technicalninja

Most amp meters apply all of the alternator output through the meter and the early 240Z versions could handle 45-50 amps of flow. Alternator out put was run up to meter and then to rest of car. Late 73/74 cars had a very complicated shunt system that did not run total power to gauge. This system was not accurate and had reliability issues. The problem with running an 70-73 amp gauge is that you Z31 alternator (and the rest of its wiring system) is set up for 80-100 amp alternators. Putting in a 240 gauge will cause major system restrictions and it may damage alternator or cause wire harness fires. A 75-78 Z voltage gauge may be a better choice as it is close to same look with out the added issues of a true amp gauge. Voltage gauges just sense voltage levels (ie the "flavor" of electricity) Amp gauges measure actual output. Volt gauges will function properly regardless of the total output of alternator. The 73-74 shunt systems were hard to get to work properly on the stock car. I imagine retro-fitting this system to a Z31 would only make problems worse as it was also calibrated for 50 amps. Replacing the Z31 volt gauge with the 280z volt gauge is easy. adding in the amp gauge is very dificult. Hope this helps Rick

The Motorsports kit I installed on a customer's car had two sideplates which bolted into each ear of the shift mount (very narrow heads to allow the shifter to clear them). This moved the shift pin point up 25 mm. The kit included a new Nissan shifter out of ? and a weighted shift knob. This kit shortened up the pattern too much and it increased shift lever force to the point it was annoying. This mod only changes fore and aft stroke and does not "narrow" pattern right to left. This kit fits all 4 speeds and the before 80? 5 speed with the short ears on the shift mount. Later 5 speeds have extended shift ears which this kit will not fit. These extended ears allow you to redrill the shift pin hole higher up yourself. Two styles of extended ears were made. Short extended ears which will allow a hole 10mm up (79-81?) and the long style which can probably stretch a 25mm gain (82-83). I one I have built I drilled at 10mm up (limited by shift ear) and I cut the shift lever just below the "ball" section and added a 10 mm spacer (used dowel stock) which I had welded in. This shortened the pattern some and the shift lever force was fine. I think 15 mm would be a better choice but it requires the long ears. The shift mount tube must be removed from the tailshaft housing and the new pin holes drilled with a drill press all of which is somewhat difficult to do. 77-83 shift mount tubes will interchange. The Motorsports kit had a small amount of slop (shifter was floppy) in it as the ear extensions could move around a little. the redrill set up felt like stock Nissan with a shorter pattern. IMO the redrill set up is superior to the Motorsport kit as it is stronger cheaper and requires no added parts but the Motorsport kit can be installed by just removing the console. The redrill requires at minimum a tranny removal. You can put a slightly longer shift lever in the stock position (3 or 4 mm) but the 10mm stretch I built really needed a bit more so I don't think you would notice a 3-4mm stretch. If you have the early short ears the kit is your only choice. The "shortened" shift levers that are commonly sold (see one on E-bay all the time) just shorten the upper section which does work but by the time you get it short enough to make a reasonable difference the shift lever is too low in the console. Hope this helps Rick

Be interesting to see if this ends up in the trash. It doesn't look like it can ever be resolved and only fuels passions. I was under the impression that ANY Z with ANY engine was what this board is about. It is the only Z board for me and I will cheer any Z owner above all else, X or not. A suggestion- When you read something that makes you angry wait at least 3 hours to reply back to it. By that time your post will be something you do not need to edit later. Keep it civil Rick

Dan Judy's comments apply to Texas just fine but it will not be the kid's mother's lawer that will get you. It will be the lawer for the family in the minivan he hits. I am a 20+ year Z car freak that has 3 boys, the oldest 14 and just two years away from driving. he will not drive any of my Zs on a regular basis (or alone). He will have some un-inspiring air bag equipt beater for the first couple years as cars are killed by begining drivers much more frequently. He will not like it but he will survive and learn to drive in a car that can be thrown away with out a care. He will get to drive the Zs with me and to race them if rules allow (drag/solo) At the type of money your asking they should be able to afford a car with multiple saftey features and be very reliable also. Not saying your car is not reliable just that a mid 90s Accord/Camary type car is more reliable than a mid 70s Z. Is there a good reason he needs this car? He may not be able to get insurance if he tells his insurance company whats been done to the car. On a more basic note- After 20 years in the automotive business everytime I get that weird feeling (I call it my Squirrel-ometer) I listen to it. Everytime I haven't in the past I have paid some price. When the squirrel-ometer pegs over I get out NOW. Your Squirrel-ometer made you post this on this board. Listen to it! Later Rick

