Tony D

You guys are reinventing the wheel, have you read the applicable FSM portions regarding the pressure limit on the fuel tank? When it's all set up like it's supposed to be, there IS a manometer reading that is applicable to the tank BEFORE the carbon cannister admits fuel, or the crankcase lets those vapors release for storage! By relieveing this pressure, you are DECREASING the ability of your fuel pump to operate at DESIGNED FLOWRATES! The fuel system is designed to take into account the head produced at maximum pressure before venting, and maximum vacuum before letting air be readmitted to the tank. If you alter this in any way, chances are good if you have a functional check of your evaporative emissions system for any sort of emissions compliance, you will fail. You are making a MOUNTIAN out of a Molehill. This is a non-issue! All EVERYONE in this post has done is give SUBJECTIVE OPINION! Put a GAUGE on the gas tank, and MEASURE this "massive pressure" and QUANTIFY it before you start reinventing the wheel! You guys are literally messing with fire? Wh is this such a big issue?

What am I missing in the translation here? Why .6 instead of 1.0mm?

The hose is a 15mm CONDUCTIVE rubber hose. -8 will work fine for it if you need it, -10 would be an appropriate size (and technically correct, as well). Tap the hole, it's easier, the thread on it is a very fine obscure metric equivalent like the banjo bolts in Weber Carbs or the water lines on the turbo.... But a nice NPT runs right down there and solves that problem. So does any of the positionable MS-Jamnutted fittings, as well!

Yes, it makes more sense now. From your e-mails I couldn't figure out exactly what you had. Make sure you have the pullup resistors in the circuit, especially on the dissy/cas unit! You can read that signal during cranking with a good meter set to 10VDC. If you got it going in, you will have it coming out. Then you only have to wire that output pullup to make it see the difference in voltage to trigger the HEI unit. I got my pullups at Rat Shack. I told ya if you asked here they would get you squared away. Hell, I'm still on Magnus' MS-n-S! I haven't sloved those gremlins, so no sense in going to "E" yet! Man, idled it for an hour yesterday...Long as the alt doesn't flash and charge, it runs FINE! Damnable filter circuits...

Watch the failure rate on NOx. That compression with standard spark advance will make loads of NOx. Make SURE your EGR system functions properly, and that you have good riser and gallery cleanlienss. Any obstructions in the EGR riser, Valve, or gallery under the intake manifold can cause a failure on NOx---the good old days of turning the spark back a few degrees to pass are gone---more than a degree off and you fail! I agree, get a pretest before you do anything else. I have a car in the back yard right now that the guy sold because it got tagged "Gross Polluter" when it failed the NOx portion of the dyno test, as well as the functional test of the gas cap (cap missing, durrrr!). A needless tag, looks like they suckered him into the "cold cat test" where they don't adequately light the cat off before running the test. Car passed CO and HC, but failed NOx, could be an EGR riser plugged as well, but there was no need to get tagged "GP" on the test!

My eyes were opened this past trip to Europe where I found the Euro Turbo cars DO NOT have ECCS! They have a special pneumatic retard cannister on the stock plain-jane ZX Dizzy, and run what looks to be an N/A style ECU. They also do not have the Air Regulation valve for idle speed, just a conventional idle speed bypass, a factory blocked EGR, with a downpipe with no casting for the heat riser nor O2 sensor! Rated at 200hp, they also have a straight pipe with no catalyst... Lucky bastards! You can change the drive assembly on the bottom of the distributor to mate with the earlier simple slot drive, but you will have some timing scatter fro the increased lash there---not what I would do. E-Bay usually has this kind of stuff in abundance.

Mine's exactly where Warren's is, in the space behing the T/B, right behind the throttle shaft, no airflow disturbance there. As for mounting it before the turbo, if you are intercooled perfectly, or even decently, it "shouldn't" make that much a difference. But on a stock setup, you will have some serious density issues as the intake air on even a 60F degree day can be 20 to 40 degrees hotter, depending on speed. I'd not recomend that position to anyone.

The stock setup in the car is VERY good, a bit TOO good actually! Under boost, the crankcase should be evacuated with the restriction the filter causes before the turbo, under vacuum the stock PCV can be restricted to .080 or .063" orifice to prevent too high a vacuum acting on the crankcase and sucking oil up into the inlet. Adding a supplementary breather box is a good idea, but as long as your rings are intact, the crankcase should never be more than -4" Water Column of pressure. That is more than enough to evacuate everything you want.

