5 speed swap NK

[02tom]

My biggest obstacle on planning out this 5 speed conversion has been the differential - I'm still trying to find a way to make the input shaft a 4 bolt rather than a 3 bolt flange.  I see there are some used final drives with 4 bolt input flanges on ebay.de that are from 1800's, but they are 4.11 rather than 3.91 and the 3.91 is what I want with the 5 speed.  I'm wondering at this point if you can swap out the input flange and cut off the centering pin that is part of the input gear (I'm guessing).  Or maybe just have the flange on the drive shaft drilled out larger than necessary so the centering pin fits through without actually acting as a centering pin.

[NickVyse]

with a warmed over 2 litre I love a 5 speed with a 4.11 rear end, perfect. It's the ratio I chose

[HBChris]

The difference in a 3.91 to 4.11 is only 5% so at 3000 rpm we’re talking only 150 rpm.  My 2000 has a five speed and 4.11, I’m glad it has the five speed!

[mich02]

go for 4.11!

[02tom]

Looks like I should strongly reconsider the 4.11; the 3.91 was what came with the 5 speed 320's, so I just thought that would be the better ratio.  

[NickVyse]

10 hours ago, 02tom said:

Looks like I should strongly reconsider the 4.11; the 3.91 was what came with the 5 speed 320's, so I just thought that would be the better ratio.  

 

NK 14" wheels have a larger circumference so it's probably about the equivalent of a 3.9:1 with a 13" (roughly, I've not done any math, and assuming the same profile of tyre). And as Chris says the difference is marginal anyway. 

[Schnellvintage]

I will be using the 4.10 ratio for my early 1800 with a long neck diff, with the 245 trans. The 14” tire overall diameter is at least an inch taller than the 2002 13” stock tire diameter. The ratios should be just right.
Matt



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[Hans]

Are you sure its a 228? I had six bolt flywheel and concluded it was 215. Switched cranks to get 8 bolt and 228. On another note, does NK tunnel require thumping to clear newer slave cyl??

[Hans]

So, 02tom, what kind of diff is that???

I had 4 ear flange welded onto original 3 ear drive shaft with long neck.

[02tom]

I just measured the surface area again, and it's a 6 bolt 228. I did not realize this was uncommon, and my car is a 67 manufacture date titled as a 68. The trans tunnel is most likely going to need some massaging. I had the block, trans and mounts all bolted up and it was pretty tight in the tunnel, bur will have to work thru that later

Are you sure its a 228? I had six bolt flywheel and concluded it was 215. Switched cranks to get 8 bolt and 228. On another note, does NK tunnel require thumping to clear newer slave cyl??

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[02tom]

I believe it's original to the car and saw a month ago that Walloth Nesch had one just like it in new condition for sale. The driveshaft uses multiple rubber discs, like some of the early 02s. What kind is it? I'm not sure, but it is a short neck, with 3.91 gear set. It has the 3 bolt input shaft with the centering pin for a rubber disc at the rear of the drive shaft. The half shafts have groups of 3 Allen bolts which have the assymetrical pattern compare with the later paired bolts with a symmetrical pattern.

So, 02tom, what kind of diff is that???
I had 4 ear flange welded onto original 3 ear drive shaft with long neck.

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[Hans]

I've never seen a short neck with asymmetric  holes. Odd. Anyway, to clarify, I had 4 ear flange welded to front of shaft with 3 ears on rear to match long neck diff.

[mich02]

4 bolt flens of drive shaft converted to 3 bolt for the longneck diff. 

[mich02]

[Hans]

Interesting solution. Requires some fairly precise engineering. Also, I assume flex disc was put in there for some reason....