kully 560

I do have the blue wire taped up neatly in the harness by the coil, but I can read it from the tachometer side. good idea, I do understand that the oem system and the msd are both square wave except the difference is the msd pulses at idle correct, which would still cause the tachometer to bounce at idle. maybe for the heck of it I will hook up the msd tach output directly to the tachometer and see what happens, all it can do is bounce I believe. thanks again

also Zed head that there is a 2.2k ohm resistor in the wire harness on the passenger side front kick panel where the oem 260z ignition module is located. I believe that is also for the tachometer circuit. I which I knew what voltage signal Nissan was looking for?

I did read on the net that there was somebody explaining that he removed a resistor from the back of the tachometer which would have lowered the voltage on stock systems and then installed a jumper to bypass the resistor and the tachometer worked great. but my dash cover will not let me remove the tachometer from the front. I do believe that the rpm idle bounce is from either noise or the msd 12v pulse. it just seems crazy to use the voltage booster to increase signal and then use a resistor to lower it somewhere between the two voltage points. if I do find the point where it works perfect with a little change in resistor value, I might leave well enough alone. the tachometer is basically a coil, but what voltage was it designed to operate on?

hello Zed head again, I don't know why but I thought with the msd 6a ingition you cannot wire the tach directly to the coil because of the 12v idle pulse? now the reason for the resistors is in the technoversion v booster the signal is a little too high and the tachometer runs about 1500 rpms higher than normal. now with a resistor value of 35.2k ohm the tachometer was spot on with the rpms except for the electric cooling fan surge. that is why I tried just for the hell of it to lower the resistance valve just to see what happens. and bingo at 31.7 k ohms the tachometer was steady when the fan came on except for the little load the alternator creates. I did have just a little at idle rpm tachometer bounce which I think going up just a little in resistance would fix that issue. am I going in the wrong direction? do you think I should wire it direct to the msd with the 12v idle pulse?

it definitely looks not centered!!! glad you might be on to a cure.

well, here is my update today. I changed the resistor value from 35.2k ohm value to a 30.7k ohm value and the tach rpm stayed accurate. the tachometer never changed when I did turn on the electric cooling fan which is a good sign. but the msd was causing the tach to bounce a little at idle. now I did just order some more resistors to have a 32k, 33k, 34k ohm values on hand to play around with. it does seem I am getting close to maybe getting it right. I was a little afraid to hook up the msd 6a tach output directly to the tachometer as the pulse at idle was still making the tachometer bounce with the 30.7k ohm resistor. with the 35.2k ohm resistor I had no bounce. I think I need to find the right value between the 30.7k and the 35.2k ohm resistor.

yes, msd makes the 8910 and the 8920. the 8910 is for the early 240z cars with current driven tach, and the 8920 is for the 260z and up with voltage driven tachs. I will try and come off of the msd tach wire and go straight to my tach and see what happens. I do not think it will damage the tach as it is still voltage. if that fails I will have to play around with different value resistors and see how that works out. I will update as this goes on. thanks for all the help

thanks Zed head, I did read that and that is why I choose the v- booster. on the early 74 260z the tach blue/white wire did connect to the ballast resistor if I remember which limited the voltage. the msd does put out 12v but on an oscilloscope it is only about 3-3.5 volts. that is why when I read the online info you found at the technoversions site about the products, I thought I needed the v-boost, but it does seem to be too much in voltage increase.

I do understand what you are saying Steve, but I have a separate fuse block new next to the battery for the fog lights, msd ingnition, and electric cooling fan,also new key switch ect. maybe I will try going from a 35k ohm resistor to a 30k ohm resistor and see how that works. I just might be limiting a little much voltage. but with resistor change comes the rpm change which is spot on. I thought about the diode to help with the current draw so it might not fluctuate but you seem to think it will not help. I do need to be care full as to not damage the tach, I do have a dash cover I installed 30 years ago, and the tach can't be removed from the front anymore. now I really don't want to pull the dash for a new tach install. thanks

hi steve, the fan runs off of the battery and the ingition circuit only controls the 30a relay to power the fan. now also steve the turn signals will affect the tach also but very slight. that is why I thought about using a diode before the resistor or after the resistor to maybe to block the current draw? not sure!

