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Can I beef up a 5speed gearbox for turbo GTI?????
Posted: Sun Dec 20, 2009 11:11 am
by flickaz
Alright, the background. I have a 91 WT SWB zook with a turbo GTI donk. Its been on the road like this for a year and Ive started having troubles getting gears, usually 1st when stationary but occasionally going up and down gears too.
It started playing up after id given it a bit on the tracks, but would be fine after a rest, which I found odd. The clutch would get really hard to press in, so I replaced the cable and it seemed better. Now Ive had to adjust the cable up numerous times and it only helps for a little while. I have an extreme outback clutch, so Im thinking my issue is either with this or my synchro's as I can get gears my matching the revs.
I normally nanna around but it does put 100Kw on the treads when I give it the beans so Im keen to see if it possible to beef the 5 speed up, in particular the synchro's. Anyone got any ideas?
Posted: Sun Dec 20, 2009 1:15 pm
by mrRocky
I had this prob with my 1ltr, turned out the clutch only can be adjusted to a certain extent before it needs replacing. I would be putting in a new h/d clutch and changing the oil in the box for a start.
Posted: Sun Dec 20, 2009 1:17 pm
by PJ.zook
It sounds a little like youre clutch isnt fully disengaging, causing hard to select gears.
Zooks have never needed heavy duty clutches, all it does is busts cables. Theres quite a few of us running higher peformance motors with standard clutches, and havent had any issues.
As for heavier duty parts for the zook box, i very much doubt you can buy anything off the shelf. But theres always custom. Im sure you could get a set of straight cut gears with dog clutches cut.
Posted: Sun Dec 20, 2009 1:46 pm
by nicbeer
vitara boxes stronger?
Posted: Sun Dec 20, 2009 2:22 pm
by flickaz
Yeah its only supposed to have 30% more clamping pressure than standard and it was fitted the same time I fitted the donk (1yr ago). So unless theres a defect with the actual clutch I cant see it needing replacement?? Its probably done 3000km max!!
I put this in because I sheared the standard clutch in half in the first 150m. This might be cos it was old, but I didnt wanna take the risk again, maybe H/D is too heavy?
How will this cause it not to disengage though? This is why I was looking at synchros. The box is 2nd hand and might just need a fresh set?? Its annoying because it seems to be intermittent. ARGH!!!
Posted: Sun Dec 20, 2009 3:08 pm
by PJ.zook
If youre clutch isnt fully disengaging, ie slightly dragging, that means the synchro's not only have to slow/increase the speed of the shaft (theyre normal job), they also have to deal with the clutch thats still trying to spin the shaft. The gear will not go in without the parts of the synchro spinning at the same speed, thats how they work, so if its taking the synchro a lot longer to slow down/speed up the shaft due to its still being driven, its going to take longer to engage the gear.
Best way of checking this actually is trying to get reverse. While the vehicle isnt moving, push the clutch in and try to get reverse. If it grinds away until you force it in, then its most likely the clutch, as reverse doesnt have a synchro.
Posted: Sun Dec 20, 2009 4:36 pm
by flickaz
Some good info from all of you guys, I appreciate it.
PJ.zook wrote:If youre clutch isnt fully disengaging, ie slightly dragging, that means the synchro's not only have to slow/increase the speed of the shaft (theyre normal job), they also have to deal with the clutch thats still trying to spin the shaft. The gear will not go in without the parts of the synchro spinning at the same speed, thats how they work, so if its taking the synchro a lot longer to slow down/speed up the shaft due to its still being driven, its going to take longer to engage the gear.
Best way of checking this actually is trying to get reverse. While the vehicle isnt moving, push the clutch in and try to get reverse. If it grinds away until you force it in, then its most likely the clutch, as reverse doesnt have a synchro.
Its funny you mention this, as I have had issues getting reverse a few times before. tighten the clutch and its the goods, but only lasts a matter of days. I was gonna pull the gearbox out for a rebuild but maybe Ill look at the clutch before I do anything too drastic.
Cheers.
PS. what clutches are other guys running with turbo gti's?
Posted: Sun Dec 20, 2009 8:11 pm
by Drew
Clutch plate is not up to it.
Try talking to doug at NPC he's the man with custom clutches
Posted: Sun Dec 20, 2009 10:07 pm
by Gutless
flickaz wrote:
Its funny you mention this, as I have had issues getting reverse a few times before. tighten the clutch and its the goods, but only lasts a matter of days.
Check your clutch fork. Its common for them to crack on the sierras and every time you adjust your clutch, it puts more strain on the fork; opening up the crack a little more, which allows the cable to go slack again. Eventually it will snap.
Pete
Posted: Sun Dec 20, 2009 11:17 pm
by flickaz
Gutless wrote:flickaz wrote:
Its funny you mention this, as I have had issues getting reverse a few times before. tighten the clutch and its the goods, but only lasts a matter of days.
Check your clutch fork. Its common for them to crack on the sierras and every time you adjust your clutch, it puts more strain on the fork; opening up the crack a little more, which allows the cable to go slack again. Eventually it will snap.
Pete
Hmmm, now thats slightly alarming!!!! Im about to drive it 400kms on wednesday to my parents place for xmas and some dune bashing!!!! I really hope that doesnt happen to me! lol. I think as soon as possible Ill be pulling the box out and having a good look at the lot.
Im in Adelaide and NPC doesnt mean a whole lot to me. Can someone put some light on this one for me? Cheers for the help guys, Id like to get this sorted before it lands me in the poo!!
Posted: Mon Dec 21, 2009 10:39 pm
by Drew
http://www.npcperformance.com.au/
Sorry npc clutches ,have been using them for years with good results in all sorts of things.
I have a new custom clutch for mine with the gze & hilux box.
its amodded 20v flywheel,EVO pressure plate with upraded spring,
V6 prado sprung center with ceramic friction material.
Posted: Tue Dec 22, 2009 11:01 pm
by oozuk
I've got one of nicks clutches behind my turbo G16b in my sierra, lite pedal feel and not an ounce of slippage