urgent gearbox question

[m.d.]

not sure what happened here, but this is what i posted

hi again people, not been on here for a long time but i always have a nose to see how things are going here,

anyway my house mate has just bought a 1.2 nova and a 1.3 sr that has rotted to beyond repair, the gearbox is shafted on it so he is going to the scrappy on lunch to pick up another,

but he wants the closest ratio gearbox he can get,

i said to look for CR in the code on the end of the box but he wanted to know what the difference was between the 'F' numbers on the top,

can anyone help as i cant remember what they mean, its f10 12 and 13 for a small block isnt it???

hes going to get a 5 speed so i said that an f10 was a 4 speed, am i right in saying that,

anyway, thanks for the help, answers asap please cos it looks like we are back in the nova engine bay again tonight, (first time since selling mine 4 years ago lol)

[Riggy]

the f figures are the amount of tourqe for the gearbox

f10's come in 4 and 5 speed and can do 100lbs of tourqe they also have loads of different final drives etc CR WR etc but they asyou said are normally under a mound of dirt on the end of the box

f13's cam on GTE/GSI/SRI and as suggests 130 lbs of torque

[Riggy]

oh welconme back my the way :thumb:

[Welsh Dan]

F10 can be 4 of 5 speed, if it has a big nut on the endplate then its a 4 speed (by big nut i mean about 40mm).

F13CR is the most common close ratio box, but an F15CR is a little closer, and still fits a smallblock engine.

The bigger the F number the more powerful the engine they were intended to handle.

[m.d.]

thanks peeps, ill go scrappy hunting lol

[Stuart]

the F number is bollocks!!!!!!

F10's and F13's have the SAME components inside them (aside from the 4spd variant) so how the hell can one take 30 NM of torque more?

check the sig link for gearbox info.... assuming its working. If the site is down pm me and ill send you the link to my server at home.

[m.d.]

thanks for the info stuart mate, think i remember you from when i was on here before,

ok then a quick question, he has both the 1.2 gearbox (does about 55 in 2nd at 7k)
and he has the gearbox that has come with the 1.3 sr engine we are fitting. which one would be more than likely the shorter one,

[garyc]

They will both be the same ratio's unless the unlikely chance you have one of the rare 221 clusters.

[m.d.]

ideal, thanks for the info,

[Stuart]

GM were never consistent witht he boxes. look in my sig link (if the link is dead, pm me for the backup server) at the speed in gear bit for lots of info on what boxes were generally fitted to what cars and how to ID a box

[mowgli]

are you sure the box is broken? when the wheel bearings go, it sounds like the box is shot.

If you are swapping the 4 speed to the 5 speed, you need the gearstick as well, they are different. The speedo from the wreck is useful if you are changing diff ratios. changing the miles is quite easy as well.

[Stuart]

The speedo from the wreck is useful if you are changing diff ratios.

not needed... the speedo drives come off the output of the diff so it matter not what the FD ratio is.