Talk:Timing belt (camshaft)

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I restore the inline external links because they are "references". I don't like commercial links in Wikipedia anymore than than the next person, but the article contains non-obvious facts (Kevlar, 1945, etc) and references should be cited. If you have better references for those facts, we can replace the commercial links. Samw 00:57, 13 May 2005 (UTC)

Question: Is it all about cars?[edit]

Ok timing belts exist in almost every car, and although this is that most common place that "normal" people would see them they are not only used in cars. The article must be expanded using mechanical information of their operation and other common usages. —Preceding unsigned comment added by (talk) 22:22, 13 May 2011 (UTC)


Is it true that not all cars, e.g. Ford Fiesta Encore, have a cambelt? If so, how is this so? Gwaka Lumpa 12:21, 30 April 2007 (UTC)

The 1.3 Endura-E engine used in the Mk. IV Fiesta is an OHV or "pushrod" engine which just has a small timing chain, and is not considered a part that requires servicing (there were several other engines in the Fiesta too). I'm not sure if this is the case with all pushrod engines, or if they're still interference engines or not - I think this needs to be clarified in the article. --Zilog Jones 16:09, 8 October 2007 (UTC)

Question: Timing belt Alternative for bicycle[edit]

Timing belts "never became popular" as a bicycle chain alternative. Why? Is the timing belt less efficient than the bicycle chain? Why is it popular in cars? Is the timing belt more efficient, or does it have a longer life, or is it cheaper to produce, or does it have less wear on the cam?

Thanks in advance. Nov 18, 2007 pashute

With a timing belt design on a bicycle, one could not change gears such as that on the chain driven bicycle. —Preceding unsigned comment added by (talk) 18:42, 26 March 2009 (UTC)

Of course you could. You'd simply need a [Derailleur] NipponBill (talk) 02:58, 28 March 2009 (UTC)
Thing is, this belt would no longer be a timing belt! A timing belt is timing the opening and closing of engine valves. What you are talking about is a toothed belt. More to the point, timing belts are just one use for toothed belts. Drive belts are another. Therefore, the redirect from Toothed belt to Timing belt should be deleted, a new article Toothed belt should be created and Timing belt be merged into it! Only then would we actually be correct on this topic. Justsail (talk) 09:46, 30 March 2009 (UTC)

I do not think there is a difference between the toothed belt and the timing belt. Timing belts are also used in printers, plotters, photocopiers and other instruments /equipments where slippage is unwanted or cannot be tolerated. Of course the name comes from the applications in automobiles and the article is heavily biased in this direction. The catalogs for timing belts and pulleys testify that.

I think (not sure) the bicycle with a timing belt failed not for economic or performance reasons. The problem is probably a marketing problem.

It is obviously cheaper to produce and less noisy in use.

Ck.mitra (talk) 19:13, 13 July 2009 (UTC)

On a total aside... the reason toothed belts aren't used widely on bikes is because the belt/chain must pass around the seat or chain stay. A belt cannot be unlinked like a chain, so the frame would have to have a cut in it to get the belt on and off...unless of course the driven cog was OUTSIDE the frame. —Preceding unsigned comment added by (talk) 16:30, 28 July 2010 (UTC)


YA I WANTS CAUSES POSSIBLE FOR IT —Preceding unsigned comment added by (talk) 03:53, 1 August 2008 (UTC)

apparently belts are less efficient than chains

Water pumps replacement when replacing the timing belt[edit]

I believe the following section should be included:

On cars where the water pump is driven by the timing belt, some technicians may recommend replacing the water pump during a timing belt job even if there is nothing wrong with the water pump. This is because most of the labor to change the water pump has already been done with the timing belt job

While the article is about timing belts and not car maintenance, I would suggest that the majority of general readers that encounter our "timing belt" article is when it fails and they are looking for information about the maintenance of timing belts. When their mechanic advises them to replace the water pump at the same time, they can't help but wonder if their already very large bill is being padded. What harm is there in including this extra bit of information? If there is a more appropriate article to include this tidbit of information, can you please suggest it and perhaps we can cleanly link it in? Otherwise, I propose we restore this piece of information. Samw (talk) 13:25, 27 October 2010 (UTC)

