[HELP] 8860 Geartrain Modification Methods for First Gear

[Grosse Kind]

Good afternoon. Has anyone had any thoughts on getting all gears in this set to work without skipping? Would like to imagine theres more elegant setups than i've used.

Tried the search function to no avail but figure even if its been done to death elsewhere i'm keen to see whats out there.

Ta muchly for your time.

[Rockbrick]

I remember when I first built this and saw that in the instructions you had to cover up first gear, I never did

its such a low ratio that when newly built you could just about push it around, as the dusts and years went by this became impossible

so I suppose lubeing everything would help but possibly just changing the gear ratio a bit may help

it really is meant for motorisation that gear anyway

Edited February 17, 2015 by Rockbrick

[Kumbbl]

Good afternoon. Has anyone had any thoughts on getting all gears in this set to work without skipping? Would like to imagine theres more elegant setups than i've used.

Tried the search function to no avail but figure even if its been done to death elsewhere i'm keen to see whats out there.

Ta muchly for your time.

Yes. I made this. I'm currently in vacation at skiing but when i'm back home i can post pictures

[Grosse Kind]

Thankyou. As i never got it new i wasn't sure that it may have been a time effected thing but my little (somewhat larger in my thirties than it would have been at 6 when i began craving it) heart was broken when i purchased it in 2009 to discover my dream sets three ratio transmission, really wasn't.

In the grand scheme of things, probably no great tragedy, but first at six to one overall isn't ridiculous compared to (admittedly, driving not driven) engines of my particular brand of automobile with ratios of 3.32:1 and 2.92:1 at the gearbox and diff respectively, in first gear giving almost 9.7:1. Admittedly they haven't got pistons a third and crank counterweights half the width of the driver seat either.

Not considered lube thus far as most if not all attract dust where you'd least want it. With all period parts and no great diversification from the stock layout, i'll still be interested to see what others have concocted. I'm keen on era specific stuff as though the printing press is mightier than the scabbard, one likely came out before and was easier to hurl at an opponent than the other, particularly if their weapon wasn't yet invented at the time.

Edited February 17, 2015 by Grosse Kind

[Rockbrick]

I left it in third gear to play with it most of the time, still ist has the best steering geometry ever in any technical set

[thomol]

Set first gear to 16:16, second to 20:12 and keep third gear (24:8). Then all three gears should run smoothly.

The first gear is only meant to be used when motorizing the chassi, as seen in the photo sequence in the instruction booklet. Then you are supposed to open up first gear and instead close third gear.

When building this as a ten year old it took some time to realise why TLG didn't use all three gears; mechanics wasn't my strong side back then.

On a side note it's quite cool that TLG showed how to motorize the model, both drive and steering some thirty years before power functions.

[Grosse Kind]

Thankyou Thomol. By rights i could run 12:20 into first to make it lesser than the 6 to one standard back to a fairly manageable wide ratio cluster with a 3 1/3 to one first. And if that was still too high i can bring it back to 2.9:1 with my 16 tooth diff pinion. Or if that turns to crap, run her as you stated in close ratio format as she handles second in the original setup without hassle.

Have you put these two gears into a trans of this dispositioning and run them please? By the look of photos the 12 and 20 are wider than any of the original gears and may take more shaft travel to disengage fully and leave both first and second concurrently engaged. Only asking as i went off some opinions with my last purchase that were untested and i'd prefer to know someone has "tried" prior to me making another parts "buy".

[thomol]

No, haven't tried it, but it should work since all gears are one stud thick and the upper shaft can move two studs. I can make a mockup and try it out as soon as the wife goes to sleep and I can get to my bricks :-)

--

Edit: Works perfectly. Can upload pics tomorrow if you want. Use bushes between gears to keep them sliding out of phase. Especially 20t can have lousy grip on the axles.

Edited February 18, 2015 by thomol

[Grosse Kind]

Pics would be wonderful thankyou. I fed this into LDD:

and they all physically fit, just concerned by the width of the 20 as seemingly thicker than the limit of one studs movement per gear either not engaging from first to second fully or still holding in the shift from second to third locking both shafts solid.

Again, much appreciated.

Edited February 19, 2015 by Grosse Kind

[thomol]

Here you go!

As you can see I have an equal distance between each gear on the upper shaft, your solution with the 16t and 20t beside next to each other works as well, I tested it this morning, but didn't take any more photos.

There may be a risk of the gears slightly engaging simultaneously, if you're not careful when aligning them. That shouldn't be a problem though; you wouldn't change gears when the car is moving when using an unsynchronized gear box like this one anyway...

Edited February 19, 2015 by thomol

[Rockbrick]

8<.....you wouldn't change gears when the car is moving when using an unsynchronized gear box like this one anyway...

you shouldn't, but we all did as kids! no double declutching facility.... a lego 'crash gearbox'

Edited February 19, 2015 by Rockbrick

[thomol]

you shouldn't, but we all did as kids!

Yeah, when our hands were small enough to handle both steering wheel and gear stick at the same time without destroying the rest of the car, all while creeping beside it on the living room floor...

Thank god for the plus forty years old's Lego construction area at ergonomically correct height and ability to appreciate technical functions in theory even though they don't work in practice :-|

[Grosse Kind]

You're a saint!

