Does the alloy flywheel make a hugh diffrence in an already built engine.

It doesn't make a huge difference on any engine -- just lets it rev up a bit quicker in the low gears.

And make it a bit twitchy and hard to drive smoothly in stop and go situations.
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I'm JohnMc, and I approved this message.

It isn't worth the hassle, trouble and cost for anything other than a real racecar, especially a sprint car can benefit a bit from a lighter flywheel.

They also tend to wear very quickly.

Some of those flashy flywheels are pure junk and downright dangerous, no holes for the dowels, so we'll just run without .... and have the flywheel cut our legs off when the bolts snap. Or a mating flange that is much too thin ...

Best regards


Stefan

122o;

I agree with other posters...there are a lot of better things to spend your volvomadmoney on...

Cheers

There are also excellent quality aluminum flywheels with steel inserts as the friction surface, dowels, and precise construction. Go through a reputable supplier, and you'll get what you pay for.

That being said, they're expensive and add significantly to the cost of a rebuild. There are many things to spend that money on that make more difference.

For $25 I had about 3 or 4 lbs taken off the outside rim of my stock flywheel. I'm not exactly sure I felt the difference, but I *think* I did. There are a lot of other things I would spend money on before an aluminum flywheel.
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I'm JohnMc, and I approved this message.

Aluminum is way to expensive. The 3 or 4 pounds off an iron wheel is all you need to do - and I have done many and always felt the difference. Takes me about 30 minutes to set up and machine, and usually the balance is still good. And I don't worry about my feet or those of my customers.....

Rhys
Assuming a person had the machining to do this, can you give us a more specific description of where from and how much you remove. I'm assuming (what do I know?) it's a uniform cut in depth, so the question is how deep, and from where to where in relation to the center. thanks much.

As John has said, the material is removed at the rim, behind the ring gear. I machine to within about .050 of the gear, and then reduce the diameter until the cut nearly breaks into the clutch cover bolt holes. I also leave a large radius in the transition between the two surfaces. I have measured stock wheels up to about 22 pounds. Some seem thicker than others. Normally this amount of machining removes about 4 pounds.
The lathe needs to be large and rigid, with the ability to get down to about 50-60 RPM. A HSS toolbit is all that is needed, and as with all cast iron, heavy feed and slow speed are the way to go, and dry. It is best to dial it up in a four jaw independant chuck - to within a thou or two laterally and axially.

In my case - just took off the obvious. The back edge of the flywheel - from the outer edge forward to the ring gear, and inward until close to the pressure plate bolt holes. Didn't take anything else off - left the clutch surface full thickness. This metal was both 100% non structural and at the rim - where it makes the most difference.
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I'm JohnMc, and I approved this message.

It is more than 6lbs lighter than the 6bolt flywheel that we put in my car with it's latest engine. I am even willing to lighten this one even more before I put it back in the car. Taking material out of the non stressed/structural areas and mainly out of the outer rim to have less mass on the outside of the flywheel to accelerate. The picture doesn't show much, but you can see how there is a "ridge" (you could say, or maybe that's stock, but the flywheel overall is only about 16-18lbs), taken out above the ring gear all around the flywheel.

My 8bolt flywheel:

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Kyle - www.OVTuners.org website and club Official Portland/Corvallis, OR - 1968 142 - current setup: 71b20b SUs, m40, part. stripped, custom CAI, 4-2-1 FI man., Simons exhaust... IPD sways +more

some points in light of inaccurate info in this thread so far.

1) good quality AL flywheels are just as durable as stock flywheels
2) AL flywheels are much less dangerous then iron flywheels - they weigh less
and are much less likely to come apart.
3) milling a stock flywheel of more than a few lbs. reduces its strength which is why we strongly recommend against taking more than a few lbs. off a stock flywheel -if you valve safety and your feet, spend the extra money on
4) the difference in performance in having to accellerate a 9 lb. FW from 1000 - 6000 rpm, several times as you go through the gears, is significant.
5) It would not be the first thing I would change when making performance modifications, but it is an important part of any performance improvement package,
recognized as such by all organizations providing performance upgrades, including Volvo.
6) Cutting FW weight in half is a guaranteed improvement in performance that can be calculated. It also is one of the few performance improvements that will have a significant affect without making other changes.
7) there is no other modification that can be done for $400, which by itself will have as significant an affect on performance.

John
v-performance