Car designers are crazy !

[bricol]

There's no reason for these odd sized bolts from an engineering perspective, they only make sense from a dealers profits perspective.

They fit in smaller spaces, they weigh less, they are easily machine fed and tightened, use less material - and when you buy millions of them, all those small bits add up to a lot of money - so it makes sense from the manufacturers point of view, but not many others.

Japanese cars, or the few I've had contact with, simply use Japanese metric standard which are different to European.

I did once get asked by a very senior VP of something important on the third floor of corporate headquarters in Philadelphia why I didn't design stuff to use all the same size screw so only one tool was needed . . . because the M6 screw won't hold quite the same as the M30 needed here, and the M30 won't fit in the space where the M6 is used . . .

But I too have two multi-splined keys for removing a Polo cylinder head . . used four times - once to get the head off, once to put it back, once again quite soon to get it off again, and one more time to put it back after having it skimmed this time . . .

 

[Ubique]

I think the worst pointless fastener variation has got to be Audi front undertrays, you need a T20, T25, T30 M10 spline and a 13mm socket. There is one T20 screw, why that couldn't have been T25 like the 1/4 turn screws, I have no idea.

 

[dobbslc]

Was it a cayenne? They are over £4k each.

I think it was.

 

[jmp49]

They fit in smaller spaces, they weigh less, they are easily machine fed and tightened, use less material - and when you buy millions of them, all those small bits add up to a lot of money - so it makes sense from the manufacturers point of view, but not many others.

Japanese cars, or the few I've had contact with, simply use Japanese metric standard which are different to European.

I did once get asked by a very senior VP of something important on the third floor of corporate headquarters in Philadelphia why I didn't design stuff to use all the same size screw so only one tool was needed . . . because the M6 screw won't hold quite the same as the M30 needed here, and the M30 won't fit in the space where the M6 is used . . .

But I too have two multi-splined keys for removing a Polo cylinder head . . used four times - once to get the head off, once to put it back, once again quite soon to get it off again, and one more time to put it back after having it skimmed this time . . .

Progress on this front stopped after Wooler's flying banana went out of production. It needed only 1 spanner to do any maintenance task...

Wooler 2 3/4 HP Flying banana 1919 - Moto Passion - Moto Collection François-Marie DUMAS

 

[bert]

Porsche supply a tool in the cars tool kit to remove cayenne headlights. Goes in through the inner wing and a 1/4 turn the headlight comes out. Probably the easiest bulb change I've ever done.

 

[bert]

Oh and the matrix headlamps on the current cayenne are £2200 each

 

[plewlandsbob]

It's not just car designers. I work for a tractor, main dealership. We have a fairly new model of tractor in, because 4Wd clutch pack is giving problems. Most older tractors, you could take 4Wd pack , out through a plate on bottom of transmission.
This one , can off, fuel tanks , halfshafts split tractor between gearbox and rear axle, then pinion out and diff out, then take out clutch pack. Warranty pays 32 hrs just to remove it, so probably takes about 50 hours!

 

[plewlandsbob]

I often wonder if it is because, modern designers, learn everything in a class room and never had to fix anything before, to gain some practical ,real world experience.
Or is it because they will be young and feel the need to change something, just because they can, just to make it different?

 

[sako243]

I often wonder if it is because, modern designers, learn everything in a class room and never had to fix anything before, to gain some practical ,real world experience.
Or is it because they will be young and feel the need to change something, just because they can, just to make it different?

To a certain extent but I also think things have got so much more complicated it's difficult for it to be reviewed thoroughly or designed by one person.

An example I was running a project, only three designers on it really, myself a CAD guy and a PCB layout guy and one or two people also involved in peer / overall design review. Modelled everything in CAD and no design clashes. Made the prototype boards and mechanics and ah, sheet. Couldn't fit the PCB into the chassis because two connectors either side were meant to poke into / through the case. Luckily the board was so big we could flex it just enough to pop it in.

