I'm just wanting some info about the tunnel mods required to fit the ca18 standard gearbox into a sedan. For the people that have done the conversion using the manual tunnel not the automatic one, have you cut the tunnel out completely or just cut the bits that are in the way and gone from there?
Thanks

people say you can still get them into manual tunnels but with a fair bit of massaging (I personally wouldn't do it as I feel the box would bee too close to teh tunnel and if the motor shifts at all the box could touch on teh body making a banging noise or make the car vibrate?

I've just cut out most of my tunnel and am just going to get some sheet metal and mould it to the desired shape and weld in.

One question is what gearbox are you intending on using if you use the stumpy skyline then just a whole lot of massaging, however if you use the silvia 5 sp then you will have to cut out the rear section of the tunnel and make up a box section and get that welded in, as the rear of the box is shaped up at the back.

Cheers
Damo

Yes I agree with Damo.

I've heard the 120Y tunnel is a good replacement. They didn't use a different tunnel for auto and manual. The tailshaft bit of the tunnel is a similar diameter from memory.

I wish I could show you a photo of a 4 speed 1200 box next to a S13 Silvia box. They are "just a little" different in size.

i took a shot of the CA box and the a12 box when i was doing my conversion. heres the two above mentioned next to each other. big big difference!!!




the bellhousing is much broader and stays that way longer than the 1200's gearbox. i reckon the idea of cutting a tunnel out of another car and welding is the best idea, i used a Z32 300zx tunnel and it worked a treat!

what a champion!. Great work.

Easiest way is to measure back 210mm from the back of the original gearstick hole & cut the tunnel down to the crease on the drivers side.
Cut along horizontal & then blend back up into the original gearstick hole - do this on both sides.
Then you use a scissor jack to jack the sides of the tranny tunnel out to suit the CA18 box & weld up the hole using sheet metal when you're finished.
Beats cutting the whole transmission tunnel out of another car!

Thanks for help, Sounds like Coops idea is pretty easy, I'll start with that and hopefully things don't get too messy!

think this is the idea??