Cam, you can get 350 from those 440's by running a tad more fuel pressure. JeffP went to 415 on 440cc injectors and a 4 bar fuel pressure setting at idle. But you gotta alter the fuel delivery (read "standalone")...

Please make constructive commentary from your observations, bj, or make no commentary at all. If you would have read the posts, you would have seen I deliniated the difference between an impeller thrust failure---which is so obvious any moron could diagnose it (case in point)---from cavitation damage which most people do not know about. Nobody said every failure was caused by cavitation damage. Though you seem to imply that the most common cause of overheating is cover damage from failure of the pump bearings "catastrophically" -- causing impeller contact... Funny, I have never had any of my L-Powered vehicles do that---so that says a lot about your maintenance powers of observation compared to mine. (Just something to think about...) Man, you have issues, please sort them out before posting usless barbs and counterproductive things like that last swarf.

"I am struggling with the concept that the forces present during cavitation within the Datsun water pump are strong enough to “mine” the aluminum from the front cover itself yet does no damage to the impeller blades, i.e. bent, broken, pockmarked etc." I have seen cylinder liner failures from ductile spuncast iron due to cavitation damage! I could take some photos if I wasn't like 7000 miles from my "example liner" (now a convienient trash can!). Many times the cast iron blades will be cavitated and erroded as well. Errosion due to electroylisis is a concern, but steam pocket formation within the head can ruin it for sure. It just has to happen consistently enough. in the head it happens at a different time than in the waterpump. In higher-pressure applications, water erosion channelling can eat a stainless steel hardened impeller win less than 18 hours of operation significatnly affecting flow! As for an L24 without a secondary external bypass line---no such animal! You may be missing it, but it's there! Even forklifts have it. Some engines are designed with a totally enclosed bypass hole----but the Nissan L-Series, like the Mercedes engine it was originally licensed from, both have dual circuit bypasses. When the secondary line is removed, the only way to insure no cavitation is to slow the pump at idle (larger pulley on pump) and keep the revs low until the thermostat is opened enough to accomodate that flow. Braap, your observation of the 1/4" hole in the thermostate is probably about the minimum flow requirement so there isn't any problems. (Done by the racing team you mentioned above) this is another method for keeping the minimum flowrate through the pump while the thermostat is closed. Makes the engine slightly slower to warm up, but provides the required minimum flow to allow operation of the engine when cold, and the thermostat is closed. Remember on a racing engine, people aren't starting it cold, and then driving away revving it to 3000 rpms 30 seceonds after the car is started! They will start it, idle it, maybe run it at fast idle to warm it faster, but no revving of any consequence takes place before the engine is at least moderately warmed. The street in this instance is far moreabusive than the track will ever be! Someone starting their car, then driving off and up to freeway speeds within 2 minutes is a prim canidate for cavitation for 30-90 seconds every morning he does it. Now it may take 1000hours of this cavitation to actually perforate a block, or other cast iron component, but a mazak die-casting will get eaten up quite handily under those conditions. My "P" for the "A&P" was completed in 1986, but never finished the second phase of thetraining to get the Airframe certification---so much for "Military Training Opportunities" But afterwards there was more time to do things related to Powerplant Maintenance since I was lead at a 5MW (6.6MW Gross)LFG Recovery Site---when the Steam Turbine end of that project fell through I decided that being in Management and having your project pulled out from underyou was not a position I wanted to be in, so in 93 I traded off to OEM Field Engineering dealing with large stationary Air and Gas Compressors. My SAE subscription lapsed long ago, I really enjoyed the papers to keep up to date with technology and mandates, so that probably answers the rest of the question pretty much, eh? Having grown up in Michigan, and gone to school there, I know many classmates who went to GMI, or ended upworking for hte Big Three, and we kept in touch regarding a lot of stuff---since we all "tread the same water" as OEM reps in many cases, war stories and "inside tales" invariably get brought up. We all laugh at our collective human stupidity (or, probably more correctly, some customer's stupidity! I mean, when I have to field a call from a "Degreed Engineer" who goes off the handle because _this is an actual quote_ "Pump? Pump? WHAT PUMP? NOBODY TOLD US WE NEEDED A PUMP!" Er, Is it a Thermal Siphon? "Huh?" Er, yes, sir, er...you need a pump to provide 2.8 GPM for the heat rejection requirements of the Oil Cooler!) But I digress... Your last paragraph is probably what sums it up the best. As I said above, the drilling of the thermostat is an alternate function of the same thing. Something must allow not only minimum flow for the impeller, but must also allow the thermostat to get sensing the actual heat of the engine. This is one of the reasons I get so upset when people cap that bypass line off---exactly as you stated, if there is only flow through the backside internal orifice, the only way the thermostat gets hot water flowing over it is through conduction! This leads to a bad temp spike on initial startup internally---but rarely shows on the gauge due to reaction time issues. And once the thermostat gets opened, it slams open because of the rush of superheated coolant rushing past it that was resident in the head being recirced... I would venture to guess that 95% of the people who are posting on the topic saying they have no bypass, have made on alternate provision like drilling the thermostat. That your engine builder did this says loads about his understanding about the functions and importance of the minimum flow, and what's required for a quick reacting thermostat. Now, if you want to get into something really interesting, do some research on reverse-flow cooling! Where the coolant flows into the head first, then down the cylinders. Greatly decreases heat temperature, helps with cylinder bore sealing because there is a more even heating of the block, and the thermostat is continually bathed in hot coolant. I was involved in a reverse flow Pontiac Trans Am when I was in School, very intersting results. And curiously Chevy changed the coolant flow in their latest SBC Design. This was based on testing and R&D done back in the late 50's and early 60's, but wasnot widely known or publicized until the mid-late 70's. But again, I digress...

