speedo gear options

Engine, Transmission and related drivetrain.
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Nustad 510
Posts: 41
Joined: 27 May 2010 04:40
Location: Newbury, Australia

speedo gear options

Post by Nustad 510 » 02 Mar 2019 06:13

Hi all,

I have a dogleg five speed gearbox in my 510 with an R180 diff running 4.11 gears. What speedo drives do you guys and girls use to make the speedo read correctly? I have a red 20 tooth gear from a zed car, however, the alloy speedo gear housings are different between the long and short tail gearboxes. Any help would be great. Thanks, Shaun

datzenmike
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Re: speedo gear options

Post by datzenmike » 02 Mar 2019 10:25

Sorry a 71B pinion wont fit the 63A transmission.

Find out what tooth count you have in the dogleg and how far out you are at 10KPH, so it's in a % amount. I assume you had a 3.70 or 3.889 so going to a 4.11 will read faster than you are actually going so slowing down the speedometer cable is needed. You can easily do this by increasing the number of teeth on the plastic pinion gear. Here are the % change in one tooth increments.

16-17.... 6.25%
17-18.... 5.9%
18-19.... 5.5%
19-20.... 5.26%
20-21.... 5%
21-22.... 4.7

I would guess this is a long dogleg from a 610 or 180BSSS? The tooth count is probably around 18* ? somewhat like the 510. Very generally if you are close to 5% out going to a 19 would drop your speedometer 5.5% which would hardly be noticeable. Now if you were at a 3.70 differential and went to a 4.11 that's an 11% change so go from 18 to 20 tooth giving an 11.1% change which is very close to perfect.

* This is totally a guess and only you can find out for sure. You will also need to accurately drive your car at 100KPH. Maybe GPS? and read what the speedometer says to know your actual error.

I did this with my 710 with 4.11s changed from a 3.70 differential. (11%) I used one of those radars that tell you you speed and it confirmed from thousands of miles of driving when bored counting the mileage markers in the States. I was just over 33 MPH @ a real 30 so 10% fast.(different tire diameter) My ZX transmission had a Red 20 tooth and I had a friend in the states send me an Orange 22 tooth for a 9.76% reduction. Close enough to 10%. That's less than .13 MPH out at 50 MPH... nothing.

I think the 510's F4W63 4 speed speedometer pinions and sleeves will fit the 63A. They ranged from 16-18 and a 19 if you got the L14 3 speed. Otherwise, any F4W63 and F4W63L 4 speed with the bolt on oil pan from the 521, early 620, 610, 710, A10 gears should fit if they have the gear count you want. Here we got only short 63A doglegs but they were standard in the S10 200sx and optional in the B-210 and A10.

Good luck and good hunting. If you know the exact pinion gear or the sleeve assembly I can get you the Nissan part number. Maybe they still have them or you can cross reference the number.
"Nissan 'shit the bed' when they made these, plain and simple." McShagger510 on flattop SUs

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Nustad 510
Posts: 41
Joined: 27 May 2010 04:40
Location: Newbury, Australia

Re: speedo gear options

Post by Nustad 510 » 07 Mar 2019 21:56

Thanks Mike. Appreciate the detailed explanation. I currently have a 16 tooth speedo gear in my short tail 63A dogleg box. I will wait to fit my new 14 inch rims and tyres and take it for a run at 100kph using GPS. Pending those results, I will make the appropriate correction.

Cheers, Shaun.

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