115mph (real not pub mph) 35mpg......no injection to annoy you.....Originally Posted by John H
I am tempted to do it myself again
115mph (real not pub mph) 35mpg......no injection to annoy you.....Originally Posted by John H
I am tempted to do it myself again
Yes thats correct, I have not tried it myself but I assured it works by someone that has done it.Originally Posted by John H
The 12ST is short stroke thats why they rev so well and the are a larger bore than the 13SB(Same as 1.4). So combine the longer stroke of the 1.3 added to the larger bore of the 1.2 and you have 1400CC:D .
Externally it looks standard aswell unles you fit twin carbs etc. The 1.2 head is actually different & I have been told its better but not sure if that is true.
I was also told a few years ago that a Sierra 1.8 carb fits(Poss a Pierburg?) and is good as twin 40's to a certain extent but not sure if thats correct.
Prob best to get a Weber carb meant for a 1.4SR if you can, should go quite well then.
Also whack in a F13CR with a 4.18 final drive in from your F10
As I have already said, I got my pistons pocketted to lower the compression a bit. apart from that, it is really easy.
Thanks rich, most helpful as usual! I have both engines sat in the shed, so won't cost me anything to do. I'll use a 1.3 inlet with a twin choke weber on. What'll the 4.18 fd give, better acceleration?Originally Posted by Novasport
Don't suppose you can remember how much you removed?Originally Posted by mowgli
yes thats right better accelerationOriginally Posted by John H
I took about 5mm from the crown out. but it was 17 years ago & I'd measured the thickness of an old head gasket, the crown volume & the head volume then calculated the compression ratio. it came out quite high & I worked out what volume was needed to get 10:1 & got a engineering shop to machine them. they never charged me for doing it because they wanted no comeback.... I will try & find the diameter out for the machining, it was based on stock pistons, and (amazingly) a photo in a back issue of CCC mag feature on tuning baby vauxhalls.Originally Posted by John H
I have looked up the piston catalogue specs. the 1200 piston has a flat outer lip. that is the limit of where to machine it. the valve cutouts are at about 4.5mm depth. I remember that the cutouts were removed so the 5mm figure is about right. I got the engineer to put a nice radius in the corner so it would have been about 2mm.
Last edited by mowgli; 11-01-09 at 09:21 PM.
I would be interested in finding out more info on that CCC feature aswellOriginally Posted by mowgli
Yes that FD will give a better accelleration, the F13 & 4.18 FD will give the same ratios as an F15CR from a Corsa Sport so you can use either.Originally Posted by John H
Wish I had kept my 12ST from the 28k mile swing I broke, and the bloody bump strips I now need for the SR!!!
Last edited by Novasport; 11-01-09 at 09:17 PM.
it was based on a conversion done by peter maiden components from tamworth. they were the men when it came to nova tuning in the late eighties. there was a copy on ebay a year or so ago, but I never got it...
Do you know the issue number?