Fulcrum and SAW+ Super DIFF problem

Koyote · Last edited by Koyote on Sat Jan 21, 2012 4:56 am; edited 1 time in total

Hello,
First of all, some caracteristics about my car :
1969 beetle (1984pds with me in it)
stock gear box 1974
3.78, 2.06, 1.26 welded, 0.82 welded, 4:12 ring and pinion
Super diff C -clips
poor man posi
Sway a way axles 28- 7/16
Engine is a draw through turbo 2276
Clutch is a Kennedy stage 1 + sintered Jay Cee disk (sort of black magic).
It's a Daily Driver + Drag races in a 12" index class
11.67" best ticket
the race tires are the M&H DOT 215x15 (tire pressure is 17 psi)
NO burnout, only a quick blast in 1st gear, just to remove water.
RPM launch (1st step) is 4200 rpm.
60 fts are 1.80 just to be in the safe side, but I can do 1.65.
During the winter pause, I tore down my gearbox, for a complete revision, because I have no trailer and it’s out of the question to be worried on the road!
Here’s what I have found, only on the left side :

What can cause this ? obviously a lubrification problem ? the poor man posi too tight, for road driving ? What can be done to improve oiling the super diff? bigger holes, another holes? where ?
Thanks for your help !

Image may have been reduced in size. Click image to view fullscreen.

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2276cc daily draw through.

Koyote · Posted: Fri Jan 20, 2012 8:08 am Post subject:

Well hum I don't know why I can't insert images here with the [img][/img]
Confused

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2276cc daily draw through.

ozarkbaha · Posted: Fri Jan 20, 2012 9:41 am Post subject:

69 with a swing,i like.looks like maybe a lack of lube,but not sure it doesnt look burnt.what kinda carrier do you have?and do you have the other side tore down,if so does it look good?

Koyote · Posted: Fri Jan 20, 2012 10:09 am Post subject:

vdubnut58 · Posted: Fri Jan 20, 2012 10:17 am Post subject:

I had a similar problem last year. Was using synthetic 90w gear oil and it was just too thin. I am now running redline medium shock proof. I also found that polishing up the ends of the axles and fulcroms help. I tried having extra oiling scoops added to the super diff first. Added 3. That didnt cure the problem 100% as your driving down the road all the oil is getting slung out of the super diff. You need some really good and sticky gear oil to keep them lubed.

This was the end result. Nice 60' by the way!

Koyote · Posted: Fri Jan 20, 2012 10:28 am Post subject:

Thanks vdubnut58. So, oil choice is a part of my problem... I will find one more sticky. May be add some "miracle additive" ! Laughing

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2276cc daily draw through.

Koyote · Posted: Fri Jan 20, 2012 10:31 am Post subject:

Do you think that adding a poor man posi, as I did, can aggravate things ? on the left size, the spider gear was very tight, starting to be seized in the super diff...and the shims of the PMP are chewed up.
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2276cc daily draw through.

vdubnut58 · Posted: Fri Jan 20, 2012 10:54 am Post subject:

I am sure it didn't help. When your setting up a Trans for drag racing you want everything nice and tight to minimize the shock on the parts. But on the street, mainly on the highway. It starts to take its toll on the parts. I would freshen it up and switch gear oils. Try GL 5 as it has a high pressure rating and has the friction modifier for limited slip in it. Or if you like synthetic find a shock proof type oil. Not sure what you have over there.

Koyote · Posted: Fri Jan 20, 2012 11:01 am Post subject:

yamaducci · Posted: Fri Jan 20, 2012 11:15 am Post subject:

Dougy Dee · Posted: Fri Jan 20, 2012 1:10 pm Post subject:

How large are the oiling holes in the superdiff?

Did the side gears/cups gall the bores of the diff?

There are tricks to setting up the PMP. BERG used to have good info on that. I'm not sure whether their website has the info up. For street trim I hang a brake drum off the end and set them up so that it takes serious effort to turn the assembly. Not locked up solid.

On another note I drill two 5/8 or 16mm diameter holes in the diff for lubrication. Drill so that diff rotation will 'scoop' oil in to the internals.

The damage you show and describe sounds like lube problems.

Koyote · Posted: Sat Jan 21, 2012 4:56 am Post subject:

Koyote · Posted: Sat Jan 21, 2012 5:31 am Post subject:

Banzai KG

Koyote · Posted: Sun Jan 22, 2012 2:37 am Post subject:

Thanks Banzai KG!
That is something I will do on my new axles for sure !
So in the end I'll have to do :
1) enlarging all the holes, the two large ones with those "scoops", and the 4 small holes, redrilling them with a angle, to act as scoops.
2) radius and polish the axles
3) use a thicker oil

There is another thing I noticed : the wear on the fulcrums. It seems the axles were not fully engaged. there is an area on the fulcrums still intact, without any marks. As a side note, I have installed the OEM spacer behind the bearing. Any ideas ?
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2276cc daily draw through.

Banzai KG · Posted: Sun Jan 22, 2012 3:49 am Post subject:

Speaking of fulcrum plates, I'm running grooved fulcrum plates that looks like what's pictured below (not my picture):

I bought my set from Gene Berg a long time ago.
_________________
Jim Kikuchi
Sunnyvale (near San Jose), CA
1964 Karmann Ghia coupe
V.V.W.C.A. - Golden Gate Chapter: http://www.ggcvvwca.org/
B.L.T.N. (Better Late Than Never) late model VW Club (San Jose/Santa Clara, CA): https://www.facebook.com/groups/bltnvw/
NorCal Aircooled Group (NAG) Facebook Goup: https://www.facebook.com/groups/NAGVW/

Koyote · Posted: Sun Jan 22, 2012 5:02 am Post subject:

I saw those fulcrum plates in my local shop. That can help oiling in that critical area ! I will add this to my "what to do" list ! Wink

_________________
2276cc daily draw through.

ozarkbaha · Posted: Sun Jan 22, 2012 7:08 am Post subject:

imo from looking over your pics,i think the drive gears an carrier are galled to bad to reuse.but i think my be something up with the carrier not supplying lub,maybe no holes,holes not in the right spot or to small,not sure of cause.i would get someone to check it out that knows transaxles.genos advice an vid are great,and as he stated his plates are gene berg.i wouldnt use anything but berg there, or good looking stock german, german are hard to beat.i also think ur wear pattern is normal for such a fail as this(the wear on the plates).no lub does strange things.the pmp isnt the reason for failure,im sure. alltho i dont think one wil ever hold up well in a street driven car.corners will take there toll.i would reassemble with top grade stuff and drive the SH#T OUT OF IT hope this helps.

Koyote · Posted: Sun Jan 22, 2012 7:52 am Post subject:

Here are some pictures of the oiling holes enlarged:

"scoop" effect "improved" and bigger hole :

The same from the inside :

The 4 small near the ring, and from the inside. at left, the stock hole, at right modified, drilled with an angle. so the hole is now in an oval shape (11x9mm) is that enough ? :

_________________
2276cc daily draw through.

Koyote · Posted: Sun Jan 22, 2012 8:12 am Post subject:


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