NewZed

For anyone interested, here's the Grape Ape Technical Articles site. The Cooling link has good descriptions of the basics. http://mysite.verizon.net/vzezeqah/id1.html Odd that it doesn't have Grape Ape in the link, but I think someone moved the files over. It seems to be the real deal. Nigel, on the use of a fan, mine is a ZX fuel system cooling fan (described in 1981 FSM EF-46) with a GM heat riser tube attached to the fan's outlet and laid down under the fuel rail on the L6. The end of the tube is plugged and 6 holes, ~1/2 diameter are used to direct air directly on to each injector. The rest of the engine just stews in its own heat, no fan, no hood vents. Only the injectors get air, drawn from the right above the oil filter. The fan is run off of a bathroom fan timer, mounted by the steering column, the factory thermal switch is not used. Your problem is really interesting since your engine is quite a bit different from a typical NA L6. Here's a link to the type of heat riser tube, it's the typical accordion-fold metal/fabric material hose that GM used to bring warm air up to the intake manifold. I got mine from wrecking yard S10's. http://www.amazon.com/Standard-Motor-Products-Pre-Heater-Hose/dp/B000C7UPQU/ref=wl_it_dp_o_pd_S_nC?ie=UTF8&colid=30R38L6H5WA0Q&coliid=I2PEPLP3OQMVN8 Coincidentally, I forgot to turn the fan on twice today (subconscious maybe...) and got typical heat soak/hot start problems. As it clears up it seems like one injector takes longer to clear up than others. Runs on 5 cylinders for a while. The second time the temperature gauge was still reading normal. Who knows, a 160 thermostat might help. I'm running Bosch 028150116 injectors, not the stock Nissan green ones. Just filling out the picture.

I've taken a few items for general response. The last two out of order. These first two things are just odd, and disingenuous, and might be self-reflective. None of it applies to me, I've never been accused of anything similar by anyone, ever, and I've never felt an inkling that I should examine what I was doing because some of these things might apply. It is sad. If there was anyone out there that I thought could dig in to this issue and come up with some rational reasons for why it happens and how to stop it, it would be you (and several others who have may have seen this thread but knew better than to get involved). Maybe though, this is your "white whale" and you're having trouble dealing with the fact that it can't be caught. You don't understand it so you just keep throwing the same old harpoon. Or you could just be a bully, in general, and can't stand to lose a bullying session. That actually fits with some of the other threads you've been a part of. Now you've given up and taken the path of full-on verbal personal abuse and bluster, in public. That is truly sad. As you're trolling the internet in the future looking for some newbie to abuse, or a thread to interject your FACTS! in to, put a little more thought in to where it could lead. Think about leaving sooner. This is a pretty ugly end to what was an informative thread. You can do better Tony D. Still lots of time left.

Measure fuel pressure. Leave the gauge on while you drive. Knowing that you have proper fuel pressure at the rail takes fuel supply off the list of potential problem sources. Filter, pump, relays, crud in the gas tank...you can stop worrying about all of those if your pressure is correct but the problem is still there.

I wrote up a whole thing here but realized I was just churning up dust. We're still left with two potential fixes for the hot start problem. A cooler than recommended thermostat (deviation from the FSM instructions based on Tony D's advice) or a cooling fan (modified from the factory ZX fan scheme, to blow air directly on to the injectors). Both deviations from factory, and apparently both work. A choice. The reasons that Nissan used three different thermostats are still unclear, as many things are since we don't have the notes or minutes from the decision-making meetings. But Tony D has listed many of the effects of using coolant temperature control. Removal of the heat soak being one potential benefit. I still disagree that using the fan to solve the problem, while keeping the hotter thermostat is incorrect, in any way. It's just another way to get a job done, completely within the parameters of correct and careful engine operation and maintenance. Using the 160 thermostat is just the Tony D way, and incorrect, by the instructions of the Nissan engineers. It's just the way it is. There's nothing wrong with deviating from instructions, but you do lose the right to say other people are doing it "wrong". Better to say "here's how I do it and here's why I think it's a better way". Somewhere in the last page or two I think there is some of that along with a lot of extra stuff. Even better, in addition, explain what the Nissan engineers were thinking, if you know, for context. I'll still be searching around for information on the effects of combustion chamber temperature on performance and how that can be affected by coolant temperature, in addition to effects on lubrication and clearances. Ideally, one could summarize things down to pros and cons of hot versus cold, for use in decision-making. Maybe it's all hidden in this thread somewhere.

