Lightening Flywheel

[akis-driver]

Hello everyone.Ive got a quick question for everyone in here.Do you have any drawings or pics or info on how to lighten a stock 2.0E CIH flywheel?It going to be used on a turbo CIH engine that doesnt rev abov 6000rpm and is got arround 190-200bhp.Ive put some pics below of the flywheel im going to work on.Any help will be appreciated

http://img113.imageshack.us/img113/2689/dsc03600ti3.jpg

http://img113.imageshack.us/img113/8143/dsc03599dz5.jpg

[namba209]

Check out this thread, it may give you what you need. It's a long one though, so read it in its entirety.

http://www.opelgt.com/forums/clutch-...-flywheel.html

[akis-driver]

Thanks for your reply.Ive already read this thread.Because im not sending the flywheel to a machinist but im doing the machining myself i wanted to know more specific measurable information on how much material and from where it can be taken out.Thanks again

[wrench459]

Remove as much meat from the outer ring as possible with end reason.
Don't worry about the inner ring too much as the end results are very small.

[oppositelock]

Here's a couple of pics of my lightened flywheel compared next to a stock flywheel (that's missing the starter ring gear.) Weight is 15 lbs.

[akis-driver]

Thanks a lot oppositelock and the rest.The pics are also great.Give me a good idea of how it should be done.Do you know how much thickness is still left in the flywheel after machining(on the area were the clutch is)?Thaks again you've been great help

[hrcollinsjr]

Oppositelock's flywheel looks like the machinist has done a few before.
If you are going to err on the amount removed make sure to err on the side of safety. YOUR feet and legs are in line with it if it comes apart.

Harold

[akis-driver]

I know safety is my main concern here thats why im asking all those questions to make sure i dont do anything stupid.My aim is not to get as low weight as possible but to refine the stock flywheel.A 17lbs weigth would be ideal for me.

[Dale .D]

Originally Posted by oppositelock Here's a couple of pics of my lightened flywheel compared next to a stock flywheel (that's missing the starter ring gear.) Weight is 15 lbs.

Nice pics.Is this flywheel the same for a 1.9.Pictures would be great just to take to the machinest & say please do this?.Does it need to be balanced after the machining.

[RallyBob]

Originally Posted by akis-driver I know safety is my main concern here thats why im asking all those questions to make sure i dont do anything stupid.My aim is not to get as low weight as possible but to refine the stock flywheel.A 17lbs weigth would be ideal for me.

Thinnest I have had machined was .440" (11.17 mm). That was this one here, and it weighed about 11 lbs or so (5 kg). I think that with 17 lbs you will not have to worry about being so thin!

[RallyBob]

Originally Posted by Dale .D Does it need to be balanced after the machining.

Always....

[RallyBob]

Just a thought,

but if OpelGT.com wants to host it, I still have my drawings for lightening a stock 1.9 flywheel to either 15.5 lbs or 17.5 lbs. I personally have no way to scan it but if (Gary?) wants to scan it and put it here in the technical section then we could simply refer people to it when ever the question comes up.

[Kadett-o-Maniac]

Dont come under ~12mm thickness with a cast iron flywheel!

You can turn the same contuor like the frontside of your flywheel, the minimum i come with my self turned flywheel was 6,5kg!

Look at the pics in the attachment and you know, where you have to turn down the material!

You can also save weight, if you make some breakthroughs between the fixture from the clutch by milling or drilling some big holes on it!

But be careful with the "meat" at the holes from a cast iron flywheel, the holes shown at the 3 last pics are at a solid steel flywheel, you cant use this 1 to 1 to a cast iron flywheel, here must be more material to the fixture from the clutch!

Best regards

[akis-driver]

Great info thanks a lot.I will follow the pics and take it down to a thickness of 13-14mm and then see how it looks like.As i said i dont really want to make it as light as possible just lighter than what it is at the moment.

Rallybob if you can arrange for the drawings that would help a lot of people i think.Thanks for the help and when im done its going to be send for balancing.Will also post pictures!!!

