Lazeum

I agree with comment above. What would happen if U-joint angle being too big is torque variation on steering. If you plot steering torque vs. steering wheel rotation, you'll end up with a sine wave. Steering feeling will be wrong (at the condition that you can steer)

I have never been able to prove for sure what went wrong on my setup... MSD or Mallory box, with or without, did not change anything for me. Most likely the root cause was spark plug wire style. I've tried many timing lights with & without advance adjustment, brands, they came out with same results. In the manual of my timing light (Gunson brand) that say wires could cause false reading. Since, I've switched my dizzy for a distributorless ignition system and I cannot be happier: torque, emissions, power, engine smoothness. Everything is now better. I've changed spark plug wires in the process and my timing light works now as it should.

Leon, I've been playing with timing today: no change regarding my lean issue. I'm leading towards carb issue. More than tuning, I'm suspecting my too small chokes to be the root cause for the lean spot. I need to get bigger chokes & check. Anyway, car runs great otherwise & I've tuned it again today. I've increased a lot timing at cruising speed. No ping or what so ever, car is very nice to drive. I've removed 2° of timing at WOT at high rpm to check lean spot. I did not notice any difference behind the steering wheel so I've left max timing at 33° instead of 35°. To go further, I need some dyno time or new chokes .

It is standard size, either M8x1.25 or M6x1.0. 90% it is M8x1.25. I can give you a better answer tomorrow with the Z in front of me.

you say NO and you should correct the mistake in perfect world Frustration, frustration.... To stop this mess on my side, I quit my job and I'm starting my own.

here are the AFR, see how lean it goes at high rpm? it is over time on this graph with a WOT pull in 3rd gear going from 2000rpm to 6000. Lean zone exists in 2nd gear pull also leading me to believe it is not a fuel supply issue. I have changed air jet from 180 to 165 with little to no effect, which led me to believe it is not carb related (or not fully I should say). AFR were dramatically different with regular ignition dizzy system. So I'm suspecting timing as being the root cause. If timing are good, what about efficiency of carbs? I've got small chokes I need to swap with bigger units. What would be the results in AFR with too small chokes? Now, I'm wondering why, why, why Regarding timing with no knock (my case) - Proper timing: Everything burns the most efficient way, WBO2 sensor reads everything accordingly - Too much: Ignition occurs too early, time to burn everything inside cylinder is enough, pressure inside cylinder keeps rising making the burn even easier. WBO2 sensor should read mixture properly - Too few: Ignition occurs too late, pressure would become lower while burn might not have occurred fully. Some unburned fuel & air might still remain inside cylinder, WBO2 would read lean since it's tracking O2. Is it what I experience? Regarding chokes: - perfect size: Air flow rises with engine demand (VE & rpm), fuel is keeping up with demand, everything is fine. WBO2 is ready proper numbers - Too big: Air flow is having issue to go to the engine, fuel is not vaporizing as it should. This is true especially at low rpm. High rpm, mix should be ok. Not my issue - Too small: 2 hypothesis with contradictory results (the 1st one is the most plausible for me): 1- Air flow is not able to keep up with engine demand at high rpm. Consequently, Air flow is not able to bring enough fuel to the engine properly. Issue could be fixed with carb tuning by having bigger main & air jet IF they can compensate the flow restriction. WBO2 would then read lean 2- Air flow is not able to keep up with engine demand, less air goes to the engine while fuel is ok. WBO2 would read rich. I'm not sure to know what to do next so I'll experiment later this week. I'll start by playing with timing (so easy now! ) and see how it changes AFR. I'll start with less timing (less chance to knock) & go with more timing afterwards if I do not get any good conclusion with first experiment. Next step anyhow would be the chokes. My L28 with ported/polished/unshrouded head with 9.5:1 comp is definitely undercarbed with 40DCOE and 32mm chokes inside. Whatever the cause could be, the car is very nice to drive. Without AFR measurement, I would call my tune great but I know I'm not safe with AFR at 16:1 at WOT above 5000rpm. Despite lean AFR, car pulls great up to 6000rpm.

