Haynes Forums - gearbox problem... doh!

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- - gearbox problem... doh! (http://www.haynes.co.uk/forums/showthread.php?t=4561)

Keep in mind that the standard design has the lower flange of the bell housing hanging 25 mm below the bottom of the chassis. So it makes much more sense to cut the bottom rail that will have to be cut out anyway, and maybe make a hole in the table as well.

By the way, I did cut out and moved back a section of my top rail in order to fit the Zetec thermostat housing.

ahh i see i thought the bottom of the bell housing was flush. i guess what i need to do is build the back end first and put a dif in there so i can line things up. problem is this engine has a massive sump rofl. chop chop chop

You can grind the mounting lug down on the 7.5" IIRC.. I should realy compare my 7" and 7.5" units..

Do you realy think your going to need a 4.1?

Are you going for an LSD?

I am going to be running a 7" Non LSD 3.6 diff to start with on the roadster and may go to LSD..

TT

ohh did not know that cool :D are the drive shaft flanges the same distance appart as the 7inch? if thats the case then game on!

Edit: just did a search on sierra owners forum....
"2wd diff top mount is 7.5 inch, 4x4 is 7 inch..... you can lop the difference off of the diff casing or cut and re-weld one of the mounting tags on the beam. As you look at back of the car it's top right hand mount you need to mod.

2wd saph arms are same as 4x4 arms so you're fine there...only ones that are different are 3dr arms (arb mount in diff place).

HTH
Dan"

happy days can use the standard rear end now. Thats makes life so easy. Man i could kiss you guys :D but i wont! so dont panic. Im saving that for then its passed its iva lol

What wheel & tyres are you planning to use?
I have a V6 type 9 with similar ratios and find 1st and 2nd low even with a 7000 rpm red line, with the amount of power you have, the 3.9 will be fine, the 3.6 probably better on the road

Another thought, on most 7 's the bottom of the bell housing is a couple of inches below the lowest point of the chassis

Quote:

Originally Posted by Eternal (Post 41103)

Thanks just seen your v8 height thread. dude that engine is massive. Im really worried about the dif to be honest. its going to be a nightmare to mount. =( the skyline dif is a 4.1 ratio do you think i can get away with a 3.9 sierra one instead or maby a 7.5inch cossy one? (RB25DET - twin-cam turbo (T3 Turbo) ~245 to 250 hp and 319 N·m) ~wiki) my one will be old so not that much power. it would save sooooooooooooooo much trouble,

Also can someone measure how high the center of the dif shaft center is from the table top? just so i can get the gearbox inline.

Thanks again all

Edit found out my gearbox ratios i dont have a clue at all about this kinda stuff all those cogs are confusing. So can anyone who knows whats what, advise me to the best dif for this 'RP71C #2', the ratios are 3.32, 1.9, 1.31, 1.0 and .838.

http://cgi.ebay.co.uk/SIERRA-SCORPIO-GRANADA-3-91-7-5-INCH-REAR-DIFF-KITCAR-/390211222449?cmd=ViewItem&pt=UK_CarsParts_Vehicles _CarParts_SM&hash=item5ada66bbb1 Found that but duno how hard it would be to fit as its a bit wider. i presume the shafts will need to be modded/shortened

the ratios are for each gear so (1st) 3.32 means for every one prop rev there is 3.32 crank revs.
1.0 is one in one out (like most 4ths are)
and .838 is a over drive where the prop spins faster so every .838 crank rev you get 1 at the prop
take this into account with your dif ratio and your rear tyre dia and you can work out speeds to revs
engine revs/gear ratio= prop revs, prop revs/ diff ratio = wheel revs and times this by wheel dia to get road speed
simples ;)

The gearbox ratios you have are very similar to the V6 type 9 and I find 1st low 2nd better and third the gear off much fun.
I run 185/60/14 if you have bigger rolling radius and big power available I think the 3.6 will be much more like it.
Remember the car the gearbox came out of was a lot heavier and designed to move of from standstill with 4 people and luggage