplified. I tried to summarize at the end of the Hybtidz thread but it seems like the solution probably depends on what problem you're trying to fix. fandsw, in summary, it's difficult to tell what is causing your problem, but the fluid used can definitely have an impact. You can see in the post #11 in that Hybridz thread that I'm currently using 75% Swepco 20, 25% Dex-Merc ATF blend. It works very well, for the bad synchros but is still a little bit notchy when cold. It's only like that for a few shifts though. To add to my own perplexation, I just took a junked ZX tranmsssion apart (it sounded like a blender on a motor I have set up to run in my garage, due to someone breaking two shift forks and destroying the main countershaft bearing) and found that the brass synchros looked fine but the dog teeth on 2nd gear were wasted. I had thought that the brass was supposed to go before the steel. It's possible though that someone "rebuilt" the trans with new synchros but left the bad gears in. Anyway, good look and sorry for any confusion. By the way, you might be able to tell something about the fluid that's in there by the smell. The synthetics like Redline have kind of a sweet smell, while the old-style fractionated fluids smell like the dead prehistoric lifeforms they're derived from.

You'll find that all of the little things add up. But the EFI 280Zs don't seem to get a whole lot better than low 20s mpg, mixed city and highway driving. Highway driving with a 5 speed would probably get you to mid-20s.

What brand and model of brake shoe do you use? It's a factor.

If it's the 1979 3.7 R200 it will bolt right in. If it's a 300ZX R200 it will have a different bolt pattern on the pinion flange. But, apparently, you can easily (with a big wrench or an impact wrench) swap the pinion flanges between R200s. Many of the 300ZXs came with open 3.7 gears. My understanding is that the LSDs were 3.54. Sounds like gira can tell from the pictures that it's open. I'm not that familiar with the insides to know.

The diff mount can look okay but still allow quite a bit of movement from the diff nose. The clunk is from the nose coming back down (my theory). The diff is supposed to stop the nose from coming down too hard also (you can see a little bump of molded rubber between the metal pieces), but it gets compressed over time. If you look at the front metal portion of the mount when it's on the car, you'll probably find that there's only about 1/8" or less separating it from the metal cross-member. If it's old and you clamp one of the metal portions in a vise, you'll probably be surprised at how easy it is to spread the mount apart with a screwdriver in the middle. The rubber gets weak over time.

There should be more numbers stamped on to the ring gear, I believe. Like 39/11 or 39/10. You could also count the teeth on the ring gear and the pinion gear and divide the big by the little to get the ratio. The 77 should be a 3.54.

Those all sound like the right things to do. I used Redline MT-90 myself to solve a grinding issue at high RPM from 2nd to 3rd. It also helped the cold notchiness. I don't know much about Royal Purple in Z transmissions. I've read a few good accounts about the Redline MT-90 though, and it definitely helped my transmission, a 1978 5 speed that I transplanted in to my 76 car.

You heard air before? This is with the engine running, when you press the brake pedal? You might have a bad brake booster.

There is some weirdness here. Shouldn't #6 be on the exhaust stroke, but in the same relative position as #1, when #1 is on the compression (spark) stroke? That wouldn't be 7 1/2 degrees off from where he is now. Seems like someone might have the plug wires in the wrong holes. That might be why he has limited adjustment at the distributor. You'll probably find that with the timing light on #1 you can't find the timing mark. The other possibility is that you've been looking at the wrong mark on the damper pulley. Might be best to start from scratch, put the pulley mark at 0 on the pulley, confirm that #1 is on the compression stroke, take the cap off of the distributor, find where the rotor is pointing to establish #1, and get all of the plug wires in the right holes. Then set timing off of #1 plug wire. p.s. Or, since it is running well, referring back to one of my original comments about making things wrong work right, just drive it and see where things are at before getting back in to it. Someone probably installed the oil pump a tooth off in the past and "made it work".

The N42 head on the F54 block with the dished pistons will give you an L28 like the 1975 to early 1979 engines. ~8.3 compression ratio. OR, some people will pay good money for the F54 turbo block. Someone, either here or on Hybridz, was looking for one recently. You might consider selling it and pickup a used L28 engine. Rebuilds are kind of expensive, compared to the extra miles you can get out of a used L28. You'll still need carbs or EFI to get it running.

7 degrees is probably from the 1976 specs (my car and FSM). It's more likely that your pulley is fine and your timing is really at 7 degrees. Your distributor might be a little off. There are many common ways to install them incorrectly but also many ways to make it work, with no damage. 12 degrees will probably be just fine until you start tuning for performance. As you've found, 7 degrees runs well, as it should. You're just not getting the absolute most performance out of your engine. You could bump it to the 1977 spec. of 10 right away or even 12 if you're running premium, with no problems likely. It would probably be a little peppier and maybe get a little better mileage.

