VC Test


Hi all , just wander if anyone has tested their VC's lately as per some of the you tube vids out there. I took the opportunity to test mine while I was playing with my brakes and found it to be a lot tighter than all the ones on you tube. The rear wheels only need to move about 45 degrees before the fronts lock up, and not the two or three revolutions that all the you tube testers have. I think mine works well and can still do U turns on bitumen , but I always do them slowly. So wander what others have experienced and what is considered to be normal. At what point did some of you decide the VC was too loose, no longer viable and fit solid shafts, or how aggressive did VC's become before some of you put in de-couplers to ease gearbox strain.  Hoping to get some feedback, Eddie.
Eddie,

Tested mine the other day with just one wheel up on a trolley jack in the garage and my syncro pulled away almost immediately - almost the same as the wheels on the ground.

I try not to do U turns but I need to do one to get in my garage down the nearby side street. The street quickly falls away and hence I only use power to tip the front over the hill then let it roll while I complete the rest of the turn to save the VC and drive-train.

Skot

On 2/03/2014 3:14 PM, bergodaz@ozemail.com.au wrote:


Hi all , just wander if anyone has tested their VC's lately as per some of the you tube vids out there. I took the opportunity to test mine while I was playing with my brakes and found it to be a lot tighter than all the ones on you tube. The rear wheels only need to move about 45 degrees before the fronts lock up, and not the two or three revolutions that all the you tube testers have. I think mine works well and can still do U turns on bitumen , but I always do them slowly. So wander what others have experienced and what is considered to be normal. At what point did some of you decide the VC was too loose, no longer viable and fit solid shafts, or how aggressive did VC's become before some of you put in de-couplers to ease gearbox strain. Hoping to get some feedback, Eddie.


Eddie,

The primary function of the VC is to allow a small speed variation between the front and rear axles such that it is a permanent all wheel drive system which does not wind up the entire driveline with conflicting speed inputs. 

The benefits of well designed all wheel drive systems are many and the Syncro is a very good example.  The benefits are spread all the way from dry bitumen to snow and slush. 

Amongst people with high driving skills and/or vehicle development experience, a tighter VC is usually preferred and usually because of the predictability of grip and steering.  A factor frequently not taken into account is the extremely high anti-lock braking forces engendered by the VC; again, the tighter the VC, the more pronounced is the anti-locking force.

Your description puts your VC into the tight end category (my own preference, in fact) and will give you a lot of service still.  Not loading it up unnecessarily helps. 

There are some who think that the VC system is a half-measure and not worth doing in the first place.  This belief was held by not a few when the early Syncros were used as support vehicles in the Dakar – to the acute embarrassment of not a few competitors who found that they couldn’t keep up with them!!!!!!

Les


From: Syncro_T3_Australia@yahoogroups.com [mailto:Syncro_T3_Australia@yahoogroups.com] On Behalf Of bergodaz@ozemail.com.au
Sent: 02 March 2014 15:14
To: Syncro_T3_Australia@yahoogroups.com
Subject: [Syncro_T3_Australia] VC Test

Hi all , just wander if anyone has tested their VC's lately as per some of the you tube vids out there. I took the opportunity to test mine while I was playing with my brakes and found it to be a lot tighter than all the ones on you tube. The rear wheels only need to move about 45 degrees before the fronts lock up, and not the two or three revolutions that all the you tube testers have. I think mine works well and can still do U turns on bitumen , but I always do them slowly. So wander what others have experienced and what is considered to be normal. At what point did some of you decide the VC was too loose, no longer viable and fit solid shafts, or how aggressive did VC's become before some of you put in de-couplers to ease gearbox strain.  Hoping to get some feedback, Eddie.

Hi Eddi,
my first Syncro which we bought in 1989 was so tight that on my first trip to SYD (450 km) I no longer could park my left foot on the floor it became that hot.
In 1990 we swopped the Transporter for the TriStar DOKA  and here too the VC is pretty tight , the floor gets warm but managable. That of course is gone with the installation of the decup. It stays cool now. I'm activating the decup only on dirt or wet surfaces. 
Hart



On 02/03/2014, at 3:14 PM, <bergodaz@ozemail.com.au> wrote:

 


Hi all , just wander if anyone has tested their VC's lately as per some of the you tube vids out there. I took the opportunity to test mine while I was playing with my brakes and found it to be a lot tighter than all the ones on you tube. The rear wheels only need to move about 45 degrees before the fronts lock up, and not the two or three revolutions that all the you tube testers have. I think mine works well and can still do U turns on bitumen , but I always do them slowly. So wander what others have experienced and what is considered to be normal. At what point did some of you decide the VC was too loose, no longer viable and fit solid shafts, or how aggressive did VC's become before some of you put in de-couplers to ease gearbox strain.  Hoping to get some feedback, Eddie.


Hi Eddie,

 

I made some lock-to-lock turns, the other day, in a car park with the tyres rubbing the bitumen.

I need to do the other test, rear wheel off the ground and drive over a 3"x3".

 

Cheers, Theo

 

From: Syncro_T3_Australia@yahoogroups.com [mailto:Syncro_T3_Australia@yahoogroups.com] On Behalf Of bergodaz@ozemail.com.au
Sent: Sunday, 2 March 2014 3:14 PM
To: Syncro_T3_Australia@yahoogroups.com
Subject: [Syncro_T3_Australia] VC Test

 

 


Hi all , just wander if anyone has tested their VC's lately as per some of the you tube vids out there. I took the opportunity to test mine while I was playing with my brakes and found it to be a lot tighter than all the ones on you tube. The rear wheels only need to move about 45 degrees before the fronts lock up, and not the two or three revolutions that all the you tube testers have. I think mine works well and can still do U turns on bitumen , but I always do them slowly. So wander what others have experienced and what is considered to be normal. At what point did some of you decide the VC was too loose, no longer viable and fit solid shafts, or how aggressive did VC's become before some of you put in de-couplers to ease gearbox strain.  Hoping to get some feedback, Eddie.

