What flywheel on a 360 Magnum

[xf69fs]

I have a 360 magnum from a dodge ram. My dart is a 3speed manual car. Will the flywheel work on it? I know the 360 isnt ballanced like the older 360s so its balanced like the current 318 right?

Ryan

[mtrv8n]

Buy a new flywheel from the dealer..it's not too expensive, and you won't have any problems with the surface or warpage.

[xf69fs]

The new one is like 300 buck. Besides I have an aluminum one sitting in the garage...just needs a resurface.

So the 318/340 flywheel will work on a magnum?

Ryan

[rumblefish360]

NO

The new magnum engine is balanced differently.

The old 360 will not work
The old (1 year only (73) internal bal.) 340 will not work.
All the others are internaly balanced. You will need to drill some spots in the flywheel in order to balance it right.
In the engines book, not the one for magnums, the one for the older "LA" engines, there is a diagram that shows how to do this conversion from 273/318/340 internaly balanced flywheel to an externaly balanced unit for the older 360's.
The 318 Magnum flywheel is also a internaly balanced unit.

IF the "Magnum" engines book has this, the book is about $25 and worth alot more than that even if it doesn't help.

[xf69fs]

So the magnums are internally balanced, but are balanced differently than the older 273/318/340 motors? I know the 360s(non-magnum) are externally balanced. I hope they dont use a proprietary flywheel.

Ryan

[mtrv8n]

also externally balanced, but still different from older LA motors.
It's worth puttuing the right flywheel on the first time..

[xf69fs]

Well I dont have a flywheel for the magnum yet. I have 2 regular ones already, a cast iron one and an aluminum one. I was hoping to be able to use one of em. How is the magnum externally balanced? It doesnt have that odd shaped weight in the front or anything. The rear of the motor just has the crank trigger.

Ryan

[rumblefish360]

Similar like the "LA" version, just different weight specs on the damper and different specs on the flywheel.

[Blown408DakotaR]

The 5.9L/360 Magnum is Internally balanced. I should know, I've had mine rebalanced twice at $1300 (included other work) a pop for the shop bill, when I built a N/A 408 and then went to a S/C 408.

Give KRCPerformance a call he could tell you if the Flywheels you have will work, and if not he can tell you which 1 to get. He might even have 1 sitting around he will sell you rather cheap.

[340duster1]

To clear all of this up:
1) the 360 magnum is externally balanced
2) it is different from the "old style" 360
3) the 318 magnum is internally balanced
4) Mopar performance has a flywheel available, last time I priced it out it was $499Canadian.
5) The magnum engine book does not tell you how to rebalance a standard flywheel to work on the magnum engine. So don't waste your money on this book, I already wasted mine. I bought the book for that reason!
6) If you have a copy of the mopar chassis manual, it explains how to put the proper imbalance into a flywheel for a number of engines (but not the 360 magnum). The location or angle for the holes is shown in the book (use the regular 360) but the weight removed will be different. You will need to remove 2.28 oz of metal at a radius of 5.625".

I successfully rebalanced the flywheel for to work on the 360 magnum in my stock car. It sees lots of 6000rpm jaunts (twice per lap) and no vibrations.

If you need more details I can probably email or fax you a drawing.

[Idaho]

Hi. First post here. I hang out at FABO. I'm resurrecting this old post as its the only example I've seen of someone balancing an LA flywheel for the 5.9 Magnum.

The Mcleod and Mopar Performance units are kinda spendy.

340Duster1 has not posted in a long time so I'm wondering if anyone else has an idea how its done. I notice a member named Sanborn seems to have some expertise in balancing.

Any input appreciated.

[John Kunkel]

The pics below show the diagram for external balancing the flywheel for the 360 LA engine, the second pic shows an LA and Magnum side-by-side. As you can see the only difference is the diameter/depth of the three drilled holes. Sorry, I don't have the size info for the Magnum.

[Idaho]

Thanks John. Very helpful.
Are these 130 tooth or 143 tooth flywheels?
To my knowledge there is no diagram in the mopar performance manuals for the Magnum so I'm not sure where one would come up with one.
Not sure if this makes sense but perhaps the smaller holes on the magnum flywheel are due to it having lighter pistons.

[Idaho]

The 130 tooth Mcleod flywheel for the 5.9 Magnum uses a bolt on weight. I presume it would be located opposite to where the holes are drilled.

There are a fair number of people putting these engines into cars which need the smaller 130 tooth flywheel. It would be great to figure out how to either bolt on a weight (which can be purchased separate) or drill the holes.

[340duster1]

Idaho

I am on FABO too as 340duster. I still look in Moparchat once in a while. This is an old post. If I get too goofy with technical stuff just ask me to explain it. Being an engineer does that to a person.

First you need to start with a neutral balanced flywheel (from a 318 or a steel crank 340). First look at the Mopar diagram for the LA 360 flywheel that John Kunkel posted. It show the center of the weight removed to be 41 degrees and 26 minutes away from the Y axis. This is 41.43 degrees. Now as I mentioned earlier you need to remove 2.28 oz of metal at a radius of 5.625". You will notice the LA flywheel has removed its weight at 3.88" Radius. I chose the 5.625" because it is near the outer edge closer to the ring and you have to remove less weight the further from the center you go.

