901

[effvee]

Hay, the 901 that I have has a bowden tube holder, but Bug at 5 speed post states it won't work well. It looks pretty stright forward, I'm trying to install this trans on the cheap. Although cheap, not cheap and stupid. I would like to have the origianl stick shifter work, and this has nothing to do with cheap; I just want when someone looks inside they only see a stock shifter.

Is this trans hard to mod? I see that the vent hole is already on the correct side and positioned correctly.

Why does the shifter rod have to be bent into a "Z", it look like it would not take that much to couple them. I see where Bug at 5 speed moves between the 914 and the 901, its kind of confusing; such as if the trans has the correct nose cone already, why change it. It is just for the 30mm savings

[owdlvr]

Heading to bed, but if you don't see me reply to this thread in the next day or two, send me a PM or reply here to remind me. I can answer a lot of your questions.

-Dave

[jmd]

so a few simple answers to your questions.
1. The bowden tube port from the 901 wont work - get the Bug@5spd Tube Adapter. (the bowden and it working correctly are very important to a happy shifting / non-bucking trans)

2. The shift linkage has to be adjusted because (and you'll see it clearly once you pull your bug trans) - the bug trans shift shaft comes out the middle/top of vw transmission. The trans shift shaft on the porsche trans is about 3 inches lower in it's output location (the part that you like your shift shaft to).

The Z bend in your shift shaft is required to make the connection while maintaining proper alignment / shift functionality.

3. you'll need a new clutch package. (my install isn't to a vw engine so I'm not able to speak to the parts needed there).

You will also need to either drill the case on the 901 for the rear mount solution or build your own mounts (which is what I have done) and depending on how far forward you want to mount your setup, you may have to remove material from the torsion tube area.

This is not a quick 2 day job unless you've done it before, have help and all the parts on hand. But it is totally doable. Follow the lead of those before you and make your own version of the install. It's an awesome project and when you first sit in the drivers seat and row through all the gears, it's an ear to ear smile of success...

There are several write up's on the install that are worth reading. Bug@5spd makes quality parts that make this an "almost bolt in" job.

Have a look through this build, it has some really nice front mount solutions as well as just an all around example of proper building techniques.


And sorry to link to and offsite resource but it's a good write up of the job: Aircooled.nets write up

It can be done - just do your research and don't try to reinvent the wheel.
best of luck.
jmd

[owdlvr]

Sorry it took me so long to jump in on this. Having just installed a 901 Transmission this winter on the cheap, I think I understand where you're coming from and what you're looking to accomplish. Reading through my build thread and all the photos would definitely help you out.

1) Bowden Tube - My transmission had the same holder, and I used it without any problems. Most of the build threads or install stuff you'll find online say to cut it off and build or buy a custom mount. I've instead lathed up a bowden-tube extender that goes on the tunnel (front) end of the bowden tube:


The eyelet cast into your transmission will need to be opened up just a touch, I used some emery paper on the inside of the eyelet and the outside of my bowden tube until it slid together.

Keep in mind that the clutch cable length will need to be determined by your own personal setup. Where you place your transmission, and how you do your bowden tube will change the required cable length. On my '73 pan, with the transmission mounted forward so the engine sits exactly where it would with the VW trans, I'm using the shortest cable I could buy ('52 split beetle if I remember correctly). This was shorter then anything suggested in the online tutorials, but most likely due to the way I pushed my trans so far forward.

2)

Is this trans hard to mod? I see that the vent hole is already on the correct side and positioned correctly.

- Depends on what you're trying to modify? I need you to post up the full transmission code (found on the bottom of transmission) before I could determine if your trans will work as is, or if it requires any modifications to install in a beetle.

3)

I see where Bug at 5 speed moves between the 914 and the 901, its kind of confusing; such as if the trans has the correct nose cone already, why change it. It is just for the 30mm savings.

If you have a 901 trans from a 914, changing the nosecone over is required to move to a tail-shifting setup. On a 901 found in a 911 transmission, swapping the nosecone saves you the 30mm in length, right where you need it most.

When you go to install your 901 transmission, there are three things you need determine before you start cutting and welding:
- Location of the engine

Most of the tutorials I found online moved the Beetle engine from it's original location (if it were bolted to a VW trans). By memory I think it was about 10mm up, and 25mm further back. You'd have to do some reading to figure that out. I also can't recall if those measurements were with or without the Bugat5Speed nosecone. If it was without, you'd have to add another 30mm back (ish). For my install I decided that I wanted the engine to sit exactly where the VW engineer's had put it, and would cut/weld/modify anything else that got in the way. All of my measurements and settings were done with the mounting face and input shaft in the factory location.

