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I thougt a dogleg trans was a direct bolt in swap into 510


DatDoug

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Pulled my 4speed outta my 69 510 goon & compared to dogleg 5 speed I have & it is crooked! Looks like it will bolt up to motor & is the same length but where it sits on the tranny mount it is @ about a 15 degree angle. WTF?!?!

 

0209002220a.jpg

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Guest kamakazi620

Pulled my 4speed outta my 69 510 goon & compared to dogleg 5 speed I have & it is crooked! Looks like it will bolt up to motor & is the same length but where it sits on the tranny mount it is @ about a 15 degree angle. WTF?!?!

 

0209002220a.jpg

Look at yer pics you hve the Wrong Bellhousing on the dogleg!!!

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My guess is that it is from a NapsZ car. However, Nissan transmissions don't have a bellhousing in the normal sense. The "bellhousing" actually encompasses the front half of the transmission case. As far as I know, the front case from a stock 4 speed doesn't swap with that of a dogleg. If you were able to find an L-series dogleg you would be able to swap the front case to make it work.

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The 1980 510 had a NAPS-Z. So yes, you got the wrong transmission. You need one that's from a 77-79.

 

Sure, you can swap front case sections, but you have to have a correct dogleg to do that...

 

The Dogleg you want is from one of 2 Datsun cars.

 

1977 - 1979 Datsun 200SX. Has an L20B engine with the dogleg 5 speed.

 

1978 - 1979 Datsun 510. Has an L20B engine with the dogleg 5 speed.

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Well you're committed in a way, so nothing to loose. Make a wedge to support that dogleg and remove and bend the shifter to the left. You may have to mod the shift hole for clearance.

 

Get it done. Keep your eyes open for a broken one you can get the front off of. BTW nice picture that shows the 12 degree tilt between L and Z motors.

 

 

DID YOU KNOW ?

While the L series dogleg has the exact same gears as the 510 sedan 4 speed, the Z series dogleg has different gears. 4th and overdrive are the same, but 1st to 3rd are slightly lower numerically.

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  • 2 weeks later...

The swap is done. Logical1 gave me his front L series housing & Datsunfish & I swapped it onto the rear Z series tranny. Works great! It sits a bit hi in the tranny tunnel tho & I av to space the crossmember down about 1/2 inch. Also sits about an inch more forward than the og 4 speed. I love the way it shifts tho & I think my car is faster now :)

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I love the way it shifts tho & I think my car is faster now :)

 

Actually it is. At least in first and second. You might notice that you can pull a longer 1st and second gear before shifting and will be going faster at the same RPMs in these 2 gears. 3rd, 4th and over drive are the same so no change there.

 

This is because the Z dogleg had different first two gears in it compared to the L20B equipped.

 

L series 3.382, 2.013

Z series 3.170, 1.921 . There will be slightly less RPM drop when shifting from 2nd into 3rd. This would technically make this tranny a close ratio. :lol:

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Guest kamakazi620

Actually it is. At least in first and second. You might notice that you can pull a longer 1st and second gear before shifting and will be going faster at the same RPMs in these 2 gears. 3rd, 4th and over drive are the same so no change there.

 

This is because the Z dogleg had different first two gears in it compared to the L20B equipped.

 

L series 3.382, 2.013

Z series 3.170, 1.921 . There will be slightly less RPM drop when shifting from 2nd into 3rd. This would technically make this tranny a close ratio. :lol:

MIKE,I always thought a Close ratio trans had "lower" gears like for takin' off the line ie Drag Racing and a Wide Ratio trans you can pull longer in a gear,Do i have this bassackwards????

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Well let's look at two trannys, one from a '79 620 and the other from a '79 280zx. Lets put them in the same car so there are no other variables involved.

 

620 'wide'

1st... 3.592

2nd.. 2.246... 37.5% drop into 2nd

3rd... 1.415... 37% drop into 3rd

4th... 1.000... 29.3% drop into 4th

5th... 0.882

 

280zx 'close'

1st... 3.062

2nd.. 1.851... 39.3% drop into 2nd

3rd... 1.308... 29.5% drop into 3rd

4th... 1.000... 23.5% drop into 4th

5th... 0.773

 

The 620 tranny has a take off advantage being lower geared but starting with an almost 3.6 first gear, the other gears have to be more spread out to avoid a severe RPM drop on the way to the 1:1 4th gear. The 280zx tranny has a slight disadvantage on take offs and runs at lower revs at the same speed as the 620 tranny. Once moving it only has to space the bottom 3 gears between 3 and 1:1.

 

Both transmissions have a similar RPM drop shifting into 2nd but from now on the 280zx next two shifts will be much closer together with much less drop in RPM on each shift, keeping the engine up in the usable hp range. Strictly on a race course, where 1st is seldom used, the 280zx tranny will need constant shifting and down shifting because these gears are so close together... which is good. The truck tranny on the other hand suffers from big RPM drops into 3rd and into 4th forcing it to remain in 2nd and 3rd longer to avoid an up shift or up shifting, loosing engine revs and then down shifting into too low a gear.

 

The truck tranny is good for stop and go driving and or carrying heavy loads in a heavy vehicle or with a 4 cylinder. This makes for easy take offs. The 280zx tranny is ideal for a lighter car or with a larger engine and allows more performance at driving speeds.

 

 

It's all relative and only if compared to one above or below for ratios. There are some competition 5 speeds with a 2.192 first gear making this an ultra close ratio box with a 27% 1st to 2nd shift and a crazy 8% drop 2nd to 3rd! This is less than a 500 RPM drop when shifted at 6,000 RPMs!!!. Compare this to a 2,200 RPM drop on the same shift on the truck tranny and under 1,800 RPM drop on the 280zx tranny.

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