# Modifying o2a/j Clutch fork for high RPM shifting...



## [email protected] (Oct 6, 2009)

So since i had a spare one laying around i decided to try strengthening it up some...this included quenching it after each weld.

I wanted to try something different from the typical plate that most people weld on top. I had a friend that bought one modified like that and it contacted the pressure plate.

Anyway without further ado...


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## vdubspeed (Jul 19, 2002)

*Re: Modifying o2a/j Clutch fork for high RPM shifting... ([email protected])*

very nice. I'm lost though. Why do they need strengthing? What makes them bend? Stiff pressure plates? Why would high RPM shifting weaken them.


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## [email protected] (Oct 6, 2009)

*FV-QR*

yes the higher pressure plate pressures cause them to flex and at high rpm centrifugal force forces the fingers out thus putting more stress on the clutch fork. So at high rpms full disengagement is very problematic making shifting a PITA.


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## GTijoejoe (Oct 6, 2001)

*Re: FV-QR ([email protected])*

That should make it pretty darn stiff http://****************.com/smile/emthup.gif


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## [email protected] (Oct 6, 2009)

*FV-QR*

yea but what sucked is there truly isnt chit for clearance in the o2j bellhousing...i had to grind down part of both sides (and all i did was at 1/16th to both sides!) to clear the bolts inside the bellhousing and part of the casting but still should suffice *hopefully* ill get some pics of it later.


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## L33t A2 (Aug 5, 2003)

*FV-QR*

Very nice.
It would be nice to see a product like this come out for the community that was produced on some CNC machines with some steel billet stock. It wouldn't take more than a day to fab up a vise and a couple jigs rough cut both sides and then set up for the finish cuts.


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## [email protected] (Oct 6, 2009)

*FV-QR*


_Quote, originally posted by *L33t A2* »_Very nice.
It would be nice to see a product like this come out for the community that was produced on some CNC machines with some steel billet stock. It wouldn't take more than a day to fab up a vise and a couple jigs rough cut both sides and then set up for the finish cuts.

shhhh


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## L33t A2 (Aug 5, 2003)

*Re: FV-QR ([email protected])*

i am willing and able to do such work, god forbid we make some profit


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## ftwelder (Feb 27, 2008)

It would be pretty tough to improve on this with a made from scratch part. I personally would laser cut 4130, stamp or brake form, TIG and heat treat for wear resistance. I would need a 200 pc order. Judging by Quenton's comments, I don't think the envelop shape would allow the required 40% increase in area to use aluminum so CNC would be pretty costly. 
How would you do it?


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## L33t A2 (Aug 5, 2003)

*FV-QR*

I left the machine shop I had been working at to go back and finish my bachelors degree but I didn't forget how to use the machines. Steel alloys suck to work with on the machining centers. The stock part would have to be mapped out on a blue print as well as the clearance inside the bell housing to see where material could be added to promote strength. Carbide end mills and inserts should definitely be used.
Get some .75" steel billet plates or whatever is just thick enough to make the part, you don't want to waste time cleaning off excess material. Skim one side, then flip it over and mount it on a jig/fixture to cut out the rough shape of one side, including the hole in the center. Flip it back over and mount it on another fixture to rough cut and then finish cut that side in one long operation. Mount it on the final fixture to finish cut the first side.
A good programmer could whip this together in a few hours as well as the inverted shapes for making the fixtures from aluminum.


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## [email protected] (Oct 6, 2009)

*FV-QR*

i agree CNC'ing a part to exceed the strength of the original would be difficult to achieve...
Below i blacked out where i had to grind the flat bar back down to base metal...


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## Agtronic (May 14, 2001)

I'm not sure I understand the quenching ... this is a mild steel part, which as far as I know, will not harden with quenching. (As opposed to high-carbon steel). That being said, it is definitely stronger with the side reenforcements. I think JUST those would be sufficient, as that is where they tend to break.


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## 2pt. slo (Jan 4, 2004)

*Re: (Agtronic)*

Flipside customs has made these for quite some time now. 

stock on top reinforced bottom.








