Why do modern car engines have different types of bolt type heads like Torx etc?

[SillyOldDufferModerator @sillyoldduffer]

Posted by JA on 29/07/2023 09:53:03:

What has Malthus got to do with bolt heads?

This topic has been taken for a good walk!

JA

I plead guilty to contributing to thread deviation, M'lud.

In mitigation, I claim to have suggested the best engineering reasons for mixing threads and heads on the same modern engine.

I don't believe it's done simply to screw-up home mechanics, because different heads are found far deeper inside the engine than maintenance normally goes. Things like the bolts holding water-pumps and the alternator together, those fixing the oil pick-up to the engine block inside the sump, fixings inside the cam-block, and those connecting cranks to the crankshaft, or that anti-harmonic thingy. Anyone on the forum ever completely dismantled an entire engine?

The engine in one of my early cars, a Talbot/Chrysler Sunbeam, or maybe a Horizon, contained a wild mixture of US, imperial and metric bolts. I think this resulted from the dreadful mess the British car industry was in at the time, where part of the answer was seen as collaboration between previously independent manufacturers in the same group. Chrysler owned what had been Rootes in the UK and Simca in Europe. Building on existing assets Chrysler UK produced a number of cars, as did others, from parts sourced from around the world. Not sure how long this went on, but many of the 'British' cars I drove during the seventies and eighties had both Imperial and Metric thread types, indicating mixed heritage. Due to being in terrible financial trouble makers couldn't afford to design new cars and engines from scratch, and had to make the best of what they already had. In the long run, not good enough, when foreign competitors have brand-new production facilities and haven't trashed their relationship with lenders, staff, and government!

Pretty sure this kind of financial pressure doesn't explain why universally metric modern engines mix hex, torx and other heads. As far as I know all modern engines are made with lots of different heads, reason unclear.

Dave

[Michael GilliganParticipant @michaelgilligan61133]

As the old saying goes “ you could write a book” just about Torx

… for convenient reference though; the Wikipedia page provides a reasonable summary:

**LINK**

https://en.wikipedia.org/wiki/Torx

MichaelG.

[Howard LewisParticipant @howardlewis46836]

Industry seems to manage pretty well using 8 mm heads on M6 fasteners, and 10 mm hexagons on M8 fasteners, in high volume production situations. Maybe they use better quality spanners and sockets?

You can bet thta some one will have done their sums to compare the strength of the hexagon against that of the thread.

I wore out a cheap 7/16 socket, but not the Britool one that replaced it

You get what you pay for, ultimately.

Howard

[VicParticipant @vic]

I’ve not read the whole thread so apologies if someone else has mentioned it but apparently some Japanese motor bikes have five sided head bolts.

[Pete.Participant @pete-2]

Torx Plus (IP) not the 5 sided are quite simply the best internal fasteners, they're amazing, there's probably a long list of reason manufacturers haven't switched over to using them as a norm, hex fasteners are decided by manufacturer quality and the quality of sockets used on them too, I've given a few of my sockets a rough measure.

The top photo is a Snap Flank drive FDX 16mm socket, these are made to precise tolerances, and show exactly 16mm.

The second photo is a middle of the road 14mm impact socket that shows 14.2mm

The third photo is a 12mm Taiwanese blue point socket showing 12.2mm.

The fourth photo is a standard snap on flank drive 16mm showing 16.14mm

[Pete.Participant @pete-2]

If you're even semi serious about mechanical work it's best to keep every possible fastener type socket to hand, a good selection of Snap On ratchets never hurt anyone either.

[Pete.Participant @pete-2]

Posted by JA on 29/07/2023 09:53:03:

What has Malthus got to do with bolt heads?

This topic has been taken for a good walk!

JA

I apologise, I need to wait to be upgraded to Moderater status before making random off topic comments and calling people nutters, luckily Neil likes me 😂 so it won't be long.

[JAParticipant @ja]

Dave & Pete

Apologies not accepted.

I rather like watching topics being taken for a good walk. It is one of the beauties about "Tea Room" topics.

Perhaps this is a future subject.

