Gearbox Help

[JK510]

Hi Guys,

 

I've the opportunity to buy a 5 speed dog leg gearbox for my 510 restoration and just wondered if someone here could help me identify the box, and perhaps let me know the ratios, etc.

 

Many thanks in advance.

 

 

 

Edited September 13, 2020 by JK510

[datzenmike]

 

 

Definitely an L series FS5W63A dogleg. The ratios are exactly the same as the saloon 510 but with an extra 14.6% over drive 5th gear..

 

1st.... 3.382

2nd... 2.013

3rd... 1.312

4th... 1.000

5th... 0.854

Rev.. 3.364

 

You could confirm this by marking the input and output spline, place in first gear (not reverse lol) and turning the input 20 times while someone counts the output turns. If they get 5.9 output spline turns (almost 6 turns) then this is what you have.

 

 

 

[Draker]

Looks like the long tail version

[datzenmike]

Good eye!!! Draker.

 

I was going to say "If I had to guess at the build date I would say February 3rd 1975 but I wouldn't put much stock in this" because we didn't get L series doglegs till '77. But Australia and Japan got the long ones for what we know as the 610. 180b with L18SSS dual SUs. So '75 isn't out of the question now.👍 Oh yeah, Norway got them also.

 

 

[datzenmike]

So this will need the driveshaft shortened about 5.5" but measure and the cross member modified..

[JK510]

29 minutes ago, datzenmike said:

 

 

Definitely an L series FS5W63A dogleg. The ratios are exactly the same as the saloon 510 but with an extra 14.6% over drive 5th gear..

 

1st.... 3.382

2nd... 2.013

3rd... 1.312

4th... 1.000

5th... 0.854

Rev.. 3.364

 

You could confirm this by marking the input and output spline, place in first gear (not reverse lol) and turning the input 20 times while someone counts the output turns. If they get 5.9 output spline turns (almost 6 turns) then this is what you have.

 

 

 

Thank you,

 

So, in your experience and opinion, is this a "better" option than a FS5W71B which I also have the option to buy? Both boxes would cost me similar money and both are probably going to need some refurbishment perhaps.

 

With a shortened drive shaft would the gearshift sit correctly then, and what modification is needed to the crossmember?

 

This particular box which is in Sweden has been pulled from an S130 which I found odd in itself, it being essentially a four cylinder box. Why would someone put that into a six cylinder car? Although having asked someone else that question I was told that a 120Y auto often used the same box as a 300ZX TT...? Maybe the boxes could handle the power..? Much as a Morris Minor used the same box as a Rover 3500 V8....

 

Again, thanks for all the help 🙂

 

JK

 

 

 

 

Edited September 13, 2020 by JK510

[datzenmike]

The 71B is much much stronger a transmission having been designed for a stronger larger six cylinder engine capable of up to almost 200 hp. They were not used with any turbo engine and only up to the 280zx (S130) and not ever on the 300zx. 

 

Post a picture of it. The '79 is a mid ratio box and the '80-'83 is a close ratio. I prefer the 'mid ratio because the over drive is more like 12% vs. the later ones that are 25% and not much use in town.

[JK510]

23 minutes ago, datzenmike said:

The 71B is much much stronger a transmission having been designed for a stronger larger six cylinder engine capable of up to almost 200 hp. They were not used with any turbo engine and only up to the 280zx (S130) and not ever on the 300zx. 

 

Post a picture of it. The '79 is a mid ratio box and the '80-'83 is a close ratio. I prefer the 'mid ratio because the over drive is more like 12% vs. the later ones that are 25% and not much use in town.

This is the other box in question. Earlier I think...?

 

And funny that you say you prefer the earlier mid ratio box. Back before we all got into the S14a upgrade the S30 guys always looked for the later closer ratio boxes...

 

Cheers

 

JK

 

Edited September 13, 2020 by JK510

[datzenmike]

Yes, earlier '77-'79 but not after. Could ve a 280z or 280zx non turbo. Either way it will be a mid ratio box.

 

Again you could confirm this by marking the input and output spline, place in first gear and turning the input 20 times while someone counts the output turns. If they get

 

5.5 output spline turns somehow you have a wide ratio box. Possible but unlikely as this is from a truck.

6.0 turns a mid ratio box. Most likely

6.5 turns a close ratio box... won't be this

 

Been in storage for a few years by the spider webs. The key that holds the speedometer pinion in place is missing.

 

L eft center with it's bolt...

[JK510]

Better option though than the FS5W63A dogleg though?

 

I'm not looking for a racing car, just a very useable, driveable, reliable motor..?

 

JK

 

[datzenmike]

Absolutely better, stronger, more conventional shift pattern. More available.

[Draker]

I love the dogleg and have them in my cars, but I agree the 71 is a better gearbox. I would consider the dogleg if it was short and essentially a bolt in. In either case you will need to move the shifter hole back and get a new driveshaft made for either of the one’s you mentioned.

Edited September 13, 2020 by Draker

[datzenmike]

4 hours ago, JK510 said:

 

 

And funny that you say you prefer the earlier mid ratio box. Back before we all got into the S14a upgrade the S30 guys always looked for the later closer ratio boxes...