Thankyou for slotting them all together for me, it's a big help to see in the solid and meshed. I'll track some down and get to playing and experimenting to see what works, what works better, and what generates the biggest grins. May grab a few extras to toy with the reduction ratios in my 8880.

Re the unsychronized shifting whilst in motion: did it, doing it, and with feel theres no real violence. I think the double bevels with how they're cut they may knock into place a tad lighter too. Possibly if i can find space i may see if the three 8's inline on the engine primary drives jackshaft will change out for twelves and try a 20 as the slide pinion. Perhaps reverse the quadrant a-la a drive-second-first pattern in my Chrysler. Possibilities possibilities and possibilities. Feel like an 8 year old again!

[Kumbbl]

here comes a MOD which allows using all 3 speeds of the gearbox... it cost about 2 handful of standard technic parts - it gears down 1:3 the drivetrain directly before the fake engine...works like a charm... AND: This mode uses only parts available at the time of the 8860 (which is FOR ME always an important criterium when modding an official set)

here are the pics:

BTW: fiddling the fake-pistons with the crankshafts into the brickbuild cylinders and making them smoothly spinning (Step 17 in the official BI) is one of the trickies and most challenging steps in official BIs - until now...IMHO

Edited March 10, 2015 by Kumbbl

[Grosse Kind]

Thanks. Bei solche untersetzung wird die kurbelwelle auch im zweiten gang drehen weniger als die hinterachse?

[Grosse Kind]

Well, took the plunge and dropped in the 12 and 20 the other day. Comfy with how it all works and put the diff pinion back to the standard 14 tooth. Life is to be a lot easier on the uni's in the swing axles at a minimum, and the gearshift still feels ok.

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The standard ratio gears and a spare diff pinion up under the front chassis. A habit of mine to keep any supplanted parts on the vehicle itself to allow easy return to standard.

My gear detent system, to prevent it jumping out of cog when rolled backward:

Slight peeling from a 4 long axle lets it slip into the detent pin traps.

Edited April 7, 2015 by Grosse Kind

[skaah]

Man, that lego is dirty!

[miguev]

And the axle is... corroded? Like of few of mine from the 80s, what's up with these axles?

[Grosse Kind]

I've an air compressor and could blow her down skaah, but realistically she's never seen the inside of a cabinet and is played with too frequently (still, a rolling testbed and in one piece since i got her in 2009) to fret about trivialities as a little/lot of dust. But seem as i'm nothing if not accomodating i'll check her for bouyancy later this eve (i've an odd feeling she's not gonna float real good), in the bathtub, and if she sinks i'll push it back and forth a few times whilst attempting to make underwater "vroom vroom!" noises, and see if it gets any less dirty. Not confident but at least it'll be the first flat four propelled submarine. May need to revise the engine fan blade pitch but. ;)

Hi Miguev. It started life as a 12 long axle with an inclusion in its moulding that cracked into two pieces around the 4.5/7.5 region. I filed a standard-like chamfer on the cracked end and have since rough pared down the splining in the middle with a pocket knife to experiment what profile taper and width would slide easily through the friction pins allotted as shift gates but not slip out the opposite way quite so easily. When the ratio of first was still six to one, she displayed a propensity to pop out of gear into a false neutral of sorts, and even in the higher two gears, if you rolled it backward the gear lever would flail the other way and often popped out of gear. What i have since used holds each ratio captive using a broken part i modified slightly rather than dispensing with. I'd never seen corroded lego before till i found some of my 80's stuff also the other month.

In places its almost chalky and there's blistering on it but i've never come across axles like yours. I have one that is so twisted that if you follow the spline one end to the other, it has a full 1/4 turn to it plus the aforementioned cracked axle, but generally they've always seemed pretty stable.

Might i enquire, in your burial grounds of sacrifices to the lego gods there, i think i can see full width bushes, with toothed ends. Are these common and/or reasonably recent as they're totally new to me.

Thanks for your time, glen.

Edited April 8, 2015 by Grosse Kind

[Saberwing40k]

Those pieces are not actually bushes with teeth, but part of an old angle connector, and have snapped off in such a way that it looks like a bush. I also am fond of modding broken parts although not for this purpose.

[Grosse Kind]

Thankyou sabre.

As a bit of a surprise (click video link below):

she does actually float!

Currently drying off.

Edited April 8, 2015 by Grosse Kind

[Jim]

Thanks. Bei solche untersetzung wird die kurbelwelle auch im zweiten gang drehen weniger als die hinterachse?

Let's stick to English! Thanks

[Grosse Kind]

Yep, no dramas.

Kumbbl: with the extra intermediate gearing you put in does that not drop second cogs ratio into a supplementary overdrive with first then assuming the revs of what was formerly second, second the old third, and third a massive 4.5 wheel turns to one twirl of the crank? I know it allows all three to be safely utilised but it slows the engine to a somewhat non viable (if we go by a T56 borg warner with a 0.50:1 top gear and run that with say a VE SS commodore and the attendant 3.45 to one diff ratio, we only come back to an overall underdrive from crank to wheel of 1.725:1, and thats a 6 litre V8 Providing the torque vs say a large flat four in our case with perhaps a 3 litre capacity) rate of rotation. The original third is unrealistic already i know, but this makes it really pronounced.