So mark this location on the flywheel. Then work out how deep the hole (or holes) need to be and their diameter. Cast iron weighs approx .265 lb/in3. Or you could bolt on a 2.28oz weight @5.625" opposite to where the holes are drilled. Hope this helps.

On a side note the units of imbalance is inch-ounces The 360LA is 19.79 in-oz. Which means you could remove 19.79 oz at a 1" radius or 1 oz at a 19.79" radius or 5.09oz @ 3.88"Radius. The magnum 360 is 12.825 in-oz. imbalance. The pistons likely make up the differnce and I also think the rods are lighter too.

[Idaho]

Hey that's perfect! Thanks for responding.

So the amount of weight varies inversely with inches from center.
I have to decide now if I'm brave enough to do it. I have a friend with a milling machine. A square bottom bit will make the calculation easier.

Hope you don't mind me asking, where the information is sourced?

BTW my hometown is Ft St John BC. I think you know where that is

[340duster1]

The in oz out of balance for the magnum I think I got from the instruction sheet from the magnum torque converter weights from mopar performance. The instructions show where to add the weights on the converter. It matched up opposite to the LA weight removal holes. I contacted the tech editor from Mopar Action (Rick Ehrenburg) and he verified what I was doing.

I took an aluminum flywheel that my machinist friend built for me and removed the calculated weight and installed it in my circle track car and no shaking, so it worked!

As far as the balancing goes, I had a few text books to help me understand it. Since then, at my work place, we purchased a large scale balancer to balance 30' long rolls for our paper machine. So I have a even better understanding of balancing. Now I am trying to justify buying a smaller balancer for pump impellors coupling etc. I can see balancing brake rotors, driveshafts, axles and anything that rotates on my cars!

I have been to Ft St John a few times...small world

[340duster1]

Also if you mess up you can always drill holes on the opposite side to compensate for yor mistake!

[Idaho]

I plan to have at it. I just have to do the calculation. I believe it can be done with a 7/8" bit, 3 holes 0.59" depth but I've got to double check the math. I used the volume of a 45 degree cone plus cylinder volume. Another possibility would be to have a friend with a milling machine use a square bottom bit. To verify my math I think I'll drill some holes in scrap cast iron and weigh before and after.

[340_GTS]

Check your drill point angle. Most are 118°, not 90° as you suggest by the 45° cone statement.

[Idaho]

Thanks. I don't have bit that large so I looked one up on Amazon. The angle given was 135 but I'll check whatever I get.

[Mroldfart2u]

There is a similar problem on another forum BUT this guy has an auto and a confussing post more or less, but has been dealing with a vib for a year due to either his machine shop, or something. Any ideas for a flexplate application?

[John Kunkel]

For the LA 360 B&M has a flexplate (#10236) that allows the use of a neutral-balanced converter.

http://www.summitracing.com/parts/BMM-10236/

Of course, if the vibration is related to some internal imbalance, converter weight is irrelevant.

[Mroldfart2u]

Originally Posted by John Kunkel

For the LA 360 B&M has a flexplate (#10236) that allows the use of a neutral-balanced converter.


Of course, if the vibration is related to some internal imbalance, converter weight is irrelevant.

Thanks for the link, did the search on Summit for the Magnum flex (what the poster on other forum has) and will post that... I am thinking his machine/shop, mech is thinking LA type balance on the magnum, but dont know that for a fact...

I did run into this statement, from another site...(copy and paste) The non-Magnum engines required 19.79 in.oz. and the Magnums need 14.65 in.oz. in order to be properly balanced.

[John Kunkel]

Originally Posted by Mroldfart2u

I did run into this statement, from another site...(copy and paste) The non-Magnum engines required 19.79 in.oz. and the Magnums need 14.65 in.oz. in order to be properly balanced.

Here we go again, your source (please cite source) says the Magnum needs 14.65 in. oz. and 340duster1 says "The magnum 360 is 12.825 in-oz. imbalance".

Who's right?

[Mroldfart2u]

Originally Posted by John Kunkel

Here we go again, your source (please cite source) says the Magnum needs 14.65 in. oz. and 340duster1 says "The magnum 360 is 12.825 in-oz. imbalance".

Who's right?

Hadta dig it back up but did find it....wwwDOTmopar1.us/sort.htm Sense I am unable to post the link as a link, due to the 25 post rule...

It is buried in the text close to bottom of the page.

[John Kunkel]

404 Error Page Not Found

[Mroldfart2u]

Originally Posted by John Kunkel

404 Error Page Not Found

Yeah me too... but try ]wwwDOTmopar1.us , to the sorting out of mopar small blocks link.,.. ( its right above the 75MPH sign icon) its still there...

[Idaho]

I get nothing with a google search.

[Mroldfart2u]

Originally Posted by Idaho

I get nothing with a google search.

On what? the site itself? If not, thats strange... I was wondering all over the site ealier, lots of different info on it.. if i could id post a screen shot of it and be done... lol

You do realize due to posts restrictions, YOU have to replace the WORD DOT with a ( . )