I believe previous setup was way out of tune (whereas it felt ok). Previous NGK plugs made the reading with timing light impossible for some reasons. I'm wondering what would happen if timing is too much advanced? the burn occurs after optimal condition if ping hasn't occured. It means mix does not have full time anymore to burn. With adequate fuel mixture for ideal timing, it would make the WB02 to read the mix as being too rich. Issue would NOT be AFR too rich but timing way out instead. Looking at my logs, AFR @ WOT was actually at 16:1, Wow!!! MJLJ is also great for that. Engine will be more efficient in every way now

Interesting findings today I've data-logged AFR. I haven't done it since MJLJ install. Car was running pretty good so I did not bother too much until now. Car before was having a cruise AFR around 14:1 and WOT @ 12.5:1 with regular dizzy and whatever timing it was. With MJLJ & last map posted, AFR @ cruise is at 12:1 - way too rich - and WOT is at 15:1 - way way too lean (but the engine still go). It's interesting to see that timing and AFR are closely related to each other. Playing with timing has a noticeable impact on AFR, both ways: rich or lean. I'm trying to understand why: - cruise is having a much more accurate and efficient timing. It should help to burn AFR properly. I guess this is why there's too much fuel now ??? - WOT, engine is more efficient, it burns fuel easier. So now engine can take more fuel and burn it ??? First easy move was to switch current 115 main jet with 125 units. AFR is back to 12.5:1/13:1 at WOT, car pulls better & it sounds a little bit healthier. Next move will be idle jets, I'll replace current 50f9 with 45f9. Without a wideband, I would say engine is properly tuned, it is responsive, there's no bog at all, it has a lot of torque to make the car moves. Car however smells rich, fuel consumption is high. If 45f9 are not enough, alternative would be 40f6 - I don't know what f6 idle jet could do... That's going to be tomorrow's task with laptop plugged to log rpm

you're very welcome!

FYI, I'm not using a bung on my car since I don't need to track afr all the time. I use an exhaust clamp, it works well. http://www.innovatemotorsports.com/resources/news3.php The clamp is not so good at idle but I set it up with rpm, not afr (some do it differently though)

The software is free to download (you can do it now if you'd like), just go in download section on www.autosportlabs.com Tuning is straight forward if and only if you know what you're doing. Software provided is really easy to use (even if some tweaks could be done) You also need to control what you're doing. I've got tools for it: a detcan to check for knock and a wideband sensor (Innovate LM2). If you don't know how to tune (yet!), best advice is to read books, some are really good and easy to read. Matt Cramer (member here) & Greg Banish are 2 authors with good references. Most difficult part of the install is VR sensor mount + wheel & Wiring. You need to purchase a good crimping tool, good connectors (not the cheap pre-isulated blue/red/yellow stuff) & a voltmeter. For VR mount, I've shared drawings to make your own. Same goes for wiring, I've shared the diagram. What I did not share was where to hack your stock harness to get +12V at ignition (got it at fusebox).

I've seen many Z with a lock on gas door. It is not as clean as a lock on cap but it could be a solution. I've got no lock on gas door or cap, anybody with bad intention could steal or pour something in my tank...

Beware with my setup, the head is custom made (ported/polished, milled, etc.). It is much more efficient than previous stock N42 head. With same bottom end, I had to decrease every jets I had in my carbs to make it runs right. Comp ratio is around 9.5, cam is made for this combo so timing is really specific to my engine. I've also posted all my maps on this topic, just look up You will also see how progress was made, starting from something safe that you can use also as a baseline. Regarding trigger wheel, I received mine already removed from the pulley. Maybe other people could help. Maybe some time in an oven help to release it... Last, punctuation is better! now you just need to make small paragraphs and it will be perfect

Wow, that's not supposed to happen. The knuckle should never have failed especially on steering arm! Especially also on not very stressed area. From a fatigue standpoint, it would most likely failed elsewhere. It would be interesting to know why (especially on straight road). Did they have a major imbalanced wheel? Improper torque on steering ball joint? Back in the days when I was suspension designer, such a failure meant a potential recall. The car is 15y old, not sure it still applies but something wrong happenned. Glad you did not hit the wheel with your car, it could have hurt somebody bad !!!

For info, I'm running 40DCOE, 32mm chokes, 45f9 idle jet, 45 accel, 0 bleed, f11 e-tubes, 120 main & 180 air. If I remember correctly. Head is done by Rusch Motorsports with Rebello "street" cam, stock flat top bottom end with correct gap to take advantage of P79/P90 quench. Engine runs really good with no ill effect, no matter what I do with it (except maybe floor it at 1000rpm in 5th gear - but who does it?) My ignition system has made the engine runs also much better than old dizzy. I'm just running out of air above 5500rpm so I need bigger chokes (I also need 45DCOE but it is another story ). Since you're not using same e-tubes as I do, not sure what effect could have __f8 idle jet on your combo but I had bad luck with them on other cars I've tuned, all with f11 e-tubes. I'm quite sure e-tube has no to very little effect on low revs but I cannot make a conclusion without trying. I have no clue about __f11 idle jet. Best way to know, would be to look at Weber manual, check f11, f8 & f9 design and analyze. It's easy when design is the same (f8 & f9 are only having one diameter hole change) but when you start having different number of holes everywhere, it gets tricky.

