JMO but, I would go with what drowssap says. He knows engines and is trying to save us some headaches down the road.

People have put 4.6 cranks in 4.0 blocks and I'm sure people have put them in and bolted miss matched balanced parts on and maybe they were ok but, maybe they weren't as meticulous as we are so, if you are upgrading to a 4.6 crank anyway, just get one with the flywheel and balancer that was on it. Probably won't run you more than $75 or $100 more. Alot less $ than maybe having to rebalance everything. Then if you ever need to change out one of those parts be sure to get one that is exactly the same part # and weighted the same as the one that was on the 4.6 crank originally.

I know $100 here and $100 there adds up but if you get a rotating assembly including the balanced parts original to the crank you would have the piece of mind of a balanced engine.

And... you can sell your 4.0 crank, flywheel, and balancer as a set to recover some of your cost. That's what I am going to do on the 4.0 block that I have.

Early on in my project someone had said that all you need to upgrade is the crank and rods and, me being tight like I am, I jumped right on that. Maybe that person had luck with that setup but, now after diving into this deeper I, myself, would feel much more comfortable with matched parts in mine. Especially since I discovered, like drowssap said, that there are alot of different part #'s and configurations and weights on the crank, flywheels, and balancers. I didn't know that until a few days ago.

Or... maybe if you get a crank and then just get the correct part # flywheel and parts for that crank you will be ok? but how would you know which one was on the crank to start with? I see the flywheels with casting # TDP 000050, 000040, and 000060 all for 4.6 and not sure if the casting # has anything to do with anything but, I see them with 5gram and 10 gram and there may be more just for 4.6.
so I guess you would need to start off with the parts that came on the crank originally.

casting # on mine:

4.6 flywheel TPD 000050
4.0 flywheel HRC 2982

my flywheel has one screw for weight ( I assume that's for weight) maybe the screw is 5 gram and one screw = 5 grams and 2 screws = 10 grams? just guessing since I didn't see any numbers for weight and don't know where the people are getting their weight numbers from on the flywheels? and then there is the screw/weight location. probably different on different flywheels? I know there is alot of guessing going on here but I just don't know. Glad I have the original flywheels and parts for both of these cranks.


The numbers on my balancers are:

4.6 balancer LHG 000060 FE 4602
4.0 balnacer LHG 100670 FE 2075

Both balancers have 10gram weights but are in different positions from the keyway on each.

Connecting rod #'s for both engines

4.0 rods HRC 3283 SDF 74
4.6 rods HRC 2382 SDF 50


anyway, maybe the numbers can help you somehow, if you have to piece parts together?

I am taking a 4.6 block and a 4.0 block to the machine shop at the same time to have cleaned and completely checked out, cam bearings installed, etc and probably the 4.0 block will get the 4.6 crank assy, since it is the earlier block and probably a better block. I will have to wait and see. (I went ahead and tore the 4.6 down since I have it out anyway... better now than later). the other one may get the 4.0 crank assy that I have or it may get a 4.6 crank assy as well. I can only spend $ on one of these at a time and all depends on how the blocks check out.

I doubt if when you contact land rover you will get much out of them but, maybe???

let us know what you find out.

 

Hey friends,

Rock Auto just sent me an email with a 5% off discount code that they said has no limit on usage or expiration! I was even encouraged to share it.

I don't know if it's something they do often, but they do carry some great stuff for our Rovers, including a cheap transmission rebuild kit. I'll be putting some use to mine a bit later.

Anyway, here's the code, enjoy:

2376122821987178

 

don't make a life or death decision on what I say, double check everything.

most of my knowledge is general and not LR specific, but manufactures are all the same.
They are not sitting there dynamically balancing every engine. but it usually goes something like this:
an item should weight hypothetically 48 grams, 46 is acceptable as log as it is match with other 46 grams parts, 50 is ok as long as it is with other 50 gram parts. follow me so far.

Now to make up for the heavy or light parts they match them with the appropriate flywheel and balancer.
this saves them tons of money $$$ otherwise they would have to have an exacting manufacturing process or balance every engine so the would not shake apart.

But that's just my theory

 

Makes sense. I'm sure they push em though the quickest cheapest way possible.

Would be best, when it comes to replacing parts, if they balanced each part individually. As much as they charge for these trucks when new seems like they could afford to balance each one in zero gravity.

My thinking was that they must spin the crank with the flywheel and balancer on somewhere along the line and move the weight screw in the flywheel around to the correct place to match the crank. I noticed the flywheels have a large number of holes drilled and tapped all the way around for the weight screw so it can be moved around to different positions. and I noticed the weight on the balancer is not always in the same position and can be moved around before it's crimped into place. So that's either to match them up to the crank or maybe the weight screw in the flywheel is just to balance the flywheel on it's own? I guess we'll never know. It would be nice to know every little detail of the factory assembly process for these engines. Anybody know anybody that knows somebody that used to work there? preferably on the engine assembly line? and was sober enough to remember it! haha!

If they did balance each crank, flywheel and balancer together then maybe, but not sure about this and going way out on a limb, if you ever had a ring gear go bad and had to replace the flywheel, and if the cranks were balanced with the flywheels,then maybe just maybe you could move the weight screw in the new flywheel to the position of the weight screw in the flywheel you took off so it would match the crank just like the old one? But if it turned out that the weight screw was to balance just the flywheel alone and not the assy that wouldn't work and would unbalance the flywheel and even if that were so you would still have to have the flywheel original to the crank to go by.