Second time we removed one connector and made a second PCB with a mini wiring harness to it.

That was a relatively simple project. We also changed a number of other things that although we'd spent ages thinking about how it was going to be assembled we could further improve them.

 

[Mark 5]

Was it a cayenne? They are over £4k each.

4!!! stone me!

 

[NickW]

While on the subject of indicators.

Can someone explain what is the purpose of the 'stripy' indicators? Why cant they just flash on and off regardless of the shape or size? Why do they have to swipe out?

Because it's much easier to sell a fancy new feature than trying to persuade customers that you've fixed(or at least improved) a previously poorly designed/engineered/installed part. As the customer, you're not supposed to consider things like making a lamp unit totally non-serviceable, and therefore expensive, equally poor design/engineering.

 

[jimbo84]

I often wonder if it is because, modern designers, learn everything in a class room and never had to fix anything before, to gain some practical ,real world experience.
Or is it because they will be young and feel the need to change something, just because they can, just to make it different?

Not sure if it applies to tractors but a lot of the decisions are to meet ever demanding emissions and crash safety requirements.

I was reading a technical thing on the merc OM651 engine the other day (granted not a current engine). The timing chain is at the back of the engine and by all accounts a ballache to get to. Why's it at the back of the engine when the front would be the logical place...to meet some NCAP pedestrian crash thing. Putting it at the back gives more space between the front of the car and the front of the engine.

Wet belts (stupid idea) and simplex chains to meet emissions (and manufacturing cost no doubt) requirements instead of a reliable duplex chain.

Not a fan of anything modern and think all the tailpipe emissions savings are counter productive against reliability but credit where it's due some of the things they manage to put out with even a modicum of any kind of reliability under the ever stringent requirements is an engineering marvel really.

 

[Ubique]

Not sure if it applies to tractors but a lot of the decisions are to meet ever demanding emissions and crash safety requirements.

I was reading a technical thing on the merc OM651 engine the other day (granted not a current engine). The timing chain is at the back of the engine and by all accounts a ballache to get to. Why's it at the back of the engine when the front would be the logical place...to meet some NCAP pedestrian crash thing. Putting it at the back gives more space between the front of the car and the front of the engine.

Wet belts (stupid idea) and simplex chains to meet emissions (and manufacturing cost no doubt) requirements instead of a reliable duplex chain.

Not a fan of anything modern and think all the tailpipe emissions savings are counter productive against reliability but credit where it's due some of the things they manage to put out with even a modicum of any kind of reliability under the ever stringent requirements is an engineering marvel really.

Where did you hear that nugget about the OM651 timing chains from? sounds like utter bolleaux to me and certainly never mentioned in any M-B training material. Given the amount of clutter at the front of the OM651 & OM654 engines, putting the timing chain there as well would make the design of the coolant galleries problematic at best.

Yes, going to a simplex chain is emissions related - but they're not really that bad of a job to replace, not compared to a lot of BMW engines - also at the rear but with far more room between the bumper cover and the front of the engine.
Wet belts are fine in a controlled environment, once 'out in the wild', there's far too many variables that will affect longevity for them to be viable.

 

[AVI_8]

There's an ever-growing list of cars where you need to remove the front bumper to change headlight bulbs, a mechanic mate told me he knows of a Peugeot 206 where they found 6 dropped headlight bulbs behind the bumper when it was finally removed

And removing the bumper requires removing the wing covers, where every fastener is seized solid, then the torque screws securing the bumper to the car are obviously seized solid and on it goes.
Just replaced the rear subframe/axle on my mother in laws Fiat 500, a simple job, took 2 days to remove it, the corrosion on a 14 year old car on roads in Scotland, everything was seized, replacing it (with lots of new parts) took about 90 minutes. Working on other people’s old Italian cars is not much fun when you’re doing it for the family (free) of course.
Having said that I got a new tool, a Milwaukee gun. 1370 NM of torque, it’s a beast, when I picked up the nut it removed it burned my hand, it’s going to be a very handy tool that I wished I’d bought years ago.

