Betty blows another Tranny

[snowsyncro]

Hi Doug,

I agree completely that the original brace is going to be much more effective than the Syncro version. I mentioned the SA guys because they have used the Syncro version, and at least some have reported an immediate and obvious benefit. Not quantifiable perhaps, but real nonetheless, to them.

The original brace acts in tension and compression, so of course it will be much stiffer than one that acts in bending. However, even in bending, it does require energy to flex it, so it will provide additional stiffness. Sometimes it does not take that much to just push the resonance frequency up above the range where it is a problem,

I didn't understand your comment about the brace being a softer material than the case. My understanding was that the Syncro brace is steel.

I am not defending the Syncro brace. I didn't design it -- I had never even seen it until Jon posted the photo. But, after looking at it I am prepared to believe that it is capable of providing some benefit, so if someone has used it, and they say that it cured a problem they were experiencing; then I am willing to believe them.

I was just pointing that out, is all.

I do not think that the use of that Syncro brace would have prevented any of the problems Jon has experienced in this last go-round. I think his current problem began with a damaged pinion bearing. The cause of the initial damage could have been one of, or a combination of, many of the possibilities cited in this thread, or it could have simply been bad luck. Bearing life is predicted statistically, and even the best manufacturers will have bearings that fail quickly. There is no way to prevent that.

The original SA brace was developed as a band-aid solution to a real problem. It worked in the short term. The Syncro brace was an attempt to make the best of a bad situation, and try to at least provide a partial solution to the case of the Syncro. I am a mechanical engineer with more than 30 years of experience. I am not saying that to brag; I am simply pointing out that I understand how these things work, and I can't say for certain, from looking at a photograph and with no specific knowledge of the detailed nature of the problem, that the Syncro version of the SA brace will not provide some benefit. And I don't think anyone else can either.

RonC

[kgold708]

I knew which brace you were talking about. I was pointing out that the factory brace also fails to meet your expectations.
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[IdahoDoug]

KG,

The factory brace is used as a diagonal member that resists compression/elongation - a very stout setup. The small black brace depends entirely on its bending strength, and is thin. Totally different designs, materials and wildly different results.

DougM
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[insyncro]

[IdahoDoug]

Ron,

I agree the brace(s) and their impacts have no bearing (heh - get it), on the issues Jon had.

On the bracing to stop trans vibration related issues, what do you think about attacking it at the source instead? The engine and trans are essentially one single long unit suspended on rubber bushings. What about using some of the "active" motor mounts such as Acura used recently? Seems to me if there is no room for an effective brace, perhaps reducing the movement of the drive train itself is called for. I don't know much about them but understand that they are powered and use engine RPM to change the damping characteristics.

Dunno. To me, the jury is still out on whether the drivetrain suffers from the vibration of the engine (I vote no), or the added power of the engine (I vote yes).

DougM
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

[presslab]

I too agree that the brace isn't the source of Jonathan's problems...

How about a tuned mass damper to reduce vibrations? I added a tuned mass damper to my Norcold fridge and it greatly reduced the "swing" compressor vibrations.

[IdahoDoug]

That's a good call. Slap an iPhone with that seismometer app on the trans solidly, at a spot you can later mount one in the same spot (key) and see what frequency(s) you are dealing with. From the driver's seat, slowly rev the engine up through the range, banging a hammer on the floor as you hit each 200rpm increase so the iPhone will measure it, or record it audibly. Then when you are watching the graph it creates, you will know what rpm range the gearbox is really wiggling and the corresponding frequency you need to dampen. Cheap fix.

Might be worth knowing what an iPhone can take - would be a bummer to damage the phone over this. Anyone know of a rented shop tool like this instead?

DougM
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

[Zeitgeist 13]

Yet again, if five cylinder engines were killing transmissions via vibrations, errant harmonics or alien abductions, we'd be hearing about it all over the interwebs...but, we're not. Here's a GM Vortec 3700. That's a 3.7L five cylinder, which I'm sure is killing transmissions via vibrations left and right.

