How do i balance the replacement flywheel?
 

I got the engine out (617) and will need to replace the flywheel with one that bolts to the Land Rover transmission. It is my understanding that the engine is balanced as a whole with the flywheel.
I'm having hart time imagining how the old flywheel's balance could be replicated in the new one.
Can someone please shed some light on it?

Before you remove the old one from the engine,mark the flywheel to crank location.

I've got a way to do this using a "aviation" style tire balancer, when I get a chance I'll type it up ( basically it involves adding temporary weights to make them zero then use the weight value to match balance. )

I would really appreciate it, thanks.

Most of the engines use flywheels that are neutral.

Some though, do have flywheels that were needed to balance the cranks.

After marking the fw before removing have it checked. If its neutral you can simply use a neutrally balanced fw in the new setup. If its not you'll have to have them match balanced and install the new fw in the same position on the crank.

Another option, but you'll need access to a hoist.

Every town of any size will have a balancing specialist who comes to a factory, etc. and balances stuff on-site. For example, if a shredder gets a new motor or other major component it may not balance up with the existing gearbox or whatever it bolts to. Anyhow, if you can get the vehicle up in the air with the engine running the balancing company can balance the assembly in place and they can take the weight off the flywheel if you give them access.

Remember that if you ever need to remove the now-balanced flywheel you'll need to mark it's location so it goes back in the right place.

We used these on-site balancing folks a lot in my dyno testing days. Sometimes we'd get a shake in the set-up and they saved our bacon more than once.

Dan

(1) Mark the FW and crank so you know the orientation of the old FW to the crank. Let's say you make the mark at the 3:00 position on each.

(2) Mount old and new FW on balancing machine as one assembly, facing the same direction. Balance the assembly ONLY removing material from the new FW.

(3) Mark the new FW at the 9:00 position (i.e. 180 degrees opposite to the old FW).

(4) Separate the two FWs, and now your new FW has been "match balanced" to the old. You also have the orientation marks on the crank and FW, so when you mount the FW, the balance of the FW/Crank/front harmonic balancer has been preserved.

Wouldn't you need to place them 180 degrees apart and facing the same direction with respect to the orientation marks to get identical balancing? ....or perhaps placing them face to face is the same thing.....I am not sure.

Dohhh!!!

Thanks for the correction.

After thinking a bit more, if the old and new are back-to-back or face-to-face, then the new FW will be 180 degrees out of balance.

They should be facing the same direction, BUT the orientation marks still need to be at the same clock position.

Another key point is to make sure the bolt holes line up identically, so that you actually can bolt up the new FW so that the orientation marks on the crank to the FW match.

I think if you marke the Old Flywheel the mark should be targeted to go through the Diameter of one of the Bolt Holes to the Crank.
I think they would make it easier to mark accurately mark the New Flywheel.

I cannot see how keeping them in the same position with respect to the clocking marks will result in an identical balancing, unless there is something in the method which corrects for it.

So I was right the first time? Sheesh...:o

OK, thanks again for the correction.

(3) should read "Mark the new FW at the 9:00 position (i.e. 180 degrees opposite to the old FW).

There still is the issue of lining up the bolt holes to ensure the new FW can be mounted correctly...

Yes!

My local machine shop match balanced the two 180 out and it worked wonderfully! I actually took awhile to find a shop that knew what I was talking about. I think it isn't done a whole lot anymore, except for forged cranks, where the material is harder. I had to call a local hot rod shop and ask where they get their match balancing done, and viola!

pretty good chance its neutral so check it first.

Thanks a lot
 

Lot's of helpful info guys.

I see others have jumped into the fray. Yep, find heavy point on both, put them back to back 180 out then take weight off the new FW.

Another way is to bolt weight to the old FW until it is zero balance then transfer to the weight to new, drill new until zero balance, remove bolt on weight and you will have 2 matching FW.

Well you do like them as correct as they can be. Yet I think way to much time and effort is spent worrying about the balance point on the flywheel. Look it over good and if you see a factory check mark on it, get it balanced. I had the choice of two 240D flywheels. No mark on either, I picked the one that I thought was just a hair smoother of the surface and went with it. No marks, no balance, new flywheel screw bolts and on with it. Works perfect! Do get some vibes from those cylinders when firing at 2000 rpm and 10 pounds boost in the winter especially. Everything is cold and noises seem to be greater. In warmer weather, with a window or two open a bit, it is perfect. If I wanted it smoother, I would have used the old Mercedes Benz trick of leaving an old fashion grease ball transmission in it. Then I had a problem with the drive shaft. The tech school that shortened it for me does it free and they made it an interference fit. But it wasn't strong enough and under a hard torque load is 1st gear it would slip. So now I drilled I think 12 small holes into the slip area and put in 12 #10 stainless sheet metal screws. I did this with the shaft on the car so it is not perfect, but it does carry the load without complaint and no vibration. I really like the car with the 4 speed, really love to drive it. But I can easily see why MB did not offer the W123 with the 3.0 turbo diesel and the 4 speed. It just has an inherent vibe in it that they knew the North American car buyer would not be happy with. So if you have a 4 speed you love it and live with it.

The 240 fw are generally neutral but not all of the 617 cranks are neutral.....not all the 280e cranks are neutral either.