Lurch, how far down in the post did you go with reading? Did you get to the very end to see the other photos, and not the Diesel Manifold? On left, 38/41 from L28E, on right, something like 26/38 from L20E

Yeah, I go down and read em, and reply. Each comment has a specific reply, wouldn't want to group them all together, and insult anyone or cause the possibility of cross-talking between who said what when... Besides, what else do I have to do? It's freakin' LIVERPOOL (and that is shouting!) for gawds' sake! Rainy, dreary, cold.... Eh, it's 9pm now, guess it's time for a couple of Pints 'o Guinness, and the rack... On the upside, I got to take a ride home today in a Lotus Elise! :^)

Just an aside, now that we've separated governmental mandates, and equipment that the Z was actually designed to have---I mean, am I totally off base in the arguement? If Nissan could save the money by leaving it off, ask youself the honest question: "wouldn't they?" I mean, EVERY engine designed for passenger car usage has a bypass line to prevent cavitation of the pump and it's pump cavity during times when the thermostat is closed, and the flow from the centrifugal pump is restricted below the flow curve for the impeller used. That is the real reason for the bypass line---the "piggyback" usages of it for manifold heating, etc etc etc are one of those things that engineers do when they say "well, we have this line here that can be rerouted"... I mean, if you plug off the second bypass, does the internal bypass flow enough water for the pump not to cavitate? You are effectively halving the flow through the pump during the warmup period. This post has gone a long way towards revealing a lot of people's understanding of the workings of the Internal Combustion Engine, that's for sure. Some people even mentioned damaged housings relating to overheating---ever notice a "pockmarked" front cover in the water pump impeller area? An area so erroded it looks like at some time terrible corrosion had occurred, yet there is nothign there when you pull it apart but pockmarks in the diecast? Care to venture a guess what the evidence of pump cavitation looks like? I'm sure it's not the same circular gouging that occurs when an impeller thrashes the casing----but then again you wouldn't notice it if that's what you thought caused it, would you? Or you would simply thinkn "corrosion"... Never "Pump Cavitation During Warmup"---when you know what cavitation looks like, you can identify it. And when you know cavitation is caused by a number of things, including too high incoming fluid temperature, insufficient flow, low NPSH....well you can see how these things can feed off one another. If you halve the flow coming in before the engine is up to temperature, you can get low NPSH while at the same time having an inlet temperature (that, while at a higher flowrate for the impeller would not cause a problem) that is high enough to cavitate the pump. Curious, slowing the pump down helped prevent overheating... Could that have been because slowing down the pump speed dropped the flow rates back within the design pump curve, and allowed the pump to operate without cavitating (which causes a flow loss, as well...) I may know what I'm talking about after all. Though feel free to disagree, and do as you will. It makes no whit one way nor t'other to me. I just find it funny to read this stuff sometimes. I really do.

