ATV rebuild

[Etches]

Picked up that atv off one of the lads on here





Planning on servicing and rebuilding it, has anyone on here had any experience of this? Just wondered for tips and what have ya.

Also do people put a longer 5th gear in as i may aswell if i am to rebuild it?

Cheers

Etches

[hayesey]

I've swapped box internals over to a new casing a couple of times, it's not too bad a job, basically don't try disassembling it too much, just unbolt and lift the whole gubbins out in one and put right into the "new" casing. 

If you want a longer fifth then use one out of an 8P

[leeg40]

If you want a longer fifth then use one out of an 8P

Thats exactly what I did used the fifth out of the 8p from my coupe S, although I got JP race to build mine along with the gripper diff I had kicking around.
I have the full casing from the 8p box sitting here gathering dust so of you need a new one give me a shout, it's in good condition had done 54k.

Lee

[dub-disaster]

What's that longer 8p ratio on the 5th like is it realy worth doing? What rpm are you doing at 70 mph ??

[Etches]

Well i am doing it with one of my mechanic mates, plannin on running a similar set up to yours hayesey have you botherd with the 8p 5th? Cheers for the offer mate but i may aswell just get an 8p full box

[hayesey]

no I didn't bother with the 8p fifth in the end, considered it but was told it makes fifth annoyingly slow by some one else.

[leeg40]

What's that longer 8p ratio on the 5th like is it realy worth doing? What rpm are you doing at 70 mph ??

Here is a bit of info i have from some research i done a few years back, all calculated asuming running of stock 175/60/13 tyres and max 7000RPM.

G40 standard gear box:
Top gear gives 23.121 mph/1000rpm and top speed of 161.846 mph at 7000rpm (hence G40's 160mph clocks)
Engine speed in fifth:
30mph=1298 rpm
40mph=1730 rpm
50mph=2163 rpm
60mph=2595 rpm
70mph=3028 rpm
80mph=3460 rpm
90mph=3893 rpm
100mph=4325 rpm

top speed in 1st=39.876 mph, change in to 2nd at 4246 rpm dropping 2754 rpm.
top speed in 2nd=65.743 mph, change in to 3rd at 4905 rpm dropping 2095 rpm.
top speed in 3rd=93.882 mph, change in to 4th at 5231 rpm dropping 1769 rpm.
top speed in 4th=125.552 mph, change in to 5th at5430 rpm dropping 1570 rpm.
top speed in 5th=161.846 mph at 7000 rpm.


then in comparison 8P standard ratios but with G40 final drive (3.333)
top gear gives 26.589 mph/1000 rpm and a top speed of 186.123 mph at 7000 rpm.
engine speed in fifth:
30mph=1128 rpm
40mph=1504 rpm
50mph=1880 rpm
60mph=2257 rpm
70mph=2633 rpm
80mph=3009 rpm
90mph=3385 rpm
100mph=3761 rpm

top speed in 1st=39.876 mph, change in to 2nd at 3968 rpm dropping 3032 rpm.
top speed in 2nd=70.343 mph, change in to 3rd at 4469 rpm dropping 2531 rpm.
top speed in 3rd=110.185 mph, change in to 4th at 4990 rpm dropping 2010 rpm.
top speed in 4th=154.580 mph, change in to 5th at 5814 rpm dropping 1186 rpm.
top speed in 5th=186.123 mph at 7000 rpm.

[Andy]

Problem with an 8P 5th in an ATV 'box is that you have to string out 4th before going into 5th if you want to stay in the power band. Remember being in the tin can with Steve when he did this mod, and it was a bit of a pain in the arse.

If you're running 175/50R13 tyres and want longer gearing, then it might be worth thinking about making all the ratios longer, not just 5th. Otherwise, if you're running 14"s or 175/60R13s then I'd question why you'd want a longer 5th anyway.

[leeg40]

If you're running 175/50R13 tyres and want longer gearing, then it might be worth thinking about making all the ratios longer, not just 5th. Otherwise, if you're running 14"s or 175/60R13s then I'd question why you'd want a longer 5th anyway.

I agree, when i posted earlier that i have the 8p 5th i should have also said i have the 2nd, 3rd and 4th in there to, lol so the gearing is longer throught the range, not had a chance to run it yet to see what its like but i had a chat with a guy from germany a few years back who only tracked his car and he had done this and spoke highly of the way it proformed on track, but as yet i can not comment, although i think if any of you use your car as a daily then this might not be the best idea as from what i have heard you need to keep the car on the bubble so to speak to get the best out of it.
For me the reason for doing it was that i seemed to constantly be running through the box and on the limiter even in 5th at about 135mph, and it just got kind of tedious after a bit, imo anyone pushing 185bhp + and especialy some of you turbo lads at over 200bhp, i think you will have the power to make good use of the extra length in the range.

[hayesey]

on the limiter in 5th at 135mph?  even with a standard rev limit you shouldn't see the limiter in 5th till just over 150mph with a g40 gearbox, are you sure it's not a GT box that was on there?

[leeg40]

on the limiter in 5th at 135mph?  even with a standard rev limit you shouldn't see the limiter in 5th till just over 150mph with a g40 gearbox, are you sure it's not a GT box that was on there?

It had ATV stamped on the casing, and I can only asume it had never had a rebuild with a diffrent gear set it had only done 44k when I got it, and yes that was stock limiter at 135mph had a chat with jabbasport when I had some work done back in the day and they never said it was diffrent to anything they had seen?

[Robin]

i looked into fitting an 8P 5th gear into my ATV box but a couple of guys who had done it told me that it wasn't ideal and advised me against it, do a search for posts under my username and you'll find my post about it.

[Etches]

Can you remember what the post was called Robin, had a look but couldnt find anything with 8p , gearbox or atv in other than irrelavant topics. Cheers dude

[Nick_S]

5th gear set is easy enough to change yourself if you didn't like it. I've put an 8P 5th on one of my spare boxes, due it having a mk4 valver 5th as stock, which is somewhere between GT and G40 5th ratio and too short for my liking

[Etches]

I have a gt box on my g at the moment is soo short , 4th is the shortest by far . I had a choice a 4 speed or a gt 5 speed. Clearly chose the wrong one!

Thanks for the info people, great as usual. Will probably stick to the standard ratios  n just slap a new casing on