Crazy Mechanical Know How (Or Not)

[Cudwieser]

I'm curious. I've two questions, one simple, the other insane.

 

Firstly this is a thread for crazy mechanical fixes you've used or can suggest to get yourself out of a hole, to improve your ride or to fix a problem on the cheap(ish). If you have ideas to pass an inspection or just to enjoy the last throws of an old junker please let us know. Also if you have a crazy (or sensible) mechanical question and just want another view point, please ask away.

 

As for my second question is somewhat nuts.

 

People go on about increasing the dispacement of an engine to up the power and torque (perfectly logical). Increasing the displacement involves turning the cylinders to increase bore so bigger pistons can be used. All this is sound, but what I want to know is what would happen if you simply engineered and placed a second clyinder block ontop of the original (making sure everything is hermetic) and fitted longer conrods and a suitable crank. What performance change would there be?

[Dottie]

 

 

As for my second question is somewhat nuts.

 

People go on about increasing the dispacement of an engine to up the power and torque (perfectly logical). Increasing the displacement involves turning the cylinders to increase bore so bigger pistons can be used. All this is sound, but what I want to know is what would happen if you simply engineered and placed a second clyinder block ontop of the original (making sure everything is hermetic) and fitted longer conrods and a suitable crank. What performance change would there be?

From an engineering and vehicle dynamics standpoint:

 

An unnecessarily high CG since you're putting a block on top of a block

 

A sh*t load of weight

 

very unbalanced frontward weight bias unless you increase the rear vehicle weight to compensate, therefore equaling a sh*t load of weight

 

Absolute 1000% pitiful, garbage handling

 

Engineering this contraption for a car is utterly nonsense

 

Just stick to turbos and superchargers. That's why they were made

Edited October 24, 2015 by Dottie

[Cudwieser]

 

 

 

As for my second question is somewhat nuts.

 

People go on about increasing the dispacement of an engine to up the power and torque (perfectly logical). Increasing the displacement involves turning the cylinders to increase bore so bigger pistons can be used. All this is sound, but what I want to know is what would happen if you simply engineered and placed a second clyinder block ontop of the original (making sure everything is hermetic) and fitted longer conrods and a suitable crank. What performance change would there be?

From an engineering and vehicle dynamics standpoint:

 

An unnecessarily high CG since you're putting a block on top of a block

 

A sh*t load of weight

 

very unbalanced frontward weight bias unless you increase the rear vehicle weight to compensate, therefore equaling a sh*t load of weight

 

Absolute 1000% pitiful, garbage handling

 

Engineering this contraption for a car is utterly nonsense

 

Just stick to turbos and superchargers. That's why they were made

 

What if you put the engine in the middle. I do agree about the weight but surely the torque will counter alot of the inertia?

 

P.s this isn't a serious idea, just a thought experiment. I someone actually wants to try it I'd like to see the results.

Edited October 24, 2015 by Cudwieser

[K1FFLOM]

The engine probably wouldn't fire at all (or just run uneven at a much lower pace) .

 

Because of the additional length of the conrod, which acts like a lever during the firing in the combustion chamber. The explosion wouldn't be strong enough to turn the crankshaft properly due to the smaller angle of the conrod (fitted centrally in the piston, and mostly at an angle at the connection-point on the crankshaft) so it wouldn't be properly able to turn the crank. Add this problem to the other 3, 5 or 7 cylinders and the more problems you will get.

 

 

The best car-engines, when it comes to torque and smoothess of firing, are the american 8-cylinder in-line engines from the late 30s until their V-8 replacement in the mid fifties. From those, the Duesenberg Model - J is the best, imho.

 

Thinking of it, there is something that would easily surpass a straight-8. Two straight 8s as a V. Preferably one from a pre-war Cadillac V-16 !

Edited October 24, 2015 by K1FFLOM

[Dottie]

Putting a double block has been done before (one block behind the other or a side by side block setup), but those are 99.9999999999% show cars, tractor pull vehicles, or drag racers and serve nearly no practical use other than driving in a straight line or looking cool.

 

 

With the 2 engines on a classic vehicle using the old body on frame principle, you will need a beefy frame to support the 2 engines, which equals more unnecessary weight (and even more if you try to balance the weight)

 

You'd get a lot of power if you do it right, but its definitely not a practical method to get a lot of power

 

There has been one notable concept using the double engine principle which is the 2005 jeep Hurricane concept using 1 engine in the front and 1 engine in the back; both hemi V8's (better weight balance). It did make almost 700 hp and over 700 ftlb of torque. There are a few oddball conversions of regular cars out there too. This would be the only practical means of a twin engine setup if you want to actually turn.

