Guest BadKarmaCreepin Posted December 4, 2002 Share Posted December 4, 2002 proportionally it is, at 15 mph, it might be 5 mph off, at 70 it's 10 off, at 130 it's 15 off. the 4 speed was taken out and replaced with the 5 speed. it's still got the r180 rear. which gear do i change and what ratio should it be? the car is a '72. btw: i also plan on putting in the r200 when the turbo motor goes in over teh winter, should i just wait and deal with it? thanks! Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 4, 2002 Share Posted December 4, 2002 BKC The speedometer cog is paired with the diff,not the trans so your 5 speed should make no difference on the speedometer calibration...Here are the colors of plastic cogs on the end of the speedometer cable going into the tranny: Red is the 20 tooth for the 4.11....white is the 19 tooth for the 3.90....blue is the 18 tooth for 3.70.... black is the 17 tooth for the 3.54 ...........Determine what gear ratio your 180 is and then see if you have the corresponding colored cog in your 5 speed transmission......... for example if you have a 4.11 diff you will need the red cog Nissan will #20 becuz it has 20 teeth..Your tire diameter may have a bearing on speedometer calibration. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted December 4, 2002 Share Posted December 4, 2002 The gear is cogged for the diff, but the 5 speed may have come out of a car with a different rear end ratio. So changing the tranny will often throw off the speedo (mine did). If you still have the 4 speed, perhaps you could swap the speedo gears with 5 speed and get your calibration back. Be sure to get both the drive and cable gear. A link to I believe zcar.com has been posted giving the part numbers and ratios of Datsun speedo gear ratios and part numbers. Try a search. Should help you get what you need from the part place if your 4 speed gears won't transplant. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted December 5, 2002 Share Posted December 5, 2002 Whoa there! All is needed is a determination of the R180 diff "gear ratio" that is presently in the car and the correct colored cog with the correct amount of teeth in the 5 speed tranny. IF it is a 3.54 to 1 gear ratio R 180 rear diif, the correct colored cog at the end of the speedometer cable inserted into the tranny will be BLACK #17. He will not need cable, gear etc from another 4 speed tranny( which I doubt is available) but a black 17 tooth gear cog that will fit on the end of his present 5 speed tranny cog gear body assembly.There cannot be much more than 6 possible diff gear ratios with 6 corresponding color coded gear cogs from 16 teeth to 21 teeth. A 4 speed speedometer cable with cog body/sleeve will probably not fit in a 5 speed tranny due to a different length sleeve on the cog gear body.If he has the correct gear cog in the tranny to match the diff gear ratio, then it maybe a speedometer problem or a tire diameter causing the error. Quote Link to comment Share on other sites More sharing options...
Mike C Posted December 5, 2002 Share Posted December 5, 2002 As far as I know, all of the R180 were 3.36 ratio. The early 5 speeds came with 3.54 and the late 5 speeds with 3.90. I would (and did) just got a 3.54 r200 and swapped into my car when I did the 5 speed. If you want to keep the lower numeric gear then swap at gears as mentioned above. Quote Link to comment Share on other sites More sharing options...
Guest BadKarmaCreepin Posted December 5, 2002 Share Posted December 5, 2002 ok, so from everything everyone's been saying...i'm guessing the guy who swapped in the 5 speed found out the 4 speed cog wouldn't work, reached for the 1st 5 speed cog he could find, and slapped it in. i can deal with the speed being off for a while, so here's another situation.... i plan on putting the r200 back there, keeping the same trans, and switching gauges (not that it matters), should i bother adjusting anything now, or just wait til i have everything apart then do it? it seems easier to just wait, BUT if i can make a change now that won't be affected by what i do later, that would be great. i suppose the only way that would happen is if i got the r200 in the same ratio as the r180 in there now. did i just answer my own question? Quote Link to comment Share on other sites More sharing options...
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