Kadett-o-Maniac great pics thanks a lot.They are big enought to understand whats going on and really good quality.

[jordan]

WOW that is alot of weight off of that flywheel!

[davegt27]

No one said anything about a SFI Flywheel shield

In this day and age you should try to buy a proper light weight flywheel

Do not use a cast iron lightened flywheel unless it is the last resort

(One reason is --for people that might buy one is you don't know who did the work)

At a minimum it needs to be magna fluxed to check that it is good

Lightening a cast iron flywheel is old school tech

I had a friend that had a stock flywheel come off the back of the motor; luckily he was at a stop light.

It did take the back of the starter off and tore up the tunnel on his GT

My race GT has .250 plate added to the tunnel to protect the drivers legs


Davegt27

[Gumby]

Originally Posted by Kadett-o-Maniac Look at the pics in the attachment and you know, where you have to turn down the material! You can also save weight, if you make some breakthroughs between the fixture from the clutch by milling or drilling some big holes on it!

FYI - either slow down your feed or increase your rpms and that wavy finish will go away.

[heimue]

Originally Posted by akis-driver Because im not sending the flywheel to a machinist but im doing the machining myself ...

Do you have the necessary equipment for balancing the flywheel?
I had a flywheel lighened and balanced for 80 bucks from a local motor and racing shop lately. It's not worth the time to put in yourself.

Dieter

[akis-driver]

heimue im only doing the lightening the balancing is going to be done by a friend of mine who was a balancing workshop business.I wouldnt dare doing that myself but the lightening should be fine i think.Good opportunity to learn!!!
Again thanks to everyone for all their info on this

[wrench459]

Here's how I've done this.
Neutral balance the crank (under 3 grams..anal under 1 gram)
Install the cut down flywheel (see the above spec)
Next install the clutch cover.. again see the above
BTW I've had great results cutting down a flywheel with a simple brake lathe.
I believe opel over balanced the crank for a reason.

[Kadett-o-Maniac]

Originally Posted by Gumby FYI - either slow down your feed or increase your rpms and that wavy finish will go away.

Sorry, i dont understand this sentence, can you explain me?

You think its risky, to make a breakthrough or to drill holes into a cast iron flywheel, because in a extreme situation it can cost your 2 legs?

The most reason for a flying flywheel (nice word game) is peoples uses the wrong screws or torque at the crankshaft, put a 2L flywheel at a 2,4L crankshift with no sleeves between hole and screw, no balancing and a lot of other things you dont have to do at a flywheel!

I doesnt know anybody here in germany who loses his flywheel, because of breakthroughs or drilled holes between the fixture of the clutch!

Best regards

Edit: Look at the attachment, i put a pic of a drilled 9,5" cast iron flywheel on it

[heimue]

Originally Posted by Gumby FYI - either slow down your feed or increase your rpms and that wavy finish will go away.

Originally Posted by Kadett-o-Maniac Sorry, i dont understand this sentence, can you explain me?

"Nimm' den Vorschub zurück oder nimm eine höhere Drehzahl, dann wird die Oberfläche nicht so wellig."

Dieter

[wrench459]

Originally Posted by Kadett-o-Maniac Sorry, i dont understand this sentence, can you explain me?

I belive gumby was talking about the cutting machine.
Too fast of a cut will not leave a good surface (feed)
Also the spindle speed( to slow /or fast) will have the same effect.
Theres a fine line when your ear is very important.

[jeff denton]

Maniac, I'm not sure why, I couldn't give you a scientific explanation, but about the flywheel you show with all the holes drilled: That's not normal. Unheard of, as far as I know.

[namba209]

Jeff, you're right. I've never seen one like that either. But I think the reasoning behind drilling around the outer perimeter is to lower the mass in that area which moves the weight closer to the center. That in itself will allow the engine to spin faster and slow down quicker than a stock flywheel does. In conjunction with the lighter flywheel, both acceleration and deceleration is greatly increased, but the heavy flywheel effect is greatly diminished, so more RPM will be needed when moving out from a dead stop. Hope this makes sense.