The picture in the Motorsport catalog is of an ATK motor. The ATK distributer in Dallas 19 years ago was Passport Engines. I worked for Passport as the warranty manager. I would go to the shop which had installed the "problem" ATK (and Vege-the european counterpart to ATK) engine to diagnose the problem. The ATK engines were the best rebuilds that I have ever worked with. Very seldomly was ATK at fault. The problems were almost all ways caused by an installer NOT cleaning radiator or NOT fixing a fuel system issue or NOT fixing the THING that caused the original engine to fail. The actual failure rate was extremely low, about the same rate that I saw factory engines fail when I worked for Dealers. Back then the engines were being rebuilt in Japan and most moving parts were being replaced. We had problems getting any Japanese engines larger that 2.0 liters because their tax laws penalized cars with larger engines and the cores were being sourced there so the 280 stuff was rare. I haven't been involved with ATK since leaving Passport and do not know what their build qualilty is now but it was GREAT in 84-85. I would check atk-engines.com One of the nicest aspect of the ATK was the fact if an engine failed under warranty ATK would pay labor to the installing shop to repair it. When I worked for Passport it was good for 1 year/12,000 miles. Now the warranty is 3 years unlimited mileage at any shop nationwide. This says something about the rebuilder! Now, IMO this warranty would be considered void if you take it apart to make preformance mods to it. But if you are looking for a well done stock engine then the ATK will work fine for many years. I just checked their website and it shows 1695 + core. (they still can't get cores in Japan) Back in the 80s ATK set the "retail price" and the distributors could sell the engine for what ever they wanted. I think that "wholesale" price on this today would be 1400-1500 and you may want to call around to see what you can pick one up for. The engines came from Japan in a very nice crate (I still use some of the base pallets today) and with all gaskets needed to install it. They were a very good deal back then and were nicely detailed as well- No Aluminum or Cast spray paint, no overspray paint on aluminum castings, no bad runs in paint. Maybe more nicely detailed than orig factory. Good stock stuff put together right that looks nice and has a killer warranty. If you are thinking about Hi-Po engine mods the the 1500 would be better spent on rebuilding a core. Core 280 engine should cost 100 and 1400 can buy most of a good rebuild. This is assuming you are assembling it yourself Hope this helps Rick

Dan is absolutley right! I've been wrenching for 20+ years and always duct tape the gauge to the windshield (outside!) on customers cars that I am diagnosing for F.I. issues. It sounds like you want to permanetly mount a gauge which can be very useful for tuning and monitoring. This is amost neccessary for a max effort turbo engine. Having a gauge permanetly mounted in the engine comp that can not be seen while operating the car is almost useless and not worth the cost. The solutions are Mount a mechanical gauge on a bracket sticking out of the hood rear parting line (or possibly through the hood). This is often seen on bracket racing cars. The gauges are hard to see and ugly hanging out in the breeze. They also represent a fuel hazard. Using an isolator- These critters isolate bad things and keep them out of the interior. Two styles available Mechanical. - Used with a mechanical gauge, Installed between gauge and F.I. basically a fixed volume system that allows the fuel pressure to push against a diaphram which applys the same pressure to the isolators fluid- usually a thin oil. Line from isolator to gauge is steel, aluminum, or hard plastic and can be difficult to route. Diaphram unit is installed at or close to fuel source in E comp. Electrical. - Changes fuel pressure into an electrical signal close or at fuel source. Requires Electrical F Pres gauge. Very easy to install. Plumb isolator into F.I. Run wires to gauge inside car. Much more expensive and far less accurate! I dislike electrical gauges. The change to an electrical signal tend to smooth out the signal and you are seeing an "average" instead of a pure signal. IMO electrical gauges are reading a "range" and although movement within the range are accurate the markings of the range (on the gauge face) may not be. Often times a sensor signal is digital which further averages the signal. Often the readings are digital which I hate! When watching E.F.I. fuel pressures how fast and smoothly the pointer moves is important to me. Watching how the needle of the gauge darts around can give you as much diagnostic help as the pressure readings. Try to watch a digital tach at WOT. Analog swept pointer gauges can usually be installed clocked so that the needle points straight when readings are the best. When you have multiple gauges all clocked this way your dash will look weird but during operation you can spot problems earlier and have less distractions. A quick glance lets you see if ALL pointer are pointing the same way. I've seen race cars that had their gauge markings blacked out to further reduce distractions. Digital requires you to focus on the gauge and take your eyes off the road. Tap into fuel system between fuel filter and fuel rail (on engine). Common brass tee with 5/16 barbed connections will work. Make sure you F.I. hose is in good shape and not old (old stuff some times cracks soon after teeing into it). My test rig is nothing more than a 6' peice of F.I. hose connected to one of these tees and a simple mechanical gauge. Close hood only untill first latch and duct tape to middle of window. Good duct tape can hold a gauge at 100+ mph! but don"t leave it on long. Baked in the sun it can form a epoxy like bond to the window that is hard to remove. You can install the isolator anywhere in E comp but I suggest the right side fenderwell close to fuel filter to keep pressurised fuel lines short. Use teflon tape on all brass to brass connections. (barbed ends into tee). Any gauge install should be checked for accuracy by a known good test gauge. IE use a real thermometer to check coolant temp gauge accuracy. One last note. The faster ,more accurate, mechanical gauges are usually much cheaper than the electrics. Hope this helped to answer your question. Rick

