Trans/gearbox rebuild

[BD55]

I read that a Registry member CJ Murray, has done 20k miles so far with the conversion in a rebuilt box. Sounds an interesting and almost fool proof mod, especially if you needed to change any of those major components anyway. I think it is only available from Elevenparts on this side of the pond.
Also has anyone fitted or using a short shift kit?

[neilbardsley]

Cliff is nice man reach out to him on FB. I'm sure he will give you his opinion. He has a 1.9/2l motor making more hp than normal

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[Adrian3]

thanks Mike....the only thing i seem to remember about tooth count is that one must not be divisible by the other....Harry's supposed dislike was referred in some other thread, not sure where

[BD55]

Thanks Neil, I'm not on Fb but I will speak to Cliff when he is allowed back on the Reg forum.
So any other improvements? I was looking at short shift kits... Good or bad thing? Do racers use the stock shifter?

[Mike Smith]

More on the Cadrobi Change

I took a look again at the differences between 7:31 and 8:31 and (assuming that I am correct – getting a bit old!)

For comparison, I used the Rolling circumference for a 175 x 15 Avon CR6ZZ
The figures will vary depending on Size Make and Model of tyre but the Avon will work for this comparison

Taking 4,500 as a sensible and comfortable rpm
1st Gear – 8:31 produces approx. 28 mph – 7:31 produces 24 mph
4th Gear – 8:31 produces approx. 104 mph – 7:31 produces 92 mph

Looking at it from another angle
Using an 8:31 v 7:31 reduces the rpm by approx. 500 rpm in 4Th gear at 70 mph
(I have to say that the drop looks more than I expected, so I need to go back and check my calcs.)

Another theory, to ponder, is that the drops between the gears should be a little less at each change. Therefore by making the changes using the Crownwheel and Pinion (not the individual Gears) means that you do not affect any of the drops between the gears.

Adrian - Yes you are correct - it is advisable not to have the Pinion Tooth contact the same Crownwheel tooth at each revolution

[neilbardsley]

http://forum.porsche356registry.org/vie ... abf9241030

On topic discussion here

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[Kneeslider]

This is all interesting info. I'm gearing up (groan!) to take my engine out again soon. The Cadrobi conversion sounds like the way to go if a gearbox upgrade is in order.

I have just noticed that when searching for matters 356 using Google, the registry forum postings no longer appear. Is this a recent change of policy over there? I'm not a registry member, mainly due to being based in the UK, but consulting old 356 talk forum posts was occasionally useful.

[Mike Smith]

I spoke with CJ today

He has 28,000 miles on a Cadrobi conversion

His 4 cylinder 356 Motor is produing 160hp from 2.1 litres