ckurtz2

@jonbill Of course, that's the goal. I left links in the document to read both (I will move one to the top so it is easier to find), as they are very different, both hardware and firmware. In addition, the STM Pro is by no means a standard Speeduino. It uses a completely different microcontroller (STM32) instead of the typical Arduino or other similar microcontrollers. The components on the board are also quite different. They only share the same firmware and software. Users will definitely need to do their own research on respective ECUs as their manuals are typically dozens of pages. I am not going to explain something in detail worse than what has already been written, thus why that section is severely oversimplified.

Hey guys, Been a while since I have been on the forum. Anyways my engine is cammed, and ever since the stock Bosch Jetronic fuel injection system had problems running the cam. Cold starts were near impossible, and mid-range throttle was never happy. I messed with it for well over a year but made the decision to go a different route. I decided to switch over to a new ECU and engine management setup. I chose the STM PRO because almost no material was out there on how to do it, and I find it to be a very capable ECU for sequential fuel injection. If anyone is considering swapping over to an aftermarket ECU, I highly encourage it. It seems super daunting at first to try and figure it out, but if you read lots of material, the fundamentals become very easy to understand, especially how different sensors and such are wired. Anyway, I provided a manual on how to put the STM PRO in your Datsun 280z. It is pretty comprehensive, but it is almost impossible to cover everything. It also references many links that you may find useful. I did make a wiring diagram, which I don't believe exists anywhere else for the STM PRO. It is specific to my setup, but you can tweak it however you need. Hope this finds someone to be of use for! The manual is listed as an attachment. PS. Special shout out to Pro TunerZ for setting me up with the STM Pro and all the other items that I bought. Everything was very high quality and I was very impressed. 280z STM Pro Conversion Manual (FINAL).pdf

Or could email ckurtz2@asu.edu

@Zed Head it would be amazing if you could reach out for me, thank you. Honestly, just drop him my number (602)-558-5458 to text or call Clayton.

@Zed Head You likely just saved the day. I can't thank you enough. Beats ebay vendors any day, I don't think MegaZip will find the gears, and the plus is he is located in Arizona. Waiting for my hybridZ account to be verified.

@Zed Head thank you. For some reason, none of those forums came up when I was researching earlier. Sounds like that is what will need to be done. I found a website that said it had the new gears in stock (megazip) although I don't necessarily believe them. I reached out nonetheless. If it doesn't work out then I'll have to chance it with some used gears. Thank you!

@inline6 no they did not. I was very frustrated with it and talked with the owner. Honestly, doing that was my plan B, so its not a huge issue if I can find the proper gears for plan A. @Zed Head I have come to that conclusion too. I have found several 3.7 R200 open diffs online. The problem is that some ring gear bolts in the 300zx had 12mm bolts, and some had 10mm. I need the 12mm. I can't come to any conclusion online as to which year and trim had the 12mm ones. Unfortunately, all of the eBay differentials are sealed, so they can't check for me either.

Shop fixed the differential. The pinion bearings failed as suspected. Shop told me gears were unfortunately toast too (something about overheating, as well as too worn). So they put new bearings/seals/ring and pinion in and repainted the housing. Does anyone have a 3.7 or 3.9 differential they are willing to part with? Unfortunately, they couldn't find the correct gear set and installed the regular 3.545 ratio. They said if I find the proper set they would replace it for free though. I really would like the 3.7 or 3.9 ratio, as that was my bread and butter behind the differential. Please let me know, maybe a deal could be made.

Does anyone have experience just using the old dizzy shaft as both the cam and crank angle sensor? I know you said it is less accurate, but at that point is it just apples and oranges? Will it really affect much? Something like this seems really easy https://www.godzillaraceworks.com/ignition/grwcaskit

@duffymahoney Did you have to use high-impendence injectors for your setup? I am reading online that for fully sequential the injectors need to be high impendence. For batch fired, that isn't needed apparently. Any ideas? I am eventually going to price out the cost of going fully sequential injection and COP, or batch fire and wasted spark. I guess could I do the sequential injection and then wasted spark? Wouldn't see the point I guess.

@duffymahoney That helped me understand things so much better, led me off on a trail or more research, thank you. My biggest question is how does the 280zxet dizzy act as both a crank angle sensor and cam angle sensor. Because it does this, it may be simpler to just do this than to get a crank angle sensor on the harmonic balancer and then a cam angle sensor where the dizzy used to be. However, both options look very simple. I was wondering which Jeep cam angle sensor you used? I can't find a part number for it on other forums. Looks like a solid setup to be honest. How smoothly does ur fully sequential motor run? I think the mega squirt platform can handle wasted spark but I would have to look further into it. I think fully sequential would be kind of fun to do, and definitely more modern than doing batch fire and wasted spark setup. I know lots of cars use the wasted spark and batch fire just fine though. Wondering how many years this mega squirt system would last if done properly. I don't want to deal with any of the pain the OEM injection has put me through with constant maintenance and tuning/fixing.