JA

[duncan webster 1Participant @duncanwebster1]

Godwins law says that all internet discussions eventually get round to Adolph Hitler and the Nazis. The civilised members of this forum have avoided that so far!

[Michael GilliganParticipant @michaelgilligan61133]

Now look what you have done, Duncan

MichaelG.

[Nick WheelerParticipant @nickwheeler]

Dave, the further into an engine you get, the less likely it is to find unusual fasteners. I wouldn't consider 12point male heads to be unusual for things like conrod bolts.

The worse offenders for this German, as they seem to have a competition for who can use the most different fasteners, seemingly scattered around at random.

[BazyleParticipant @bazyle]

You don't really want a 16mm socket to be precisely 16mm or it won't fit on a bolt head that had a little more plating.
I have a 5 sided socket extension bar and wondered what it was for. Thanks for that info above.
Bear in mind that a car is an assembly of modules made in various places. A factory making say heater assemblies will make a batch taking 3 days. Then a batch for another car maker for two days etc. They will not want to change the tooling on the assembly line and will charge if they have to.
So the production engineers make sure the designers use what the factory prefers to save costs. Fighting against this is the design office wanting to use 'what we used last time' to avoid the management complaining they are holding up the schedule.
Meanwhile the bolt salesman is offering both factory and designers special deals to try to trap them on their product. Then the company MD gets taken to lunch and golf and declares that something else is the preferred product and production is switching to his brother-in-law's factory.

When we first switched to 'security' screws on a product it came as a surprise to field operations that thousands of field engineers needed the special screwdrivers. EEEK!

[Pete.Participant @pete-2]

Posted by Bazyle on 30/07/2023 12:54:22:

You don't really want a 16mm socket to be precisely 16mm or it won't fit on a bolt head that had a little more plating.

Never had that problem with them fitting, they're designed as specialist socket to stop rusty fasteners rounding off, after rusting they reduce in size slightly, they also do less visual damage to bolt heads that are aesthetic like motorcycle fasteners that you don't want looking marred up.

[Pete.Participant @pete-2]

Posted by Bazyle on 30/07/2023 12:54:22:

You don't really want a 16mm socket to be precisely 16mm or it won't fit on a bolt head that had a little more plating.

So a sample of plated and stainless fasteners

Photo 1, 13mm plated bolt

Photo 2, 10mm plated bolt

Photo 3, 13mm stainless bolt

Photo 4, 14mm plated bolt

Photo 5, 11mm plated brake pipe union

Photo 6, 13mm plated brake pipe union

Photo 7, 13mm OEM bolt from BMW if my memory serves me.

Believe it or not, Snap On as a tool manufacturer knows what they're doing.

[Howard LewisParticipant @howardlewis46836]

Re five side fastener heads.

Had just told a potential supplier that were not looking for anything out of the way.

"We don't want five sided heads"

Looked at a Japanese Fuel Injection Pump, and saw that it had five sided heads on the fasteners.!

The governor shaft on the Bosch EPVE injection pump was retained by fasteners with triangular heads.

Guess the only source of a socket? DON'T ask the price!

Howard

Edited By Howard Lewis on 30/07/2023 23:06:51

[John Doe 2Participant @johndoe2]

Posted by duncan webster on 27/07/2023 16:53:39:………..

We really ought to clamp down on long haul flights. My brother in law has had short trips to both Vietnam, Japan and Colombia this year. In comparison my pootling around locally in my car is chicken feed. There is no tax on aviation fuel.

I already try to use the train for long trips, it's cheaper than driving. My next car will be electric, when I bought the current petrol one 10 years ago electric were a much less practical option

Aircraft worldwide contribute only 4-8% of global CO2, whereas surface ICE transport produces around 30%. So it is far more pressing to reduce personal ICE use.

However, for this to happen, viable alternatives need to be introduced first. Forget HS2, we should be re-laying all the rail branch lines ripped up by that idiot Beeching. And only allowing new houses to be built within half a mile of a railway line, and new railway stations built to serve those developments, to reduce personal ICE use. Forget the extended London ULEZ until sensible transport alternatives are available, and I don't mean electric cars that cost far too much for just a motor and a battery. They should cost much less than an ICE car.