- Location of the Axles

CV joints last longer when they're only moving through one plane. So, if you mount your transmission in a way that the axles are angled forward or back, you will wear out CV joints faster then an install which has them straight across. In a high-powered, high-traction vehicle (such as a turbo GL-look), the risk of weakness in the CV's might be enough to have the axle angles as the deciding factor of where your transmission should sit. I never actually measured the angle on mine, but they definitely sit on a slight angle with the transmission CV's forward of the axle CV's.

- Interference with the Torsion Tube

The front nosecone of the Porsche transmission _will_ interfere with the torsion tube. Where you decided to mount your transmission, given the above two factors, will determine how much the trans interferes with the torsion tube. Using the Bugat5Speed nosecone will reduce the interference quite a bit, and might even give you all the clearance you need. In my build, I used the Porsche nosecone and ended up cutting out over half the torsion tube right in the middle. I couldn't mount torsion bars in my car if I wanted to, all the splines on the inside are gone. You'll also see on build threads about grinding down the factory nosecone. Go easy and be careful, I've got JB-weld filling the hole on mine where I went all the way through. Some build threads show very little grinding of the torsion tube required, but don't make any mention of where the engine sits or what angle the axles are on.

Anyway you slice it, mounting location of the transmission is going to be a compromise between where you'd like the engine to sit, what angle you determine is "okay" for your axles, and how much of the torsion bar tube you're willing to cut and/or grind away.

4)

You'll need a new clutch package. (my install isn't to a vw engine so I'm not able to speak to the parts needed there).

Actually, not totally correct. I'm using the same Type-1 flywheel, clutch and late-style pressure plate that I had in my car with the Type-1 transmission. I'm using the Porsche 901 clutch arm and throw-out bearing. A good friend at Intermeccanica Roadsters (who have done a tonne of these swaps into 356 roadster replicas) tells me that this combination will be good for close to 40,000km. After about 35,000km you're at high risk for the Porsche throwout bearing to wear through the pressure plate fingers on the Type-1 late-style pressure plate. The solution here is to use the pressure plate with collar over the fingers. This again may effect the clutch cable length required (I don't know) but Henry tells me it does fit. I figured I would run mine as is until I pull the engine next, and then swap the Pressure plate.

The other issue to consider is the starter. I'm using a VW Autostick starter, but it did require modification. We mounted the starter in the lathe and took .125" off the mounting face of the starter. This moves the starter in for more teeth engagement on the flywheel. Before the modification the starter was using about 1/3rd of the flywheel teeth, and would grind the starter on engagement approximately 1 out of every 3 tries. After the material was removed from the starter I get about 3/4 tooth engagement, and it grinds about 1 out of every 10 tries. After talking to a few 901-swapped guys they all admitted that this was common and accepted as part of the swap, but you don't really read anything about it online! haha.

5)

Why does the shifter rod have to be bent into a "Z", it look like it would not take that much to couple them.

As already stated, there is a big height difference between the two transmissions and where the shift-rod enters. You will need to do the Z-Bend or fabricate another solution to account for the height difference. The Bugat5speed shifter setup drops the shift rod to eliminate the Z-Bend, which should make the shifting much easier on the side-to-side action. Anytime you use a Z-Bend, the shifting is going to end up a little vague. I'm considering redoing my shifting with universal joints, but this will require welding in up to 4 mounts inside the transmission tunnel to support the shift shaft. One of the other GL guys had PM'd me about my shifter, and I had sent him a bunch of comments on it. Note that my shifter is actually stock beetle with some carbon-accents. I could pull the carbon off, put a stock knob on and you'd never know it wasn't factory beetle.

I'm using a stock bug shifter with EMPI aluminum short shift kit and then a custom carbon knob and custom carbon tube over the stock shift shaft. If I pull the knob and carbon tube off, it's 100% stock VW Beetle...even the lock out plate. I did double up the lockout springs (using two stock ones), and the shift rod is a cut-and-weld mix of stock beetle, steel tubing and Porsche shift rod.

I have a shorter-then-stock-beetle throw going forwards and backwards, but what feels like "stock" throw going side to side. It's easy to figure out where all the gears are and works quite well...most of the time. The problem is the Z-bend in the shift rod. This makes the side-to-side action somewhat vague at times, and appears to bind occasionally. A quick wiggle of the shifter in neutral sorts everything out and the gears become easy to find again, but this doesn't help much if you're on a race track! I believe I have some more R&D to do before I'm 100% happy.