When I worked for Cartech in the early 80s one of the kits we sold was a blow through triple Mikuni set up which was very complete. It included all manifolds, turbo, carbs, intercooler, bypass valve, external waste gate, higher pressure fuel pump and boost sensitive regulator, down tube, air filter, all intake tubing, and a host of small parts. It was very expensive in 83/84 (approx 5000.00) but made 350-375 hp with excellent reliability. The Mikunis were the best carbs to use as they required the least amount of modification for a blow through application and required less 'tinkering" to keep in tune. The Mikunis worked pretty well up to about 15 psi and suffered fuel leakage issues above 15 psi. This system is pictured on page 103 of Corky's book "Maximum Boost". This book is a must-read for anyone considering modifying or designing a turbo system. The book is not car specific. It is theory specific and will answer most turbo questions while giving the reader a good basic understanding of turbo systems. Chapter 8 is devoted to carbs, both draw through and blow through, and adresses the special problems associated with them. Blow through triples can and have worked but it takes extreme attention to detail and proper engineering. F.I. is the way to go unless you have to have the "Triple Look". F.I. will be cheaper (maybe not at first but in the long run), have a greater adjustment range, require less maintenance, and produce more power IMO. The same aftermarket brain (laptop programmable) will probably support any engine you can put in the car (rotary, 4, 6 or 8-NA or blown). Although they look great the TWM peices will not make their value in EXTRA power and give the buyer back some of the problems of the triple carbs (more places for a boost/vac leak, syncronizing linkage, etc). The wonderfull triple sound is greatly reduced when a turbo is involved. I believe a stock intake plenum with a 60 mm T-body and minor port work can support 400 hp + and will prove very user friendly and be affordable. Your current engine might work with a P series head. If you are at 11-1 now the P90 should knock it down to 9.1-1. Mild chamber work should get you below 9. My suggestion would be as follows P90 head: mild chamber work, port matched to intake and exhaust, stock cam L28 intake: 60mm t body, mild porting at t-body and runner exits L28 ET: exhaust manifold, mild porting at runner entrances and turbo flange. Alternate injectors and fuel rail. Many types available High flow fuel pump and regulator. Stand alone EMS (engine management system-MegaSquirt to AEM- many different types and styles available. try to get one that controls spark timing also) T3T4 hybrid turbo (I like the T3 stage 3 with a T04E-50 compressor). Air to Air intercooler (700 cfm- less than 1 psi restriction). Minimum 2.25 inch intake tubes Good exhaust system (2.5 will work but 3 inch is better- all mandrel bends) Properly tuned this set up should make 360-385 hp on pump gas (93) at 14 psi and 425 plus on race gas at 18-20 psi. These figures assume the lower end is built properly and forged pistons are used. Cast pistons will actually work but I don't think they will last very long at 425 hp. I also don't thick cast pistons will last long in a 11-1 L-series N/A. Although I am a Nissan guy and like the L-series the Chevy small block/LT1 may be cheaper and provided same hp with less complexity. Changing to a V8 also allows you to sell the entire L-Series engine which should further reduce the cost of the Chevy. I believe the upper limit (within reason) of L-series power is 500hp and the Chevy is close to 1000 (both engines would be maximum effort turbocharged). this means your 425 hp Nissan is close to the limit and when failures occur they will tend to be catastrophic where a 425 hp Chevy is much less high strung and may be more dependable. Further mods to the Nissan will be far pricier than further mods to the Chevy. The V8 conversion helps the resale value of the entire car better than the blown 6 cylinder IMO. Well There's my ramblings on this subject Hope it helped Rick

