# What`s the scoop with VW Flywheels



## onegreenev (May 18, 2012)

GoElectric said:


> Hi - RE: Beetle conversion,
> 
> Does anyone know, or has there been a discussion anywhere here on the need or lack thereof for:
> 
> ...


Im one without one of those aluminum flywheels but that will be changing soon. Connectors for the flywheel are actually the problem for VW vibrations. Not the flywheel or dowel pins. For any performance VW you should use a flywheel that has 8 dowels and the long ones. Not the short ones. Minimum should be a Stage II for any electric motor on the VW. I currently use a lightened flywheel. You don't need a full weighted flywheel with an electric motor even if you still use the clutch. Don't bother going clutchless on the VW. Some do but I say NO. As for the lightened flywheel vs the full weight flywheel? No real difference in everyday use. The VW flywheel is not very heavy anyway. 

The flywheel EVWest has utilizes a more modern porsche bolted on flywheel along with the interference coupler that will not move and will remain square. Stock pressure plates slip real easy under the torque of the electric motors. Im using an 11" Kostov motor in my current conversion. 

But no, you don't need the EVWest Flywheel but you will have to really play with the taper lock connector to get the balance right. 

But regardless of which one you use, you need to balance your flywheel and pressure plate together to get a good smooth running system. Vibration will fail down the road and usually without warning.


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## GoElectric (Nov 15, 2015)

Hi and thanks, your explanation(s). Help. I still don`t get for sure why you say the dowel pins are not an issue, but that I need more of them. I mean, I get that more will keep the pressure plate more stable - especially true for aluminum, as it is so soft perhaps.

What do you mean by balancing the flywheel with the pp on it.

Main purpose of my post fulfilled - I just wanted to make sure Mike hadn`t gone off the deep end: there are issues and the aluminum flywheel will make it easier and more reliable. 

I look forward to seeing the taper-lock method - only worked with a key before this.


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## onegreenev (May 18, 2012)

GoElectric said:


> Hi and thanks, your explanation(s). Help. I still don`t get for sure why you say the dowel pins are not an issue, but that I need more of them. I mean, I get that more will keep the pressure plate more stable - especially true for aluminum, as it is so soft perhaps.
> 
> What do you mean by balancing the flywheel with the pp on it.
> 
> ...


Dowel pins are to keep the flywheel in place and won't allow it to spin. 4 dowel pins are fine for the 56hp VW engine with low torque. But when you apply gobs and gobs of torque you risk those sheering off and allowing the whole flywheel to spin. The short dowel pins are even more at risk of that then if you use the longer ones. More grip with more. 

The Aluminum Flywheel from EVWest does not use the dowel pin setup like the VW engine. The Aluminum Flywheel uses bolts. I believe 5 of them. They will not sheer under this torque. Holds better. 


But if you want to use the stock VW Flywheel get the ones that allow you to use the longer pins if possible and 8 of them. 

I do have a setup with a GE 9" Motor that uses 4 of the stock size dowel pins but it was not setup to give super high torque and should be just fine under low voltage and lower amperage. 

I have on my VW Roadster project an 11" Kostov Motor and an Eventics Adapter plate that uses 8 dowels and I have a lightened flywheel and a stage I pressure plate. I slip the clutch under full out throttle. So I have to be careful not to burn up my pressure plate and disk. I just need to be easy on it. 


If you go with the standard setup be sure you balance the flywheel and pressure plate and be very very precise when you setup the flywheel and pressure plate. Take your time. It will work. Can be a pain in the butt but it will pay to be precise and patient when doing this part of the build. Don't rush and don't cut corners.


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## onegreenev (May 18, 2012)

GoElectric said:


> I still don`t get for sure why you say the dowel pins are not an issue, but that I need more of them.


They don't cause wobble problems. they are for keeping things from sheering and spinning under power loads. The pins are the link between the flywheel and shaft. The big bolt on the VW is what keeps it locked. 


With many VW setups you need a taper lock coupler. Its the taper lock coupler that causes wobble. The coupler is the problem. 

The coupler from EVWest is an interference fit coupler. No issues like you get from the taper lock style. 

I'll do a quick video on what I am talking about. 

Pete


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## onegreenev (May 18, 2012)

Here is a quick video of my AC-35 with the taper lock in place and you can see it is not square. The dowel pins you see are the long ones. This taper lock only allows the use of 4 dowel pins but should be setup for 8. This setup needs to have a square stop of the proper length to allow solid sure squareness and 8 dowel pins. Then this would be a great setup for a standard lightened steel flywheel.


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## GoElectric (Nov 15, 2015)

Thanks. I will get to the video soon, but just saw the post now. Some confusion on my part, I think: I thought you meant the dowel pins on the clutch which line it up on the flywheel. Confuzing because bolts hold this on. Soon all will become clear.

