Lazeum

I'm passing the news, just to make sure the theft (or buyer) could not get away with it without showing it off on the net... http://cars.donedeal.ie/vintagecars-for-sale/1974-datsun-260z-stolen-tonight/5931286

I've used Amsoil in my Evo with a lot of sucess; smoother trans than with stock oil, no noise and a lot of abuse on the car with no issue or what so ever. http://www.amsoil.com/shop/by-product/gear-lube/ It's not me who's saying this but in a comparison test, Amsoil is ranking as the b... (I'm just teasing! We're on the net, you can choose to trust or not the data - I can see an Amsoil logo on the very top of the page...) http://www.syntheticoilhq.com/gearoilcomparisontest.html

You should build your engine to your goal with parts matching each other. It goes with head work, cam choice, comp ratio, etc. I had this experience with Braap who knows what he's taking about. Everything has been setup as a whole project. I wanted torque for a fun street machine, This is what I've got now and I'm very pleased with the result. People around me are asking why I did not put forged internals, why I did not put this & that in my engine, why I did not balanced the whole assembly, the pistons to 0.1g, etc.. My answer is always the same: "it was not needed for an engine with power band from 2500 to 6000 rpm" If Braap is not available, you could try Bryan Blake (1 fast Z) who's also doing some head work. He's almost local to you, he's in Phoenix, he should be able to help you also with your combo. His website: bandmzcars.com

it seems 240z rack are different than 260z. You might have some slack with bushings being too small for your rack. Check it, a visual inspection is possible. RebekahsZ is bringing a good point. It is also easy to adjust rack play as long as your have the tool to unscrew it (I use a pipewrench to do so). However loose rack should also rattle, you would complain also about noise over bumps.

I don't think you're missing anything. Not sure though to understand your concern. Anyway, if I would have built a stroker with the budget involved, I would get an ignition up to the task to deliver most of the torque/power of the combo. To go the simple route, I would lock the centrifugal advance in the dizzy & get an CDI box with timing management such as MSD AL2-programmable (if it is still available since MSD is in chapter 11) Once more (I'm alway repeating ), I've ditched the dizzy and went with Megajolt/EDIS ignition, difference is night & day. I love my ignition setup but it cost more (~$800 total)

A M10 bolt with a 1.25 pitch is called a fine thread pitch . It is very well included into the norm. Regular pitch for M1 is indeed 1.5. A general comment: - Suspension bolts are all fine thread pitch - Motor bolts are all regular metric thread pitch. I've changed them all all my car, they're all in metric form. You have to know that only Brits & US people are not using metric system, everybody else in the world in using metric (even GM & Ford are using metric now!)

Your bracket is very though! It will never move which is a very good point. I love also your coil setup, would you mind showing us a pic on the other side to see it better, please? I see your master cylinder which is yellowish. Look for "retrobright" on google if you'd like to solve that

I'm glad to see the thread being helpful overtime! Believe it or not, I've lost my paperwork about it so I'm also using it from time to time since everything has been shared in the thread.

It's looking good. I thought about such solution also but I thought it was safer to get a shorter fixture, so I decided to attach it to the front cover (not the alternator ) Since we have no capability to run detailled analysis, it is a test-and-see process. As long as it works, we're fine. Yours in addition looks good & you can keep stock fan! How is it made? one piece, two pieces? have you added some webs to make the flat part of the fixture stiffer or you just left it alone? What about the rest of the project? Is the car running yet?

FWIW, this is what Braap has made to the shaft I run in my L28.

They could be dirty and not spray fuel properly for instance. It happens on my friend's 911. He cleaned his injectors with ultrasounds, car behaved much better. It could also be a sensor not ok or vacuum for dizzy not working properly.

My opinion is you should check timing & injectors. You might just need a tune up.

That's a very valid point about my exhaust. Such observation on AFR has been made roughly when I've redone my exhaust. I've kept the msa 6-2-1 exhaust manifold, the dynamax muffler but I've redone the pipes + an intermediate resonator. We've made sure with my friend to avoid any leak but we might have missed one... To check AFR, I've got an Innovate Mototorsports exhaust clamp at exhaust tip (single exit)

I have the feeling gravity etube are made to tune AFR right at WOT also. I believe he's trying to get rock steady AFR with gravity etube while he's asjusting AFR level at WOT with wet jets. Am I missing something here?