Edited October 24, 2015 by Dottie

[Cudwieser]

MTM did a conversion with 2 engines. Evo Mag did a review of it a few years back and the tester (Jethro Bovington if I remember). Near sh*t a brick with the wayward nature of the power delivery. They tested the car on the Autobahn to see if it was possible to hit 200mph and what it took (they discovered the Pagani Zonda C12 was only good for 190mph). The MTM strayed from lane to lane at above 180mph all the way to 207mph before Jed's nerve broke.

 

All this mention of power and torque reminds me of another question. The Bugatti Veyron runs an 8 litre 16 cylinder with 900hp+ and 900lb/ft+. The engine, as big as it is, is still smaller than the engines used by tractors (either semi or agricultural) that throw out similar figures. Why aren't tractors using such engines instead of the big 14 litre+ lumps to make the same power/ torque.

[epoxi]

Why aren't tractors using such engines instead of the big 14 litre+ lumps to make the same power/ torque.

A conventional engine design is more reliable and less complex, plus cheaper to manufacture: when you're running a business you want as little maintenance cost and downtime on your capital as possible. Also, you don't need particularly marvellous handling in a vehicle that never breaks 30mph.

 

Do remember that even with all the resources and parts at their disposal, VW made losses on every Veyron proving what a black hole of R&D money the car is.

Edited October 24, 2015 by epoxi

[Cudwieser]

I am aware of that, but surely it proves that with suitable development that from small things big power comes. Surely there is a balance that a truck the size of a delivery van can be made to handle some line haul duties as well, making a cost effective, all rounder for big distributors. Surely what you save on more specialist items can be covered with a broader general fleet?

[epoxi]

There's no incentive: in most big trucks and vans the driver sits above the engine, or it is transversely mounted so its size does not present much of an issue. Efficiency isn't really improved over a regular turbo diesel either. Reliability will always be worse for a more complex engine, if you have twice as many cylinders you have twice as many points of failure and every moment spent in the garage is revenue down the drain (never mind the repair costs themselves). If it ain't broke don't fix it.

Edited October 24, 2015 by epoxi

[K1FFLOM]

There has been one notable concept using the double engine principle which is the 2005 jeep Hurricane concept using 1 engine in the front and 1 engine in the back; both hemi V8's (better weight balance). It did make almost 700 hp and over 700 ftlb of torque. There are a few oddball conversions of regular cars out there too. This would be the only practical means of a twin engine setup if you want to actually turn.

 

The double engine principle has been used on at least one PRODUCTION-car:

 

The Citroen 2CV 4x4

It had an engine for each axle (two gearlevers, ignitions and fuel-tank too). The last one auctioned-off in the states (from a large micro-car collection) was sold for a 6-digit Dollar sum...

 

Another car that springs into mind was a Mercedes A-Class with two engines. It was a special conversion from Mercedes-Special-Vehicles to celebrate their winning Formula-1 season (either 1998 or 1999) and two cars were given to their then F1-drivers as a present.

 

 

But that wasn't what the general question was.

The question was if was better to fit two cylinder-blocks on top of each other to gain more torque....

Edited October 25, 2015 by K1FFLOM

[Cudwieser]

Or power. There was a more primary reason for the thread and that was crazy and less conventional solutions to mechanical problems

 

I must say good shout on the Sahara. Citreon was well know for craziness. Here's a question, How would you go about building a tyre testing rig?

[Dottie]

Here's a question, How would you go about building a tyre testing rig?

Go on the internet

Search a dyno design that satisfies my test requirement

There's no use in reinventing the wheel where there is really no need

Look how ridiculously overpriced it is and boldly say I can build one for less

CAD dat bish (make sure everything works)

Outsourse dat bish build it and hope it works

Edited October 27, 2015 by Dottie

[K1FFLOM]

 

.... How would you go about building a tyre testing rig?

 

Fit three extra axles and a couple of feet in length to a Citroen DS Break, widen it about three feet and paint it orange.

Thats what Michelin did in the 70s, lol.

Edited October 27, 2015 by K1FFLOM

[Cudwieser]

True. Costs aside, Do you think components are better tested at length in the real world or in a lab environment?

[K1FFLOM]

Real world.