That's uncalled for bj, and is simply an extension of your ranting elsewhere. I never said everyone else is wrong, nor have I said I am right all the time. Though, you seem to have issues with reading comprehension regarding the other matter. I live in a world where more than one person can be right. But then again I'm not insisting anything. There can be two sets of facts that each are correct. If you fail to see that, or comprehend that, then I feel sorry for you. Hell, I even found Zane's "Lion Rock" comment hilarious! I'm going to use it myself. Probably in response to a post by you in the near future. Lighten up, dude, quit taking yourself so seriously. I do.

I don't think I did that in the least bit. I emphasise certian words, perhaps I should edit it to use italics, but caps on a word actually conveys the way I speak. Anyone who has talked with me, and heard me speak will know that I will emphasise words with a raised tone. Not yelling, but there's no "half caps" unless I type a bunch of HTML in there. Not that I wish the emphasise Hyp...er, 'html in caps'... Oh, wait, this is being P.C. now.... Would everyone feel better if I went back and edited my post to italics or bold italics instead of the caps for the individual words? I'm not typing in allcaps, only certian words. And to the point in the post, many of the things you mentioned were mandated by the USEPA (er, acronyms are O.K. to capatalize, right? and O.K. is O.K. to capatalize as well, right?) and Nissan would have loved to run along without them. Matter of fact, in most markets outside the USA (er, USA is O.K. to capatalize, right?) these terrible abominations did not exist on the S30 series. But one thing remained constant: the bypass line from the lower thermostat housing, to the pump inlet to compliment the internal bypass line on the oil filter side of the engine. It was available, and present in every market. Please don't confuse a component designed by the manufacturer, and one dictated or mandated by a govermental agency! Remember the Honda CVCC was required to run a catalyst in 1981, even though the engine, due to superior engineering and design, met all required emissions criteria set forth by the USEPA. The EPA mandated EGR, they did not leave it up to the automakers to come up with their own, unique pollution remedies. So please, remember things on an engine may be there from the manufacturer, or from the government. The Thermostatic Bypass Line is not one of them. It's on SBC's from the 50's... Now, as to this: "On modern throttle valves, early ‘80’s and up, Nissan also added a coolant port to the throttle valves thus pumping 185+ degree coolant through and around the throttle valve. In fact, most, if not all auto makers are also doing this. (We tuners prefer to NOT preheat the incoming air charge)." While you may not like to preheat the charge, the automakers do, due to the litigiousness inherent in the system these days. Throttle Icing---serious throttle icing, is nothing to sneeze at! Having gone through an almost tragic incident involving my throttle plates being blocked 1/4 open due to throttle icing, I tend to run a bit of preheat... This was more of an issue on carburettors, but it can happen at low throttle openings on EFI cars as well. Would I recomend removing the preheat line? Probably... I would also inform the owner why I was doing it, what he could expect in performance gains (er...minimal) and the oft chance that his throttle might stick partially open in some combinations of ambient temperature, humidity, and manifold vacuum situations. Does this have anything to do with water pump cavitation and the bypass line? No. But it does illustrate a point: Know why it's there in the first place before you go disconnecting things willy-nilly because someone on the internet said it was O.K.! Many people have grave misinformation about why some components are on the vehicle in the first place, and they are the dangerous parrots who squawk myths and legends and turn kids round the wrong way when advising them on this great internet medium. Once people know why a component is installed, and what it's function is, then maybe they can make an informed choice about it's removal. But to just cap it, or yank it out....well whatever floats yer boat I guess!

Sure enough does---comes from under the thermostat, thorught the heater block in the throttle body, the heater block under the Cold Start Ari Vavle (whatever it's acronym is) then returns via a 10mm line around the front of the engine to the inlet of the water pump through the fitting that is vertical in the inlet to the pump.