You've missed a lot of discussion about why flipping the cages doesn't always work, in your searches. If CV axles are crucial, this thread is probably where you want to go - http://forums.hybridz.org/topic/112204-order-for-shorter-z31-turbo-axles-from-the-driveshaft-shop/page-2 Search "chequered flag joe" for the other parts. Here's one - http://forums.hybridz.org/topic/103581-billet-z31-cvcompanion-flange-adaptors/ Use "site:hybridz.org" with your search terms, on Google instead of the Hybridz search engine. You'll find more stuff.

Seems like all you really need is two new yokes. All of your damage pictures are yoke only. The yokes fit the u-joints so two new (stronger) yokes should get you back in business. I assume the twisty portion wasn't there in the beginning. Looks like the CV axles with no heat treatment. JTR may have got a batch of yokes with poor heat treatment.

How hot everything is when you shut the engine off determines how hot the things around it will get once the coolant flow stops. So the thermostat used will affect the heat soak/hot start issue, since it allows more heat energy to reside in the engine while the engine is running. If the engine is hotter when it's shut off, the things attached to it will be hotter after it sits for a bit.

The very simplest way is to pop the stub axles out of the R200 that's in your 78 now and pop them to the 87-89 CLSD that you want to install. The CLSD will then bolt in just like the open diff that you're replacing, and you can use your u-joint half-shafts. Your scenarios 1-3 are all about getting CV half-shafts to work, which you probably don't need unless you're making lots of extra torque and have big tires, and want to use both to the extreme. bZ writes faster than me...and I forgot the part about the pinion flange...

Crack or cut a fuel line and see how fresh the gas is. That will give you an idea on potential for the EFI parts, like injectors, FPR and fuel rail. The 78 engine in my 76 now sat for ten years (I bought the whole car and the tags were ten years old) before it was re-energized. It's in great shape, no oil-burning, no blow-by, no problems.

This would be either a math or a conversion error. And the words about when the thermostats are fully opened or closed aren't mine, so the conversion or math error isn't either. My point is, 100 degrees C means the same things as 212 F, that's what I meant by units are irrelevant. I understand everything that's been discussed about cooling. My new, moving-on questions are: what is an engine's optimum operating temperature, and what is the root cause (the physical actions taking place with the fuel) that causes the poor running after heat soak (e.g. bubbles from fuel vaporizing in the lines, fuel vaporizing as it leaves the hot injector tip causing poor metering, sticking injector internals...). My fan works, your 160 thermostat works. There is no universal ideal, the method used to avoid heat soak is conditional. Your method gives up engine coolant temperature control. You have to choose between running hotter coolant and accepting heat soak as a condition of hotter coolant or solving heat soak and running cooler coolant. I don't, I can run whatever coolant temperature I want. I have more freedom of choice with my solution. As far as what people write on the internet, it's nice when you find well-supported writing but the bulk of what's on the internet is placed there by people who like to write, or talk,with no data to support their theories. Quite often, 90% of what they write is correct, but then there's another 10% of conjecture. Grain of salt material. Discussion about Oregon's weather and gasoline quality variables are context, for discussion, probably only useful to people who know the weather in Oregon or Arizona or Southern California, and something about gasoline formulating. At the the center of the issue is what's happening to the gasoline. It would be foolish to ignore differences in formulation in trying to explain why different people see different results. And just for anyone interested, the main difference between our two styles of discussion is that I start with the assumption that the other party knows what they're talking about and you seem to start with the assumption that they don't. It has a big affect on how you format your arguments. My way causes me to go out and learn new supporting data for the other side's case, your way is to take things you already know and use it to attack the other side's case. You're going over the same ground again and again, with nothing new, and inferring things that aren't true about the person making the other case ("choosing not to observe" - ad hominem), in an attempt to win an argument instead of shed some new light on a subject. Still interested in pharoahbq's 280Z thermostats, for the record, if the information becomes available in the future. And, if anyone is interested and wants to take a shot at it, the two questions about optimum engine temperature, and the mechanism behind the hot start problem.

Pretty sure (I hope) that we've been discussing EFI. Your 260Z carbs are a different scenario, I believe. Your 280Z's are interesting. Are they still EFI and do you have any details on the injectors, insulators, etc.? In all of the discussion, the mechanism of what actually happens hasn't been clearly defined. You're down in the DOE's national lab zone, maybe they get better gas. The thermostats have the temperature rating stamped on them, I think, along with the part number. If you ever get a look, post the numbers please, it will be one or two more data points.