Searching "T56 L28" returns 3084 matches. This does not help anyone. It seems that some times the search function causes more issues that it solves. BradMan- If you know of a thread that just deals with L28/T56 please point everyone in the right direction. Thanks

Vacuum pump is not a requirement. Good 1 way valve is. Stock 1 way valve in 280Z is acceptable. adding a secong valve at intake can help. Make sure valves are in correctly. Vacuum should be present beyond the valve when engine running. Find out which side of the valve you can suck air through (part disconnected completly from car) and place that port towards plenum. The FICD opens a passage between the plenum and the hose you have blocked off. Set up this way it will not work. The additional air has to come through the blocked off port. It should run up to a T in a larger hose that is part of the auxilary air system. This line can actually be plumbed into intake between airflow meter and turbo inlet. The FICD is not a vacuum source. It uses vacuum from the vacuum tank plumbed through one of the solinoids. This solinoid will only operate it compressor is on. If system does not have enough freon the pressure switch in receiver dryer will not allow the compressor or the FICD solinoid to operate. Get a Nissan SM for your car if you can. The factory ones are very good and it will save you money in the long run. Most aftermarket SMs are not any help except for basic repair. Rick

Two styles of "factory" air can be found on 74 260s. The Dealer installed air and the system that was actually installed in Japan. The Japanese system has rubber hoses ONLY at the compressor. All other lines are hard copper/brass?. The Japanese compressor (Hitachi) was round and located on drivers side of engine. the Dealer installed compressor was a big square York mounted on passenger side of engine. The Japanese reciever dryer had hard lines going to it and usually had a pressure switch mounted in dryer. It may be NLA. Autozone is not the source for this. Nissan or specialty Z parts source is. A/C supply store may be able to match something up The dealer installed R/D has rubber hoses to it, normally does not have a pressure switch in it, and will not show up in anyone's parts book for a Z. It is a "universal style" and needs to be matched at the store. It was used in thousands of applications and is the most common of all early aftermarket A/C parts. If you need this type it will be readily available and should be the cheapest R/D in the store. Store your R/D in the refridgerator (low humidity) and do not take caps off of it until you are ready for install. I have the vac pump attached to system before I connect R/D and immediatley pull vacuum after R/D installed. Save caps in tool box! Later- when you need to break into system again remove R/D first (after recoverering freon) put caps back on and stick it in fridge for storage. Put it with the beer. Your friends will wonder if you've gone crazy. But you will be able to use it again. You mentioned fresh PAG on threads. Have you changed over to R134? A brand new reciever dryer will fully saturate in 1 day exposed to atmosphere (probably take longer in Arizona and shorter in Hawaii). It is a water removing filter. A/C systems cannot stand water in them. Any water will freeze inside of expansion valve reducing cooling drastically. Moisture will contaminate the oil running through system and form acids as a byproduct. Initally the system will appear ok but just like the early Z rocker panels by the time you notice problems the entire system has been effected. I would not accept a R/D that was not sealed or looked like it has been sitting on shelf for years. Many people think when a system is put under vacuum we are trying to remove all of the air from the system. This happens in the first minute. The real reason we pull a vacuum (and leave it under vacuum for 30 min +) is to boil the water out of system. The deeper the vacuum is and the longer its applied both affect how well the moisture is removed from the system. If you are reusing a old exposed R/D store it uncapped in fridge for a few days then pull a deep vacuum and leave it on for a long time (5+ hours). It may help. I was able to use a Subaru R/D for my factory 78Z but it is different than a 74. if you have a Japanese system take R/D to an A/C supply house and try to match it something. Nissan wanted 100+ for mine, Think I got it for 45 Good luck Rick