Q your welding is improving greatly. looking good man http://****************.com/smile/emthup.gif


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## [email protected] (Oct 6, 2009)

*FV-QR*


_Quote, originally posted by *2pt. slo* »_Flipside customs has made these for quite some time now. 

stock on top reinforced bottom.

 
yes i know

_Quote, originally posted by *[email protected]* »_
I wanted to try something different from the typical plate that most people weld on top. I had a friend that bought one modified like that and it contacted the pressure plate.




_Quote, originally posted by *2pt. slo* »_
Q your welding is improving greatly. looking good man http://****************.com/smile/emthup.gif 


Thanks!


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## [email protected] (Oct 6, 2009)

*FV-QR*


_Quote, originally posted by *Agtronic* »_I'm not sure I understand the quenching ... this is a mild steel part, which as far as I know, will not harden with quenching. (As opposed to high-carbon steel). That being said, it is definitely stronger with the side reenforcements. I think JUST those would be sufficient, as that is where they tend to break.


it can be done with mild...using the right recipe http://lametalsmiths.org/news/robb_gunter.htm
Standard quenching with water though may only just barely harden the surface.


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## Passenger Performance (Nov 11, 2005)

I don't see why Milling it from 4140 would be an issue. We machine it here all the time, cuts nice.


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## GTijoejoe (Oct 6, 2001)

*Re: (Passenger Performance)*


_Quote, originally posted by *Passenger Performance* »_I don't see why Milling it from 4140 would be an issue. We machine it here all the time, cuts nice.

I would agree, its not like its carbon carbon.
IMO opinion the proper way to make this part because of clearance inside the bell housing would be to stamp it out of higher strenth steel, and/or be able to increase the thickness or change the geometry slightly (if that is possible judging by clearances)...
This part can be easily backwards engineered, its geometry is not very complicated, although you would need to right kind of equiptment.


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## [email protected] (Oct 6, 2009)

*FV-QR*

there's no such thing as easy in the VW world Joe! lol


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## Passenger Performance (Nov 11, 2005)

Stamping would be ideal, but, I doubt there is enough demand to justify the custom dies. For qts under a few hundred milling them is likely your best bet, we machine 4140 lockout pins for the railway cars here, we mostly machine stainless and I find 4140 more forgiving.


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## GTijoejoe (Oct 6, 2001)

*Re: (Passenger Performance)*


_Quote, originally posted by *[email protected]* »_there's no such thing as easy in the VW world Joe! lol 

Can't argue with that









_Quote, originally posted by *Passenger Performance* »_Stamping would be ideal, but, I doubt there is enough demand to justify the custom dies. For qts under a few hundred milling them is likely your best bet, we machine 4140 lockout pins for the railway cars here, we mostly machine stainless and I find 4140 more forgiving.

I would agree, stamping would be something like +$200/part for very low volume, or something crazy like that. I've had very small brkts made that were +$100/ea. Those though were a series of forming progress and tandem dies.


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## boost_addict (Dec 4, 2009)

*Re: FV-QR ([email protected])*


_Quote, originally posted by *[email protected]* »_i agree CNC'ing a part to exceed the strength of the original would be difficult to achieve...
Below i blacked out where i had to grind the flat bar back down to base metal...









Working hands.








Fork looks great http://****************.com/smile/emthup.gif


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## [email protected] (Oct 6, 2009)

*FV-QR*

thanks brah!


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## kkkustom (Jun 5, 2007)

Wait up here.... is this one of the root causes of the dreaded 02J anything past 4000 rpm grinds like a mofo problem??
I noticed that when I got my SPEC S3 clutch I actually grinded MORE between shifts. Even now with my rebuilt shift hubs i still grind a bit. However my 1 to 2 shift is nice, thanks to big tooth 02A shift hub and syncros! 
I too have a left over o2J case, another one of those bad boys in your hand and a TIG welder... I might have to give it a shot!