 

See what happens when you test everything only on a computer :

- Mercedes A Class topples over

- Audi TT (1st. gen) is unsafe at high speeds

Edited October 27, 2015 by K1FFLOM

[Dottie]

True. Costs aside, Do you think components are better tested at length in the real world or in a lab environment?

Coming from someone that works for an automotive supplier, both (including computer simulation) are equally necessary to fully develop a component, especially for vehicles. Lab environments can be much better controlled than in-vehicle testing (a big example is temperature and corrosion testing), but in-vehicle testing is also needed to make sure that your product performs as it should and that your lab tests are accurate.

 

If you are just making some part for your car in a garage (ex a new driveline) and you do not have lab equipment, fancy simulations and sensors at your disposal, then slapping it on the car and hoping it works is the only option you have. Unless you build a dyno first (highly recommended)

Real world.

 

See what happens when you test everything only on a computer :

- Mercedes A Class topples over

- Audi TT (1st. gen) is unsafe at high speeds

lab testing is not limited to just being simulation on a computer

Edited October 27, 2015 by Dottie

[epoxi]

Yes, you definitely need both, that goes for any product not just automotive ones.

 

You can design a product perfectly to specification, computer simulations help you avoid the obvious pitfalls without wasting money on prototypes that are guaranteed to fail, and then lab testing makes sure it does what you designed it to do. However only real-world testing will reveal what the customer will actually do to it.

 

For instance with your tyre, it might be the most perfect creation from fuel economy, to speed rating, to grip in wet weather. However if it can't for example handle dry-steering, if you cant park half on a kerb, if you can't abuse your product in all the ways customers will (even though they're not supposed to), then you are in for a nasty surprise when it hits the market.

[sivispacem]

- Audi TT (1st. gen) is unsafe at high speeds

Common misconception. The TT was never "unsafe", Audi intentionally dialed in a degree of lift-off oversteer to make it more sporting. When a number of high speed accidents happened due to driver error and they were getting negative publicity, they decided to replicate the understeer biased handling of earlier Quattro badged Audis and adjusted the rear bump, camber and rebound to basically remove it, instead resulting in chronic understeer and woolly handling.

 

Several people have reverted TTs to pre-recall specification and they apparently drive much better.

[K1FFLOM]

 

True. Costs aside, Do you think components are better tested at length in the real world or in a lab environment?

Coming from someone that works for an automotive supplier, both (including computer simulation) are equally necessary to fully develop a component, especially for vehicles. Lab environments can be much better controlled than in-vehicle testing (a big example is temperature and corrosion testing), but in-vehicle testing is also needed to make sure that your product performs as it should and that your lab tests are accurate.

 

If you are just making some part for your car in a garage (ex a new driveline) and you do not have lab equipment, fancy simulations and sensors at your disposal, then slapping it on the car and hoping it works is the only option you have. Unless you build a dyno first (highly recommended)

Real world.

 

See what happens when you test everything only on a computer :

- Mercedes A Class topples over

- Audi TT (1st. gen) is unsafe at high speeds

lab testing is not limited to just being simulation on a computer

 

It was in those two cases I listed though. Otherwise the manufacturers would have found-out the blatant problems that got found-out by the press (A-Class) and relatives of the deceased (Audi TT).

LoL.

 

I just love German engineering and their constant fcuk-ups. Everytime it's worth a decent laugh.

 

" Vorsprung durch Schadenfreude " as the "Technik" doesn't work rofl

Edited October 27, 2015 by K1FFLOM

[Cudwieser]

german and constant f**k ups? Now I'm curious?

[K1FFLOM]

VW

Audi

Mercedes-Benz

BMW...

 

Is it ok for me to post details ?

Or would it be too offtopic ?

[epoxi]

Is it ok for me to post details ?

Or would it be too offtopic ?

As long as it's substantiated criticism about their products then I'd say it's relevant. As long as you keep sensationalism to a minimum though and treat the responses of others with respect.

[Cudwieser]

Agreed.

[K1FFLOM]

I'll be with you with this then, but not before Sunday. This will be anohher busy weekend for me.

Just so much until then:

The Audi TT recall was a more substantial one as the vehicles were sent back to the factory in Hungary and the ESP system was fitted amongst others...

The accidents were fatal and it was due to the fact of next to no downforce on the rear axle.

