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mexican bellhousing?

Printed From: The Brick-yard
Category: T3 Section
Forum Name: Syncro
Forum Description: The Brick-yard syncro forum.
Printed Date: 03 Apr 20 at 20:49
Software Version: Web Wiz Forums 12.01 -

Topic: mexican bellhousing?
Posted By: colinegreen
Subject: mexican bellhousing?
Date Posted: 18 Sep 15 at 04:56
I have a 1987 Syncro with a 2001 ALH motor installed.

I am in the process of planning new mounting for the motor and a new way to mate to the transmission, and in the process eliminate the current KEP plate.

I will also use '82 Diesel carrier bars and Audi 5000 hydraulic mounts.

The goal is to reduce vibrations which have caused problems with my transmission, a known issue with TDIs in Syncros.

Question #1)

Ideally, I will get the so called "Mexican Bellhousing" and install this on my trans, perhaps with a modified input shaft.

I am told this will make the whole engine/transmission assembly 1.5" longer. 

Will it still fit? With my ~1/2" KEP plate, there is not much room left in back, less than 1", so this makes me nervous.

I also don't know which BH is the right one. I have seen a post on the Samba which says the right part# is 191301107D.

Weddle sells a number of BH options, but none with this number. Please look here - and give me the part # for the correct one -

Question #2

I am considering using a dual mass flywheel to further isolate the trans from motor vibrations.

Anyone know which is the right one? I have a KEP flywheel at the moment, and a stock size LUK heavy duty clutch.

If I need a different PP and clutch disc, can someone advise which specific parts will work best?

Question #3 -

I understand that the clutch cylinder mount will need to be welded on to allow this to be mounted. Any sources for exactly how to do this?

Also I am told my current Hi Torque starter will not fit and either some kind of adapter is needed, or a different starter. Which one?

Any further wisdom from European experts?


Posted By: syncroandy
Date Posted: 18 Sep 15 at 11:17
Hi Colin,

Interesting post, but where to start.. I looked in some detail at a 15-degree install of a TDI (earlier block type though not ALH) and the Mexican bell was one of the options I considered. In the end I went with a 'conventional' 55-degree setup, using some JX mounting parts, but retaining donor Passat exhaust manifold and turbo, which required fabricating a modified LH engine mounting:" rel="nofollow - AFN TDI install

However I would still very much like to do a 15-degree install, and have a later type TDI engine very similar to the ALH stashed away for this.

Whilst on a first glance the Mexican bell does look to provide a solution, it does have some problems. As you say it's quite a bit longer than the standard T3 I4 bellhousing, but also it's not big enough to take a 'proper' TDI flywheel, and it's designed for an old Type 2 petrol starter. As you probably know, there are (were ?) conversion kits on the market using it, but as far as know, they resort to bespoke flywheel and starter.

I want to use as much stock unmodified parts as possible, including clutch, flywheel and starter. The conclusion I came to was this required use of the T3 I4 (diesel) bellhousing, with either an adapter plate between bell and engine (and bell milled down), or clocked, with an adapter between gearbox and bell.

The best documented install I've seen using the latter approach was done by Chris Schimke (for a 1.8t, but a lot would be similar for I4 TDI):" rel="nofollow - 1.8t conversion details ?

My plan is also to use a number of parts from the longitudinal setup in the Passat, namely engine-mounts, manifold and turbo. I've not verified this yet but I believe the mounts used on the PD engine in the Passat should also fit the ALH type TDI block (which was never actually fitted longitudinal by VW). The Passat manifold/turbo may be needed for clearance with these mounts.

Re. DMF, if using the TD bell, look at Sachs" rel="nofollow - Sachs 3000 951 790 . I understand a small clearance may be required, but it fits. You'd need the TDI spline input shaft of course.

Re. Starter, again with the TD bell, use the stock transverse TDI starter from the 02A type transmission, eg. 02A911023R, plus an adapter plate which are commercially available, or you could make one if you have a lathe.


'90 252 EJ25
'90 246 AFN" rel="nofollow - Syncrosport
Volkswagen Transporter, reloaded.

Posted By: colinegreen
Date Posted: 18 Sep 15 at 23:23
Thanks so much for all the info, Syncroandy.

are you able to say if any of the BH options sold by Weddle is the correct one?

My current transmission has a shortened TDI input shaft and larger 3rd and 4th gears. 1.14 I think for 3rd, and 0.7 for 4th.

I also had the low/reverse syncronizer removed as mine had failed twice as a result of excess vibrational energy, I am told by my knowledgeable transmission re-builder Tom Lengyel. This means I will have to fully stop to go into reverse or granny, which is preferable to additional trans repairs...

Other than replacing the BH, would I need to make any additional mods to my trans for installation with the TD BH? How do I know I have the correct input shaft? 

You say (and it is the first I have heard of this) that this BH still requires an adapter plate. I though the point of using this BH was to make the connection strong as stock and eliminate flimsy adapter plates. Can you please elaborate?

I have bought many parts from Chris Schimke via the excellent T3 technique. I can ask his advice now that I know he might be a good source of info here in the US.

Regarding the starter adapter - machining one is not really in my wheel house. Are you aware of one which can be purchased?  Perhaps Karl Mullendorf's adapter, seen here? I can ask Karl.... He has been helpful in the past.

Know of any documentation on the required clutch cylinder mount which needs to be added to the BH?

Many thanks again for providing answers which have been elusive for some time.


Posted By: colinegreen
Date Posted: 19 Sep 15 at 00:19
how about this?

same as the SACHS?

Posted By: syncroandy
Date Posted: 19 Sep 15 at 20:04
From the Weddle website:

Standard T3 diesel/turbodiesel (I4) bellhousing for fitting the engine at ~55 degrees:

'Mexican' bellhousing for fitting I4 petrol engines into the T2 bus at ~15(?) degrees:

You may want to research this a bit more, there's plenty of information out here. Chris's Samba thread is a good starting point.

I did find some old notes including the following info (the diesel and WBX would have been my measurements, can't recollect he origin of the Mexibell info):

Mexican bellhousing:

    Engine mating surface to cross shaft C/L = 112.5mm
    Gearbox mating surface to cross shaft C/L = 71mm
    Overall length = 183.5mm

Diesel bellhousing:

    Engine mating surface to cross shaft C/L = 97mm
    Gearbox mating surface to cross shaft C/L = 46mm
    Overall length = 143mm

WBX bellhousing:

    Engine mating surface to cross shaft C/L = 81mm
    Gearbox mating surface to cross shaft C/L = 43mm
    Overall length = 124mm

'90 252 EJ25
'90 246 AFN" rel="nofollow - Syncrosport
Volkswagen Transporter, reloaded.

Posted By: colinegreen
Date Posted: 20 Sep 15 at 21:03
Thank you so much, Andy.

My engine is 15 deg now, and I assume it needs to stay this way, so this means the Mexican option, correct? Can you confirm that this will bolt up to my motor and trans without any adapter plates?

I studied the images you posted to correlate them to the Weddle site. Can you confirm that the one you mention is this one? Sorry, I appreciate that you went to the trouble to post those pics, but they look the same and I want to be sure I have the right one.

Part Number: 

I think this one looks the most the same. It says a special input shaft is needed, I assume just to make it a bit longer. I would need to find a shaft like this with the TDI splines, is that correct? Please elaborate.

So this BH will fit the DMF FW and clutch?


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