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## whiteriot (Nov 10, 2004)

*Re: Modifying o2a/j Clutch fork for high RPM shifting... ([email protected])*

Did the same kind of thing with mine, never really got to try it out but will this spring. Nicely done! http://****************.com/smile/emthup.gif


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## mechsoldier (Aug 14, 2004)

*Re: Modifying o2a/j Clutch fork for high RPM shifting... (vdubspeed)*


_Quote, originally posted by *vdubspeed* »_very nice. I'm lost though. Why do they need strengthing? 

They break even in stock transmissions, I run across a couple a year that are snapped, usually due to the pressure plate becoming more stiff to disengage the clutch as the clutch disk wears. Just did one in a 98 GLX Jetta last week that was snapped.


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## MKII16v (Oct 23, 1999)

*Re: Modifying o2a/j Clutch fork for high RPM shifting... (mechsoldier)*

I bent a stock one so far it was touching the pressure plate at idle with only a Sachs power pressure plate. I have been running the Flipside unit for 2 years now and it handles the Clutchnet Red pressure plate great. At $70, its a bargain.


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## need_a_VR6 (May 19, 1999)

*Re: (kkkustom)*


_Quote, originally posted by *kkkustom* »_Wait up here.... is this one of the root causes of the dreaded 02J anything past 4000 rpm grinds like a mofo problem??
I noticed that when I got my SPEC S3 clutch I actually grinded MORE between shifts. Even now with my rebuilt shift hubs i still grind a bit. However my 1 to 2 shift is nice, thanks to big tooth 02A shift hub and syncros! 
I too have a left over o2J case, another one of those bad boys in your hand and a TIG welder... I might have to give it a shot!

The clutch fork won't help at all unless yours is bent. Other then full 02a big tooth syncros, etc try *good* gear oil. I've had good luck with Torco.


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## diive4sho (Feb 7, 2004)

*Re: (need_a_VR6)*

listen to paul...he knows his ****


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## TeemuM (Feb 10, 2006)

*Re: (need_a_VR6)*


_Quote, originally posted by *need_a_VR6* »_
I've had good luck with Torco.

Have you used RTF or MTF?
http://www.torco-oil.com/produ...ssion


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## [email protected] (Oct 6, 2009)

*FV-QR*

i really wish i swapped in o2a sychros while i had it apart swapping r&ps! of course i didnt remember at the time


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## [email protected] (Jan 2, 2009)

I looked at machining them. There isn't any room in the bellhousing to increase the cross section where the critical stresses are found, and it would need to be machined in at least 3 or 4 different setups. The worst part is since most steels have roughly the same youngs modulus, you can easily stop them from eventually breaking- use 4140 or 4340- but to make them stiffer so you get all the throw out of the PP, isn't very easy. All you can really do is harden up the steel somewhat which is why Q was quenching. 
I think a machined part could be made to be stiffer then stock, especially if the transmission case was ground down to give a bit more room for install, but when i looked at it, it wasn't cost effective. 
You certainly don't want to make one out of aluminum regardless of the tensile strength of whatever alloy. 
FWIW, these do flex significantly in regular usage even when they aren't "bent"... Like a bit over .060" with a single diaphragm "race" style pressure plate. It may be what causes a lot of these transmissions to drag clutch disks at high rpm. You can't shift a transmission that still has load on it. 

PS: Found oooooollld pictures. 
























I don't think I ever got past "seeing what i could fit in the bellhousing" so that certainly isn't a production ready design by any means. I already see some corners that would need a radius or they would be impossible. 


_Modified by [email protected] at 2:52 AM 12-15-2009_


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## need_a_VR6 (May 19, 1999)

*Re: (TeemuM)*


_Quote, originally posted by *TeemuM* »_
Have you used RTF or MTF?
http://www.torco-oil.com/produ...ssion

RTF is in there now, works a lot better then Redline.


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## Agtronic (May 14, 2001)

*Re: FV-QR ([email protected])*


_Quote, originally posted by *[email protected]* »_
it can be done with mild...using the right recipe http://lametalsmiths.org/news/robb_gunter.htm
Standard quenching with water though may only just barely harden the surface.

