stu21t

I run a Renault un1 gearbox and I've found out that they can't shift at high rpms(over 6500)does any1 know what can be done to improve it?
I have heard of 2 things that can be done.
They are,
polishing of the synchro setup
removing every other tooth on the synchros and polishing.
Is this something any1 has done or had done?
does any1 know of any alternatives?
Or any reasons why not to do the above?

I really need to solve this.
And before I get told to ring chris cole or Gto, I have and Gto said it's a slow changing box due to the wide ratios, and you have to live with it or upgrade to quaiffe,
chris cole has offered to do some improvements but will do it as part of a rebuild that's costly and wouldn't tell me what gets done.
I'm happy to rebuild it myself and can get the work done locally for less.

If I can find out what to do?
Any1 got any bright ideas?

Thanks

markk

iTrader: (2)

you need to find out why the change is slow before you can modify it, one thing that alot of people miss is oil grades.

the only thing that slows the gears down so that the input and output match to allow a change is the synchro ring pressing on the gears cone, if the oil is so slippy then the gear your trying to slow down to change onto quickly, just keeps spinning. a gear oil with less friction modifiers will slow the gears down quicker.

allot of people use synthetic oils in gearboxes, great for temp control, crap for gearchanges. the same goes for poor semi or mineral oils.

stu21t

http://www.opieoils.co.uk/p-1022-red...il-75w-90.aspx


i use this, it is what was recomended by opie oils,
even tho it says on the site not to use it in a synchro box it didnt say that when i was told to use.
i just rang them the main reason for the refrenece on the site is they had some1 have a box failure and the company blamed the oil, they have tested it and couldnt find anything wrong, and redline will garentee their road oils not their racing oil, which this is. also they have sold it to shit loads of other people with no problem. lol

75w90 is what is recomended for my box.


how would i know what was wrong?
ive had a couple of gearbox people look at the design and cant see anything technically wrong it, they say theres no reason why it shouldnt work.

but i have spoken to some1 who specialises in these boxes and he says theres something he can do, but wants to rebuild the box and do the mods together at quite a high cost.
and he wont tell me whats done. lol

id rather take the parts to a local firm to be worked and rebuild the box myself.
if i can

FletchCossie

iTrader: (4)

Speak to Hardy Engineering on 01372 378 927 and see if they can offer you anything Stu

stu21t

will ring em tomorow steve, theyre shut now.
they any good with unusual stuff then?

FletchCossie

iTrader: (4)

I have no idea mate They are the only gearbox place I know of and are constantly busy, so must be good at what they do They should know how to make a box stronger or point you in the right direction.

stu21t

i dont even want it stronger atm, ill be happy to have it change properly lol

FletchCossie

iTrader: (4)

lol, I spoke to Bill and Neil who work there today. They said they basically strip, rebuild and fit gearboxes. They don't uprate things due to the R&D into improving things is not cost effective. They do rebuild gearboxes daily, so may have some knowledge to help you get sorted or maybe able to sort it or point you in the right direction?

Best thing is to ring directly

or speak to Pete Doughty who built my Esc Cos box. Give him a ring on 01159 262 073 and tell him Steve Fletcher sent ya and he will sort you out if he can

stu21t

Nice1 steve, the other people couldn't help.
I have found a few things out recently that could b fun.

Also some1 on rtoc worked for pete and has been talkin to him, has some interesting ideas.
Will defo ring him tomorow.
Got a spare box coming soon to play with.

Where's pete based?

stu21t

Nice 1 steve, I'm sendin him a broken box to play with and see what can be done.
He's talking about a straight cut dog box tho :biggrin:

FletchCossie

iTrader: (4)

Did you tell him I sent you to him? I should actually ring him as his building a new prototype box for the Esc Cos and I should be getting one of them. One's already been done and given to a bloke, but I can't be arsed pulling my box out again

stu21t

I did, think he remembered. Lol

he also confirmed what Ive learnt about poor mans dog boxes lol.
I'm gunna get my synchros machined next week, hopefully I'll b able to change properly then.

FletchCossie

iTrader: (4)

Cool, hope ya get it sorted mate

My Escort really needs looking at by MAD. She's running lumpy low down the revs and its starting to become annoying