Great for the 34's!!! There's no rush either on my side I'm still breaking in the engine (800-1000mi since rebuild) so high rev and high power can wait a little! Regarding your bog, you're running an usually setup with F2 E-tube & 60f8 idle jets. At the beginning of this thread, zredbaron has made some test with O2 curves & different e-tube (F2 & F11 if I recall). A friend was running 55f8 jets in his L28 with poor results. We have switched them with 50f9 and the car has become very smooth. __f8 idle jets are leaner than __f9.

Steve, Based on the chart below, it seems 32, 34 or 36 would have a small influence on air flow (so performance). It's good to believe it still makes a difference to move from 34 to 36. If you don't know what to do with your 34's, I would be interested

The flywheel option is very nice. Besides workmanship to get to the flywheel for sensor, I was concerned about position of those holes, sensor & TDC. Some of my friends complained about me using Megajolt instead of Megasquirt for the same exact reasons you go with Megasquirt. Good luck with your build! Mine has been a blast to drive since it hit the road again.

First Welcome to the board Then, you absolutely need to put some punctuations in your messages. It is very hard to read. This is how you'll get flamed! not because you ask relevant questions. To answer your questions. I've used the EDIS trigger wheel provided with the kit I've purchased on ebay. It came from the donor car, most likely an Explorer. A friend of mine turned the pulley in a lathe to provide a good interface with the wheel. It could have been done with a pressfit but in my case, it was a loose fit. It allowed me to slide the wheel exactly in front of VR sensor, make a mark on parts, remove everything & get them welded together. I've got an offset of 2° to match what my timing light reads vs. Megajolt output. Megajolt can accept an offset of +/-5°, so it is all good. Choice between TPS & MAP. First, my cam is aggressive & I did not know how MAP reading would behave at low rpm. MAP would have required hose inlets on every runners to be optimum (Leon is running MAP on 1 runner with Cannon manifold - so it is doable. I could have done it also this way) Those are very little & simple parts but it was almost impossible to find those parts in Europe. TPS was easy to mount. I've made a small bracket, got a tps from a BMW e36 323ti with no spring loaded actuator (less stress on mechanism & bracket) and I was good to go. I've got 3 or 4 different TPS before I found the proper one. Almost every modern car is having a TPS so it should be easy to find in a junkyard. MAP would offer a better resolution than TPS to setup properly your ignition map. If you're torn between those 2 solutions, go with MAP. Either way, it is easy to change if we have to afterwards. Regarding budget, between Megajolt, EDIS, wires, brackets, fixtures, plugs, relay, fuses, etc. Total cost is close to 800€. It was not so cheap but results are great. You also need to figure out about fan; stock fan could interfere with VR sensor. I've switched to e-fan since I've already got some in my garage waiting to be installed. Others have played with fan versions to get proper clearance.

If it could make you feel better, I've filled my rings to get slightly bigger gaps than what's written in FSM. I've followed T. Monroe book if I remember well. Rings orientation is also different according to which book you refer to; FSM and "How to rebuild...." are not in agreement. +600mi after rebuilt, I haven't seen any oil consumption occuring that needed me to add some oil to the engine and I'm driving it hard - a WOT as soon as I can (but below 5000rpm).

Weather was very nice, I've been able to play more with MJLJ today. I've increased max timing as well as timing under load. Car is much more powerful than when I started. It is becoming too fast to check everything properly on open roads, even with rev limiter set at 5000rpm So far, everything turn out great, including carbs, they respond very well with no issue or what so ever, they just go. They will just run out of air above 5000rpm (32mm chokes inside), I will need bigger chokes. here's the map so far. No knock detected. All I can say is ignition system is great & really easy to set. Powerwise I might not have gained anything compared to a properly dizzy setup but power/torque during throttle transition, cruizing is by far greater than previous setup with Mallory Unilite + 6AL cdi box. I can also set total timing exactly where I'd like it to be. I'm not guessing as I was doing with dizzy, for sure I've got more power now also. On roads with curves, visibility issues where you need to slow down, cities/villages, it makes a huge difference regarding the experience with the car I've detected some conditions that could be improved where power/torque comes suddently. It shows some power/torque could be gain before torque increase event happens. So I've made another map that should address that but I haven't tested it yet.