30 percent sounds right to me or maybe a little more. The problem will be R134 works at higher pressures than R12 and the R134 molecule is much much smaller than the R12. R134 requires "barrier" style hoses to stop leaks. Standard (R12) hoses will work its just I get tired of constantly recharging system to keep max cooling. Lose just a little R134 and the system gets warm. Never needs a full can to get it back to temp. Can be annoying. Because of the higher pressures the compressor (used) is stressed harder that its ever been and its internals and seals have been soaked in R12 oil which is NOT compatable with R134. R134 compressors are more "robust" internally and designed to work with operating pressures 20 to 30 percent higher than R12. Another problem is that the R12 condensor will not remove enough heat from the R134 and high side pressures and temps will be much higher after core than with a proper R134 core. Increased pressure and temp going into evap equals less cooling inside car. In a much smaller way the evap core has the same probelm as the condensor. It was not designed to work at the higher pressures and is not as efficient as a R134 evap. Not as great a temp change occures across core and the lower side pressure rises accordingly. With a gas in a sealed system tempature is pressure. All these factors work against trying to retrofit R134 into a R12 system. The increased pressures and tiny R134 molecule make things leak like you would not believe! A system that holds R12 fine can leak R134 like there is no tomorrow. I have always wanted to build a complete a/c system using the R134 parts (except the expansion valve) but using R12 as the referidgerant. Talk about cooling power! It would probably never leak and the compressor would last a long time. One of my good friends owns an Auto A/C shop (mainly American stuff) and he loves the R134 systems as they are more prone to serious failures which means work for him. A complete retro-fit new system (with all R134 parts) will work well and should last a good long while. I do not believe it will last as long as if it were set up for R12 and I know it will not cool as well. It gets waaay hot here during summer and vent temps below 45 degrees are important to me. My 98 Infinity (glorified Maxima) has a well designed R134 system that works pretty good but cannot compare with my Mom's old ratty 88 Maxima (all original ac stuff except reciever dryer) or my 78 Z systems. My Infinity's mileage is over 130k and it's system has never been worked on so R134 systems can last. They just need to be properly designed. Exceptions Always Exist and I am sure that some one here has made a junkyard system function well. I would not change an R12 system to R134. If I had to use the R134 I would get one of the complete replacement systems for R134. A rumor I heard is that DuPont recieved the patent for R134 just after their patent for R12 expired. R12 is still available dirt cheap in most other countries and is still released at a massive rate into the atmosphere.Strange how the R12 destruction of the atmosphere is no longer a news story. I will always wonder if it was all a money game. On blends- I will never use them and I refuse to work on any system that has had blends in it. Neither will my A/C shop owning friend. Blends gone bad call for complete system replacement. Customers are never satisfied with repairs to blend systems and many blends use hydrocarbon bases (butane, propane, heptane) BANG-tane. Avoid blends if possible. Hope this helps- I know it probably doesn't but its better to know the pit falls that are possible before you start your modification. All of you parts will work fine with R12. Bite the bullet. Use R12 and the system will last longer and get colder. I can commonly source R12 for about $30 pound. I have seen R12 go pretty cheap on E-bay (be careful-probably lots of scammers). Do not know how R12 licensing is done now. When I got my license (first month it was needed to purchase R12) it was an open book test that was sent to my house in the mail and the booklet that test was based off of had all of the answers and came with the test. $10 if I remember correctly. If you could read English you could be certified and legally purchase R12. It was such a JOKE to me. Good luck on you system. Stay with R12 Rick

Would have been interesting to see the outcome if the hunters had been armed with swords and spears. Would have been a lot more "sporting". Probably the Lion would not allow the Humans within spear range as it appeared the Lion was trying to avoid a conflict The Hunters would have had something to brag about with edged weapons. Pretty sad IMO. I would not want the woman who is impressed by this video. I am a hunter and gun enthusiest but to me these guys looked mean and very stupid. They also couldn't shoot very well and the Lion suffered unnecessarily. I was rooting for the Lion. Rick

If I am understanding your post the 77 dashpot is used to slightly open throttle when compressor is on. The ZX has a similar system but its dashpot is much smaller and is located on main plenum about 3/4 the way back. This style of dash pot is not adjustable and screws directly into plenum. it has a 1/4 inch or so line coming out of it an going into the intake tubing at front of manifold. Both cars have only 2 vac lines going from HV/AC to engine. One is what I call "vacuum main" as it supplies vacuum to the system and the other is idle control through either style of dashpot. My 82 Nissan SM refers to this smaller dashpot as a F.I.C.D. (fast idle control device) and the book shows no differences between turbo and N/A. I verified this valve exists on a 81-83? ZXT manifiold I have. It is about 3 inches forward of the boost relief valve and is yellow cad plated. vacuum application opens a small fixed size port inside of valve to vent tube out of on side of valve raising idle speed slightly. Most dashpots change vacuum into mechanical movement. They don't usually supply vacuum although exceptions may exist. Hope this helps Rick