I opened an access panel once, and literally had the failure occur at THAT moment. As I pulled the panel back, something went FLYING out missing my laft hand by inches, and a terrible racket ensued. I dropped the panel, my helper and I ditched and waited for everything to come to a stop (which, with that flywheel took a while...) It is very disturbing when you see big dents from INSIDE a piece of equipment while hearing it come apart. The thing that flew out? The entire piston/cylinder/rod/head combination, minus most of the rod cap, and one pushrod tube... Blew right off the gearcase, and flew away. We found it by the trail of oil it left on the clean flowthrough parking area concrete. Oh yeah, it was a long day at safety... Until that VERY moment, that very exact, specific moment, I was trying to figure out exactly how to make that engine fit mid-engined into my 62 Microbus. It ended when I saw that. Similarly, the usage of the -60A GTC Turbine powerplant and gearbox reducer in the Z was the next thing I moved onto....until one of those chucked an exducer up through the roof of the hangar, and out onto the flightline one day. It was then I decided to do safe things like Land Speed Race instead...

Brazing John! BRAZING! Make a VKA48!

I never said they got it all right. Chevy has coolant internal recirculation, Ford does, Chrysler, everybody does! And the "small hole" is not the same thing as the internal bypass. The internal bypass casues a quick warmup and gradual heating of the coolant mass, rather than a prolonged warmup that would occur with a 3/8" hole in the theromstat. Every manufacturer used coolant bypass for warmup, and for other reasons. Not one doesn't use it. Yet, here we are again, with someone talking anecdotally about it never causing any problems (that they can see---have they even looked?) I mean, I got to ask why every single manufacturer in the world used that kind of bypass system--at added cost for external plumbing in almost all the cases, when they simply could have deleted it and saved millions of dollars? You have to admit the car companies aren't in the business of leaving beneficial things in cars (oh, like power) unless there is a price increase. What makes anyone think this is any different? Why would they put it there if they could stuff that hose money in their pockets? Nobody has answered that question about the charity of the Big Three and everyone else giving us these little coolant bypass lines all over the place. I have seen firsthand what coolant cavitation does to cylinder liners, and it's not pretty. You can eat through a casting, literally! Steam impingement is a bad foe...

Obviously you have never witnessed a failure of the cylinder mounting studs on that Lycoming. If you had, you would seriously reconsider the project. Put it in an Air Boat, instead, then when it goes, the debris flys around BEHIND you! This is a hopped up version of the Continental Packette PE175. They sound pretty good, but water cooling? Forget it! They DO make a flywheel mounted fan conversion for these engines in stationary generator usage (probably out of the inventory by now, the units I worked on were being converted to Diesel quickly, and that was over 20 years ago now!) Problem is, the fan is 3 to 4 feet in diameter. Not your quickest revving engine... You want a 400HP Air (Oil) cooled engine for your Z that packages MUCH better? Go pick up a 930 Turbo Porsche engine.

Did Rebello plug the internal passage on the oil filter side of the block as well? If not, why not? But it's internal, and nobody knows the answer---my bet is the did not plug that internal bypass. The external bypass is a balancing act, because the internal bypass hole is a "dead area" in the head when the thermostat is opened, and it will boil!!! If the thermostat is closed, thethermostat side of the head is a dead spot, and it can boil! Steam is not a good coolant. Incidentally, steam makes a great heat transfer barrier... N/A really isn't that stressful when dealing with cooling systems anyway. Make twice the HP Briann is, and see if the cooling system is still up to par. Like I said earlier, Nissan put how many hundred-thousands of these bypass lines on, all unrequired on a street car---they just wasted their money because they like to use odd-bits of tubing and hose... C'mon, I'm not buying it! If they could've left it off and saved a $$$, they would have, the US Spec 240's didn't have Splash Guards or Fan Shrouds for gawd's sake. You think something that could be deleted worldwide across the entire L-Engine line would have been deleted if it was so unrequired!

that is what john is betting on... They are from portable diesel compressors, and we are binning the engines on three of them, hence the availability of six turbos nobody will miss! Unfortunately they are a bit much to handle in my checked baggage when I return to the USA. And after what the bastards did to me in Newark raping me and stealing my Differential Coolant Pump (TSA IDIOT, thank-you-very-much!) after three continential crossings, I don't trust those bastards further than I could throw one of their portly countenances...