I had a lot of fun today! 3 hours driving the Z in forest roads was fun. Especially when the car runs great! No issue at all! First, I was able to reproduce the BANG, it is coming for sure from the soft rev limiter. So there isn't any worries there anymore Then, I had plenty of time to play with timing. To support my tuning, I had my nose, my butt & a DIY detcan that works great. I'm sure I can go further in tuning but I start to be close from the limit of the engine. Each change has produced positive results with no downfall. Coolant temp while engine is running is good. With 75°F weather & cruising speed of 70mph (around 3000rpm), needle is right in front of the bar from "E". Here are the progress I've made. You can see difference between maps to check what I've made. Load is TPS%. 1st map, a conservative reproduction of what my Mallory dizzy was doing. Timing is the same whatever load is. So TPS is not part of tuning yet. Since no knock has been heard, I've ramped up a little max timing. From idle to 3500rpm, slope is linear. I've used Excel to better see the shape of the map (even if MJLJ software allow us to visualize in 3D the map) Still, no TPS tuning involved. Car feels great, better than with Mallory unit. Power & torque are definitely above previous setup. Still no knock of whatsoever to spot even when going up-hill in high gears. I started to play with TPS with next map. First attempt was really to check impact with TPS, so I've only modified one small area of the map while cruising at 50kph in villages & 100kph on roads. I've put the cell modified in blue. Results were good, engine feels a little more responsive at cruising speed. Nothing crazy however; if somebody would have changed the map without telling me, not sure I would have noticed it immediately. Since it was going towards the right path, still without knock, I went further. I've forgot one cell in the following map. I'll have to adjust it next time. For this last map, I've changed load impact on entire rev' range (engine can go only up to 4800rpm for now with soft rev limiter) I've noticed a good impact on engine output this time. Still no knock to report. I still believe I can further but I'm getting close to the limits, a dyno could truly become useful now but I need a load controlled unit - not so common in France & expensive... Progress are also during acceleration, car pulls faster while pressing down the pedal, I can feel more torque during throttle progression. It goes better from steady speed to full acceleration. Something amazing happens also with the last map: Fumes smell issue with open windows is gone with the last map!!!! I wasn't expecting some impact here but it makes perfect sense, with better timing, efficiency went up, more fuel is burnt. (maybe instead of raw fuel, I'm breathing more CO & NOx now ) Since I can literally smell AFR change, I need also to control AFR with my wide-band next time, something I haven't done yet. I did not change anything on carbs yet but they run flawlessly with no hesitation.

Cooling issue could be due to clogged motor internals. When I've rebuilt mine, I use high pressure washer, a ton of gunk came out from the engine. It could also be a clogged or partially clogged radiator. For Idle issue when it is warm, not sure how I can help. Just make sure you're not getting vapor lock with too hot fuel line.

I did not balanced the engine while doing the build. Engine was already balanced from factory and I don't expect to rev the engine past 6500rpm. The cam is not made for high revs anyway. I think I will try to reproduce the issue but at lower speed such as 4000rpm and see what happens. I'll report back but it will be next weekend. ...and indeed, it is fun. Much more fun than tweaking stuff in the garage. It is the rewards to all the hours spent working on it to make it good (hopefully, it will last!).

From a fuel stand point, I'm running Triple carbs. It could be an issue with fuel but I would believe power would drop off with a ramp down before getting a bang. Wideband analysis would help. The soft rev limiter in my ignition system is setting up advance at 0° when it hits the limit. At 0° advance, fuel might not be able to fully burn, resulting in deflagration when hot gases meet 02 from outside. I remember at school to make noise with bikes, friends were revving up their engine to cut everything with ignition switch while at high rev. This was making some loud bang & flames from the exhaust tip. I could have experienced the same effect on the road. Nice feature from Megajolt is I can datalog everything (but I need to enable it!). I can try to play with rev limiter at lower rpm and see if problemm occurs with same symptoms. On my to-do-list, I need to check VR sensor mount and check if it is still holding tight. I drove the car another 20km afterwards with no problem. It is most likely not the problem.