Jim


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## onegreenev (May 18, 2012)

GoElectric said:


> Thanks. I will get to the video soon, but just saw the post now. Some confusion on my part, I think: I thought you meant the dowel pins on the clutch which line it up on the flywheel. Confuzing because bolts hold this on. Soon all will become clear.
> 
> Jim



Yes. On the back of a VW Crank shaft the pins keep the flywheel from spinning. The big bolt holds it against the crank shaft and prevents wobble. The same applies to the adapter but the difference is the adapter must be connected to the shaft of the motor. That is where the problem lies. A taper lock device is used to attach the connector and if the taper lock is not square you get wobble. Getting the taper lock square is the tough part. Issues of not being able to put the taper lock on square can be the keyway and the ability to slowly tighten the bolts. If you can't tighten the bolts squarely you get wobble. I guess I need to show you a picture to give you a better view. 

So you see the piece that has the pins? That is like the back side of the VW Crankshaft. Dowel pins and Big Bolt hold the flywheel to that piece. 

That piece (before you install the flywheel) needs to be slipped over the other piece which is the taper lock. They both slip over and as you tighten the taper lock you also press on the flywheel adapter to the taper lock. Two places of wobble occur here. If the adapter is not square on the taper lock and if the taper lock is not square to the shaft for any reason you will encounter wobble. Its hard to see wobble on the adapter by itself. Once you bolt on the flywheel you will see. 

You don't want wobble at all. You also want balanced.


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## Duncan (Dec 8, 2008)

Hi Onegreen
Are you sure that the torque goes through those pins?

Everything else I have worked on transmits the torque through friction with the clamp loads of the bolt(s) providing the axial loading

If there isn't enough clamp load then the flywheel moves and those pins die in a couple of hours
If there is enough clamp load then all that the pins do is provide an assembly aide

If I was having alignment problems I would simply omit the pins altogether


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## onegreenev (May 18, 2012)

Duncan said:


> Hi Onegreen
> Are you sure that the torque goes through those pins?
> 
> Everything else I have worked on transmits the torque through friction with the clamp loads of the bolt(s) providing the axial loading
> ...



The pins are for alignment and for torque. These are some seriously hardened pins. Slightly larger diameter and longer pins are best if you can use them. The big bolt does play a large role in keeping pressure on the connector. But there is little extra actual area the flywheel covers. But if you tighten your large bolt properly you will not have an issue. But 8 dowel are mostly used in high torque race engines so the dowel pins do play a huge role in keeping the high torque under control. With the taper lock style setup you add in an added point of failure and a point of imbalance or wobble. It is not like the crank of the VW. It is actually adapting the end of a crank to the shaft of your electric motor. 

The setup from EVWest actually is an interference fit and will be nearly impossible to twist off. The flywheel is connected via bolts instead of a central bolt and 4 hardened dowel pins. For a low power and low rpm setup the old way is fine. But for high power and rpm it requires more. 

Pete


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## electro wrks (Mar 5, 2012)

onegreenev said:


> That piece (before you install the flywheel) needs to be slipped over the other piece which is the taper lock. They both slip over and as you tighten the taper lock you also press on the flywheel adapter to the taper lock. Two places of wobble occur here. If the adapter is not square on the taper lock and if the taper lock is not square to the shaft for any reason you will encounter wobble. Its hard to see wobble on the adapter by itself. Once you bolt on the flywheel you will see.


Technically the bushing is called a QD (Quick Disconnect) type bushing. Here's a vid that explains how they're assembled:
https://www.youtube.com/watch?v=_7zWbKRsh04


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## Matej (Dec 4, 2015)

Personally, aluminum flywheels seem scary. I used to go to a lot of drift events, and I have seen a couple of them shatter. Luckily no one was injured, but the shards from them tore up the frame rails on the cars, shot through the transmission tunnel, and even embedded themselves in concrete barriers.
If an ICE can destroy an aluminum flywheel, then it seems even more likely with the instant torque of an electric motor.


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## electro wrks (Mar 5, 2012)

This is a potential problem with all flywheels. With the newer, much higher RPM brush-less motors, serious thought needs to go into the safety of using stock ICE flywheels where the normal maximum ICE RPM is exceeded.


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## onegreenev (May 18, 2012)

electro wrks said:


> This is a potential problem with all flywheels. With the newer, much higher RPM brush-less motors, serious thought needs to go into the safety of using stock ICE flywheels where the normal maximum ICE RPM is exceeded.


Thats the purpose for balancing the flywheels and pressure plates. I see no problem with the Aluminum Pressure Plate. Its not like I'm going to be spinning it up to 10,000 rpm. A well balanced wheel that is sound should hold up just fine but as with all things, some could break apart.


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## nucleus (May 18, 2012)

A Tesla can spin up to 16,000 RPM...

If you have that hooked up to a clutch and transmission, you might need one of these:

http://www.jegs.com/i/TCI/890/980000/10002/-1


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## onegreenev (May 18, 2012)

nucleus said:


> A Tesla can spin up to 16,000 RPM...
> 
> If you have that hooked up to a clutch and transmission, you might need one of these:
> 
> http://www.jegs.com/i/TCI/890/980000/10002/-1


Well if you can get your DIY conversion to spin up to 16,000 rpm then I highly suggest you go direct drive or single gear drive. But for the most part most DIY conversions are rather low rpm and low power and do require a good transmission to multiply the torque to the wheels. 

Im aware that there are limits to any mechanical device. But some flywheels Im sure could handle that. Wouldn't want to be in the way if one let loose.


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