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Syncro Jael Samba Member
Joined: December 19, 2013 Posts: 2204 Location: Utah
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Posted: Thu Jan 02, 2014 7:29 pm Post subject: Calling the Experts : Flange angles on Syncro's. |
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I am still digging into my small vibration in the drivetrain.
From what I have been told a 2 degree flange angle is preferred on both the front diff and transaxle.
What is the stock angle? Is it 4 degrees?
Does anyone have pics of their front diff shimmed? Or transaxle shimmed?
I have heard the GoWesty laser alignment system is good, but I have also called around and heard it was not a fix all either. I also use the VanCafe method to tighten the front diff.
Here is my math:
85.9 + 0.2 = 86.1 - 90 degrees = 3.9 degrees on front diff.
85.9 + 0.2 = 86.1 - 90 degrees = 3.9 degrees on transaxle
I am almost perfectly flat on a concrete slab and the frame is at 0.2 degrees.
I am right at the 4 degree maximum that I have heard is the limit. Please correct me if you don't agree.
I can easily see how to shim the front diff flatter by adding washers, but with an early Subaru conversion I am not sure how to change the angle on the tranny. I have a full skid plate that is also attached to the motor mount bracket and rear bumper so dropping the engine is not an option I want to tackle. Plus I don't want to loose any ground clearance. Can anyone tell me how to change the angle on the front transaxle mounts that will work?
2 degrees would be sweet, but I also heard to keep the flange angles exactly the same or within one degree. I am not sure if I can get them that low.
The front diff is measured with the mounting bolts only hand tight. If I tighten them with a wrench until bottomed out, I get a worse vibration.
I have had my slip yoke driveline balanced with new spicer joints installed. I also have a new GoWesty driveline ordered. My splines on the slip yoke have a tiny bit of play. So I am hoping that is what is causing this. With the three front diff mount bolts hand tight I have almost no vibrations except from 30-40 mph which I understand many Syncro's have.
Help. |
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Dampcamper Samba Member
Joined: October 07, 2013 Posts: 788 Location: Rainy Portland, Oregon
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Posted: Thu Jan 02, 2014 7:37 pm Post subject: |
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I don't know much about Syncros, but your math? I think you added 0.2 degrees instead of 2.0 degrees? Making your angles more like 87.9 / 1.1 degrees? Just asking. |
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Syncro Jael Samba Member
Joined: December 19, 2013 Posts: 2204 Location: Utah
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Posted: Thu Jan 02, 2014 7:50 pm Post subject: |
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The smart level reads both directions.
0.2 degrees is correct. If you look at where the decimal is and the degree sign. |
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SyncroChrick Samba Member
Joined: January 10, 2005 Posts: 1010 Location: San Francisco, CA
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Posted: Thu Jan 02, 2014 8:04 pm Post subject: |
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On my last Syncro, I got rid of my vibration by replacing one of the front cv-axles.
I never did any of the alignment methods and I had a custom driveshaft with u-joints.
just one more thing to consider...
Last edited by SyncroChrick on Thu Jan 02, 2014 8:46 pm; edited 1 time in total |
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Syncro Jael Samba Member
Joined: December 19, 2013 Posts: 2204 Location: Utah
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Posted: Thu Jan 02, 2014 8:19 pm Post subject: |
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Link
I had someone ask me about my math.
So I looked up this video.
The front diff angle is down.
The frame angle is down.
The transaxle angle is down.
So how I read this is instead of adding the frame angle of 0.2 I should subtract it.
85.9 - 0.2 = 85.7 - 90 degrees = 4.3 degree flange angle.
Does anyone concur?
So I am passed the 4 degree limit.
I am replacing the rear CV's this weekend.
I just serviced the fronts about 4 months ago and I believe they are fine.
They are tight with no play.[/url] |
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Syncro Jael Samba Member
Joined: December 19, 2013 Posts: 2204 Location: Utah
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Posted: Thu Jan 02, 2014 8:28 pm Post subject: |
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For any of you with a vibration in your drive shaft, here is a video that explains the causes of it.
Link
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Escorial Syncro Samba Member
Joined: May 02, 2004 Posts: 437 Location: Manitou Springs, CO
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Posted: Thu Jan 02, 2014 10:54 pm Post subject: |
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Syncro Jael wrote: |
The front diff angle is down.
The frame angle is down.
The transaxle angle is down.