I have to disagree with this statement. Units are irrelevant, they describe the same reality. It seems like the essence of what you're saying is that the purpose of the three choices of thermostat is to keep the oil above a certain operating temperature. Apparently, because radiative cooling from the block and the oil pan overpower the control by the coolant circulation and radiator, keeping heat in the block maintains oil temperature. Therefore, once you're above that temperature your next worry is overheating. Makes sense since the thermostat is really a heat-retaining device, not a coolant flow inducing device. The anecdotes from KTM and Grape Ape are interesting but, in my case, here in Oregon, I have zero over-heating problems. I just got stuck in 3 mph, stop/go traffic out here on a hot afternoon in the sun for 40 minutes and thought for sure that I would see a sign of overheating if I was ever going to, at least the Temp needle creeping a little higher. It didn't budge. I don't have overheating problems, no signs of nucleate boiling, no overflowing coolant reservoirs, burping or bubbling from the over-flow tube, none of that. Signs are that I don't even get any in- or out-flow from the reservoir (I've checked), expansion and contraction of the fluid seem to be taken up by the flexibility of the hoses. My cooling system seems to work perfectly in removing heat. I've checked my thermostat housing with an IR gun and my thermostat seems to work perfectly in retaining heat. So my only reason to go to a 72 degree thermostat would be to stop the heat soak problem. My system meets all other design requirements, oil is hot, engine stays cool. So I'm still at the question of what is the best temperature to run my engine? Since I like performance - both on the high end, raw power, and the basics like a smooth idle, clean-smelling exhaust, crisp engine performance - I would make a change for things like that. I don't see any evidence that the 72 thermostat will offer that. And I am sitting right where the Nissan engineers intended me to be, by their own instructions in the FSM. At this point though, I would make the change just to see what happens, but Nissan (Courtesy Parts in this case) doesn't appear to stock them anymore. They have the other two, by part number, but not the Tropical. I don't like the aftermarket alternatives and that would be mixing variables anyway, so I'm stuck until I find an OEM Tropical thermostat. Hopefully I'll find a decent source, and can take a look at any performance effects (tiny of course, from a HybridZ perspective) of running 72 versus 82. It will still be anecdotal, based on how things feel and sound, but worth a look. Where's the OP? He should have something to say by now... Edit - apparently the Nissan L6 Tropical thermostat part number has been superceded to 21200-F3160, for any future readers. Shows up as a 1984.5 Pulsar NX part on the interweb, but the dimensions must be right. Has 160 in the part number so the odds are decent.

Seems like we're just looking at two different ways to keep whatever fuel system component it is that matters from getting too hot. One is to run a cold engine (160 thermostat) so that residual heat doesn't transfer in to that component. The other is to remove the heat from the component (via the fan) as it is transferred in, before the component reaches the critical temperature that cause the "heat soak" problem. In choosing between the two you have to decide if running your engine at a cooler than design temperature all of the time is what you want to do to avoid 20 seconds of extreme aggravation. Or if having a two pound electrical/mechanical band-aid is the way to go so that you can run your engine at design temperature (assuming that 180 is design, and 160 is not. If 160 is design, then going to a 160 thermostat is obvious). Aside from proving points with data (if I had the cash flow I would have a scanner and simple data-acquisition setup in my garage and it would have been used already for this and other issues - but thanks for sharing, I wish I had something similar to offer), the question at this point is what temperature to run your engine at. I've never really understood the cool, normal and tropical thermostat options from Nissan. The tropical and cold options seem like band-aids for a limited cooling system design. In principle, the radiator, fan, water pump, coolant channels, etc. work together to keep the engine temperature stable at a set point, regardless of the climate. The thermostat determines what that internal engine temperature will be. You should change thermostats because you want the engine temperature to change, not because the external climate is changing. So, the evidence from the cooling fan and the thermostat experiments both support the idea that residual heat from the engine is the problem. Now, what is the optimum temperature at which to run your engine? If it's 180, then you need a fan or some other method to avoid the heat soak problem. If it's 160, then put the 160 thermostat in and avoid the complexity of the fan. Kind of how I see things. I don't know what the best temperature is to run my engine. Seems like Nissan would have made the 160 thermostat the standard if 160 was optimum design temperature and it removed the need for the cooling fan, for the ZX's. But, maybe it's just a simple emissions or mileage issue and they had to stay with 180 as the standard. Maybe 160 is better for power and longevity? An "Optimum Engine Temperature" thread could get pretty long, I assume, but it would be interesting.

Not specific to the original topic, but the Victor Reinz gasket is not cardboard, it's a thicker multilayer gasket. Another option. Plastic-y outer layer with a thin metal core. Quality isn't great, some trimming around the ports is necessary but it's different from the Fel-pro cardboard. I think it's the same gasket MSA sells. Harder to install because of the thickness and weight, definitely a different design. I've used the MSA gasket for about 20,000 miles with no issues, then used Fel-Pro's paper and had to retighten several bolts/nuts after the back of the exhaust manifold started leaking. I have a RockAuto Victor Reinz gasket waiting.

