[REVIEW] 8043 - Excavator

[shimon]

cant you just remove the axle that connect the two LA's and just manually spin the top to adjust them and when you build the bucket assembly put the axle?

[DLuders]

Did anybody TRY to use Olive Oil (as discussed in this Eurobricks post here) to lubricate the Linear Actuators? If they don't work well, what have you got to lose? If you REDUCE FRICTION, the maxxed-out Power Functions Medium Motors will have a better chance to lift the arm without binding up. Pneumatic cylinders need to be lubricated, so why should Linear Actuators be any different? Maybe the Chinese didn't adequately lubricate the batch of LAs for Set 8043.

When you next go to the market, head over to the Cooking Oil section and get a bottle of Olive Oil. From http://en.wikipedia.org/wiki/Olive_oil (1/3 of the way down that webpage), you can see the various Olive Oil grades used in your country.

[Jurgen Krooshoop]

I finally received my 8043 this morning and started building directly. Now it's finished I can say that although the M-motors need to work a bit, the model functions completely. I checked the alignment of the 2 LA's and lifting the boom works well. One other thing I noticed is that the switching-motor sometimes needs to run twice before it has completely moved all the 3 driving-rings.

I like the model very much exept for the buchet-attachment. The bucket is way too big, the angle of movement is not big enough and the point of rotation is misplaced. I will replace the big bucket with the smaller one and extend the movement-range of the bucket. I'll post pictures as soon as it's done.

[jason-l]

Only criticism is the simpler gear trains mean more speed/torque reaches the LA bevel gears, which seems to cause them to jump teeth if you hit their travel limit.

Now I've found this link TB - Linear Actuators - Part II I've since realised, of course, that this will be the clutch(es) in the LA rather than the bevel gears jumping

This is developing into a great thread. Glad I found this forum

[rgbrown]

Not possible for 8043 as there is not enough space, but more generally, the two outputs of a differential could be used two drive two parallel LAs, which would make the configuration self-balancing even if one started slipping under clutch, etc.

[Blakbird]

I am starting to develop a new theory. My excavator worked fine at first with "normal" balancing of the linear actuator length. Now, despite the fact that I have balanced the actuators much better than they were originally, it seems to work worse. By that, I mean that the motor is working harder to move the boom. It still works; the motor doesn't stall. It simply moves slower and with more effort. Oddly, it now seems to take more effort to LOWER the boom than to RAISE it. At first, this doesn't make any sense since obviously gravity should be helping on the way down. If you use your finger to take a tiny bit of weight off the boom, then suddenly everything speeds up and the gear and motor system sounds fine. What this suggests to me is NOT that the actuators are misaligned, but simply that they have a lot of internal friction when being forced to move under load. And this behavior seems to get worse over time. If any of you have brought motorized MOCs to a convention and let them run all day, you have observed the fine bed of ABS dust that is generated by the wear of the gears over time. Eventually, the gear teeth will wear off, but even before that the dust gets into tight places and causes binding in the mechanisms. I found, for instance, that I had to rebuild my V-8 after Brickcon to get it running smoothly again, despite the fact that nothing had been done to it other then letting it run. My guess is that the LA outer ring (tube) gear which drives the threads on the rod is wearing when being forced to run motorized under heavy load. Over time, this dust builds up in the LA and makes it less efficient.

This is only a theory. If correct, it calls into question the lubrication solution. A linear actuator which is lubricated when NEW may have reduced wear and last longer. But a LA which is ALREADY WORN when lubricated may just cause all the wear dust to stick together and make things even worse. Who wants to find out?

[JunkstyleGio]

@ Blakbird:

When a MOC runs all day on a show or convention some wear and tear on gears and beams is obvious.

But do you think that a LA has already dust and ABS/plastic dust in it when in action for less then an hour?

(Most of us may have run the LA's 40 to 50 times. That is no more then 10-15 minutes.)

Further more i don't have any spare LA's.

But your theory sounds plausible.

@DLuders:

Your heavy advertising for olive oil makes me think that your pushing "the Family Business".

[Anio]

To work perfectly, the 8043 need very new batteries (9V).

With rechargeable batteries (7,2V) the model can not work well.

[rgbrown]

What this suggests to me is NOT that the actuators are misaligned, but simply that they have a lot of internal friction when being forced to move under load. And this behavior seems to get worse over time.

@Fyredog, CP5670: There was some debate earlier as to whether it would be better to simply use 1 actuator. Load reduction, and hence reduction on wear is the argument for using 2 parallel actuators (so long as you can balance them)

[Blakbird]

When a MOC runs all day on a show or convention some wear and tear on gears and beams is obvious.

But do you think that a LA has already dust and ABS/plastic dust in it when in action for less then an hour?

(Most of us may have run the LA's 40 to 50 times. That is no more then 10-15 minutes.)

It all depends on the load on the gears. My MOCs which have run all day at a convention have had very low loading and yet have shown visible wear. The linear actuators for the boom in the excavator have very high loading so the wear would happen much more quickly.