@dutchzcarguy @Patcon . I am very new in teaching myself how DIY fuel injection works, let alone the ignition system. I think you have convinced me to go coil on plug, and sequential injection though. I think the modern approach definitely is the approach, I just don't understand how to do COP without the 280zxet dizzy. Would something like this work?https://protunerz.com/collections/sensors/products/onesix-industries-l-series-crank-sensor-hall-billet-new From my understanding to do sequential injection you need something that can measure cam and crank position, and CAS is the way to do the crank? I think this little dingy is just a distributorless CAS. But then what measures the cam? Trying to get educated. The more I learn the easier and more complex it gets at the same time. @duffymahoney I pulled up the sight. How do I navigate it haha. I am not versed in Japanese lol.

@Terrapin Z I saw some on ebay for like $1000 dollars which is rediculous. I agree even $350 seems steep, especially because that one doesnt look to be in the best condition. Going to check it out now. Thank you!

View Advert 280zx Turbo Distributor Looking to convert my car to megasquirt. Requires the 280zx turbo distributor or equivelent, so that is what I am looking for! Advertiser ckurtz2 Date 02/06/2024 Price Category Parts Wanted Year 1981 Model 280zxturbo

Amazing description @inline6. Makes absolute sense to me, I bet you nailed it right on the money then. Everything carrier/ring gear side looked super solid to me, I couldn't even find a micro scratch scratch on any of the bearing surfaces. Yes, definitely an oil starvation issue. Hopefully the few miles I had to drive with no backlash and loud wine didn't ruin my gears! @AK260 I agree! I kinda am sad I am not doing this job by myself, but I could use the time saved. I will be checking the gear contact pattern myself though before sealing the cover, so as not to get jipped by another shop:).

Pulled the ring and carrier. both side bearings rolled smoothly and seemed to be in perfect condition. The races looked shiny and felt buttery smooth. Rotated pinion and it felt smooth with no clicking or other oddities besides that slight binding point. Looked closer and the idler/pilot bearing @inline6 mentioned indeed is defective. About 1/3 of the rollers on that bearing were not spinning/rolling but just sliding across the bearing surface. I still can't justify why backlash went to zero from this... Bit the bullet and called a very well-known differential shop in PHX. They said they could take care of it and would look it over and give me a quote. Judging by the problems some forum members have been having rebuilding diffs, I decided I don't think I want to go that route. If I had more time, I would as it does look like a great learning experience. I will let you all know what I am quoted, and what the failure actually was.

@inline6Oh boy, what a mistake to make! But that's why I want to save this one, the CLSD combined with the 3.7 is just a solid setup. Especially because I have it matched with the 280zx close ratio 5 speed. It's fun in the twisties haha. Anyway, measured ring gear run out because I can with nothing apart. The manual provided says less than 002 in. Mine measures exactly at 002 from the lowest point. Maybe even possibly a quarter of a thou more. My gauge setup though was only around $45 so I can't imagine its that accurate. What did ur runout measure? Ok so I rotated it slowly. I truly can not make out any noticeable bumpiness, it does seem pretty smooth. However, about 4/5 of the rotation is free and smooth and about 1/5 is noticeably harder to spin. I did it over multiple times and kept finding that small binding point. So, another clue!

Yes, and that clicking directly correlates to the pinion moving and tapping the ring gear. To be honest, I spun both the good-condition open R200 I have and this one. The good R200 doesn't make the clicky noises or have any slop from the pinion, but both feel about the same smoothness when spinning.

@inline6Thank you! I will read up on all that. This shows what I am talking about with zero backlash. There is zero back and forth action on the ring gear. I can only get slop to form from moving the pinion.

@Zed HeadFantastic idea! Maybe that could be. Is the race apart of the diff housing or the bearing itself? I want to take things apart, but I am waiting to get that gear marking paint first. I want to get documentation on what the wear patter looks like before things come apart. Just so I have all the details. That Idea does make sense, as the zero backlash issue just seems so weird to me. Taking this one step at a time slowly, so as not to shotgun buy. I would say that the gear moves freely with some force with no weird binding points. However, I noticed my open diff spins easier comparitively, so definitely some problem somewhere. @Patcon Do you have any idea the amount of $ they would charge? I seriously am warry of shops from here on out, whether "datsun specialists" or not. The same datsun shop that blew this diff also blew my engine due to not torquing the cam sprocket when replacing a cam. Sprocket came off and pistons met valves. I only took things to them as a last resort for my engine and they blew it... literally... lol. This diff took things to the next step in my trust issues. @inline6 Thank you for the detailed advice. I am just learning about the realm of differentials. They don't seem too complicated, just a very exact science like you mentioned with the pinion depth and bearing preload. Something I would like to avoid, but I never have backed down from a challenge yet. Can you describe to me which one is the pilot bearing? I can't seem to locate it in general diagrams.

