Bluejack

So still trying to get to the bottom of this, thanks for your comment.

So the secondary gear set in the TSB, Part no. 23432-PCY-316, wouldn't work with a UK spec 2005 car, but only an AP2 gearbox? Is that right?

Nottm_S2

try googling that part no, i found threads talking ap2 only in a 5s search

https://www.s2ki.com/forums/s2000-un...-336-a-889280/

lovegroova

This might help.

All UK cars use AP1 engines and gearboxes.

The AP2 is the 2.2 litre engine which only has 8,000rpm but more torques and uses a different gearbox and different ratios.

anyway,

Here's a diagram of a UK 2005 Gearbox along with part numbers:
https://www.lingshondaparts.com/part...ckref/M__0500/

I'm pretty certain that the service bulletin does not apply.

martin j

l know someone building a kit car using S2KI engine and box, he’s interested in what the difference in the ratios are, ie is the us box 5th and 6th better suited to cruising, using less revs at m/way speeds? NVH levels are pretty high in some of these things.

lovegroova

It's all on Wikipedia.

Scroll down to the Specifications Table https://en.wikipedia.org/wiki/Honda_S2000

Here's the AP1 gearbox:
1st: 3.133
2nd: 2.045
3rd: 1.481
4th: 1.161
5th: 0.970
6th: 0.810
Secondary gear reduction: 1.160
Final drive: 4.100
Reverse: 2.800

And the AP2:
1st: 3.133
2nd: 2.045
3rd: 1.481
4th: 1.161
5th: 0.943
6th: 0.763
Secondary gear reduction: 1.208
Final drive: 4.100
Reverse: 2.800

Note that, while the ratios are the same for the first 4 gears, the difference in the Secondary Gear Reduction 1.160 vs 1.208 means that the AP2 gearbox is shorter for the lower gears but longer for the top 2.

Here's a useful table of the max speeds in each gear for the various options:
https://www.s2ki.com/forums/s2000-un...-info-1124653/

Bluejack

​​​​​​Thanks, familiar with the AP1/AP2 differences but that link to Lings is useful, thank you. It looks like the relevant part number is 23618-PCY-326, so you're right in that the part numbers in the TSB don't appear to apply (presumably because it's a US TSB and they used different part numbering for whatever reason?). Some more googling does suggest that 23618-PCY-326 replaced 23618-PCY-316, and that 326 strictly speaking applies to 2006 cars onwards.

I wonder therefore that there may be truth in the TSB, but these different part numbers apply.

lovegroova

Part numbers are the same across the world.

It's just that the US AP2 cars have a different part in this case, and it's that different part the TSB applies to. It does not apply to UK cars.

FWIW, here's the diagram for the MY02 car
https://www.lingshondaparts.com/part...ckref/M__0500/
The equivalent part no is 23618-PCY-306

And it's the same part for an MY00 car
https://www.lingshondaparts.com/part...ckref/M__0500/
23618-PCY-306

So for UK cars you have either 23618-PCY-306 or 23618-PCY-326.

If you want to look up US Part numbers, you can do so here: https://www.hondapartsonline.net/
US 2002 https://www.hondapartsonline.net/v-2...countershaft-1
23432-PCY-306

US 2005 https://www.hondapartsonline.net/v-2...countershaft-1
23432-PCY-336

US 2009: https://www.hondapartsonline.net/oem...BlZWQtbWFudWFs
See the note which says: So, in summary:
All pre-2004 cars use 23432-PCY-306
UK post 2003 cars use 23618-PCY-326
US post 2003 cars use 23432-PCY-316 which was replaced by 23432-PCY-336 It's these cars that are affected by the TSB

Bluejack

Cheers, appreciate your time on this!

I agree with all of that, the only bit I'd add is that it still looks like UK 2005 cars had 23618-PCY-316 replaced by 23618-PCY-326, similar to the US situation: www.parts-honda.uk/honda-cars/S2000/2005/S2000/TRANSMISSION/COUNTERSHAFT/17S2A01/M__0500/2/20733

lovegroova

I wouldn't trust that site, it's French

Bluejack

of the symptom just for records. Will be picking up with transmission specialists in the new year to get some advice and quotes.