And why are cars with large engines still being produced and still legal to be sold? There should have been an immediate cap of, say, 2 litre size for new car engines, and a cap of 1 litre size in 5 years' time, then a total ICE ban after that. Streets could be wired for charging by lifting the kerb stones and replacing them with purpose cast curb stones to accommodate electrical cables and charging posts.

As far as cars having different fasteners; many components are bought-in, not designed and built by the actual car company, So the fasteners used throughout an engine and engine bay will very likely be a mix, depending where each component comes from.

[SillyOldDufferModerator @sillyoldduffer]

Posted by Nick Wheeler on 30/07/2023 12:34:20:

Dave, the further into an engine you get, the less likely it is to find unusual fasteners. I wouldn't consider 12point male heads to be unusual for things like conrod bolts.

The worse offenders for this German, as they seem to have a competition for who can use the most different fasteners, seemingly scattered around at random.

I wondered if anyone had made a youtube video of an engine being dismantled so we could count them! Of course they have – there are loads of 'em.

'I do cars' is entertaining, but it's not easy to count different bolt head types and sizes, other than 'several'. And I was led astray by the many other interesting details!

This example may be of interest because it's the Ford Eco engine steviegtr reported, where the internal fabric belt frayed and blocked the oil feed. There was some discussion on the forum about chains versus belts. ECO Video here. (https://youtu.be/0yx1-50iqnA)

Now I've seen how a Ford Eco engine is built, I don't know what the designer was thinking! My guess is the belts did 150000 miles in a test rig, but there's something different about what happens inside a real engine, or that a different belt was used. In principle protecting a belt inside an engine not intended to last longer than the car is good, but if it goes wrong, bad things happen!

Back to why different heads are used, perhaps production convenience is a factor. Maybe on a production line, a robot puts in a set of triple-square bolts for an engineering reason, (high-torque needed), and then bungs in a few unrelated others because they happen to be in the right place at the right time, even though plain Hex heads would be more logical. The opportunity to speed production could save more money than resetting to use cheaper bolts, or fitting bolt heads that suit maintenance work!

Dave

[duncan webster 1Participant @duncanwebster1]

The southern section of the West Coast main line is full, so they can't shift more freight to rail. At present any hiccup causes major disruption. If instead of selling HS2 on speed they sold it as extra capacity it would make a lot more sense. To increase capacity on WCML they'd have to close it for years. What is ridiculous is putting it in tunnels when they don't have to just to please the nimbies. Not only has it massively increased the cost, I can't think of a much worse place to have a train accident than in a tunnel. It costs massively more to build infrastructure in this country than in comparable European countries. This needs to be addressed. According to the press we have spent more on planning enquiries for a proposed Thames tunnel than Norway spent on actually building a very long tunnel, and Boris's garden bridge cost £15 million before it was abandoned without turning a sod.

This doesn't mean I disagree with reopening some of the lines that Beeching closed. Times change. Beeching did what the government tasked him with. Ernest Marple was minister of transport. He made his money building roads. Nuff said? 

Edited By duncan webster on 31/07/2023 15:01:49

[JAParticipant @ja]

Duncan

I like the change of subject following John Doe 2's posting! I agree with every you have written.

I have been in a railway accident in a tunnel, the Severn Tunnel. While I would not wish it on anyone, it was a very interesting day and it hurt.

JA

[Nick WheelerParticipant @nickwheeler]

Posted by SillyOldDuffer on 31/07/2023 10:29:08:

Posted by Nick Wheeler on 30/07/2023 12:34:20:

Dave, the further into an engine you get, the less likely it is to find unusual fasteners. I wouldn't consider 12point male heads to be unusual for things like conrod bolts.

The worse offenders for this German, as they seem to have a competition for who can use the most different fasteners, seemingly scattered around at random.

I wondered if anyone had made a youtube video of an engine being dismantled so we could count them! Of course they have – there are loads of 'em.

'I do cars' is entertaining, but it's not easy to count different bolt head types and sizes, other than 'several'. And I was led astray by the many other interesting details!