Yes, the spider gears is more of an intuitive question, because I have never seen the inside of an LSD diff, and I am not sure if slop is allowed in those gears. If that movement is considered bad than the LSD carrier is useless, and thus there isn't even a point in saving this thing. Regarding backlash, yep did it just like that. Zero backlash whatsoever. Interestingly enough if I instead hold the ring gear still and move the pinion flange, the pinion has slop on the ring gear. However, if I hold the pinion flange and try to move the ring gear it won't budge. Doesn't make a lot of sense to me, but that is how it is, thus indicating no backlash in the method above^. I actually considered cleaning it and throwing it back in the car with full oil like you mentioned. However, the fact that it was completely quiet even with low oil and then started whining during that pull (likely due to high speed oil starvation) shows that I did do real unreversible damage. I even waited till the next day to film the video provided. However, it still was whining really loud on the street. Highway completely unbearable without earplugs. So i know something is amiss. Now it makes me think gears may be relatively ok and instead some sort of failure caused the backlash to completely go to zero and thus induce the gear whine. Just not sure why or if worn gears can cause zero backlash, have zero experience in the differential realm. Trying to find the best course of action. Ive thought about buying a 300zx 3.7 open diff and swapping carriers, but I also don't know if that is possible. Plus rebuilding this one %100 may be worth the money and I will never have to think about it again. Lots of thoughts.

Hey Guys, Every time I post on this forum it's due to bad news:( I really need advice on this one though from some diff experts. Decided to find the top speed of my car the other day and around 90mph the car started screaming from the rear. Luckily only about 2 miles from home so I limped it back. I took note that the noise was only under acceleration, and sometimes a slight grinding noise would occur. Ok, so I jacked it up, put on stands, and ran it in gear. Heard noise was from the differential. Drained diff fluid. Only about a cup came out 😭. I had a shop swap in this diff and transfer inner stub axles about 3 years ago. Apparently, they decided checking diff oil or changing diff oil after talking about it was not a part of their job responsibility. Even though diff was delivered with open axle seals. I could spend a whole post dogging on that Datsun resto shop, but I won't. Never trust, always verify... Here is the noise I had Here is the diff oil removed. Mostly a dark brown color with maybe a light metallic sheen. No metal chunks or shards. Maybe like one slight flake about the size of a grain of sand. Diff internally looks ok with no gears exploded or any visible wear. The black stuff wipes off, I think it is burnt diff oil. Lots of metal sludge on fill plug magnet. I pulled the diff from the car so that I can further analyze it. I don't know if the whole thing is now junk, or if I can rebuild it on my bench? I have a press and tools, but I don't know if it is saveable. At a minimum, I know the bearings and seals should all be replaced, even if they look somewhat ok. Running with almost no fluid makes that seem like a must. I checked backlash. Absolutely zero backlash at the ring gear when holding the pinion still. Ok, so somehow I lost all backlash. Does anyone know what would cause this? Some sort of bearing failure maybe? I would think if the gears themselves failed the backlash would be much greater as they ate away at each other with no lubrication??? I just bought some gear marking paint, and I will analyze that pattern when it arrives in the mail. Also when turning the outside stub axles, should there be any slop in the spider gears within the CLSD? I can see some movement in there. I am assuming those gears were almost completely if not completely starved of oil. Here is a video of what I mean regarding that. Just looking for anwers to the question above and general opinions as well. These diffs are so hard to find online and expensive its hard to just "buy another". If it is a lost cause, it is what it is:( The shop could have just ruined the OEM diff and this wouldn't have been such a big issue...

Wow, what a difference! Cleaned and regreased upper and lower bearings. I also added two new 1/8in balls to each. My steering column is completely rock solid now:) A great tool for anyone removing the bearings is a blind bearing puller such as this! https://www.harborfreight.com/slide-hammer-and-bearing-puller-set-5-piece-62601.html Keeps the bearing from being damaged and makes the job real easy.

@Captain Obvious do you remember what size/ where to get the extra ball bearing balls from? Doing this on my Z right now.

Hey sorry, wasn't able to check everything till today. History of engine... Long story short the head was rebuilt between 500-1000 miles ago (sorry can't give exact number) after pistons met valves (timing sprocket came off while running) at a shop. Shop replaced pistons/ rebuilt head and replaced valves. Before this happened at the shop the head had been rebuilt already, new timing chain, tensioner, etc. Engine was completely refreshed but the block never taken apart if that makes sense. Oil pressure when cold sits around 65psi and when hot around 30-40psi. It is running a comp cam 260s / MSA 6-1 headers / aftermarket fuel rail. Everything else is pretty much stock. Compression 155psi across the board. In regards to the valve springs. Honestly, I have no idea if they were replaced or tested (I assume they are the stock ones). Cam wipe patterns look good on rocker and cam.