Again, it is just a theory. The only way to know for sure would be to tear one apart. And of course, some people have had problems with their 8043 even when it is brand new.

@Blakbird: Thanks for trying. Which train rugulator do you meen? And how is it connected to the model? In other words: Pictures please!

You connect one of these train regulators (which outputs 9V at a good current) to one of these PF extension wires which lets you connect it to the old 9V system. Sadly, this requires you to tether the excavator to a wire.

Alternatively, you could also use one of the old Control Center units to get more power.

[JunkstyleGio]

@Anio: We already came to that conclusion.

Working on this problem it kind of keeps you wondering: TLC must have tested, reviewed, rebuilt and tested the model over and over. I wonder how they could have overseen these problems.

[eMHa]

@Anio: We already came to that conclusion.

Working on this problem it kind of keeps you wondering: TLC must have tested, reviewed, rebuilt and tested the model over and over. I wonder how they could have overseen these problems.

Yeah, that's wondering me too. Perhaps the look and functions overweight the playability? TLG also says they bake them to test if they resist heat. I'm wondering if 8043 was working after TLG had baked it

As someone said here before, perhaps we have reached the maximum complexity what can be safely build by the common consumers!?

[tomacwhite]

I've put yet another brand-new set of Energizer batteries into the Excavator and it has improved slightly.

- Raising the main arm (dual actuators) is quicker, but the motors still sound like they are straining. Is this normal to other peoples?

- The Right track (right stick) is noticeably slower than the left, and after a short distance of driving forward the model starts to veer to the right quite sharply (much, much more aggressively than the 8275 Bulldozer did where one motor was also driving the V6).

- The middle boom still strains and slows right down when lifting (when actuator is contracting in length)

EDIT:

I have noticed a couple of things

1 - When raising or lowering the main arm, you can see the two linear actuators flexing independently.

2 - My left actuator (looking from the front) 'rocks' in my hand if I hold it, whereas the right is stiffer. This probably doesn't help!

Edited August 10, 2010 by tomacwhite

[DLuders]

For those folks who have already built their own Lego 8043 Motorized Excavator:

How does your own 8043 perform (and sound) relative to ssugawara1955's in this YouTube video? There doesn't APPEAR to be anything wrong with that one:

In regards to the idea that it's better to leave ground-up plastic filings UNLUBRICATED inside a used Linear Actuator, think about an analogy. Would you leave your lawn mower engine underlubricated, because there are metal filings in the engine's cylinder walls? I doubt it.

[tomacwhite]

For those folks who have already built their own Lego 8043 Motorized Excavator:

How does your own 8043 perform (and sound) relative to ssugawara1955's in this YouTube video? There doesn't APPEAR to be anything wrong with that one:

In regards to the idea that it's better to leave ground-up plastic filings UNLUBRICATED inside a used Linear Actuator, think about an analogy. Would you leave your lawn mower engine underlubricated, because there are metal filings in the engine's cylinder walls? I doubt it.

Arm movement on that is far smoother and efficient than mine. His right track seems to be equal to the left track too, so I guess my build has some serious issues.

[DLuders]

Do you think that it's time for somebody to contact Lego Customer Service about the (apparent) defective Linear Actuators for the 8043 Motorized Excavator set? After all, TLG issued a "Fix" to the 8275 Motorized Excavator (scroll down to the last item listed in the dropdown menu on http://technic.lego.com/en-US/buildinginstructions/8258/8258%20crane%20truck%201%20of%204.aspx#8275 Group ). If you download that 1-page "fix", it says:

"Why do the front blade and back ripper not raise and lower properly?

This problem is caused by improper alignment of the crossaxle in the model.

Symptoms: The bulldozer struggles to raise and lower the front blade and back ripper.

What causes the problem, and how can you solve it?

You did not properly align the crossaxle in the model. The two functions, front blade and back ripper, affect each other. The crossaxle must not stick out of the beam. Part of the model must be disassembled to solve the problem. Push back the crossaxle to make sure that it is aligned and not sticking out of the beam.

Location of problem: BOOK 1, PA GE 45, STEP 22" [shows picture with circle around troublesome area]

Maybe a similar "fix" needs to be issued by TLG. It seems a real shame that, in the course of several weeks and multiple posts, this 8043 set has gone from possibly being "the best Technic set ever" to a non-functional, $200 shelf decoration. We paid too much to settle for poor-quality parts.

Lego Customer Service can be contacted by the links on http://us.service.lego.com/en-US/BuildingInstructions/default.aspx ; "Change Region" at the top-right corner of that webpage to get the appropriate Customer Service for your country. Everyone says that they're super-helpful and replace defective parts. Ask for replacements for your messed-up Linear Actuators, and reference this Eurobricks topic.

Here's the Bricklink part reference ( http://www.bricklink.com/catalogItem.asp?P=61927c01 ) and the Peeron part reference ( http://peeron.com/inv/parts/x1918cx1 ) for the x1918cx1 "Electric Power Functions Linear Actuator".