It's not only in there, it has been included twice.
This section doesn't belong, mostly on quality issues:
  • It's unreferenced. That one ref doesn't really hold up.
  • The topic is mostly a huge confusion between timing belts and serpentine polygroove belts. Engines where the water pump is driven by the timing belt (and not a serpentine belt) are rare as hen's teeth.
Don't know where you've been, but timing belt driven water pumps are common on European and Japanese imports, Volvos, Audis, Hondas. And since most of these also have interference engines, if your water pump bearing goes, so does your timing belt and then so does your engine.Cloudswrest (talk) 02:56, 28 October 2010 (UTC)
If by "Volvo" we mean the Volvo modular engine, I've got a 960 2.5 myself. 200k miles, no idea how many cam belts, and still on the original water pump. Like I said, pump life is far longer than belt life. Cambelt driven pumps aren't unknown, but they're still less common than ones driven by the polygroove belt. Any discussion of valves that digs up that whole "interference engine" malarkey as if that's a bad thing has descended into Bubba and Billy Bob arguing over their V8. Andy Dingley (talk) 10:46, 28 October 2010 (UTC)
S70 Tbelt.JPG
I have a Volvo S70 with 230K+ miles on it. The t-belt has been changed twice and the water pump once. The factory recommendation is to change the water pump every other t-belt change. Here is a picture looking up from the right wheel well. The bottom is the crank shaft, directly above it is the tensioner, to the left is the water pump (note, it's just several bolts to remove it if you've already gone this far), to the right is the idler roller, and at the top are the two camshaft sprockets. The Volvo S70 I5 2.5L engine IS an interference engine. It's not "malarkey".Cloudswrest (talk) 18:32, 28 October 2010 (UTC)
So what's your point? Of course there are engines with timing-belt driven waterpumps. There are also engines with polygroove driven pumps, where mechanics give just the same advice on much the same grounds. None of this is changed by the incidence of such engines being either "rare" or "common". So long as some engines in the mass market are using them (which we both agree is the case) then the question is legitimate, and both its answer and appropriateness for inclusion here isn't swayed by this.
As to "interference engines", then I'm just tired of Bubba and Billy Bob mechanics in the US putting this forward as a reason not to trust them dang furriners with their funny exploding engines. If an engine isn't an interference engine, I ask myself what sort of echoing great tiny-valved inefficient combustion chamber design does it have? I think my lawnmower is still a non-interference design, but even my pre-war OHC crossflow MG is. Andy Dingley (talk) 23:26, 28 October 2010 (UTC)
  • It's unclear what our position is. Should pumps be replaced? Or are we warning against a scam?
  • It's unclear if this is justified. What's the service life on a belt, and the MTBF of a pump. On my cars (and I've had cars with timing belts since Fiat twin cams (strangely unmentioned here) in the '70s), the pump life is >4 times the belt life. It makes no sense to swap a pump that should out-last several belts, even if the "labour outweighs parts" argument holds up. There's no sense in doing something for cheap, if it doesn't even need to be done.
When (If!) I ever get time to do some research on this, for current production cars, based on real references (Bosch handbook for starters), I would like to re-write it. A re-write that might still end up reversing the current statement, or deleting it entirely. Andy Dingley (talk) 22:47, 27 October 2010 (UTC)

Timing Chain[edit]

Timing chain should not be redirected here, but rather have a page of it's own, or this artical split as "Engine Timing Mechanisms" with belts and chains. The chains point here but only gloss over their role or details. Why redirect "Timing Chain" to this belt artical when the chains - as I have on my own car and they do have unique and different features than belts - are uncovered in any meaningful way nor discussed at all other than "or chains as in older cars...".

They used plastic gearing to quiet chains over belts. Prone to failure, solid medal ones were aftermarket accessories. Durability. More expensive and harder to access, but again not needed to be accessed nearly as often.

Some things that could be elaborated on, but if not mentioned, take the cross reference out and put the creation of "Timing Chain" out in the open as one of Wiki's "help create" articles. Redirecting from one thing to something unrelated to the item itself merely frustrates the reader and undermines the whole effort that Wikipedia embodies. And on the whole it's all too common; not just on this issue. —Preceding unsigned comment added by (talk) 23:36, 28 April 2011 (UTC)

Should be obsoleted[edit]

Why do timing cam belts and chains still exist today? Modern automobiles are highly electronic, so it would be simple to actuate invididual petrol engine valves via direct computer control, using solenoids or piezo crystals for each one. That way engine tuning could be continously adjusted on the move, to minimise fuel consumption and exhaust pollution. Today even the steering wheel goes like electric.

If not electronic, the engine's vales could be hydraulically actuated, eliminating the rigid machanical link of a cam belt or chain. A lot of cars have hydraulic type brakes and steering wheel boosters. (talk) 14:30, 20 March 2012 (UTC)

They're simple, they're cheap, they work. Even better they're also reliable and work pretty well.
One alternative system is to use pneumatic actuation of the valves. Some Formula One engines do this, but it's unlikely to appear on everyday road cars any time soon. Andy Dingley (talk) 14:48, 20 March 2012 (UTC)
This discussion doesn't have anything to do with how to improve the article. Please avoid general discussions. Wikipedia is not a forum. See WP:TPG. -- JoannaSerah (talk) 17:27, 20 March 2012 (UTC)

Time to arrange the articles - Wrong title[edit]

As mentioned by a number of others also with a wide experience it is a bit disconcerting to look up timing belts and get a slap in the face with an automotive cam shaft timing belt.

