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Discussion Starter · #1 ·
Hi When I started racing some years ago it felt to expensive to by an close ratio gearbox..so I did build one ..

I thought that it must be possible .. and after finding the best option of gears I did get som help and put them together..

The best gearset at that point was with final ratio 3:54
1th Stock
2nd Stock
3rd 1:35 from Alfetta
4th stock 3rd
5th 1:04 from Alfetta

The gears did not fit at once but an frend helpt me with some turning..
cut the double 3-4 gear apart turning the 4th inside and 5th outside
change places some welding and there it was not perfect ratios but it did function.. some years ..
I also did some lighting..and that did broke last year when I started to race with the supercharger ..

So the next gearbox will be without lighting hols...and better ratios...

Send some fotos on the cheap gearbox..
/ Hans
 

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Richard Jemison
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8,258 Posts
Proper CR Gearset

Close Ratio gearsets with 2.0/1.34/1.04/.95/.83 gears before lightening (back-cut only, holes kill strength for use in stronger engine application).
True race sets for our faster tracks.
Pics:
Stock gearset in middle of the 3 input shafts

.92 5th gear for 105/115 transmissions

Mildly lightened gearset that was built for Porsche 908 application in Au.
 

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Discussion Starter · #5 ·
Close Ratio gearsets with 2.0/1.34/1.04/.95/.83 gears before lightening (back-cut only, holes kill strength for use in stronger engine application).
True race sets for our faster tracks.
Pics:
Stock gearset in middle of the 3 input shafts

.92 5th gear for 105/115 transmissions

Mildly lightened gearset that was built for Porsche 908 application in Au.
Nice work.. did you harden them after welding ..
and kan you use 105 gears in 116 boxes (are the gear axis distance the same)..
/Hans
 

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Richard Jemison
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8,258 Posts
CR Gearsets

Nice work.. did you harden them after welding ..
and kan you use 105 gears in 116 boxes (are the gear axis distance the same)..
/Hans
You canniot use 105/115 type gears in a 116/119 type transaxle. The shaft separation distance is different.

Gears are not annealed. They are cut and bored using diamond tiped cutting inserts.
Welding (tig) is done in a jig where the gear is immersed in a cooling solution to prevent heat soak.
 

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Gears are not annealed. They are cut and bored using diamond tiped cutting inserts.
Welding (tig) is done in a jig where the gear is immersed in a cooling solution to prevent heat soak.
Very slick Richard. OK so you TIG weld to localize the heat and then quench quickly to localize the heat even further.?

b :cool:
 

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Richard Jemison
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8,258 Posts
Gears

Very slick Richard. OK so you TIG weld to localize the heat and then quench quickly to localize the heat even further.?
No, the gears are in a saline solution while being welded. Never gets hot out at the teeth, where there is plenty of surface area to disapate heat, only the area welded gets hot.
 

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No, the gears are in a saline solution while being welded. Never gets hot out at the teeth, where there is plenty of surface area to disapate heat, only the area welded gets hot.
So the fixtured gear assembly to be welded is immersed horizontally in the water to just below the centerline and you weld and spin as you go.?

Very inventive stuff from both you folks.

b :cool:
 
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