I call that critter an expansion valve- It is replaceable and it is for R12 system. it is also still available cheap. This style of valve was used in aftermarket systems for thousands of different makes and models. the rest of your parts are also set up for R12 but changing to the GM style orifice tube is a LOT of work as the passages in the evap core are different for the two different valves. I would use everything out of the engine comp of a 75-78 280z and have two custom hoses built to adapt the 280 stuff to the 240 evap. I would also get a new expansion valve as the original ones rarely lasted more that ten years and a new receiver dryer. If you can afford it stay with the R12. Its thermal characteristics are much better that the 134 and it is much less likely to leak. Both 134 evap and cond cores are 50 percent more dense than 12 cores. the manufactors had to do this just to get the systems to the point that customers would not complain about them. Stuff that has had 12 and the 12 oil in it usually does not work well when converted (oil between the two systems is vastley different). Having the evap core so far away from the center vents also reduces the systems performance, makes that side of dash harder to work on, and effects passenger foot area. I am working on a retrofit of the complete 280 system into the 240 using original dash and HV/AC control head. Will post this mod but not soon as other stuff is coming first for me. The 280 system has a cool adjustable theromstat rod and I can get 33 degree center vent temps out of this system in hottest day of year (I am in Texas) freeway cruise/recirc/low blower speed. The original 240 evap should have also come with a rotary temp switch (fit in little pod on drivers side of console) and has a sensing bulb (long copper/brass tube) that has to be properly installed in evap core. It needs to be pushed into center of core about 3/4 depth of core. You should put some sort of heat sink compound on it to assist in temp transfer of core to probe interface. Rout the tube carefully through under radio area forward of console. Try to keep it off of other things (especially things that get hot). This helps keep the signal from the core pure. This rotary temp switch is used to cycle the compressor. It usually has two spade terminals that should show continuity when sensing bulb is above freezing (32 F) and no continuity below. The compressor is cycled to keep evap from going below 32 deg F and freezing up. One interesting note is that all early Z firewalls have the later factory mount locations already center stamped in the metal. I've always wondered why Nissan did not factory A/C the pre 74 1/2 cars. It is obvious they were thinking about it. The temp sensing bulb from the expansion valve should be insulated fully (using the black tar stuff). This valve works as a varible orifice in place of the GM fixed orifice. Colder the core get-less freon is allowed through which lowers the low side pressure causing even colder temps. This set up will provide a colder core that the G.M. set up which shoud have a much more stable low side pressure reading but never reaching freezing temps. G.M. used this set up mainly for cost reasons. The inline orifice tubes require a very specific mount location in the evap high side line at a specific distance from the core. Probably difficult to re-create in an early z car. Good luck- hot days with no A/C reduce fun in a street car. Rick

Temp gauge is only a general indicator of engine temp. 240 degrees will not damage a head or head gasket that is in good shape to begin with. Head warping occures beyond 300 and not seriously until 400 degrees. Its the people who run the car AFTER its in the red that wipe out stuff. "Its was only 15 miles to home and I didn't want to stop and wait" is what makes us mechanics LOTS of money. I've seen heads that got so hot that the aluminum powders and has the consistance of sandstone. If you got it shut down before the red you should be fine. Put a new belt on it and watch it during first warm up. Make sure warm up is normal- No serious spike up before t-stat opens. I bet engine is fine. If coolant level is below temp sender it will never register full hot and serious damage can result (not a problem with your car but lots of folks do not know this fact). The stock head bolts are fine for what you have (especially brand new ones!) Your description of belt failure is classic for a v-belt that has wierd side loading on it. Cheap belts compound this problem. I really like the factory Nissan belts but a Dayco or Gates belt will be fine. I do not purchase low end (Pep Boys/Autozone-store brand belt) these belts are the inside cuts of the brand name stuff and will need many readjustments before they stop streaching- their service life is 1/2 the high end stuff. Good Luck- hope this helps Rick

