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patand
Joined: 12 Jan 2007
Posts: 91
Location: Sweden
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 Posted: Mon May 28, 2007 6:46 pm Post subject: Manufacturing syncro rings for G31 tranny! |
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Hi all!
This weekend I talked to a friend who works in a workshop. He got really interested in trying to manufacture the synchrorings for the G31 tranny. I know he can make the correct shape of the rings with his CNC machines. He also have connections with a firm which can harden the metal to what the customer specifies.
I'm going to take my spare tranny to him as soon as possible so we can start take measurements of the rings (also measure the hardness of the metal).
But now I would be really interested in any comments from the people here about this.
What could be the most difficult part in manufacturing these rings, any fallpits that we might end up into?
Might we end up destroying more in the gearbox if we don't get for e.g the hardening just right?
What could we do to improve the bad lasting original rings? Why don't they last?
If possible we would like to, of course, make these replacements better than original, any ideas are welcome! 
If this is a success, then we will most probably try and make dogteeths as well, and not only for 2nd gear, but we must start with something and decided try this first.
Now give me comments!
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Rasta Monsta
Joined: 12 Jul 2006
Posts: 11733
Location: PacNW
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| Posted: Tue May 29, 2007 3:55 am Post subject: |
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I would think the number one issue would be figuring out and obtaining the proper material. They aren't mechanically complex if your friend can exactly duplicate the porsche part.
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Toofah King Bad
- WeiBe (1987 924S 2.5t) - 931 S3
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patand
Joined: 12 Jan 2007
Posts: 91
Location: Sweden
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| Posted: Tue May 29, 2007 4:39 am Post subject: |
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| Rasta Monsta wrote: | | I would think the number one issue would be figuring out and obtaining the proper material. They aren't mechanically complex if your friend can exactly duplicate the porsche part. |
That's exactly what I think to. We (or he) have the possibility to measure how hard the material is, but then there is the issue of friction and so on which might not have to do with the hardness of the surface.
It will anyhow be an interesting project and why not try, if it fails then atleast we have learnt something. I'm counting on having to try a few different prototypes atleast before giving up.
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Rasta Monsta
Joined: 12 Jul 2006
Posts: 11733
Location: PacNW
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| Posted: Tue May 29, 2007 4:45 am Post subject: |
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Synchro 'friction' actually comes from viscous gear oil clinging in the grooves. . .
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- WeiBe (1987 924S 2.5t) - 931 S3
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Min
Joined: 04 Nov 2002
Posts: 2368
Location: Vernon, British Columbia, Canada
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| Posted: Tue May 29, 2007 4:51 am Post subject: |
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| Rasta Monsta wrote: | | Synchro 'friction' actually comes from viscous gear oil clinging in the grooves. . . |
Depends on the synchro design, on the audi gearbox 2nd gear, the syncro just has a rough surface like sandpaper, rather than grooves. That if is I'm remebering properly anyways.
Min
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Custom means it didn't come from a box.
1980 n/a with EDIS and Megasquirt II Injection. 7 different colors and counting. |
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patand
Joined: 12 Jan 2007
Posts: 91
Location: Sweden
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| Posted: Tue May 29, 2007 5:02 am Post subject: |
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| Min wrote: | | Rasta Monsta wrote: | | Synchro 'friction' actually comes from viscous gear oil clinging in the grooves. . . |
Depends on the synchro design, on the audi gearbox 2nd gear, the syncro just has a rough surface like sandpaper, rather than grooves. That if is I'm remebering properly anyways. |
So what you are saying is that it is the structure of the surface on the syncros that is important not so much the friction of the material it self?
That is actually good news then, the surface of the syncros we can probably manufacture pretty much like we want it.
Does anyone know why the G31 syncros fail so much compared to e.g the audi tranies in the 944s (us 931s after -81 as well)? Is there something we can do to improve the rings for the G31?
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Raceboy
Joined: 01 Mar 2004
Posts: 2327
Location: Estonia, Europe
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| Posted: Tue May 29, 2007 5:54 am Post subject: |
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On G31 the syncros need special tranny fluid to operate correctly. Conventional fluids are too slippery.
First "compatible" fluid that comes to mind is Redline MTL.
I'd be interested in both syncro rings and dogteeth.
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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold 
'84 924, turbocharged, sold.