 

[AVI_8]

I saw a Porsche in town this week with masking tape over both headlights or more accurately where the headlights had been before some turd stole them.

Porsche Taycans are being written off nowadays because people are using angle grinders to remove their headlights, in doing so they’re causing massive amounts of damage to the surrounding body work, £60,000 cars going to Copart because of this

 

[Nomad]

Porsche Taycans are being written off nowadays because people are using angle grinders to remove their headlights, in doing so they’re causing massive amounts of damage to the surrounding body work, £60,000 cars going to Copart because of this

Also, some Porsche lights are held in with a quick-release clip that you can undo without opening the bonnet - and that the powerful lights work well to grow weed

This Design Flaw Made Porsche Cayenne Headlights So Easy To Steal, People Apparently Started Using Them To Grow Weed - The Autopian

Although a unique headlight locking mechanism made Porsche Cayenne headlights easy to install, it also made them easy to steal.

www.theautopian.com

 

[Erie Fred]

I often wonder if it is because, modern designers, learn everything in a class room and never had to fix anything before, to gain some practical ,real world experience.
Or is it because they will be young and feel the need to change something, just because they can, just to make it different?

You would not believe the pressure they are under.
Try walking a mile in their shoes for once.

I work with a design engineer that came from Ford.
The stories he tells of accounting shooting down ideas over pennies.

Also....there usually is not "An Engineer" there is many engineers, in many groups.

 

[AVI_8]

Also, some Porsche lights are held in with a quick-release clip that you can undo without opening the bonnet - and that the powerful lights work well to grow weed

This Design Flaw Made Porsche Cayenne Headlights So Easy To Steal, People Apparently Started Using Them To Grow Weed - The Autopian

Although a unique headlight locking mechanism made Porsche Cayenne headlights easy to install, it also made them easy to steal.

www.theautopian.com

Yes they’re very easy to release if the bonnets open, but if it’s not …..

 

[premmington]

I think the worst pointless fastener variation has got to be Audi front undertrays, you need a T20, T25, T30 M10 spline and a 13mm socket. There is one T20 screw, why that couldn't have been T25 like the 1/4 turn screws, I have no idea.

I wondered this - why you gotta get a big pile of tools out to get the undertray off an Audi. But to be honest - getting anything off an Audi is always a big pile of tools - VW Skoda are better on this front.

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I did a Hyundai hybrid oil change Sat morning - it has access holes for oil drain and oil filter in the undertray - what a nice job - round bits of plastic you remove with a 10mm socket. They even have "oil drain" and "oil fitler" embossed into the little bit of cover you remove.

 

[premmington]

Where did you hear that nugget about the OM651 timing chains from? sounds like utter bolleaux to me and certainly never mentioned in any M-B training material. Given the amount of clutter at the front of the OM651 & OM654 engines, putting the timing chain there as well would make the design of the coolant galleries problematic at best.

Yes, going to a simplex chain is emissions related - but they're not really that bad of a job to replace, not compared to a lot of BMW engines - also at the rear but with far more room between the bumper cover and the front of the engine.
Wet belts are fine in a controlled environment, once 'out in the wild', there's far too many variables that will affect longevity for them to be viable.

Your quote "Wet belts are fine in a controlled environment, once 'out in the wild', there's far too many variables that will affect longevity for them to be viable."

I got a few customers with Transits/Rangers and 1.0ltr ecobooms - that have done high mileage with no problems - but these are the punters who change the oil regularly and insist on dealer spec supplied oil.

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@Ubique Taken me a little while to get to this - in my simple mind - but I am begining to think - it's down to the oil - wet belt failure - dealer supplied oil is the right spec - not all this badged up "approved stuff" the aftermarket and big named oil suppliers are selling to the indie trade (me) and the public at motor factors.