My reverse (and 1st) lockout works well, but I need to build a single-spring that is heavier weight. The two springs occasionally bind and don't allow the shifter to snap up, thus the lockout "sticks on". If you're not careful it's easy to select reverse instead of second. I have learned that if I go into first, and the shifter snaps-up immediately, everything will be okay. If I don't hear the snap, I have to be super careful.

On the catching reverse front, instead of second, even when the shifter snaps up it's possible to 'rub' reverse on your way into second. I had a chance to talk to a couple of 901-Equipped Porsche owners, and the problem is found in those cars too.

Bottom line is that I have fully sorted out perfect shifting yet...I'm currently considering going back to the stock beetle shifter shaft (small diameter) and adding a "gate plate" and tower above the transmission tunnel. Imagine a Ferrari shift-gate-plate, but mounted on a 4-post tower. That should eliminate miss-shifts if it were precisely machined. Possibly ugly, but I will try and find the photo of a factory Audi rally car that used one. The other option is to go with two universal joints in the Z-bend so that when I move the shifter left and right the shaft rotates at the transmission as it should. Currently it rotates and "swings" due to the hard Z-bend. Going universals, however, would require between 2 and 4 mounts welded into the trans tunnel which could be a challenge with the body on.

Hope this helps.

Hope all this helps you out, it took a while to get to but I've tried to be complete in my answers!

Feel free to post here with more questions.

-Dave

[effvee]

1) Bowden Tube - My transmission had the same holder, and I used it without any problems. Most of the build threads or install stuff you'll find online say to cut it off and build or buy a custom mount. I've instead lathed up a bowden-tube extender that goes on the tunnel (front) end of the bowden tube:


Thank you very much, I plan to relocate the bowden tube much lower, hope to start this weekend after I buy trans mounts.



2)
- Depends on what you're trying to modify? I need you to post up the full transmission code (found on the bottom of transmission) before I could determine if your trans will work as is, or if it requires any modifications to install in a beetle.

I'll look for the code, the guy that sold the trans to me said it was from a 912

When you go to install your 901 transmission, there are three things you need determine before you start cutting and welding:
- Location of the engine



- Location of the Axles

CV joints last longer when they're only moving through one plane. So, if you mount your transmission in a way that the axles are angled forward or back, you will wear out CV joints faster then an install which has them straight across. In a high-powered, high-traction vehicle (such as a turbo GL-look), the risk of weakness in the CV's might be enough to have the axle angles as the deciding factor of where your transmission should sit. I never actually measured the angle on mine, but they definitely sit on a slight angle with the transmission CV's forward of the axle CV's.

I will only be able to relate to all of these insights one I do my first rough fitment.

Also the 25 to 30mm foreward/aft shift of the trans assembly will effect 12.5mm on each end of the axle. Also I am going to use some 930 CVs


The other issue to consider is the starter. I'm using a VW Autostick starter, but it did require modification. We mounted the starter in the lathe and took .125" off the mounting face of the starter. This moves the starter in for more teeth engagement on the flywheel. Before the modification the starter was using about 1/3rd of the flywheel teeth, and would grind the starter on engagement approximately 1 out of every 3 tries. After the material was removed from the starter I get about 3/4 tooth engagement, and it grinds about 1 out of every 10 tries. After talking to a few 901-swapped guys they all admitted that this was common and accepted as part of the swap, but you don't really read anything about it online! haha.

some one said using a regular starter will work, I know of a company that sell reduction starters, I'll see if they have other nose or bendix lengths on the same platform.

5)

As already stated, there is a big height difference between the two transmissions and where the shift-rod enters. You will need to do the Z-Bend or fabricate another solution to account for the height difference. The Bugat5speed shifter setup drops the shift rod to eliminate the Z-Bend, which should make the shifting much easier on the side-to-side action. Anytime you use a Z-Bend, the shifting is going to end up a little vague. I'm considering redoing my shifting with universal joints, but this will require welding in up to 4 mounts inside the transmission tunnel to support the shift shaft. One of the other GL guys had PM'd me about my shifter, and I had sent him a bunch of comments on it. Note that my shifter is actually stock beetle with some carbon-accents. I could pull the carbon off, put a stock knob on and you'd never know it wasn't factory beetle.

I worked for the Los Angeles Unified School District as a mechanic. While there I have to replace several shifter u-joints and supports for the shifter rods. Those shifter rods came in three pieces and were about 18 feet long. Due to the supports, it shifted very well, there was only slope because of the support bracket bushing wearing; and as a quick fix we just rotated the support 180 degrees. You have given me a good ideal, thanks





Feel free to post here with more questions.

OK
-Dave[/QUOTE]