California Top Motor Mod

zzdelta · 04-07-2010, 04:12 PM

I have one of the many California tops that have lost functionality of that stupid gear in the motor which dirves the top back and fourth. Unfortunatly, I do not have the motor as the previous owner removed it, and am not willing to spend $400 on this. I am looking into getting it working in a much less expensive way. I am thinking of finding anohter small 12v motor, attaching torque converting gears, and see if I cant get it operational again. does anyone have drawings or pictures of how the origional motor connected to the cali top?

Thanks!

-B

pnosker · 04-07-2010, 04:21 PM

I can take some pictures next time I'm home from school. I'll try to explain now: Motor drives a worm gear, worm drives a series of two helical cut gears on top of each other with opposing helix angles (so the bottom gear is //////, top is \\\\\\)... they're identical but just flipped and held together by some rubber gasket thing. One of these breaks. This set of two gears drives another metal gear (this interface is what wears the gear) which has another smaller gear stacked on top connected by a short axle (one piece) which goes into the sunroof. The gear-sunroof interface is essentially a metal gear on a worm drive, as the worm drives the cable pushing and pulling the roof.

zzdelta · 04-07-2010, 06:05 PM

I figured it would be a similar setup. Im thinking that if I can find an alternate way to engage the worm drive or find an alternate mode of operation, I can get the thing to open and close with a custom motor. I guess Step one in this is to see how many amps are delivered to the lines, and select a small 12v motor from there. Plastic interfacing to metal seems to be a design flaw however. I know it lasted several years before breaking on average, but this common mode failure is something I though BMW would have seen and corrected, especially for a higher end feature. Oh well, enough complaining, more fixing.

zzdelta · 05-10-2010, 08:28 PM

So I picked up the motor from the person who sold me the car origionaly, and I am really supprised that no one has replicated this already. Did anyone try a CAD drawing or something to that effect? I am refocusing my effort to replicate this gear instead of modifying the motor drive assembly.

pnosker · 05-10-2010, 09:36 PM

I tried to get it replicated and nobody would make it with CAD because of the difficulty in making a helical cut gear.

VAC motorsport which has a large cad system quoted me like $1500 per gear though for 10 gears.

roadrash · 05-10-2010, 09:43 PM

Perhaps eMachineShop.com would be affordable if you did the CAD yourself?

pnosker · 05-10-2010, 11:30 PM

Probably but I have no idea how to do that!!

spidertri · 05-12-2010, 03:27 AM

Pat, if you send me the dimensions of the gear I could do it in CAD. You might be able to find someone at your school who could do it too. I know in my CAD course we made a helical gear, it wasn't very hard at all.

pnosker · 05-12-2010, 06:44 AM

9AM is my last final so I should be home in the next couple of weeks. I have a spare gear from my broken motor that I'll measure up for you!! Thanks man!

DancingSnail · 05-12-2010, 01:58 PM

I posted, recently, about the same issue with the gear inside the motor. I am needing that gear.

I agree, it seems that as common as this problem was/is there would have been a fix for it --- why BMW engineers had metal gears meshing with plastic gears is puzzling.

Anyway. I would like to be included on any breakthroughs anyone has in replicating that gear. Or as I posted, has anyone examined any other BMW sunroof motors to see if the gears are interchangeable?

But if you folks are going to actually machine a gear, I would like to get in on that. Are you considering machining it in metal rather that the original plastic?

Thanks.

dave45056 · 05-12-2010, 04:06 PM

Try this place for the machining
http://www.firstcut.com/

This place has configurable metric helical gears which you may be able to use, too
http://www.misumiusa.com/

By the way, metal gears meshing with plastic gears is not as bad as you might think. Usually it's done to make the gears last without lubrication.

DancingSnail · 05-12-2010, 04:29 PM

Thank you Dave for those leads. I will report back with the results of this search.

And not to argue, but personally...... I would rather be confronted with having to lubricate the gears in this motor that having to try to fabricate a worn plastic Helical Gear (or give up and have to buy a whole new motor).

spidertri · 05-12-2010, 05:18 PM

Quote:

Originally Posted by pnosker

9AM is my last final so I should be home in the next couple of weeks. I have a spare gear from my broken motor that I'll measure up for you!! Thanks man!

Cool, sounds good. Send me a PM when you are ready to take measurements and I'll tell you what I need. I have finals until the 18th...

tiFreak · 05-13-2010, 01:54 AM

Quote:

Originally Posted by DancingSnail

And not to argue, but personally...... I would rather be confronted with having to lubricate the gears in this motor that having to try to fabricate a worn plastic Helical Gear (or give up and have to buy a whole new motor).

yeah, but BMW knows that the yuppies who had the money for the Cali top would probably not want to be bothered with stuff like that

pnosker · 05-13-2010, 02:55 AM

Oddly, it IS lubricated, but with the same stuff the window sliders are lubed with. It sucks. I squirted lots of white lithium grease and silicone grease into my new motor before I installed it.

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