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patand
Joined: 12 Jan 2007
Posts: 91
Location: Sweden
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| Posted: Tue May 29, 2007 6:10 am Post subject: |
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| Raceboy wrote: | On G31 the syncros need special tranny fluid to operate correctly. Conventional fluids are too slippery.
First "compatible" fluid that comes to mind is Redline MTL. |
Redline MTL is a GL4 oil, G31 tranny should have GL5 classified fluids which in the Redline range should be Redline 75w90ns ("ns" is important since Redline also has 75w90 (without "ns" in the name) which is inteaded for use in trannies with LSD and thus is more "slippery".
I myself have however tried MTL in the tranny one season and it worked fine. But the season after I had the crunching on second gear back again after the winter standstill and thought it best to switch to 75w90ns just in case it wasn't good using an GL4 oil. Made no difference changing oil though and later that season I lost 1st gear...
So I changed tranny resently (1 week ago). And now I'm abit afraid to try MTL again in my "new" tranny which crunches badly on 4th gear but not so much on second. 
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patand
Joined: 12 Jan 2007
Posts: 91
Location: Sweden
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| Posted: Tue May 29, 2007 6:22 am Post subject: |
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| Raceboy wrote: | | I'd be interested in both syncro rings and dogteeth. |
Well I will surely let you guys know how it goes! We are not doing this to become rich, so if the manufacturing isn't to expensive I'm sure we can give you a good price. But we want to be sure that we have tested enough and have a working product before shipping anything.
And as said before all input is apreciated, help us do this right and maby we can save our G31 trannies! 
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Raceboy
Joined: 01 Mar 2004
Posts: 2327
Location: Estonia, Europe
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| Posted: Tue May 29, 2007 6:37 am Post subject: |
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Hmm, yes, G31 is GL5, NA boxes are GL4 and that's why there's MTL.
Sorry for confusion.
ANyway, using the right oil is vital on G31 BEFORE it crunches gears
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'83 924 2.6 16v Turbo, 470hp
'67 911 2.4S hotrod
'90 944 S2 Cabriolet
'78 924 Carrera GT replica
'84 928 S, sold
'91 944 S2, sold
'82 924S/931 "Gulf", sold
'84 924, turbocharged, sold.
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patand
Joined: 12 Jan 2007
Posts: 91
Location: Sweden
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| Posted: Tue May 29, 2007 7:09 am Post subject: |
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| Raceboy wrote: | | ANyway, using the right oil is vital on G31 BEFORE it crunches gears |
Yes! Just have to get my hands on a G31 without gear crunching first...  Hopefully we will get there!
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Rasta Monsta
Joined: 12 Jul 2006
Posts: 11733
Location: PacNW
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| Posted: Tue May 29, 2007 7:20 am Post subject: |
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My owner's manual says straight 90w for the turbo, 80-90w for the NA (1980).
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- WeiBe (1987 924S 2.5t) - 931 S3
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endwrench
Joined: 07 Dec 2002
Posts: 1631
Location: Victor, Montana
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| Posted: Tue May 29, 2007 12:07 pm Post subject: |
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When I pulled my NA box apart I found the rings to have some sort of "texture" like parkerizing or maybe some sort of plating.
Any chance these would fit an NA box?
Todd
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'79 924NA. Rebuilt 9.5:1, MSDS header, Mega Squirt Injection, MJLJ-EDIS Ignition, 1.6L Whipple Charger and Intercooler, 10lbs Boost, 944 Trans, Custom HD Clutch.
"simsport" said....superchargers are better than turbos its official!.... |
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patand
Joined: 12 Jan 2007
Posts: 91
Location: Sweden
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| Posted: Tue May 29, 2007 4:00 pm Post subject: |
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| Rasta Monsta wrote: | | My owner's manual says straight 90w for the turbo, 80-90w for the NA (1980). |
Well that doesn't supprise me. I think Porsche changed the recommendation for the turbo some time after 1980. In Hayens it specifies GL4 for all but Turbo model. I will have a look in the service bulletins I have for the turbo model and see if anything is stated there.
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Smoothie
Joined: 01 Jan 2003
Posts: 8032
Location: DE (the one near MD, PA, NJ)
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| Posted: Wed May 30, 2007 1:48 am Post subject: |
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The Tech Specs booklet (1st edition 1/91 "status as per 10/1990") covering '78-'85 924-931-CGT says "multi-grade transmission oil, SAE 75 W-90, API classification GL 5 or MIL-L 2105 B" for all manual transmissions and the final drive of auto transmission'ed cars.
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'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox |
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