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Machining early gearbox to accept 200mm flywheel
karmannghia60 - October 22nd, 2003 at 05:35 PM

I've been told that even if I find a 6v/200mm flywheel, its not a good idea to use it with the bigger engine (the starter will just eat the ring gear quickly) so now I am looking into using the 12v flywheel with the early gearbox. The g/b needs to be machined, right? Is this a home job or too much?
I've been quoted about $550 to machine and fit a new 12v starter.
Raf

vw54 - October 22nd, 2003 at 05:51 PM

Raf

This is a job U can do yourself. Remove the engine and get a grinder with a fine sanding disc and gently grind to remove enough material to make the flywheel fit.

theres 4 lugs in the bell housing that need about 1 or 2 mm off them fit evenly to make the flywheel fit.

read the other post as well.

do you have access to a lathe cause you can make a oddsize bush for the starter.

GL1972 - October 22nd, 2003 at 09:14 PM

Raf,
Just a safety tip. Whilst you can grind out the gearbox housing remember that the gearbox is made of magnesium alloy which burns very hot. 20 years ago a friend and I were having turns grinding for a 200mm flywheel. He touched one of the 4 gearbox bolts and created a spark. All of the magnesium dust on his lap went up (he was not waring a shirt). He spent 3 painfull months in hospital and I wore bandages on my hands for weeks.

Protective clothing a mate and a fire extinguisher is the go for this job. :jesus

MickH - October 22nd, 2003 at 09:30 PM

Fire extinguisher wont help you much....Try using a rotary file in the end of a drill.Have done this many times.Metal stays cool !!Remove gearbox mounts after marking how much of the bolts are required to be cut off. Grind the excess off with the grinder-leave the nuts on!!Gather all the filings of magnesium and throw them on the fire next time your camping...pretty:bounce good luck

Craig Torrens - October 22nd, 2003 at 09:44 PM

Quote:
Originally posted by karmannghia60
I've been told that even if I find a 6v/200mm flywheel, its not a good idea to use it with the bigger engine (the starter will just eat the ring gear quickly) so now I am looking into using the 12v flywheel with the early gearbox. The g/b needs to be machined, right? Is this a home job or too much?
I've been quoted about $550 to machine and fit a new 12v starter.
Raf



Huh??? the starter eating the ring gear ??? Its a 6v starter turning over a 6v flywheel, how is that any different to the other millions of 6v beetles .:jesus

I have that same setup in my 65' that I'm working on now, 1600TP with the 200mm 6v flywheel. Bought the car without the starter, tried fitting a 12v but it wouldn't turnover, pulled out the motor and found this combo !!! The great thing is that the motor turns over twice as fast with 12v running through the starter, starts so easily:thumb

For the 12v option , ten minutes with a grinder max !! and the bush can be pressed (hammered) in for the 12vstarter pinion.

555bug - October 23rd, 2003 at 12:39 AM

i don't know if this is the acceptable method but when we moddified my mates oval we just bolted up the engine and hit the starter :) pull the engine and clean up with a file :bounce

vw54 - October 23rd, 2003 at 07:44 AM

Quote:

Just a safety tip. Whilst you can grind out the gearbox housing remember



GOOD POINT

Raf the magnesium is soft and comes off easy so be careful and dont take too much off the areas needed. Use the flywheel loose to test each time you use the grinder

Grey 57 - October 23rd, 2003 at 08:35 AM

Raf , I just been thru the same thing with my oval. The ring gear was chewed up real bad. But it took a long time to happen and if the motor is in good tune and starts easily it will last a while.
I replaced the 6v 200mm one with a good 2nd hand one and dont think I will need to worry abut it again for sometime.
My call would be to keep the 6v 200mm one and not clearance the housing. I have been told it weaks them and it danger of fire.
I might be able to help you out with one. Let you know in a couple of days.

karmannghia60 - October 23rd, 2003 at 09:28 AM

Thanks a lot to all of you, great info (I love this forum :thumb). My preference is to stick with a 6v/200 flywheel at this stage but can't find one yet. So to confirm, if I do find a 6v/200 one, I don't neet to touch the 6v start, it will work, right? Dean, it would be great if you can help me out Mate
Raf

TheGermanFolks - October 23rd, 2003 at 10:13 AM

well that just depends, if you are converting the whole car to 12 volt, then you need a 12 volt solenoid put on your 6 volt starter, and you will love the way that thinkg starts.

68AutoBug - October 23rd, 2003 at 10:34 AM

Yes, I would use the 6 volt 200mm flywheel and use the 6 volt solenoid or you could change the solenoid to 12 v to keep the flywheel & starter pinion speed at an acceptable level.... otherwise I have read where You can just turn the engine over and do the engine bolts up slowly and the flywheel teeth will cut into the magnesium alloy and You won't need to machine the case.... it does it itself...

karmannghia60 - October 23rd, 2003 at 10:34 AM

Its already 12v. Been like that for 10 years. And yeah, it starts first click

lowrider - October 25th, 2003 at 05:35 AM

The other way ,but harder, is to get hold of a 12V
swing axle 'box; its already clearanced for you by the factory! Ratios may be better too!
Andy

tassupervee - October 29th, 2003 at 06:22 PM

Using the 6V starter on 12V is fine but the solenoids are a bit prone to dying, usually when you most need it!
A good source of 12v solenoids is any old grey engine holden starter.

Grey 57 - October 29th, 2003 at 06:41 PM

Thanks for that tip supervee. Handy to know.
Raf, no joy on that flywheel yet sorry. How bad is the one you have. You are welcome to use my old one if you are desparate. It wasnt completely stuffed but as I had to replace the clutch I thought I would change the flywheel too.