4speed gbox swap to 5speed

[PeePee]

Today I took off the original 4speed gearbox from my 510 to swap it to a 5speed one, which comes from a '71 240Z.
I managed to bolt it on without any troubles, but the problem is that the clutch really doesn't work. So I disassembled it form the car.
Then I measured the distance from the splined gbox mainshaft end / the gearbox housing flange from both of them boxes just to see,
that in the 4speed box it was 18mm as in the 5speed box it was 32mm.
Seems, that this gearbox would either need a thicker flywheel, or a thicker clutch asssembly in order to get it working.
Has anyone had a similar problem? What's the solution to fix it? Would the 240Z clutchpack be "thicker", or what?

[Byron510]

There is definitely a difference in clutch diaphragm heights between the two cars, matching the clutch throw out bearing sleeve to the correct clutch diaphragm is the key.

As far as I’m aware, all L series transmissions are interchangeable with each other. The only combo that doesn’t work is the larger clutch pressure plate (225 and 240mm) cannot be used with the older 510 4 speed transmission as there is a clearance issue in the bell housing.
I think you have a mismatched throw-out bearing sleeve to clutch pressure plate issue.

Byron

[datzenmike]

Use the throw out bearing sleeve (or collar) that was on your 510. It's mated to your clutch not the transmission.

The 240 used a 225mm clutch and your 510 is a 200mm. The 225mm PP is taller so the sleeve is shorter than the 200mm. Using a too short sleeve the clutch pedal will run out of travel before completely releasing the 200mm PP.

By "the clutch really doesn't work"... you mean that you cannot disengage the clutch from the flywheel. Put the 510 sleeve back on and all should be fine.

[Byron510]

As Mike pointed out, there are diferences - I went in search of this because I know I've posted the answer many times before - I ended up Googling it and found this link;

http://www.zparts.com/zptech/articles/t ... pecs1.html

The three onthe RH side are the (far right) 510 stock and Z car depending on the clutch used.

Hoep this helps.

Byron

[datzenmike]

Byron I've seen that picture before also and have to say that it may be misleading. It is, I think, from a Z car site and refers only to Z car transmissions. The earliest z car 4 spd was an A type shifter and isn't likely a 510 transmission as we know it but an F4W71A. That and the Z car PP was a 225mm. The 510 collar would be much taller.

Here...

[okayfine]

And the accompanying T/O bearing collars:

Throwout Bearings.gif (34.98 KiB) Viewed 5167 times

[datzenmike]

200mm


225mm and 240mm

[Byron510]

Hi Mike,

If this information is quantified and accurate, we should make this a sticky as it always comes up.

Thanks for posting.

Byron

[PeePee]

Seems, that the thrust bearing collar in my 5-speed gbox is of type 30501-0H600. The one in the 4-speed gbox remains unknown, since I don't want to take it apart right now (just installed the gearbox back last night before reading these mesaages).
However, the thrust bearings seem to be of different size as well. The one in the 4-speed gbox has 68mm outer dia as the one in the 5-speed gbox is 75mm - both naturally with same inner dia.

Would someone happen to know the part code for the 75mm bearing?

[datzenmike]

Outer diameter shouldn't matter as it's the front face that contacts the PP diaphragm fingers.

[PeePee]

I did swap the 5speed box in a while ago and did one rally with the car. I have a feeling that when pressing the clutch pedal all the way down it isn't quite enough. Question is whether the 5 speed box requires a "longer stroke" slave cylinder, or longer push rod? Or are those parts 100% compatible with the 4speed boxes?

[okayfine]

Stock 510 pushrod is adjustable for the fork stop, however later Datsuns and Nissans used a non-adjustable pushrod in the slave with no issues. Many have also used a later slave on an otherwise stock 510 with no issues.

You'd need to detail the exact parts you used, with measurements if available, to determine if you have the correct parts for your combo. Also perhaps describe what you mean by:

I have a feeling that when pressing the clutch pedal all the way down it isn't quite enough.

5-speed doesn't require a longer-stroke slave. It just needs the correct parts for the clutch assembly you're using.