For information I've overlaid AFR curves with 32 & 34mm chokes. Lean AFR at high rpm did not change at all; neither "intensity" nor within rpm range. It means to me this issue is not air flow dependent since I would have expected something to change with different choke size. Even if 34mm chokes are still too small, it would have made the change less "dramatic" but it isn't. Regarding white pages from Sidedrafts central, I found this: I have the feeling Keith (Sidedrafts central Admin for those who did not subscribe - yet!) has changed his mind about it with Gravity etube. However with regular Weber etube it seems etube are not the key to my lean issue at WOT. I've always considered air jets as tuning tool for AFR in high rpm which isn't what Keith thinks about them: I've experienced some stumbles at WOT at 3000rpm in 4th gear (very minor), trying different air jets might be something to do. I'm using 165 jets, I've got 180 & 195 in my jet box. What would happen if my air jet is way too small resulting in maximizing out the vacuum signal in the aux venturi? I would have expected AFR to be way too rich at high rpm but I might be thinking the wrong way...

AZGhost623, I know how DCOE works sort of... I'm missing some details here & there such as why AFR curve shapes are very different with different heads. With N42 head, AFR were almost even accross the entire rpm range, with p79, it is a totally different animal, why is the question I'm wondering about. As far as time I spend on idles, I can guarantee you that I'm spending less time that this but don't tell the police With full programmable DIS ignition with load control, you decrease a lot your gas mileage too with proper timing. Some downfalls coming from carbs could be outweighed with proper ignition now versus old dizzy setup. It helps to burn the mixture when it needs to be Last comment, I'm running F11 so it should be quite acceptable but it is not (but close, once more car is very nice to drive) Somehow Leon & Keith might be right but why was it working before and not now anymore is over my head for now. So I'm trying to see what could have gone wrong in my setup to give me unnacceptable/unsteady AFR. - etube could be tweaked somehow. I can try to plug some holes and see how it goes. I can try to plug top holes to affect low end which would require to get richer main jets (which I've got, up to 145) - Intake manifold has been ported a little, I left a step between head and manifold (manifold smaller than intake head port) to keep some anti-reversion feature for driveablity. Could that cause some turbulence at high speed (=high rpm) lowering flow (= less fuel mixture going to the engine, hence the lean spot) - I strongly believe fuel supply is out of the picture and works quite well (pressure ok, lean spot at every gear, new filters, new hoses, fuel tank fully restored - cut opened, sanded, welded back & seal with resin) - Carbs still to small, venturi change was not big enough? Last question, how would you plug holes on etube? Some solder (how to remove it afterwards?), some wooden toothpicks? My friend with his 280zx is using F7 etube, I should try to borrow them and make some trials with them.

70f9 is huge!!! How is your fuel economy with such idle jets? I'm running 45 accel jet. I've also got 40 in my jet box. Looking at my AFR shows that, lean spot starts by being too rich & not long enough so trying again 40 now might make sense & bring good results. I'll see that tomorrow. My o'ring for accel pump jet are pretty bad, that might not help either even if I did not see any leakage from the outside.

This is what I have on my setup also, some bleed valve shut with solder. car is very driveable with no majot stumble issue. Since my last message some hours ago, I've been working on my Z (not the s130 from my previous message - if you still follow ) to swap 32mm chokes with 34mm units. I did not have to change anything at all on idle jets to make the car runs perfect. So I came to the conclusion that choke size should not make any change on idle jets. Something is going on my friend's car we need to find out. I think we need to get to the basics (fuel level, jet inspection air leak, etc.) Regarding my Z: Low rpm stumble is more noticeable now. With 32's & an agressive way of driving (WOT after each corner :/ ), I could not get any stumble. With 34's, if I'm a little bit too low, like 2500rpm in 3rd gear, I've got some. I'll try to play with timing and see if that could help, timing map is conservative around that engine state. I've recorded some AFR logs, I still have the AFR going lean as it was with 32mm so choke size did not help... I'll try next emulation tube modification and see if that would solve my problem then. Anyway, car with 34mm is really really nice to drive. AFR are a little rich so lean spot is at the leanest around 13.5:1 while richest point is at 11.5:1. Cruising AFR are between 13.5:1 & 15:1, O2 sensor came up clean after a 45 minutes session. If weather is ok, I'll play around with parts tomorrow.

I've tuned last week a stock L28: N42 block, P90 head, dished pistons, stock cam It has 40DCOE 22-23 & 6-1 headers with 2.5" exhaust system. Car was previously tuned with 34mm chokes, good transition, AFR in 14:1 range at steady state, 12.5:1 at WOT. Carb setup was: idle: 45f9 Main: 135 Air: 170 etube: F7 We have changed to 32mm chokes, Car reactivity/power at WOT is better, car feels more powerful which is good at WOT. Problem is the car was pig rich at cruising speed. WBO2 measured AFR at cruise at 10:1 !!!!! We did not have anything smaller than 45 with __f9 idle so we've switched to 55f8 to get AFR at 14:1 at cruise but transition is now very poor, engine sputters with low throttle input. Something is not right to me & I'm not sure it is carbs related. First I though choke size would not impact much AFR with idle jet whereas it has changed it by 4 points. Secondly, I don't think stock L28 with 40DCOE and 45f9 should be that rich. I drove the car (280zx) and I did not think power was high (comparison point is my tuned L28 in my 240z with Megajolt, so I might not be very objective) Owner is also having a Ford Capri with a V6 2.8L, single carb which is more powerful also. Do you think problem could come from timing? Apparently it was check to be 34° max and around 10° at idle. I haven't checked it that day Do you think we should check something else?