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But on a syncro not all angles are down, right? The whole arrangement is more of a "U" shape, or droop driveshaft. Like:
Transaxle is down
Driveshaft is up
Front diff is up
Or:
\_/
I was waiting in that video on correct phasing to try out this arrangement! The angles still need to be correct, but this might help with your math. _________________ Joel Lane
1985 Vanagon converted to syncro, ALH TDI, Reimo Primus top with Westy interior
2002 Toyota Tundra 4x4
1974 Honda CL360 Scrambler (for sale!) |
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SyncroGhia Samba Member
Joined: August 21, 2009 Posts: 2458 Location: Highnam, UK
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Posted: Fri Jan 03, 2014 1:52 am Post subject: |
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Have you tried disconnecting the prop at one end, twisting it 90o and then attaching it again?
This might sound mad but believe me, it's worked on my Syncros in the past when I've had a vibration.
It doesn't make any mathematical sense but at no cost to your self (or need to modify anything), it's certainly something I would try before changing the angles of your gearbox and front diff.
I also had the prop rebuilt and CV joints were in good condition bu the vibration remained until I tried this.
MG _________________ T3 Syncro 16 S6 Westfalia Limey SOLD
T3 Syncro 6x6 SOLD
T3 RS6 Bluestar
T3 Tristar Syncro 16 SOLD
T3 Tristar Syncro RHD SOLD |
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Syncro Jael Samba Member
Joined: December 19, 2013 Posts: 2204 Location: Utah
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Posted: Fri Jan 03, 2014 8:41 am Post subject: |
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If I am correct the front diff flange angle is down /
The prop shaft angle is down (front diff flange is higher than transaxle flange)
Transaxle flange angle is down \
Once I get the new prop shaft installed I will get these angles instead of using the frame as a reference.
With a slip joint drive shaft the splines can be off and make the joints (out of phase). A solid shaft does not have this issue. So I have ordered a GoWesty donut-less drive shaft to see if my slip yoke is the problem.
Here is another video that explains phasing and angles.
Hopefully all this helps someone who wants to understand the causes of vibrations in the drive shaft.
Yes, I did rotate the drive shaft 90 degrees on one end. And also swapped it end for end and put the slip yoke at the front diff. Thanks for all the comments.
Link
Last edited by Syncro Jael on Fri Jan 03, 2014 8:43 am; edited 1 time in total |
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hans j Samba Member
Joined: May 06, 2006 Posts: 2714 Location: Salt Lake City UT
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Posted: Fri Jan 03, 2014 8:43 am Post subject: |
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I used a laser level that I could hold flat in the center of the flange. I then held a piece of cardboard on the other side, and marked where the laser pointed. This allowed me to check it sideways also. I just moved stuff around until the laser pointed in the same spot on both sides.
I got my driveline rebuilt at GRS on 2100S and 900W? The only did an adequate job, I had to reshim one of the joints since there was too much play under the c-clip. I think I am around 3.8* or so based on the math, I'll have to look up my old threads. _________________ 1986 Canadian Syncro Westy TDI - 1989 Syncro Single Cab - 2001 Audi S4 - 1981 VW Caddy ABA - 1980 VW Caddy EV - 1973 VW T-181 |
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Syncro Jael Samba Member
Joined: December 19, 2013 Posts: 2204 Location: Utah
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Posted: Fri Jan 03, 2014 8:54 am Post subject: |
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I would be interested to know if you are at 3.8 degrees
Since the front diff is in it's stock position and I am close to 4.0 degrees
I spoke to Mike at Rocky Mtn Westy and he wanted me to check my engine clearance from the lip of the engine cover deck to the top of the bell housing. My 1994 EJ2.2 conversion was done back in 2004 and is an early Kennedy Calif. compliant conversion. He said back then the engine sat higher than a stock WBX and that can change my transaxle flange angle different than a stock application.
I will check that measurement also. Engine sitting higher in a Syncro, that is a good thing!
Does anyone know what the "STOCK" flange angles are from the factory? |
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hans j Samba Member
Joined: May 06, 2006 Posts: 2714 Location: Salt Lake City UT
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crazyvwvanman Samba Member
Joined: January 28, 2008 Posts: 9920 Location: Orbiting San Diego
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Posted: Fri Jan 03, 2014 11:08 am Post subject: |
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The video is a good beginning for illustrating the basic principle but it only shows the simplest case. It does not mention the fact that there is more to the angles than just simple up and down. There is also side to side angles and if one of those is off then you can end up with the joints working out of phase even if they are clocked correctly for up and down angles. That is where the laser methods come into play. The laser method can detect other alignment errors that a simple gravity angle finder can't detect.
Mark |
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insyncro Banned
Joined: March 07, 2002 Posts: 15086 Location: New York
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Posted: Fri Jan 03, 2014 12:27 pm Post subject: |
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North - South - East - West.
A flange mounted center laser works beautifully. |
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SyncroGhia Samba Member
Joined: August 21, 2009 Posts: 2458 Location: Highnam, UK
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Posted: Fri Jan 03, 2014 2:51 pm Post subject: |
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Which engine mount setup does your Subaru engine use?
