AA 200mm 12V flywheel

[Dave Erickson]

AA makes a 200mm flywheel for 356 with a standard VW 12V ring gear. I recall from my days of working on VWs (40 years ago at least) that to swap a 12V engine into a 6V VW (as part of a change to 12V) required changing the starter bushing in the transmission and the use of a 12V starter with a different pinion from the 6V.

So my question is: can I do the same thing with a 356 transmission: install a VW 12V starter bushing and use a VW 12V starter along with the AA 12V flywheel? Next question would be, which VW 12V starter bushing? Google shows more than one.

[Dan Epperly]

AA makes a 200mm flywheel for 356 with a standard VW 12V ring gear. I recall from my days of working on VWs (40 years ago at least) that to swap a 12V engine into a 6V VW (as part of a change to 12V) required changing the starter bushing in the transmission and the use of a 12V starter with a different pinion from the 6V.

So my question is: can I do the same thing with a 356 transmission: install a VW 12V starter bushing and use a VW 12V starter along with the AA 12V flywheel? Next question would be, which VW 12V starter bushing? Google shows more than one.

Th bushing had to be the adapter one, which is thicker to fit the OD of the hole in the bellhousing but has a smaller ID for the starter.
On VWs you had to grind down the bellhousing above the mounts or the larger flywheel would hit. I think you also have to clearance around the bushing hole. Not sure if this has to be done with a Porsche trans.

[Dave Erickson]

Th bushing had to be the adapter one, which is thicker to fit the OD of the hole in the bellhousing but has a smaller ID for the starter.
On VWs you had to grind down the bellhousing above the mounts or the larger flywheel would hit. I think you also have to clearance around the bushing hole. Not sure if this has to be done with a Porsche trans.

Thanks Dan, that clarifies which bushing. I think back in the day some people did not bother to grind the transmission bellhousing for clearance, they just let the flywheel do the machining .

[Dan Epperly]

Th bushing had to be the adapter one, which is thicker to fit the OD of the hole in the bellhousing but has a smaller ID for the starter.
On VWs you had to grind down the bellhousing above the mounts or the larger flywheel would hit. I think you also have to clearance around the bushing hole. Not sure if this has to be done with a Porsche trans.

Thanks Dan, that clarifies which bushing. I think back in the day some people did not bother to grind the transmission bellhousing for clearance, they just let the flywheel do the machining .

Yeah they would turn the engine by hand as they shoved it in and let it grind away. Not sure that would work with those aluminum cases!

[Dave Erickson]

Yeah they would turn the engine by hand as they shoved it in and let it grind away. Not sure that would work with those aluminum cases!

I think that would be the way to go with a 356 as well, although maybe only to get the initial fit so as to know where to grind.

[cory cotherman]

I have the 200mm AA flywheel in my 644 transmission. No grinding necessary. I am using a 6v starter running off 12v.

[Jacques Lefriant]

That flywheel was made for 36hp VW engines for use with the bigger 200mm clutch and later VW transmissions. they make the normal Porsche 200mm with the 6 Volt ring gear for the Porsche transmission.
j

[Dave Erickson]

That flywheel was made for 36hp VW engines for use with the bigger 200mm clutch and later VW transmissions. they make the normal Porsche 200mm with the 6 Volt ring gear for the Porsche transmission.
j

Yes, that makes sense. But it also provides an interesting way to upgrade a 356 to a 12V starter.

[Martin Benade]

It has 4 dowel holes for the VW application? And who is putting 36 HP engines in later VWs? And wouldn't the smaller clutch be plenty?

[Greg Bryan]

I bought an AA flywheel recently that has the accommodations for a 200mm VW clutch, but it has the 6v starter ring gear on it - 109 teeth if memory serves (which it doesn't always ...)

[Martin Benade]

That is a more likely offering, with the 6V gear.

[Martin Benade]

On the subject of flywheels, is there a good way to measure the very slight angle on the mating surface of the flywheel to crank? I understand that this angle is important to keep the flywheel tight.

[Ron LaDow]

On the subject of flywheels, is there a good way to measure the very slight angle on the mating surface of the flywheel to crank? I understand that this angle is important to keep the flywheel tight.

This was probably a good idea given left-over WWII tooling at the time, but it really stinks now.
I'd arrange a really good straight edge across the 'flat' surface (assuming IT was flat) and use a "Best Test" indicator trammed across the surface, and then a bit of trig.
A HS steel lathe cutting tool blank will give you a really flat surface for that distance.
So far, I've trusted the suppliers and have yet to be bitten.

[Martin Benade]

Is it safe to assume it's ok as long as long as there has never been a loosening incident?

[Norm Miller]

Porsche starter pinions were the same for 6 & 12 volt applications. Same bushing
VW 6v also.
On certain cars the VW 12v starter is difficult to use due to the solenoid location and requires a different bushing.