This car is coming from a Belgium shop called Kamikaze Garage. He's used BMW air suspension system he custom fit into Datsun struts. So there're still springs and strut in addition to air bag to lift the car while running.

I'm buying them in UK I did not look for spannish source but I've never seen anything about Weber in Spain besides DCOE 151's & 152's. Still it isn't cheap when you start having main jets from 115 to 145 for L6, same goes for air jet with 165, 180, 195, ditto for idle jets, etc. Etube are definitely more expensive so I did not mess with them yet.

I'll put etube modification on my to do list then. How would you plug the top holes? Wooden tooth pick? Copper wire? I've got JB Weld also (but something inside my head is saying "no-"no") There's a classic car event this coming WE in Le Bourget (where the Paris plane show occurs if you have heard about it), I'll ask around but people, even pros, are not as knowledgeable anymore about DCOE unfortunately. I'm usually the one explaining them how to tune DCOE for specific operation.

I got it but shipping between Keith and me would outweight the benefit of the swap for free, unfortunately. If I would be in the US, it would make my life much easier. I would have got some etube from him for a while I'm curious to see how chokes will affect AFR. I'll see from here what I could do. I've got also some retired engineers responsible for the Alpine A110 program in Rallies back in the days who could probably help me locally with DCOE's. I've got small problems (because car is still awesome to drive - with no AFR readings, I would not suspect any problem) but it is part also of my hobby to solve problems, so it's all good (I know you've made the same comments some time ago )

I'll extend a little bit my setup for some thoughts First, I'm running a L28 with flat tops, P79 modified by Braap. CR is around 9.5:1. Cam is a Rebello unit made for the street: lift is around 0.49", rev band should be 3000-6000rpm roughtly. I'm indeed running megajolt system. At WOT I'm running 33° max timing for now. I've tested timing at 35°, I did not feel any difference in performance, AFR were about the same. So I put timing out of the picture for lean AFR. Lean AFR starts at 4500-5000rpm. I need to get rpm signal from Megajolt to be sure but it's in the ball park. Regarding carb setup: 40DCOE-18 Chokes: 32mm Aux chokes: 4.5" Idle jet: 45f9 Accel jet: 45 Bleed jet: 0 Main: 120 Air: 165 etube: f11 Needle jet: 200 Fuel level on every carb has been set according to Weber manual with gages. So they are even. Regarding root cause analysis: - Issue did not exist with previous setup with previous head, stock N42. I was actually running too rich at high rpm. - Air jet did not help much - I was running 180 before, lean spot was not impacted that much - Main jet helped a little. Getting main jet bigger made the lean spot coming later. - Fuel pump / fuel pressure did not change anything - So it is not a fuel starvation issue. - There's no misfire or anything to believe timing is not OK. It is quite the opposite actually, engine performance has gone up tremendously with MJLJ system. Difference between old N42 head and P79 is important. I had to lower every jet in my setup to get the engine running ok. P79 head is more efficient than N42 for sure. etube could be the root cause but intake pressure at WOT should be at atmospheric pressure ideally. Too small choke will make intake pressure lower, by increasing chokes, I would increase intake pressure at WOT (less restriction), I'll see what happen with choke change then. Regarding Keith Frank's work, I'm following closely what he's doing. Obert Etube & gravity etube are very promising.

I'm trying to understand on my setup, why I do have a lean spot at high rpm. As rpm go up, AFR become leaner. I've got 40DCOE with 32mm choke & mallory 4070lp pump. Engine is F54 with P79 ported/polished by Braap with "street tight lash" Rebello cam Mallory pump for some reason is not able to deliver more than 2 psi of pressure which is fairly low. Flow is good, lean spot happens at 2nd or 3rd gear (4th & 5th are too high for open roads test). I suffered no fuel starvation on highway being at WOT on 4th gear. So I suspected 2 causes: - Too small chokes - Too small fuel pressure So I've switched the fuel pump with a Carter unit at 3psi. It didn't solve my problem but AFR readings allow me to show how fuel pressure (hence fuel bowl level) could impact AFR. It is very significant. Lesson learned: fuel level is very important, so fuel pressure. It makes no sense to compare settings between cars if fuel pressure is not documented. On the following chart, carb settings hasn't been changed at all.