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MG TD TF 1500 - Lightening Flywheel...

I have checked the archives and there are numerous suggestion to check Bob Grunau's drawing for lightening the TD flywheel...however, the page is no longer available...does anyone have a drawing I could use? From what I can determine, you can take the 8" down to 16# without it effecting the idle etc.
Bob Dougherty

Bob, i had always assumed there was a reason the factory engineers included all the mass they did in the flywheel...but i have read many posts here about the benefits of redesigning the flywheel. regards, tom
tm peterson

Hello Bob. I ran an all aluminum flywheel for many years until I wore the surface out. The car idled very nicely running 1-1/4" carbs, 1-1/2" carbs and with my Wade supercharger. The flywheel with ring gear weighed 11 lbs.

Butch
R Taras

I can lighten stock flywheels from about 21# to about 14#
Len Fanelli
914 420 8699
Len Fanelli

Bob

A few comments gleaned from the web;

"Don't forget that flywheel mass stores up energy which is very useful when blatting along the motorway and wanting to pass cars."


"Lightweight flywheel without balancing with the crank, bad idea?"

"General consensus is that the lightened flywheel, not only revs faster but also drops revs quicker."

Graeme
G Evans

Bob

This provides even greater "enlightenment"

http://www.millersmule.com/blog/tech-articles/flywheel-lightening-doing-it-right/

Interesting points raised.

Graeme
G Evans

Bob Grunau's info is still available - http://www.mg-tabc.org/library/BG_flywheel.htm
Gene Gillam

The drawing is for the 7 1/4 flywheel and there is a better drawing for the 8" flywheel, but I can't find it now.

In the 'factory' drawing, a lot of weight is left on the outside, when ideally that weight should be removed?

Attached is the picture of my 8" flywheel lightened as per the Bob Grunau drawing.
If I would have to do it again I'd remove more from the outer rim, where the lightening will have more effect.

Balancing of the flywheel and crankshaft is essential for a good running engine.

Willem van der Veer

The pictures and drawings were on the millersmule site!

http://www.millersmule.com/blog/projects/mg-td-flywheel-lightening/

(the picture has MGB GT flywheel lightening as a title but that's wrong because the MGA/B type flywheel looks different as can be seen at: http://mgaguru.com/mgtech/clutch/ft_202.htm)

Willem van der Veer

This is what the 'millers flywheel' looks like. As you can see it has more material removed towards the outside.

Willem van der Veer

Stock versus lightened flywheel, about 20 lbs versus 16. Next time I may go even lighter.

Steve S

It's an interesting question. I would be hesitant for obvious reasons; firstly as someone has already pointed out, the mass of the flywheel acts as a damper to 'even out' changes in revolution. So reducing weight will reduce that damping ability. Secondly, removal of metal from any part that rotates at high speed is probably going to lower the lifespan of the part, from internal stresses. However, it's probably not going to be noticeable especially in a car that will never be a "daily driver"; and most cars built back in the day had overkill when it comes to metal mass, unlike today's cars which are all designed to minimum weight and tolerances, where every ounce of weight has been shaved.
Geoffrey M Baker

One of the reasons I lightened my flywheel is that David Vizard wrote in his 'Tuning the A-series engine' (page 366, 2nd edition): 'it can move the critical vibration frequency much further up the rpm range' ..... 'Lightening these parts can reduce fatigue induced crankshaft breakages'
With the XPAG's breakage prone crankshaft this seems a good idea!
I also had the complete rotating mass balanced, first per part, then as a whole.

Further proof that the thinking about the right weight changed through the ages is that the MGA 1622/early MGB flywheel is 8 pounds lighter than the MGA 1500 item.

Lastly and most importantly; the lightening and balancing also vastly improve the bragging rights.....
Willem van der Veer

Willem,

If you really want to have "bragging" rights get one of these for your XPAG:



Gene Gillam

What machine is used to balance the wheel after the lightning procedure? PJ
Paul S Jennings

I am making new steel light weight racing flywheels that weigh about 10 pounds bare. These suit the 7-'1/4" clutch and use a TC 93 tooth ringgear or early TD 120 tooth ringgear. Use of this flywheel does not seem to effect idle and engine performance is improved. I used this flywheel for racing for 10 years, even with a full race engine, idle was acceptable. If photos wanted, please email me. Cost is $450.00 each.

Yes my MG Car Co flywheel lightening removes about 4 or 5 pounds from an original cast iron flywheel.
Thanks from Canada, Bob Grunau, grunau.garage@sympatico.ca
Bob Grunau

Bob I'd been very keen for an 8" version. Needed to work with the my Skyhook gear box.


Gene your killing me.. :-)

MG LaVerne

LaVerne,

I'd have had one of Bob's if he had had one available at the time I needed it...much, much more affordable.

Gene
Gene Gillam

Gene,

I'm not playing Top Trumps with you!
Willem van der Veer

Nice, Gene!
Steve S

Gene - tell all - who, where, why and how?

Tom Lange
MGT Repair
t lange

Tom,

This is one of Manley Ford's - here's the rest of it except for the throwout bearing (roller).

As for why? Just because...and my wife let me spend the money because she knew she wanted to hit me up later for a bathroom remodel. How could I complain?



Gene Gillam

This thread was discussed between 24/01/2014 and 30/01/2014

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