So all we know now is...or think we know now is... when a crank comes on the market later with it's flywheel and balancer missing and an off the shelf one gets put on with the weights in a different position, you get an unbalanced engine, could be alot unbalanced, could be a little unbalanced, or you may just get lucky. I'm not a lucky person! Unless, UNLESS, each part is balanced individually and the weights are just to balance the individual parts alone.... then it would be plug and play with replacement parts.

 

When it comes to cost on assembly (my field of study and work, Manufacturing Engineering), its cheapest to have all parts interchangeable. Just like balancing a tire with a machine that can specifically do that, it would be cheaper tohave all parts individually balanced than to have to try to match parts in rotating assemblies.

Apple was only recntly able to do this procedure with high power imaging to match cases and inserts based on imperfections and size. It takes automation computing that definitely didnt exist when our Rovers were built.

And when working with CNC machining and weight distribution in a rotating assembly, remember that the lathes they were made on all have balancing sensors to compensate and prevent damage to the bearings. It would only take a mildly intelligent CNC maching engineer to take that and program specific points that could be used to balance a part. The program would take those points, and choose which of them to use based on which point it would have to remove the least material from, and how deep to drill to balance the part.

Something I noticed on my 4.0 crankshaft was that it had those machined holes drilled in various places on the counterweights to various depths. Thats a tell tale sign that the part was balanced. If any of you have a crank or two lying around, check and post picks of where the holes are in your counterweights and how deep. I'll post picks tomorrow.

In manufacturing, you can trust people to produce a part to spec, but in assembly, you can only trust people to take a part from the shelf and place it in the correct spot and use a pre-programmed air torque gun to make sure it meets measurement spec. The training fequired to teach them how to balance an entire assembly based on choosing parts from the shelf with different weights and offsets would be nuts. No training needed if the parts are all interchangeable, though, and you can compartimentalize the labor requirements. It also means lower cost of wages in labor. Otherwise all of the people on the assembly line would need to have an engineering degree or at least a college level course in statics and dynamics. I hated and loved those two classes. They tried to eat my soul. But... They also made it possible for me to design my wheel spacers, lift pucks, replacement bolts, etc.

 

the holes in the crank are for balancing but it is not that quite that simple.
the holes are drilled so that they can be filled with Mallory metal, a very special and extremely heavy alloy steel. So the holes are there just as much to add weight as to remove weight.

from Eagles website:
Since different rods and different pistons are different weights, it is impossible to make a crankshaft that is balanced "right out of the box" for any rod and piston combination. All crankshafts must be balanced to your specific rod and piston combination. When an Eagle crankshaft is listed as "internal balance" or "external balance" this is stating how this crank is intended to be balanced. It can be balanced otherwise, but it is much more difficult to do so.

 

Well since this has gone from the shade tree to the laboratory I should probably go outside and play. hehe!

But seriously, thanks to you guys for having this discussion, this is the kind of stuff that all engine builders need to know.

I used to true old harley panhead and shovelhead flywheels/crank pin combinations with a truing stand and a dial indicator and years before that with homemade V blocks, a rubber hammer, and a bent coat hanger in place of a dial indicator... talk about shade tree! haha! but those were modular parts and intended to be bolted together off the shelf and trued up by the rebuilder on the bench. Times have changed and I'm left standing here with my coat hanger and rubber hammer.

I had originally intended to take my lightest rod and subtract weight from the others to match and also on my pistons, thinking every little thing would help and how much more balanced my engine would be BUT, if these were balanced as an assy, then that would throw off the balance as a whole. So since we don't know what the heck they did over there, I better just leave well enough alone.

I did label each piston rod combination as to what hole it went in on the 4.0 parts and haven't pulled the crank and rods yet on the 4.6 but will do the same.

Since LR has changed hands so many times, I doubt anyone could track down any of the old manufacturing engineers and part manufacturers to see exactly how these were balanced? Would be good to know.

__________________________________________________ __________________________________________________ ____________________

Tex, you should send me a copy of your CAD/machine drawings for the wheel spacers, lift pucks, replacement bolts, etc. Unless it's in it's raw state and has to be plugged into CNC equipment. I would like to turn some out for myself but only have old school conventional machines and have to do everything manually.

 

So didn't Harley they had a guy they called The Big Thumped who would use a lead hammer to balance flywheels on crank pins at the factory. But them yuppies came along and the new EVO's had to be dynamically balanced so the mirrors wouldn't shake.

 

haha! yea sounds right. My bones shook. I gave up on mirrors with those and would have to rubber neck it. Couldn't see a thing in the mirror especially if you were idling sitting at a stop light. didn't help that the motors were mounted rigid.
I see you have a BSA lightning, I had a 650 lightning years ago, if I remember it was a 65 YM with A65L motor?, (chrome tank, side covers, and fenders from the factory and would blind you on a sunny day), anyway, shook so bad that when I would stop it would take a few minutes for my eyeballs to settle down and get focused. Nobody would ride in front of me because they said my headlight shook so much it looked like a wreck happening behind em.

 

So a few ways we could solve this is to do a few tests:

1. Measure the locations and depths of the holes cut in our different cranks and post them here.
2. Have the cranks tested for balancing. I'm already going to be getting a 4.6 crank and have a 4.0 crank, so I could have my machinist test that. I don't know what it would cost, but I'll check.
3. Give LR a holler and see if we can talk to one of their engineers.

Which are you up for? I'm good for all/any of the options. I want some definitive answers on this one, personally. I know other people have swapped 4.0s for 4.6 cranks and con rods, so I know it's possible, but it would be nice to know it's not going to die in a few months/years.