Recipe or no recipe, the carbon level are so low, I doubt you will be seeing any change in hardness at all. According to wikipedia, quenching carbon steel works for steels containing at least 0.4% carbon, and mild steel has between 0.05 and 0.15% ... Anyways, sorry for bustin' balls, don't mean to nitpick.








edit : Okay, I read the article, and they pitch their theory well, but it just goes against everything I have ever learned about metallurgy.


_Modified by Agtronic at 9:55 AM 12-15-2009_


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## Eganx (Apr 30, 2004)

*Re: FV-QR ([email protected])*


_Quote, originally posted by *[email protected]* »_
Standard quenching with water though may only just barely harden the surface.

when I harden anything I quench in used motor oil. the way I understand it, the metal will actually draw carbon out of the oil to harden the surface of the metal. it has worked quite well for me for a while.


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## Agtronic (May 14, 2001)

How are you guys testing for results in hardening?


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## GTijoejoe (Oct 6, 2001)

*Re: FV-QR (Eganx)*


_Quote, originally posted by *Eganx* »_
when I harden anything I quench in used motor oil. the way I understand it, the metal will actually draw carbon out of the oil to harden the surface of the metal. it has worked quite well for me for a while. 


Than you understand correctly....
The key feature to harndening is depth, normally this type of 'I did it myself' hardening is very shallow, unless you know exactly what you are doing, and what temp is needed, and duration etc etc...


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## [email protected] (Jan 2, 2009)

*FV-QR*

I'd say yes and no- You can take a piece of welding rod and quench it a couple of times and it's so brittle it won't bend 1/10th of what it did before you hardened it. But, it's also a small cross section so you don't need a lot of depth to do anything. 
This particular part isn't exactly thick either though.


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## Eganx (Apr 30, 2004)

*Re: FV-QR (GTijoejoe)*

right, I usually call it case hardening. If I ever need to harden something this has worked for me, but then again I have never had to harden anything really thick, or under enough stress to need anything more than a good .020-.030 hardened shell/case


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## GTijoejoe (Oct 6, 2001)

*Re: FV-QR ([email protected])*


_Quote, originally posted by *[email protected]* »_
This particular part isn't exactly thick either though. 

I'd agree, I was speaking in generalities


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## davojuri (Aug 28, 2009)

*Balkan reinforced fork in 02J hybrid 6 speed powdercoated housing*

Hi guys 
just wanted to show you how we made our reinforced fork in tuning garage called Herc tuning in Cacak Serbia from the guy who makes all the champion geraboxes here from the first class steel from Kosovo that is normaly exported to Italy. 
He did my 02J gearbox to 6 speed one and incorporated my Quaife LSD into it. 
Ratios are: 
1. 3.7 
2. 2.2 
3. 1.6 
4. 1.25 
5. 1.04 
6. 0.87 
Final Drive 3.64 
First two remained OE for the comfortable daily driving without killing the clutch and the rest is killing machine. 
It is calculated for shifting on 7200rpm and drops only to 6000rpom where I do have 375Nm - meaning pulls like hell all the way. 
Than we added reinforced fork that I have seen at inaeng. 
Ours looks even better I think. 
Still no billet pinion brace but to come. 
I'll share my results than. 
Here is the link to the pics: 
http://s537.photobucket.com/albums/...ed close ratio synchromesh gearbox/?start=all 
:thumbup::thumbup::thumbup::thumbup::thumbup::thumbup:


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## [email protected] (Oct 6, 2009)

davojuri said:


> Hi guys
> just wanted to show you how we made our reinforced fork in tuning garage called Herc tuning in Cacak Serbia from the guy who makes all the champion geraboxes here from the first class steel from Kosovo that is normaly exported to Italy.
> He did my 02J gearbox to 6 speed one and incorporated my Quaife LSD into it.
> Ratios are:
> ...


 I like  :beer:


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