I see the new msd 6a has a plugin harness where my older msd 6a has the tach output on 1 side with a recessed spade male connector. and on the other side the harness for ingition and power.

or tachmatch v boost

I sorry for not answering your question, it is not the tachmatch convertor it is the tachmatch voltage booster.

thanks Zed head for the reply, the signal from the voltage booster is 2 strong for the oem tach, I am running the msd 6a ingition which on the output tach connection it puts out about 3-3.5 volts according to msd ,that is why I went with the voltage booster. I now have to lower it with a resistor. I tried a 24k ohm resister with little change to the rpms. then I went to a 47k ohm resistor and the tach never moved. I then went to a 35k ohm resistor and the tach work great and the rpms are spot on. according to technoversions he had some 260z cars work fine just with the voltage booster. it now works great except the current drop when the electric cooling fan comes on. I thought about a diode in line with the resistor. what do you think.

I installed the technoversions tachmatch voltage booster on my early 260z today so I can have the stock oem tach working off of the msd 6a ingition direct. at first it was about 1500 rpms to high, and when I did start playing with resistors, I found that a 35k resistor worked with accuracy. the only problem I have is when the electric cooling radiator fan comes on the tach drops down and then back up to normal after the fan is running. now my thoughts are to maybe add a diode in line with the resistor. I did wire the tachometer direct from the voltage booster. I am looking for some input from any electronic gurus. thanks

I change ever thing just like you. a new steering rack, tire rods inner and outer, techno toy tension rods, lower control arms from techno toy, struts and new springs I went 2 tire changes over the years and several balancing of the tires just like you, it was really starting to wizz me off. I never looked at the front pads when I went to drilled and slotted rotors as the caliper comes off without removing the pads. I did a lot of chasing of that same problem to find out about the shims sticking. well good luck and let me know what you find, and maybe my post will help some other members with the same problem. kully

I do not know if you ever looked at the front brakes! I change all the stuff you have done including the techno toy front end parts and I still had the shake between 60 and 70 mph. I never check the front pads as they were new from about 20 years ago with little mileage maybe 3000 miles. my shake would go away after I drove the car and got the tires warmed up. I thought maybe flat spot from sitting in the garage for a month at a time. now about a month ago I did have a front wheel bearing seal leaking a little and I decided to install new bearings and seals on both sides for the little that they cost. now at this time I said let me install new front pads, and what I did find was the oem shims were partially sticking to the brake pads. I had to pry it off on one pad it was stuck on. I did clean them up like I posted early, and the car is perfect!!!! If you have not checked them, then after the wheels take a looked it and it might just be the finishing touch you need.

I did chase the same problem. what solved my problem was the front stainless steel brake shims. I removed them and used a bronzed wire wheel in a drill and cleaned them up completely and applied brake grease to both sides of them, and bingo that was my problem. now also new hardware on the calipers with brake grease. also, I did also use some sandpaper for the caliper piston where it touches the brake shim. just remove any rust that might be there. hope this helps

the kit comes with all the adaptors. it even has the plastic washers for easy rotating of the strut.

you would have to punch out the center pin on the oem strut. then you would use the adaptors that come with the kit. very easy to do about a 1/2- hour job. do not make the bolts that hold the strut to tight, and I did use locktite on the nuts.

just to let the forum members know I have a 260z with the 2 lift struts for the hatch. today I did install the Stabilus brand strut part # is 3b250273 and the hatch opens up 95% on its own. after I push the button to open the hatch, I raised it maybe 3-4" and it goes all the way to the top. what a difference. I believe the force is 44lbs for each strut and it does close really easy. just an update for the forum.

I did finish the rear axle stub bearings today. thanks Zed Head for the help, I removed the stub axle and you were right about the seal causing friction. I did set it flush with a block of wood and a hammer yesterday. now after looking at the seal again today the seal has to be set in almost a 1/4" from the outside. there is just a small lip that I felt and set the seal up to that which just about touching the inner bearing. I torque the stub axles down to 200- foot pounds and it does spin freely with no noise and binding. I guess the flange has just enough flex when being torque down that it must just flex enough to cause the binding. it is a very simple job besides that little problem. the shop book says nothing about the seal install and I did it the usual way which is wrong. now anybody looking to do the bearing replacement make sure the seal is all the way in and you should be fine. thanks again for the great help. kully

I am going to put the shaft out again and measure the b spacer and start from there. it did look good and not egged or crushed but I will measure it and see where it is at. thanks

I do have a 20 -ton press and I did use to install the outer bearing. the inner bearing I set it in with a socket and hammer and I did make sure it was installed correctly and not crooked.