[DMC14]

 

- Audi TT (1st. gen) is unsafe at high speeds

Common misconception. The TT was never "unsafe", Audi intentionally dialed in a degree of lift-off oversteer to make it more sporting. When a number of high speed accidents happened due to driver error and they were getting negative publicity, they decided to replicate the understeer biased handling of earlier Quattro badged Audis and adjusted the rear bump, camber and rebound to basically remove it, instead resulting in chronic understeer and woolly handling.

 

Several people have reverted TTs to pre-recall specification and they apparently drive much better.

 

 

they also added a small rear spoiler to help keep the arse down.

[Cudwieser]

There is a remarkable recall history around the world. I have to ask Kiff if Opel were made recall some of their cars about 4-6 years ago due to slipping handbrakes? It happened in the UK with Vauxhall and the companies being related I'm wondering if there was a contamination.

 

For those that aren't aware, vaukhall owners were appling the Highway Codes pratice of pushing in the button on the parking brake before engaging, but this was wrong practice for use of vauxhall handbrakes which the driver was supposed to simple pull to engage so that the ratchet was constantly and correctly engaged. If the driver pushed the release button in first (as instructed by the Highway Code to maintain integrety of the handbrake mechanism) the pawl would fail to engage the ratchet. This lead to cars parked on a grade to roll and cause damage. GM (owner of Vauxhall and Opel) fought the issue but were forced to recall affected cars and compensate owners who they initially accused of mal-practice for not simply pulling on the brake (a common if ill-advised practice).

 

 

P.s I've another question. I have heard advice that incase a parking brake fails that a car should be left in gear that opposed the grade it is on. I am suspect the truth of it, but if for example but park a car pointing down the hill, will parking in reverse retard or stop the roll if the brake fails? If so how (or why not)?

 

I do believe the advice of parking with the wheels turned into the curb though.

[sivispacem]

The Audi TT recall was a more substantial one as the vehicles were sent back to the factory in Hungary and the ESP system was fitted amongst others...

The accidents were fatal and it was due to the fact of next to no downforce on the rear axle.

As I said above, this is fundamentally false:

 

 

...The TT was never "unsafe", Audi intentionally dialed in a degree of lift-off oversteer to make it more sporting. When a number of high speed accidents happened due to driver error and they were getting negative publicity, they decided to replicate the understeer biased handling of earlier Quattro badged Audis and adjusted the rear bump, camber and rebound to basically remove it, instead resulting in chronic understeer and woolly handling.

 

Several people have reverted TTs to pre-recall specification and they apparently drive much better.

The whole case is an example of the press turning an effective non-event into a nonexistent public safety issue. Inherently, the characteristics that apparently made the TT "unsafe" are dialed in to many of the best hot hatches of all time- the 205 GTI, RenaultSport Clio 182/182, Integra DC2- as well as any mid-engined RWD vehicle by design. It's fairly well catalogued in enthusiast circles that the physical set-up of the pre-alteration suspension is actually better from a handling perspective than the "rectified" setup; much less prone to front end wash and understeer. http://www.ttforum.co.uk/forum/viewtopic.php?f=2&t=76276&sid=b7a1a00060c33d810b02022a0b5d7daf

 

It also wasn't really a "recall" as it was voluntary, rather than mandatory.

[Cudwieser]

That's a good point. In the UK at least it was never mandated. In saying that a lot of recalls aren't mandated unless there is a distinct safety concern such as the toyota acellerater fix and as I mention before, the vauxhall parking brake fix. I've had at least one recall notice for my corolla regarding a possible wiring fault in the airbag. Not a safety concern in the accepted sense, but certainly not mandated. All it largely means if something goes wrong then it is the fault of the owner for having been told as opposed to the fault of the maker for not telling.

 

Having said that a partial onus lies with Audi for the fishtailing TT. While no law can mitigate stupidity (except the laws of natural selection) if a car was designed to be sporty while the expectation was to be safe then Audi should have done some homework for thair own end to see who might actually buy the car and how they were likely to drive it.

 

Out of curiousity, have there been many mechanical recalls across they world?

[Dottie]

Across the world, yes (even for very small issues). But not all of them are documented

Edited October 31, 2015 by Dottie

[sivispacem]

Having said that a partial onus lies with Audi for the fishtailing TT. While no law can mitigate stupidity (except the laws of natural selection) if a car was designed to be sporty while the expectation was to be safe then Audi should have done some homework for thair own end to see who might actually buy the car and how they were likely to drive it.

It's less of a failure of general market understanding and more due to the completely unfathomable market appeal of the TT. I don't think it was every thought likely to be the massive sensation it actually became.