EDIT: Better yet, maybe the Lego Technic Designers (Sariel, Blakbird, and Conchas) could contact the 8043's designer ( Anders Gaasedal Christensen -- http://technic.lego.com/en-us/Designers/Bios/Anders%20Gaasedal%20Christensen.aspx ). It would be good to confirm that the parts he DESIGNED WITH are the same quality as what is being MASS-PRODUCED by the manufacturers. Maybe he could issue a "fix" notice just like the 8275 had.

[Blakbird]

Do you think that it's time for somebody to contact Lego Customer Service about the (apparent) defective Linear Actuators for the 8043 Motorized Excavator set?

I wouldn't call anything "defective" here. The motors and actuators are simply being used at the limits of their capability.

It seems a real shame that, in the course of several weeks and multiple posts, this 8043 set has gone from possibly being "the best Technic set ever" to a non-functional, $200 shelf decoration. We paid too much to settle for poor-quality parts.

Who said anything about a "shelf decoration"? That's an exaggeration. The boom raises and lowers slowly under some circumstances, but this does not ruin the model. It is still an excellent model and among the most playable Technic sets possible. It is certainly still functional, but perhaps not perfect.

Better yet, maybe the Lego Technic Designers (Sariel, Blakbird, and Conchas) could contact the 8043's designer ( Anders Gaasedal Christensen - ).

I've stated it many times before, but I guess I'll do it one more to make sure it is clear. I am NOT A LEGO TECHNIC DESIGNER! I just wrote some articles for their blog. I have no access to anyone at LEGO any different than any other AFOL in the world. I have no ability to make recommendations on behalf of the community. You need an ambassador for that.

At any rate, I'm still happy with my 8043. If anyone comes up with any modifications to the design to help improve it, they would be great to see. But it is a pretty special design out of the box.

[TechnicJuan]

I have to admit that while building this I had mixed opinions, whomever designed this did some very awesome things, but also some very strange things that I was very surprised that a real Lego designer would do.

[Fyredog]

Question on inserting the Youtube videos - How? I am using the embedded code - but it seems not to work properly here

Edited August 11, 2010 by Fyredog

[JunkstyleGio]

Question on inserting the Youtube videos - How? I am using the embedded code - but it seems not to work properly here

Don't put the embedded code in the link; just the url!

Should work like a charm!

@DLuders:

I've already written an email to the customerservice. Haven't had an answer yet.

Maybe i'll give them a call when i'm at friends. (Since i don't have a landline calling them with my mobile is going to be very costly! (over € 1,30 per minute!)

I've to agree with Blakbird on this model NOT being just "shelf decoration". If you build it correctly out of the box it works rather well. All of the functions work just fine except for the slow, batteryconsuming, high friction double LA'd armpart. The AFOL's here just try to find out what to do about those minor flaws.

So let's get working on this problem!

And remember: it's IS just a toy!

[Jimbo]

I think I have a fix for the boom movment of the excavator. I simply used the same idea as the 8851 excavator. I used rubber bands on the back of the main boom conected to a cross axel and then down to the main chassi. The rubberbands (I used two) should be fairly thight in the upmost position of the boom. I dont have any pictures now, but if you look at this picture you´ll get the idea It works a ot better now.

:)

[JunkstyleGio]

@Jimbo:

This is an idea that might work. Please keep us informed and try to place some pictures of the results!

EDIT:

why wait while you can do it yourself!

It kind of works. It stabilizes the the whole arm a bit. Raising the arm goes quite a bit faster! Even on batteriers that are not fresh!

Fun detail: By adding these rubber bands (Which are actually pulling back the arm.)lowering the arm goes a lot faster.

Edited August 11, 2010 by JunkstyleGio

[Jurgen Krooshoop]

To work perfectly, the 8043 need very new batteries (9V).

With rechargeable batteries (7,2V) the model can not work well.

I'm using it with the 8878 Rechargeable battery and it works fine.

And I love this model. OK, the raising and lowering the entire boom is a bit slow, but this is mainly due to the fact that 1 M-Motor is just not powerfull enough. So for me buying this was worth it. I actually love this model, and enjoyed digging Lego-pins for a long time.

[Zerobricks]

Did you guys think of changing the both 20 tooth idle gears, so they face the same direction? Right now when the LA's rotate through the idle gear's axle, one LA slightly shifts one way, and the other reverse way, because the 20 tooth idle gears are not facing same direction. This amy cause the LA's to lock up...Try moving one idle gear in the contr position, so they both face same direction.

[DLuders]

Question on inserting the Youtube videos - How? I am using the embedded code - but it seems not to work properly here

In augment JunkStyleGio's answer, if you copy the URL of the YouTube (or other) video into the "Insert Media" icon (three icons TO THE RIGHT of the one circled below), your video will appear on your post. Don't use any "imbedded" text string obtained from within the video itself; just Copy/Paste the URL right off the address line at the top of your web browser.