He's planning for a turbo - L28t - so needs a turbo EFI harness. The L28ETs have their own harness, ECU, distributor, exhaust system, intake, etc. Most people buy a broken down turbo ZX and transplant everything they need over as esmit208 suggested. The alternative is to piece together the mechanical parts and use an aftermarket engine management system like Megasquirt. Here's a good link for options - http://forums.hybridz.org/index.php/forum/92-turbosupercharger/ The third one down is good for the transplant method. Look around the other sub-forums there for alternate EMS.

This car will probably require substantial work before it's a daily driver. The FSM, Haynes and Chilton manuals will be of limited use because the engine is customized, the brakes are not stock, and it has coilovers. Since it's not running and has been sitting, you'll be spending a lot of time and more money (possibly a lot more money) rebuilding or replacing things like the hydraulics and carburetors. That's not even considering any body damage that might need repairing. I would look at this more as a project that might sit in your garage or shop for quite a while, than something that you'll be driving. Any car can be a daily driver if you know how to work on it every day to keep it moving. I see lots of extra time and money necessary to get this one back to street-worthy. Forget about the winking, just find a level-headed friend who knows cars and take them to see this one. A flashy looking red sports car and an automotive newby are a recipe for an expensive mistake.

Sounds lean. Have you measured the fuel pressure yet?

It's probably running rich. Without the AFM, the ECU only adds idle enrichment fuel. When the AFM is attached the extra fuel from the flap movement probably makes it extra rich. Your shop should check the coolant temperature sensor for function and make sure that they didn't accidentally connect the sensor plug to the thermotime switch by accident or leave it disconnected. Two plugs on the thermostat housing that look the same but have different functions.

That is some different kind of logic there. Which hose did you remove? What do you mean by "no longer run well"? Did it run well before you replaced the intake gasket?

There's plenty of thread left for the double-nuts. You can't beat that method if it's possible, you'll get enough grip to break the rest of the bolt right off. Try all of the methods, none of them should make the broken piece more stuck. Put the nuts on before you tap on the top of the it though, before you damage the threads. Heat and cool the area around the stud several times while soaking it with PB Blaster. Try to twist it out but don't over-do it. You might find that it comes out pretty easy, the top probably broke off because the bolt was stuck in the thermostat housing, not the head.

One for sale on hybridz.org - http://forums.hybridz.org/index.php/topic/104039-r200-diff-sale-336-390-lsd-378/page__pid__972945#entry972945 Shipping could cost you though. The R180 should work fine if you don't beat on it. Datsun used it on a lot of models even though the R200 was available. Who knows maybe it's inherently quieter.

It's odd that a factory turbo car would have an R180. I don't believe that that is the standard diff. It's fairly easy to swap between the two, from my understanding. Something needs to be turned upside down and you might need a new rear diff mount, from what I've read. But the necessary bolt holes are on the car already. Might be easier overall to get an R200 from a wrecking yard though.

I think he might be talking about the large rubber piece that fills in between the bumper ends and the body. They are all saggy, cracked and chipped up after years of sun, heat and abuse. I've been pondering mine recently also. I haven't seen a reproduction piece anywhere either. I'll probably take them off and see if some later model trim from another car can be customized to look good, but with the plastic bumper fascias everywhere it will probably be difficult. One option might be to remove them, then push the 5 mph bumper shocks in to tighten up the gap. You could probably retrofit on the 77 or 78 pieces also, but then you'd have the accordion piece look on the wrong year car. It's a dilemma.

The 20 minutes at 2000 RPM seems to be the standard procedure for breaking a in a new cam shaft. As far as breaking in the rest of the engine, I believe that the focus is on getting the rings to set to the cylinder walls properly and that will be more dependent on the type of rings and the cylinder wall finish, which should be specific to the type of ring used. I would look for the ring manufacturer's recommendations. There are a ton of custom "this is what I do" break-in procedures out there, like your friends lugging procedure. Many of them are based on odd, incomplete ideas about how an engine works, and what happens during break-in. You might have answered this in a previous post (I can't remember for sure), but why are using the E-88 head on your L28? Did you modify it with the the bigger valves? An N42 or N47 will give you the same CR but with bigger valves, for more power. Just wondering. Good luck.

Have you checked both sides? Maybe the side you're looking at is broken. They seal at the bottom, so the top could be broken off and it would still hold pressure. http://www.carpartsmanual.com/datsunS30/DatsunZIndex/Brake/RearBrake/ToJul76/tabid/1735/Default.aspx

The heads are also drilled for carburetors as an alternative. Place the intake/exhaust gasket on the face of the head and you'll see where the studs go. The carb holes will be blocked. There are good drawings in the FSM also - http://www.xenons30.com/reference.html