Board Logo

moding a fly wheel
seagull - July 21st, 2005 at 01:26 AM

I would like to talk about STEEL fly wheels , and how to weld a new center in for a motor conversion > say to subaru or what ever turns you on .

1) what is the grade of matirial the fly wheel is made from ? codes ect

2) welding > the correct welding rods to purchase

3) method of cooling the fly wheel after you weld it
why this ? > some some one like me can machine it !
I use lime ( powder )

Ideas WES ??


Desert Moose - July 21st, 2005 at 02:14 AM

Glad to see you have seen the light............:thumb


boof2332 - July 21st, 2005 at 07:49 AM

What will you do...turn out the centre of the vw one, then machine the relevant centre to fit...would it help in strength if the centre was a clearance fit(I think that is what you call it when you drop it in liquid nitrogen to enable its placement) then weld after that????

How is the trike....how does the exhaust note of your extractors sound?

Matt


Baja Wes - July 21st, 2005 at 06:11 PM

seagull,

if you want a steel flywheel then just make a complete steel flywheel.

Standard flywheels are generally castings.

Steel flywheels are called for in higher drag racing classes as the cast iron type flywheels have a habit of exploding at high rpm due to their brittle nature and dis-like for cracks (which grow normally at the friction face).

You basically don't want to weld the castings unless you have too, and then only really to a similar material, not steel.


seagull - July 21st, 2005 at 07:41 PM

yes I agree with you are the vw fly wheels chrome molly ??


tassupervee - July 21st, 2005 at 07:50 PM

Yep agree with Wes here.
By the time you either make or source your steel fly and then machine up a centre for it, weld it and then remachine it for true, you would be well advised to simply machine a complete custom fly.
As for the fly material? Dunno exactly.

L8tr
E


Baja Wes - July 22nd, 2005 at 11:45 PM

I think most flywheel materials are a high grade cast iron. I think they are generally either grey cast iron or CGI (compacted graphite iron). CGI is stronger than your normal grey iron, partly because the graphite particles are smaller and slightly rounded (hence the name compacted). It is kinda like a cross between grey cast iron and SGI (spheroidal cast iron). CGI is difficult to weld properly.

Have a look at the 4th, 5th and 6th pic on this page - http://www.offroadvw.net/bajawes/V6_baja/december.html

I made my flywheel by putting a VW ring gear on the outside of the mazda flywheel. I did this by having a vw ring gear machines off an 1800 flywheel (as on those the ring gear is machined into the actual flywheel, and is therefore the same cast iron material as the flywheel). This meant the two should weld and work together quite well as they should be similar cast irons. My engine sees up to 8,000rpm every now and again and hasn't explode yet.

So I don't think your welding idea is good because you wouldn't want to weld steel parts to cast iron parts.

If you cut the center out of one flywheel and weld it into the center of another cast iron flywheel, then that's a whole other story and would work fine (and has been done for ages by off-road racers.


choppa - July 31st, 2005 at 12:49 AM

Neil.
You need an engineer for this, or a metalurgist.
But then they would be driving BMW's or Merc's, id guess.
And probably not watching this forum.
However I would doubt very much that VW flywheels are cast.
I machined a 1600 flywheel years ago and damn it was tough.
Id say they are some sort of Chrome moly.
I have read that you can weld to chrome moly without post weld heat treat, but that its not as strong as if PWHT was done.
But for us, id say its gotta be better than some cast iron ive seen.
Saying that, my Sherman Engineering conversion flywheel looks like cast iron. It hasnt busted yet. But then im easy on the clutch let up and i dont run slicks.
Bright bar has some chrome in it. Get a lump of that and machine that up for the centre.

Choppa


seagull - July 31st, 2005 at 12:56 AM

its going to be a very big bit of steel .

your bros , was very hard when I machined the weld section , looked good , but shit it was hard going .


nbturbo - July 31st, 2005 at 09:02 AM

Neil- A mate of mine here is putting a Datsun 2lt into his Bay Kombi at the moment and he bought all the bits from some body in Castlemaine in Vic.The whole lot was only about $350 which included modifying the flywheel.I gave him one of my spare 1600 VW ones to convert, because his from the Bay was cast iron.It was away for less than a fortnight to have the Datsun centre welded in,and it looks like a great job.I will find out today who does this work,and will get a phone number for you.


seagull - July 31st, 2005 at 11:01 AM

Cheers for that .
I been looking at your oval , some great work there .I have to come past and have a look when I come over .


helbus - July 31st, 2005 at 06:28 PM

You could make a whole new flywheel out of steel.


nbturbo - July 31st, 2005 at 08:38 PM

Neil-checked my mate out about the flywheel-it only cost $290 for the adapter plate and to modify a steel VW flywheel that he had to supply(Which he still owes me for).They supply the machined centre to suit the specific relacement motor.Check them out at http://www.rodshop.com.au  - phone them,my mate reckons they are really helpful.Oh and your welcome any time for a visit.nn[ Edited on 31-7-2005 by nbturbo ]


seagull - July 31st, 2005 at 08:48 PM

Thats well priced .I have a look at the web page , thanks neil

O I will take you up on that offer for a shed visit :)


1303Steve - July 31st, 2005 at 11:00 PM

Hi

36 hp through to 1600 Type 1 & 3 motors all use steel flywheels. The type 4 motors use cast flywheels. The steel Beetle flywheel is a beautiful piece of metal.

Steve


seagull - July 31st, 2005 at 11:38 PM

yep and very hard !