I did a huge test to the VC about 5 years ago when a rear CV joint failed due to bolts coming loose then snapping meaning I had to remove the CV joint completely and drive home in 3wd using one rear wheel and the front drive to get home.

I drove about 400kms using this and its amazing how well they still drive in 3wd.


Skot


On 2/03/2014 4:41 PM, Theo Weiss wrote:

Hi Eddie,

I made some lock-to-lock turns, the other day, in a car park with the tyres rubbing the bitumen.

I need to do the other test, rear wheel off the ground and drive over a 3"x3".

Cheers, Theo

From: Syncro_T3_Australia@yahoogroups.com [mailto:Syncro_T3_Australia@yahoogroups.com] On Behalf Of bergodaz@ozemail.com.au
Sent: Sunday, 2 March 2014 3:14 PM
To: Syncro_T3_Australia@yahoogroups.com
Subject: [Syncro_T3_Australia] VC Test


Hi all , just wander if anyone has tested their VC's lately as per some of the you tube vids out there. I took the opportunity to test mine while I was playing with my brakes and found it to be a lot tighter than all the ones on you tube. The rear wheels only need to move about 45 degrees before the fronts lock up, and not the two or three revolutions that all the you tube testers have. I think mine works well and can still do U turns on bitumen , but I always do them slowly. So wander what others have experienced and what is considered to be normal. At what point did some of you decide the VC was too loose, no longer viable and fit solid shafts, or how aggressive did VC's become before some of you put in de-couplers to ease gearbox strain. Hoping to get some feedback, Eddie.


The decoupler was a wonderful development.
I "cooked" my VC about seven years ago when forced to drive with uneven diameter wheels on black top.
So when the new VC came so did the decoupler.

How did I discover the VC was cooked ?
I got bogged on very wet clay in the bush at the back of my place.
There was minimal or no real 4WD traction.
My neighbour brought his tracked machine in and pulled me out enough to drive out in what was 2WD.

The VC is a great boon on slow twisty rough descents, as Les has expressed.
It acts as a brake and I have found it in those conditions to be very useful.
Did a decent down from Gloucester / Barrington Tops National Park once, back in the days when you could drive in the Park and camp in your vehicle there. There was a gate into the State forest behind it, you weren't supposed to use it, but I didn't want a big detour to get to Scone.
The road down the hill was almost continuous down hill hairpins.
The VC was very effective at slowing her on the bends.

Lessons learnt:
Check that your VC is operational before doing serious 4WDing.
I would not like a weak one.
Use the decoupler whenever you don't need 4WD.
Make sure all tyres are evenly worn.

Peter


--Original Message Text---
From: Hartmut
Date: Sun, 2 Mar 2014 16:08:27 +1100



Hi Eddi,
my first Syncro which we bought in 1989 was so tight that on my first trip to SYD (450 km) I no longer could park my left foot on the floor it became that hot.
In 1990 we swopped the Transporter for the TriStar DOKA and here too the VC is pretty tight , the floor gets warm but managable. That of course is gone with the installation of the decup. It stays cool now. I'm activating the decup only on dirt or wet surfaces.
Hart





On 02/03/2014, at 3:14 PM, <bergodaz@ozemail.com.au> wrote:




Hi all , just wander if anyone has tested their VC's lately as per some of the you tube vids out there. I took the opportunity to test mine while I was playing with my brakes and found it to be a lot tighter than all the ones on you tube. The rear wheels only need to move about 45 degrees before the fronts lock up, and not the two or three revolutions that all the you tube testers have. I think mine works well and can still do U turns on bitumen , but I always do them slowly. So wander what others have experienced and what is considered to be normal. At what point did some of you decide the VC was too loose, no longer viable and fit solid shafts, or how aggressive did VC's become before some of you put in de-couplers to ease gearbox strain. Hoping to get some feedback, Eddie.









Eddie,

 

I've done the "rear wheel off the ground" test (with a trolley jack), the front wheels climbed effortlessly over  the 3"x3". So I reckon my VC works fine.

 

Cheers, Theo

 

FWIMC,  some bedside table reading on the topic:

http://users.rcn.com/derekdrew/vanagon/viscous_couplings_vanagon_syncro.htm

Concerning the VC test method and correct interpretation of findings, I believe what Rainer Woitok says is pretty much spot on. Though for many, these findiings are an inconvenient truth. 

Cheers.
Ken


To: Syncro_T3_Australia@yahoogroups.com
From: bergodaz@ozemail.com.au
Date: Sat, 1 Mar 2014 20:14:24 -0800
Subject: [Syncro_T3_Australia] VC Test

 

Hi all , just wander if anyone has tested their VC's lately as per some of the you tube vids out there. I took the opportunity to test mine while I was playing with my brakes and found it to be a lot tighter than all the ones on you tube. The rear wheels only need to move about 45 degrees before the fronts lock up, and not the two or three revolutions that all the you tube testers have. I think mine works well and can still do U turns on bitumen , but I always do them slowly. So wander what others have experienced and what is considered to be normal. At what point did some of you decide the VC was too loose, no longer viable and fit solid shafts, or how aggressive did VC's become before some of you put in de-couplers to ease gearbox strain.  Hoping to get some feedback, Eddie.
Did the VC test today with rear wheels on rollers and fronts blocked by a 3 inch thick sleeper. While some torque is transferred to the front immediately , it takes about a full revolution of the rears before it pulls over the sleeper. Can get over the sleeper earlier with quicker acceleration. I'm now satisfied that my VC is working correctly. Thanks for all the responses. Eddie.