As for why different people see different effects, location could be a factor, as described below. We're not all using the same fuel. http://www.google.com/url?sa=t&rct=j&q=gasoline%20blends&source=web&cd=9&cad=rja&ved=0CGoQFjAI&url=http%3A%2F%2Fwww.gao.gov%2Fassets%2F250%2F246752.pdf&ei=SuPiUdrCHqr-iwLbmYCYAg&usg=AFQjCNEtVR2slSlQyHx6vqE68Uou0MnJag&bvm=bv.48705608,d.cGE Note the date - 2005. Who knows how many blends are out there now with ethanol addition. Here's another, newer, more general article - http://www.weeklystandard.com/articles/bureaucratic-gas_634424.html

Lots of interesting factoids listed there. But on my essentially stock EFI system, with N42/N42/N47 (intake/head/block) engine, and all the factory heat shields, new Nissan 180 degree thermostat (opened at 185 on the stove), new radiator, temperature needle rock-steady at a hair over center; the fuel rail priming and purging (new cool fuel run through it while waiting for fuel tank bubbles to stop) does not have any effect. It just doesn't do anything. The fan bandaid (fandaid?) has immediate and consistent effect. If I turn the fan on when I leave the car, it doesn't matter when I get back, 5, 10, 15, 20 minutes, doesn't matter. Get in, no priming, start engine, drive away. Just like a modern car. The only way it could get better, for my situation, is if I could find a decent automatic timer for a reasonable price. The hundreds of Asia-made turbo timer options look interesting but seem way overpriced for what they are. That's my anecdote and I'm sticking to it. Priming doesn't work, fan on injectors does.

I recall a difference in gland nuts between KYB and Nissan. My 76 had the Nissan originals on the front and I spent some time comparing the two gland nuts trying to decide which was best, when I installed KYB's. The Nissan nut just looked better, but it wasn't right for the shock. The gland nut is a precision fit on the top of the shock, centering it and giving proper pressure on the shock when tightened (sometimes with a washer needed). The OEM nut was looser. You could probably build a collar to make it work, but it's not going to be right without some extra work.

Weren't you the one that proposed that it was fuel vaporizing on its way out overheated injectors that was the source of the problem? Can't remember who said that. I didn't have luck with priming the rail either. But I did build my own injector cooling setup using a ZX blower and some GM heat riser tube. Air blown directly on the injectors, with a timer to keep the blower on from shutoff for about 20 minutes (the critical time period for most people). It was just an experiment but it worked so well that it's still on there and I always use it. I forgot to turn it on twice, in the winter time, and the problem came back really bad. Here in Oregon, I'm convinced that they use winter blend gas from early fall to late spring, and that's when it's worse. Fuel quality as the other half of the problem could be why the automakers all went up in fuel pressure from mid-30s to mid 40s and higher. I tried to find a low flow injector so that I could run higher pressure but didn't get anywhere.

I've had the hot start issue and noticed that my gauge was always up at the three quarter mark after sitting. But my radiator was fine. It's just heat soak in to the thermostat housing once the coolant stops flowing. There is also heat flow in to the injectors and rail from the block and manifolds. Changing your radiator based on what happens when the engine isn't running wouldn't make sense. The radiator isn't really in use unless coolant is flowing.

You're describing three things that might not be related. Oil burning, cylinder pressure and throttle response. Quarts per mile is a common indicator of wear. How much are you burning? In general, these engines seem to run well while burning lots of oil though, so your lack of throttle response is probably due to something besides worn rings. Oil-burning would come from bad bottom (oil scraper) rings, poor compression and blowby would come from bad top rings. The wet test will affect the top rings, not the bottom. Cylinder pressure numbers vary a lot due to all of the different gauges out there. One person's 125 is another's 160.

A few of us - http://forums.hybridz.org/topic/113836-warnings/?do=findComment&comment=1066123 SuperDan initially commented that Google was screwing things up but removed his comment. Maybe he found something. Seems to come and go, I got two notices, but no more since.

I wrote a whole funny thing about your excellent use of grammar to convey your lack of knowledge about your car and its engine but chose not to post it. Seriously, you write unusually well. Therefore: Find and open the FSM for your car from the link below and read the Engine Fuel chapter to understand the engine, and the Emissions chapter to understand the thing under the throttle body. Good luck. http://www.nicoclub.com/FSM/

Batteries take time to recharge. It's not instantaneous. Measure voltage while revving without the headlights on. Should be mid-13 to mid-14 volts. Or just watch the dash voltmeter before you start the engine and after. If it goes higher than it was at start, when revving, your alternator is working. If it just sits there, or slowly drops, you have a problem.

EF-7 has a diagram. You might find that relay and check it for power.

You only have 5 posts and none of them describe the engine or car that you're working with. "280 with a fuel pump hooked up to a switch" isn't enough information.