A manual transmission should be able to easily make it past the 200k mile mark without lunching its innards, so anyone claiming their 17 cylinder Isubasuki mated to a Syncro trans has made it 70k miles without a problem isn't advancing much of any theory at all. Anything short of that 200k figure and we're dealing with either weak source parts, incompetent builders or an inherent design flaw. All this obsession with the astrological/numerological vibration theory is nothing more than a rehash of the "how many angels can dance on the head of a pin" cogitations, and do nothing to further our understanding of why these transmissions fail at such high rates, no matter the powerplant.

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'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[IdahoDoug]

Point taken, and I agree. Mebbe a separate thread on vibration mitigation, but its not going to solve the OP's issue(s).

DougM
_________________
1987 2WD Wolfsburg Vanagon Weekender "Mango", two fully locked 80 Series LandCruisers. 2017 Subaru Outback boxer. 1990 Audi 90 Quattro 20V with rear locking differential, 1990 burgundy parts Vanagon. 1984 Porsche 944, 1993 Toyota LandCruiser, 2002 BMW 325iX, 1982 Toyota Sunrader

[kgold708]

Re: vortec 3700
I wonder what lives in that cylindrical area under the starter location?
Hint: the vortec 4200 6cyl doesn't have one. They are the same engine family.
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ASE L1 Advanced engine performance specialist.
ASE L2 Advanced electronic diesel engine specialist.

[zeohsix]

[D Clymer]

Jon,

The successor to the AEL 2.5 5 cylinder TDI was a 2.5 V6 TDI and it had similar output. It would be a useful comparison to try to find someone who has installed one of these in a Syncro and to hear how well the transmission has held up for them with the V6. I know Bernd Jaeger has been running one of these for years and there must be others in Europe who also are running the V6 TDI.

D

[snowsyncro]

[Jon_slider]

Hello friends of Betty,

Here are some links to a yahoo SyncroSA group, and the content, which I am posting here for reference on the 5 cyl brace. The SA group is member only, so I wanted to save the posts here. Note the second link is a long thread, it reads from the bottom up, as it is a quoted thread..

http://autos.groups.yahoo.com/group/SyncroSA/message/20054

You will also need a specially made (because of the rear mounted fuel tank) brace which ties the block, bell housing and gearbox together.
Derek Besuidenhout in PE supplied mine.
Maybe Stuart can do the same?

Without it, my bus was almost un-driveable, due to the noise generated by the oscillations of the motor.

I thought it was the exhaust causing interference till DB put me right.

===

http://autos.groups.yahoo.com/group/SyncroSA/message/16297

RE: [SyncroSA] Gearbox brace

Posted By:

thomasmockridge


Mon Dec 10, 2007 12:39 pm  |

Gilbert
 
Stuart is your man – it is not easy to make as the clearance between the gearbox and tank is rather close. I believe it is laser cut and close tolerance.
 
I have been waiting for one for my v6 for a few months - but give Stuart (www.syncrohospital.co.za) a call, he can get one for you.  If you get in on the current deal the wait may be shorter.
 
Thomas
 

From: [email protected] [mailto:[email protected]] On Behalf Of Gilbert Roberts
Sent: 10 December 2007 06:26 PM
To: [email protected]
Subject: [SyncroSA] Gearbox brace
 
Hi all
I fitted a 2.3 5cyl and was told about the noise.
I am looking for an engine gearbox brace similar to the one fitted to 
the 2.6 but for a Syncro.
A photo will do if it is easy to make.
___

http://autos.groups.yahoo.com/group/SyncroSA/message/15821

Re: [SyncroSA] Looking for engine/gearbox brace

Posted By:

• vdveera200

Tue Sep 18, 2007 1:55 am  |

HI Thomas,
 
I have one somewhere - I will look for it and let you know.
 
Cheers,
Adri

----- Original Message ----
From: Thomas Mockridge <thomas@...>
To: [email protected]
Sent: Sunday, 16 September, 2007 9:39:13 PM
Subject: [SyncroSA] Looking for engine/gearbox brace


Hi all
 
I am looking for an engine gearbox brace similar to the one fitted to the 2.6 but for a Syncro, ie low enough to clear the Syncro petrol tank. … Anybody know where I can source one?
 