This example may be of interest because it's the Ford Eco engine steviegtr reported, where the internal fabric belt frayed and blocked the oil feed. There was some discussion on the forum about chains versus belts. ECO Video here. (https://youtu.be/0yx1-50iqnA)

Now I've seen how a Ford Eco engine is built, I don't know what the designer was thinking! My guess is the belts did 150000 miles in a test rig, but there's something different about what happens inside a real engine, or that a different belt was used. In principle protecting a belt inside an engine not intended to last longer than the car is good, but if it goes wrong, bad things happen!

This LINK is a good example of what we're talking about. And while I agree that the wet timing belt is a terrible idea(ours was done last year at over £1500), the Audi Vee timing chains are a different nightmare especially when you see how the Japanese do them.

[John Doe 2Participant @johndoe2]

Posted by duncan webster on 31/07/2023 14:58:34:

The southern section of the West Coast main line is full, so they can't shift more freight to rail. At present any hiccup causes major disruption. If instead of selling HS2 on speed they sold it as extra capacity it would make a lot more sense. To increase capacity on WCML they'd have to close it for years. What is ridiculous is putting it in tunnels when they don't have to just to please the nimbies. Not only has it massively increased the cost, I can't think of a much worse place to have a train accident than in a tunnel. It costs massively more to build infrastructure in this country than in comparable European countries. This needs to be addressed. According to the press we have spent more on planning enquiries for a proposed Thames tunnel than Norway spent on actually building a very long tunnel, and Boris's garden bridge cost £15 million before it was abandoned without turning a sod.

This doesn't mean I disagree with reopening some of the lines that Beeching closed. Times change. Beeching did what the government tasked him with. Ernest Marple was minister of transport. He made his money building roads. Nuff said?

Edited By duncan webster on 31/07/2023 15:01:49

For what it's worth, to get HS 2 past Wendover in Bucks, there is simply no physical room beside the road bypass, the existing Chiltern line railway, the electricity pylons, and the existing housing, for a new track to run, so digging a tunnel under the existing houses is the only way through.

And as far as NIMBYs are concerned, people are very quick to condemn NIMBYs, but think about if it was your own garden fence that a new high speed rail, (or road or housing), development was being built on the other side of. Would you welcome the intrusion with open arms, given that your life would be made unbearable by the noise every 15 mins?? Or would you prefer it to be tunnelled or sited elsewhere so that you could sleep?

Tunnelling-in such close-by sections will make life more bearable for all, and certainly should not be begrudged.

What annoys me is that back in the day, our government refused EU money to build such new transport links, because they apparently thought it would 'look bad' to accept the funds. So we have saddled ourselves with the full cost, and it's too late now.

[John Doe 2Participant @johndoe2]

Posted by Pete. on 30/07/2023 00:38:13:

If you're even semi serious about mechanical work it's best to keep every possible fastener type socket to hand, a good selection of Snap On ratchets never hurt anyone either.

Agreed, but Snap-On tools really hurt my wallet !!

[Pete.Participant @pete-2]

Posted by John Doe 2 on 06/08/2023 18:27:46:

Posted by Pete. on 30/07/2023 00:38:13:

If you're even semi serious about mechanical work it's best to keep every possible fastener type socket to hand, a good selection of Snap On ratchets never hurt anyone either.

Agreed, but Snap-On tools really hurt my wallet !!

They are a bit on the pricey side, I used to buy most of my stuff from someone selling it privately on behalf of an official dealer at seriously knocked down prices, because they have areas their franchise is only allowed to operate in, so whoever it was just got a friend to sell it for them.

All my hand tools have paid for themselves by avoiding garage fees, having worked briefly in a garage when I first left school I've seen first hand the attitude some have to the unaware and ignorant regarding pricing of jobs, and the standard of work by people you wouldn't trust checking your tyre pressures, sadly it's still an industry that attracts a lot of unscrupulous people so I'll continue doing my own work and use it as an excuse to buy more toys, I means tools as and when not really but kinda needed.

[duncan webster 1Participant @duncanwebster1]

Search for Godwin's law, if I knew how to do it on a mobile phone I'd add a link, but that's black magic to me

[Author]

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