As long as no vacuum leaks are present any Z manifold will work fine with out misfire. Some far more likely suspects are corrosion in wiring harness (connectors) and injector patterns. Injector patterns can be checked by removing injectors and rail system from intake (leaving fuel hoses attached), pressurize fuel system, and apply a 9 v battery across each injector terminal (remove injector harness from injector). You should have a nice clean upside down ice cream cone shape. Check each injector multiple times as when an injector is having problems it doesn't have problems all the time. Be careful as you will be atomizing fuel into the atmosphere (very flammable). I use a 2 L bottle that I have cut thr very top out of to catch the fuel. This test is done with the key out of the ignition and the F.P. relay jumpered. A bad pattern will have breaks in the cone shape and sometimes it will spray in a solid stream (called streaming). fuel that is not completely atomized will not burn until it reaches the exhaust manifold causing your pop-pop. The TPS puts EFI brain into idle mode (different FI map) and should be used. I do not think clean idle can be had with out it. This goes the same for the 02 sensor. With out the 02 installed the brain is receiving signal (actually lack of signal) that makes it think car is very lean causing it to richen mixture at all times. Install and adjust TPS, add 02 back into system, adjust afm to solve off idle flat spot. A test you can do to simulate a good 02 sensor is to grab o2 sensor harness making skin to metal contact with the sensor wire and with your other hand grab positive terminal of battery. Try this while idling and see if idle smooths out. Although these cars can run with out some of their systems Nissan would not have spent the money to instal if they were not nec. Disconnecting things is not the "proper way" to make modifications. tricking signals or remapping fuel curves is a better choice. Stand alone systems are the best choice IMO. I bet you injector patterns will be your culprit. Look closely at purchasing "rebuilt" injector. My parts supply house allowed me to unbox some Beck Arnley "rebuilts" allong with some Beck Arnley "new" injectors. They were identical including the silk screened part # on their sides. Cost me $30 each when individual cleaning costs me $22. No brainer and they have worked perfectly for me. Hope this helps Rick

Rear seal is inundated with oil during operation. 1/2 of #7 main bearing's oil pours into back side of seal before draining back into pan. Seal will not be damaged by oil; infact if it had no oil on it at all it would only last minutes. It is possible for the sides of the rear main cap to leak (but unlikely). Oil level should have no effect on oil leaks unless oil level is so high crank throws hit surface of oil in pan and froth it up (then oil will come out everywhere!). On a funny note- Once had a female customer call about amount of oil to put in a Fiat Spyder. She had put in 18 quarts and "it still isn't full but the car is running really wierd and oil is leaking everywhere". Congrats on your success. Rick

I would not use any head which had port liners in a turbo application. The port liners can loosen with the heat changes that the port will undergo between boost and non-boost. Also any restriction in exhaust port does not assist turbo motor as it can a N/A. I would stay with the P90. Also the P series heads have a larger squish area which helps reduce detonation. The stock L28ET has to low a compression ratio IMO and I am building a flat top F54/P90 combination for my Challenge car. This set up should net me approx 8.5/1 with minor combustion chamber mods. A compromise is to use a N42 head which has smaller comb chambers that the P90 but it doesn't have the improved squish area. I would stay with the P90 and change pistons first. Rick

Early TPS is basically a double contact switch that give the EFI a signal at idle and on a different pin a signal a WOT. It can cause problems if either side of switch is bad but you can disconnet it. It may not idle perfectly or give proper enrichment a WOT (wide open throttle) but if your symptom goes away you have found your problem. The plastic housing cap can be easily removed and the contact point rebent to give proper function. The adjustment is continuity between center contact and one of the side contacts with engine off/throttle closed and this continuity shold be lost as soon as you crack throttle open. After adjustment of TPS recheck this a few times to verify TPS internals have "taken" the new set. TPS is adjusted by loosening mount screws and rotating housing. Sometimes you have to readjust a few times before it works properly. After adjustment check that you get continuity between center pin and the other side pin at approx 80 percent of WOT. This check/adjustment cost nothing and is fairly quick. Fuel pressure should also be checked to rule it out as a contributer to you problem but the fact that the car runs ok cold/cool tends to elimanate fuel pressure as a factor. Is this vehical "California Emissions". 48 state vehicles did not have "lean cycle mapping" back in late 70s but Cal vehicles may have. This era L-series distributor has a habit of the breaker plate bearing retainer(plastic) failing and allowing the breaker plate to sag on one side causing erratic operation of vac advance and contact between the mag pickup tips and the senor. This is usally easy to spot as one or two small ball bearings will be laying on the breaker plate fixed plate. 80 percent of dist I inspect have this problem. Fixing this usually vastly improves drivability. Fix is to replace breaker plate (60-75$ part at Nissan dealer) Check AFM flap to see if it binding in housing (try to check as installed. I once had one that would check fine on bench but had mild interferance problem when installed). Any contact between flap and housing during operation is bad. At last resort adjusting AFM spring can change mixture. Loosening spring a couple of notches may richen your mixture enough to solve lean issues. Might also overcome factory "lean mapping" Might also violate emissions laws- Never do this for profit, its a felony. Doing it to your own vehicle is a misdemeanor (at least in Tex) Hope this helps out Rick