Thanks
Thomas
http://autos.groups.yahoo.com/group/SyncroSA/message/13896
3K rpm vibration

Posted By:

feelstranger 



Hello all,
Can someone please tell me more about the 3K rpm vibration issue I have read about related to the 5 cylinder engines?  I understand there is a brace that VW installed from the Trans bell housing to the engine somewhere... right?  What is the nature of the vibration?  Causes?
The reason I ask is that I have a 2.3 L (NF) in my syncro and the engine produces a significant change in its tone right at 3K rpm.  I initially thought that it was the exhaust system harmonizing/vibrating, however, I recently completely changed the exhaust system, and the same harmonic is still there!
Any info appreciated!
Thanks
 
Nathaniel
Vermont, USA

http://autos.groups.yahoo.com/group/SyncroSA/message/14098

Re: [SyncroSA] 3K rpm vibration of 5-cyl Audi engine






You're right Dave, the Audi 5-cyl in-line engines produce this type of vibration.   It results from reciprocating mass (pistons & con-rods) vibration, and manifests itself as a transverse vibration attempting to rock the engine up & down about the bell-housing when viewed from the side.  The brace stiffens the connection between the engine block and the bell-housing-g/box, thus reducing the effect thereof.  However, the inherent vibrating characteristics of the 5-cyl engine are still there, only the effect thereof is reduced.  In Syncros this 5-cyl vibration problem has been solved by many, although there are cases where guys eventually used a different engine since they couldn't get rid of it.  Not all 5-cyl Audi engines vibrate the same, state of engine set-up, tuning, intake, exhaust and rebuild quality (if relevant) all seem to play a role.
 
(I've always thought the Audi 5's should have had either 4 or 6 cyl's......)   Is Audi (or anyone) still making in-line 5-cyl engines?
 
Rgds,
 
Jan
        
 
----- Original Message -----
From: Ky Pulvermacher
To: [email protected]
Sent: Tuesday, October 17, 2006 6:30 PM
Subject: Re: [SyncroSA] 3K rpm vibration


Hi Nat.
 
The symptoms of the vibration are very loud and irritating 'resonance' that would lead one to believe that there was something amiss with the exhaust system. (as it did me!)
The phenomenon has been well documented on the SyncroSa forum.
 
As soon as I fitted the bracket the vibration disappeared. Just as well since divorce had been threatened...!
 
Apparently the 5 cylinder crankshaft flexes at about 3200 revs causing the vibration. The bracket effectively braces the block, gearbox and country box to form a cohesive whole, thus damping the oscillations.
 
Damage can be caused by resonant vibration in support brackets of the alternator, a/c pump and power steering pump and others. Not to mention potential damage that can be caused to the engine itself....
 
So I would advise that you get hold of one or at least a drawing.
By the way It's Derek Beziudenhout that you need to contact, or Selwyn Robinson at Carcraft in Port Elizabeth. +27414872365 or Fax +27414841955.
 
Good luck.
 
DP.
 
 
 
----- Original Message -----
From: Feelstranger
To: [email protected]
Sent: Tuesday, October 17, 2006 4:24 PM
Subject: Re: [SyncroSA] 3K rpm vibration


David,
Now I see it.   I just looked at some photos I saw previously, and see that the bracket does mount between the bell housing and trans like the design you provided.
I would really like to know what the symptoms and causes were that prompted VW to add this in the first place.  What were the problems your van had that this bracket fixed?  You mentioned potential damage - what can happen?
Thanks!
Nat
 
----- Original Message -----
From: Ky Pulvermacher
To: [email protected]
Sent: Monday, October 16, 2006 11:44 AM
Subject: Re: [SyncroSA] 3K rpm vibration


No Probs Nat
 
The bracketes that you have seen were probably on the standard 2.3 / 2.5 / 2.6
Because of the position of our fuel tanks you can't use the standard straight bracket, hence the 'kink' in the syncro bracket.
 
I dont have Dereks email address.
Why don't you just send him a text message to get it?
Cheaper...
 
Kind regards
 
Dave P.
 