 

Cheers

 

JK

 

 

 

The later '80-'83 close ratio has an extreme over drive ratio making 5th more suitable for the highway or a car with a larger displacement engine. For a 4 cylinder 2 liter engine I think the mid ratio is better all round. The exception when using the close ratio would maybe be the 510 which is light at 2,300 pounds. My 710 is almost 500 pounds heavier than a 510. I had a mid ratio in it but currently a wide ratio 71B from an '85 200sx turbo. With 4.11 gears there's a lot of shifting or skipping gears. I do have an '81 close ratio but needs a bearing replaced in the adapter plate. I'm in no hurry and think it not worth the bother to try it in my car. I like the fast rev using the wide ratio and the '85 71B has a better 2 to 3 and 3 to 4 RPM drop than the other truck wide ratio.

[JK510]

Thanks both.

 

I used to be indecisive, now I'm not so sure...!

 

So head is saying go with the 71B as you've both said its a better box.

 

Heart says Dogleg 63A just for the percieved cool that they have..?

 

The guy with the 71 has several boxes availalble so I guess if I go that way I'd just have to make sure he can supply the complete thing including the missing key mentioned.

 

Thanks again and I'll let you know how I get on 🙂

 

JK

[DanielC]

I did not know a 510 weighs that much. 

I have taken scrap steel to be sold, with one of my 521 trucks, and I think I remember an empty weight of 2240 Lbs, with about 160 to 170 pounds of my clothed carcass sitting in it.   I would think that a 510, without a ladder frame, would weigh significantly less than a 521, that has a frame, and can easily carry well over an additional 1,000 to 1,500 pounds more.

 

Back to transmissions, and gear ratios.

I have two 521 trucks.   Ratsun has a L-20-B, and five speed , I believe a 3.6 first gear out of an 1980 720 truck.  Dragon has a L-18, with a 3.321 first gear.  Both trucks have a 4.375 rear axle.  In almost every driving situation, except on the freeway, Dragon with the smaller engine is one gear lower.

With the closer gear ratio transmission in Dragon, I just wait to let the engine rev higher, before I shift.  Then when I do have the engine in a higher RPM range, the closer ratios work better.  

With a stock 4 speed in a 521, 3.6 first gear, there is simply too much of a drop in RPM from second to third, for performance driving.   The closer ratio five speed gets rid of that problem, and I think is is almost a better bonus than having the five speed.

 

With Ratsun, L-20-B, wider ratio five speed, the gap between second and third is no problem.   I drove Ratsun with the stock 521 four speed for a while.   However, with the L-20-B having the fifth overdrive gear is the greatest benefit of the five speed.

 

But you have a 510.   I am pretty sure you have a lower (numerically) rear axle ratio than a 521.   But the 510 I am pretty sure weighs less than a 521.   I think I would prefer a closer ratio transmission in a 510.   I think the dogleg transmission has that more desirable to me, gear ratio.    I have heard from more than one source that the dogleg is a weaker transmission, but it was being used in a 521 truck.  Another factor on the transmission durability is how you drive it.   Some people could break a brick with a Q-Tip.  (cotton tipped ear swab)

 

If you have the dogleg already, I would go ahead and use it.   If it breaks, you know where you can get a 71C transmission.

[datzenmike]

I think one of the 720 5 speeds has the same 2/3 and 3/4 ratios.

[JK510]

Any ideas of the weight roughly of the 63A

 

I may need to ship 

 

thanks. 

[datzenmike]

A long one looks like it would weigh about the same as a 71B. Close to 70 pounds.

[JK510]

A friend of mine who builds Z cars and raced in the Historic Touring car series over her, a chap called Dave Jarman, has thrown a spanner in the works and said why not try an S13 box...!

 

So can I ask is this a good, more modern alternative to the boxes mentioned earlier. More readily available over here with parts available to rebuild if needed.

 

Is there any issues I should be aware of? Will the bellhousing swap over?

 

Anything you can offer is appreciated, thanks.

 

JK

 

 

 

[datzenmike]

 The 71C box came it two lengths, cars long trucks, short, neither are an exact match to the 71B so driveshaft mods.

 

The 71B front case will swap, but again some crucial mods. The 71C first/second shift rod is larger so the 71B hole in the case needs to be drilled out 14mm to 16mm? Thee counter bearing on the 71C is 62mm while the 71B cases through '84 are 56mm so the easiest thing is to pull the 62mm and put a 56mm bearing on. If you have a machine shop you can enlarge the 71B hole to 62mm but be aware a small flycut needs to be made around the counter bearing hole for clearance.The 71C gears are thicker and the front stick out and will jam when the case is tightened up.

 

 

Like this

 

[JK510]

Thanks again Mike...

 

That sounds like it's not really the ideal box for the car then, quite complicated to make it work.

 

This is harder than I thought it might be....😆

 

JK

[JK510]

So, back on the FS5W71B.....

 

I'm getting better at identifying them but just confirm this is what I think it is, thanks 🙂

 

Thanks again,

 

JK

Edited September 20, 2020 by JK510

[datzenmike]

L series 5 speed made between '77 and '79. Most likely from a 280Z or first year 280zx.

[JK510]

36 minutes ago, datzenmike said:

L series 5 speed made between '77 and '79. Most likely from a 280Z or first year 280zx.

71B then yes..?

[datzenmike]

Oh yes.