Small-car? If so does it use the original Syncro engine bar?
Did you try more than just one 90o twist? Again, as it's free, it's worth spending a little bit of time trying all 4 positions.
MG _________________ T3 Syncro 16 S6 Westfalia Limey SOLD
T3 Syncro 6x6 SOLD
T3 RS6 Bluestar
T3 Tristar Syncro 16 SOLD
T3 Tristar Syncro RHD SOLD |
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Zeitgeist 13 Samba Member
Joined: March 05, 2009 Posts: 12115 Location: Port Manteau
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Posted: Fri Jan 03, 2014 3:25 pm Post subject: |
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So, why are Syncro drivelines so prone to issues with angular orientation and such? I can't recall ever encountering this subject in any of my Audi, BMW or Mercedes group discussions or personal experiences. Would Syncros benefit from the addition of an adjustable center support bearing and a two piece shaft? _________________ Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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insyncro Banned
Joined: March 07, 2002 Posts: 15086 Location: New York
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Posted: Fri Jan 03, 2014 3:43 pm Post subject: |
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Zeitgeist 13 wrote: |
So, why are Syncro drivelines so prone to issues with angular orientation and such? I can't recall ever encountering this subject in any of my Audi, BMW or Mercedes group discussions or personal experiences. Would Syncros benefit from the addition of an adjustable center support bearing and a two piece shaft? |
IMHO, the reason so many Syncro vans have vibration issues is that once they begin, they are not dealt with immediately and the van is still driven.
The issues compound themselves and bring other parts into the mix.
The driveline contains many "wear" items and vibrating does not help the longevity of any of them.
Many have asked me to diagnose and fix problematic vans.
The ones that the owner is willing to drive it to me, I pass on.
The ones that get sent on a flatbed and have not been driven once the vibes started get my attention.
Grease is your friend, alignment of the suspension and driveline is crucial for for a road feel that is smooth.
FYI, I have been laser aligning the donutless GW driveshafts and aligning the rest of the driveline with the Van Cafe Method + a few of my own tweeks with great success.
Without the internal bushing and rubber donut, the alignment is much more straight forward if you ask me.
Two less variables in the mix.
I still run the slip yoke aftermarket shafts in my converted Syncros and one has over 100k miles on it now...still vibration free.
Engine height, engine/driveline mounts freshness and the condition of all internal and external bearings seems to be the most important factors from my experience.
The failed or failing VC can also be the source of vibrations. |
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hans j Samba Member
Joined: May 06, 2006 Posts: 2714 Location: Salt Lake City UT
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Posted: Fri Jan 03, 2014 3:44 pm Post subject: |
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Zeitgeist 13 wrote: |
Would Syncros benefit from the addition of an adjustable center support bearing and a two piece shaft? |
Yes and that's what I'm doing when adapters get finished being machined. Detlev in California does this too. Super smooth with CV joint ends! _________________ 1986 Canadian Syncro Westy TDI - 1989 Syncro Single Cab - 2001 Audi S4 - 1981 VW Caddy ABA - 1980 VW Caddy EV - 1973 VW T-181 |
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SyncroGhia Samba Member
Joined: August 21, 2009 Posts: 2458 Location: Highnam, UK
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Posted: Fri Jan 03, 2014 3:45 pm Post subject: |
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Zeitgeist 13 wrote: |
So, why are Syncro drivelines so prone to issues with angular orientation and such? I can't recall ever encountering this subject in any of my Audi, BMW or Mercedes group discussions or personal experiences. Would Syncros benefit from the addition of an adjustable center support bearing and a two piece shaft? |
They have a fairly long propshaft (not that unusual) but it's not supported and doesn't have a UJ in the centre like most vehicles.
With it being a one piece (generally speaking) structure, the flanges need to be running at the same (or close) angle to make sure that you don't get vibrations.
Many people have tried to add a propshaft with a slip-joint with varying degrees of success but nobody has yet to add a propshaft with a UJ in the centre that is supported by the chassis.
Maybe this is the sensible next step?
MG _________________ T3 Syncro 16 S6 Westfalia Limey SOLD
T3 Syncro 6x6 SOLD
T3 RS6 Bluestar
T3 Tristar Syncro 16 SOLD
T3 Tristar Syncro RHD SOLD |
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Zeitgeist 13 Samba Member
Joined: March 05, 2009 Posts: 12115 Location: Port Manteau
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Posted: Fri Jan 03, 2014 5:51 pm Post subject: |
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Wouldn't the addition of a guibo at both ends also remove some of the potential for vibration? It strikes me that that Cardan joint is more than likely the source of the imbalance, no? _________________ Casey--
'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik? |
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