 
----- Original Message -----
From: Feelstranger
To: [email protected]
Sent: Monday, October 16, 2006 4:49 PM
Subject: Re: [SyncroSA] 3K rpm vibration


Sorry for the delay!
Thanks David.  That is odd.   I swear I have seen brackets that go between the trans and the engine.
Maybe not!  Any chance Derek has email?  I'm in the US and don't want to pay for a call!
Nat
 
 
----- Original Message -----
From: David Pulvermacher
To: [email protected]
Sent: Tuesday, October 03, 2006 12:17 PM
Subject: Re: [SyncroSA] 3K rpm vibration


Hi Nathaniel
 
Here's a sketch of the bracket that I got from Derek Bezuidenhout in Port Elizabeth.
Speak to him. (+27724152610)
 
Works a treat, and without it my bus was seriously awful and noisy to drive, not to mention potential damage.
 
Good luck.
 
Dave P
 
 
 
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My Soapboxes: Inflation; Handling; Gearing; Decoupling; Swepco

[Jon_slider]

Posting these pics together so they can be found easily in one place.

A South African OEM transaxle brace for use with 5 cyl motors paired to 5 speed trannies in T3 Vanagons

A South African Syncro brace by Russel Johnston

a couple of a SA syncro brace sketches, thanks to David Pulvermacher

and some photos thanks to Gilbert Roberts

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My Soapboxes: Inflation; Handling; Gearing; Decoupling; Swepco

[SyncroGhia]

This makes for an interesting read.

I still have the brace pictured above and as I'm now pushing around 280bhp and probably similar ftlbs through a Syncro trans with 6.17s, I'm half tempted to put the brace back on and modify the petrol tank around it!!

I once had a lot of oil appear after a long journey (with the AAT 2.5TDi) above the gearbox and bellhousing joint... on the tank!! I was cruising at 60mph but towing around 2500kgs up and down steep hills on the autobahn. The gearbox was doing ok but the oil was enough to have leaked some onto the exhaust and I could smell it... hence looking around.

The next time I had the trans out, I checked that all the bolts were tight on the bell housing - they were as they should have been. I never worked out where the oil came from. The mating surfaces were still perfect and it didn't happen again. That said, I didn't try to tow 2500 kgs again as the gearbox had to come out for a rebuild about 3 weeks later due to the main shaft moving fowards and jumping out of 4th!

I've recently bought a new set of gears from Weddle for Limeys next gearbox rebuild (the current one was made up of what I had left over) and I have the 22S bearing housing which I will modify and fit a bearing plate to hold the mainshaft bearing in place.

I'd be interested to see how the T4 transporter (Eurovan) does with the 5 cylinder engines. The gearboxes do suffer from failures but I don't know if this is from the 5 cylinder harmonics.

MG
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[kgold708]

I once had a lot of oil appear after a long journey (with the AAT 2.5TDi) above the gearbox and bellhousing joint... on the tank!! I was cruising at 60mph but towing around 2500kgs up and down steep hills on the autobahn. The gearbox was doing ok but the oil was enough to have leaked some onto the exhaust and I could smell it... hence looking around.

The next time I had the trans out, I checked that all the bolts were tight on the bell housing - they were as they should have been. I never worked out where the oil came from. The mating surfaces were still perfect and it didn't happen again. That said, I didn't try to tow 2500 kgs again as the gearbox had to come out for a rebuild about 3 weeks later due to the main shaft moving fowards and jumping out of 4th! Quote.

This is what I've been waiting to hear!!
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[insyncro]

[Jon_slider]

> These look promising

yes but not sufficient, lacking dimensions, I am forced to provide my transaxle to the welding shop

what I really want is a product that can be built from a blueprint, without requiring that my transaxle be used as a jig

here are a couple other random thoughts on controlling tranny vibration, that came up in an offline branstorming session

1. use an airbag to stabilize the transaxle, possibly build a bolt on mount for the bag so it becomes a kit-able product

I dont do my own work, so I look for solutions that can be bought and bolted, not custom fabricated by the installer

another idea
2. Replace the Syncro fuel tank with a fuel cell, so that the original SA tranny brace will fit..

I dont know anything about what size tank would fit, or the complexities of installation

any feedback welcome, from the ridiculous to the sublime..
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My Soapboxes: Inflation; Handling; Gearing; Decoupling; Swepco

[240Gordy]