Another point- If the oilpump pick up is not well sealed to its mounting boss then a air leak can form causing no oil to be picked up. Are you totally sure it sealed well? The process I mentioned in last post will not overcome a leak in the pick up tube. Rick

As the engine is already assembled try this. Remove oilfilter and use a "squirt can" to feed oil into the outer port of the filter housing while a helper turns engine backwards. It is possible to actually see the oil being pulled into the pump and I have used this trick many times. The 231 Buicks of the mid eighties had an extreme issue with losing pump prime and this method worked great. I would run 1/2 quart into engine this way before trying a start. Removing spark plugs may reduce wear on helper turning crank but is not a requirement. Rick

Your results are fine. If you did test with different compression gauge you would probably get different results. I once did multiple comp tests with different gauges in a large dealership (just to see how accurate gauges really were). Got wildly different readings. What you are most interested in is all readings at a reasonable level (for your gauge) and all cylinders within 5-10 percent of each other. Your readings are within 1 percent of each other which is excellent. Valve timing and adjustment can have a lot of effect on compression pressures. Due to your readings I would guess your valve adjustment is perfect. Check it anyway and post results. Valves too loose would increase compression readings/ too tight decreases readings. Pull a plug and check for carbon and which pistons are installed. I prefer flat tops in a turbo. The resulting 8.5/1 ratio works fine with properly modified systems and has much better off-boost response. Rick

Factory Nissan pistons do not have pin locks and they have a large amount of pin side clearance at small end (.250-.375). When I get home this evening I will measure this clearance on a set of L28ETs that I have in a box and post results. Floating pins with pin locks are a feature of forged aftermarket pistons.

Every air-cooled VW I've be in to (too many) has had a cast crank and rods althought I do not believe I've ever rebuilt one that was made in Sweden. Done some Volvos and Saabs that were (all of those had forged internals). The cast VW parts held up fine anyways. I was just trying to remember any Imports that had cast internals and air-cooled VW is the only one that sticks out. Did not mean to insult the "BUG People." Lots of American stuff is cast but they can hold up fine also. I am also surprised to find out stock forging dies can be used to forge a "stroker" crank. I would like to see how that works. I was under the impression that the forging dies would be shaped reverse of the final part and used in a press that squeezed/struck bar stock multiple times forming part. Would be neat to find a video clip of a crank or rod being forged to see how it is really done. Back to Nissan- Only issues I've had out of L-series rods is failure of reused rod bolts. I've put together many reusing the rod bolts and had them last fine but I've also seen failures reusing rod bolts so I now REQUIRE new rod bolts on any rebuild. As the upgrade ARP bolts are just slightly more expensive that factory Nissan I use them. Occasionally the ARP bolt heads have interfered with circular cut out in rods and I've had to dress up the rod to clear bolts. Mild deburing/polishing and shot peening of stock rods is all that is needed for a max effort street Z and totally stock stuff is probably good for 400 hp level. For a performance engine I would use a matched set (all 6 rods originally from same engine- this is more for balance than strength) and have the balance checked /adjusted. I would not use any lower end part out of an engine that suffered a major lower end failure- good core stuff is cheap. Stock L-series rods are not a weak link in the engine.

Does the symptom stay the same regardless if engine is running? Have you checked amp draw on pump as pressure bleeds off? What you are describing is a pump pick up restriction or a pump heating up and failing. Two different pumps usually rules out pump failure. Running pick up hose into gas can usually rules out pick up restriction. Were you using same pick up hose to tank for the gas can test? Maybe weird internal damage to hose. Truly strange. Please post when you figure out what problem is. Maybe resistance of pump feed wiring or bad ground causing problem?