75ZT Community

Yes another one. Probably for TakeStock (Dave).

I have a couple of VIS (Variable Intake System) motors I scrounged from the local beakers and have tested them on Dave's kindly donated club tester and both failed. I intend to have a crack at taking them apart this weekend.

One is completely dead the other gives a constant light on the tester and 'clicks' but does not move.

What if anything should I be looking for and in what order?

Cheers,

ceb

We will assume you have the tops off the VIS.

First thing to do is use some electrical cleaner to disperse the oil that will be in abundence, especially on the balance one.

Use a small electricians driver just under the grey metal cog of the motor and prize upwards the worm drive/motor. this will enable you then to lift out the PCB (Printed Circuit Board) with a wiggle or so, there are no further clips to undo (watch out for the washers on the end of the worm drive)

Once you have the PCB and motor out of the casing turn the pcb over and examine the tracks of the PCB closely, any burnt out track is a sure sign of an oil clogged motor. check the microswitch Soldered connections with a magnifying glass looking for dry joints.

Micro switches should show continuity ar rest so a quick test with a multimeter will eliminate them as a fault.

You can prise the motor off the board ( it will just clip back into place when you refit it into the casing, no need to glue. A crude test for the motor is to just connect it up to a 12v or 9v battery and see if it rotates at a good speed without smoking . These can also be saved (50 - 50 chance) by spaying copious amounts of contact cleaner into every orafice of the motor

Burnt out tracks should be traced back to the nearest soldered connection and wired point to point.

If all that checks out you are looking at the 8 pin relay failing, these come in two sizes and like the switches are not really servicable.

Have fun

Many thanks for that Dave

Have sent the other half off for the day Sunday so I have a clear kitchen table, multimeter, cans of Servisol, screwdriver set and my anglo saxon swear book all prep'd and ready to go

takestock wrote:We will assume you have the tops off the VIS.

First thing to do is use some electrical cleaner to disperse the oil that will be in abundence, especially on the balance one.

Use a small electricians driver just under the grey metal cog of the motor and prize upwards the worm drive/motor. this will enable you then to lift out the PCB with a wiggle or so, there are no further clips to undo (watch out for the washers on the end of the worm drive)

Once you have the PCB and motor out of the casing turn the PCB over and examine the tracks of the PCB closely, any burnt out track is a sure sign of an oil clogged motor. check the microswitch Soldered connections with a magnifying glass looking for dry joints.

Micro switches should show continuity ar rest so a quick test with a multimeter will eliminate them as a fault.

You can prise the motor off the board ( it will just clip back into place when you refit it into the casing, no need to glue. A crude test for the motor is to just connect it up to a 12v or 9v battery and see if it rotates at a good speed without smoking . These can also be saved (50 - 50 chance) by spaying copious amounts of contact cleaner into every orafice of the motor

Burnt out tracks should be traced back to the nearest soldered connection and wired point to point.

If all that checks out you are looking at the 8 pin relay failing, these come in two sizes and like the switches are not really servicable.

Have fun

Update - and some questions (probably for Takestock!)
Well I've just had a fun day getting to know VIS motors intimately - , and can now pronounce myself a VIS engineer level 2!

Balance -
burnt track
dry joints
faulty switch
faulty relay

Power -
faulty switch
faulty relay

After a good clean (jeez, I think there was more oil in the balance VIS then there is in the engine!), followed Dave's excellent advice and worked through the issues. Track repaired and dry joints dealt with o.k.
I actually found that with some patience the micro switches (once off the board) were repairable (they clip together a little like the VIS motor cases themselves) once apart (they have a gasket and the switch is just like a miniature morse key) the fault in one was a disconnected spring and a bent arm in the other. Motor's were both fine, so the only component's I couldn't deal with was the relays (the whole VIS motor enclosure leaks like a whatsit and yet they used sealed relays and glue them to the circuit board!).

So questions now are:
Does anyone now were or if I can get replacement relays?
The plastic cogs that are driven by the worm spindle have cams on (which activate the micro switches), when I put the motors back together do I need to make sure the cams sit between the switch pairs or will they re-set on there own when powered up?
Should I put a lubricant on the spindle etc before sealing?
Should I put a sealant around the joint between the two halves of the VIS motor case when reassembling, and if so what?

Opinions gratefully received


Cheers,

ceb

Nice one Chris, switches, yup took one apart in the early days but at around 99p each new, didn't bother again. You have a PM.

Cheers mate,

Only by standing on the shoulders of giants and all that......

Thanks for the pm.

Just out of interest do you lubricate the internals with anything when you put repaired ones back together?

Thanks again.

ceb

just a dab of white grease don't think it is really needed though.

Sorry for jumping on this thread but speaking of VIS motor after-parts do we have a list anywhere with suppliers?

The balance VIS we took apart had all the windings coming off the motor.

Tell me your mot was a success ?

Lates wrote:Tell me your mot was a success ?

I don't know yet, I left it there all day. I did notice one of my number plate bulbs was out so changed it first thing this morning (happens every year, looks like someone has overtightened a screw in the holder in the past and broke it so it's now not sealed).

Thanks once again for your sterling efforts as usual. Even without the brakes bedded in they are already better and the car feels "smoother" oddly. But then those rear brakes were shocking, I normally look after such things better.

P.S. Will get money things sorted out later once I get a min to do the Internet Banking things!

GagHalfrunt wrote:Sorry for jumping on this thread but speaking of VIS motor after-parts do we have a list anywhere with suppliers?

The balance VIS we took apart had all the windings coming off the motor.

The motors are the hardest to get, I have around 20 sets of brushes for them but they are the wrong type of connection to fit the board, not impossible to fit though, small 1mm drill through the board and solder the motor in place as opposed to clip in place. The problem with the motor is securing the metal cog back on once you have prised it off the old shaft. I did locate some splined shafts but as the splines were smaller than the orafice in the cog that failed as well.

Russ did find a supplier in the US for the motors but it was unclear if the unique cog was included as the suppliers minimum order was 2000 at around $4 each. So every broken VIS I receive the first point of call is the motor to see if it can be salvaged

I very much doubt this motor is salvageable to be honest unless someone fancies rewinding it as I know some used to in the model railway scene.

What about other parts such as microswitches etc.? I'm sure I read somewhere that they were available but not clear as to where from.

One day I'm going to take these VIS things to my uncle (who is extremely technical), slap them in front of him and ask him what the permanent solution is!

The permanent solution is to unsert an oil seal and have them running dry, The vast majority of faults on the VIS motors are caused by oil ingress. Both Bigruss and i run dry VIS motors, neither of us has a VIS failure in around 18k.