What is jarring is the pretence that 'cam belt' is the primary use of 'timing belt'

The last sentence of the head is also just bad. The belts had trade names like Synchroflex etc. when they were developed because they were intended for timing, they were not called 'CamFlex'.

The popular usage is probably in automotive but it should not be the encyclopaedic usage. Toothed belts were invented for timing long before the conservative automotive industry was interested in gambling on the new technology.

Much of the discussion here exists because the page is incorrectly titled. With a bit of show of support changes could be implemented pretty easily. It is clear that something needs doing.

The way it is now is that it glosses over the bulk of the applications and the rich history and development of timing belts in favour of one popular usage.

[[1]] Standards exist for timing belts that are not automotive biased

Relevant Standards
The British Standard for timing belt drives was
BS 4548:1987 :Specification for synchronous belt drives for industrial applications . This standard is still in use but is declared as obsolescent the current standard in europe for timing belt drives is
ISO 5294:1989: Synchronous belt drives -- Pulleys
ISO 5296-1:1989:1989: Synchronous belt drives -- Belts -- Part 1: Pitch codes MXL, XL, L, H, XH and XXH -- Metric and inch dimensions
This is not equivalent and belts and pulleys to the British Standard are not interchangeable with the ISO standard.

[[2]] Timing belt invented in 1945

[[3]] timing belt introduction in early 1950's

[[4]] new processes for timing belts in 1952

[[5]] start manufacture of timing belts in 1957

[[6]] first production car to use a timing belt in 1962

To clarify what others have suggested perhaps the following with links where appropriate, some of these are quick to create category pages but I am not a power editor yet.

timing (mechanical)[edit]

describes gears, chains, toothed belts, linkages, cams, pneumatic (many of these pages exist I expect)

belts (mechanical)[edit]

this article is actually very well done until one clicks on the 'timing belt' link Extract the 'toothed belt' section to a new page or redirect to relevant section here

toothed belt[edit]

or add to section on belts (mechanical) page with a redirect, describing the use of teeth to prevent slip and transmit additional torque and point to 'timing belt' when indicating the synchronous nature of the non-slip feature. Indicate the fact that most synchronous applications have integer multiples of teeth on the synchronised shafts (motor shafts can have teeth that give convenient ratios to step numbers or engine speeds).

timing belt[edit]

with a pointer to PUPULAR useage of 'cam belt', 'camshaft timing belt' and 'engine timing belt' that goes to a cleaner version of current page. The timing belt article can then focus on the history, standards, specifics of the various tooth profiles (there are many), materials and pitches that have been developed over the years for timing on mechanisms in general and point to the engine cam timing article when sections can be better addressed there like the rare automotive usage of double sided timing belts to gain synchronous drive on both sides of a serpentine belt (Porsche I think uses one)

This page should not be part of WikiProjects Automobile which is why there is such confusion with the editing and the heavy bias. — Preceding unsigned comment added by Idyllic press (talkcontribs) 10:09, 9 April 2012 (UTC)

cam belt[edit]

move the current article here and make sure any homeless links redirect to this page until they are properly created. as this is possibly a valid term in some locale it can serve as an unambiguous primary page and mention other names; popular and technical as required. Add the automotive history and valve damage here where it would be relevant. Link to engine timing and timing chains as required.

engine camshaft timing[edit]

pointing to timing gears, timing chain, camshaft timing belt, mention push rod, tappet, OHC, side valve, hydraulic variable timing (Alfa Romeo 159i and Alfetta GTV), discuss formula one electronic valve timing

10:04, 9 April 2012 (UTC)

hi i want know the diffidence between timing pulley belt drive and gear drive — Preceding unsigned comment added by (talk) 10:04, 26 November 2012 (UTC)

Rename this page to Cam Belt[edit]

The informative section in the wiki page Belt (mechanical) points timing belt incorrectly to this camshaft timing belt or cam belt page.

Time for a change in the name of this page (or move the content to camshaft timing belt or cam belt with links or disambiguation from here), this change will cause the other changes to follow automatically as the mess is cleaned up. Idyllic press (talk) 07:45, 4 March 2013 (UTC)

  • weak oppose These are all plausible names, but I'm not seeing sufficient reason to favour one as canonical over the others.
If we had an article for timing belts (i.e. the non engine-specific toothed belts used in many machines) then we might have more reason to move things around. Until then, no. Andy Dingley (talk) 10:11, 4 March 2013 (UTC)

What is the point of reference 4?[edit]

Reference 4 only points to a complaint of a car owner about a timing belt failure. It does not bring any benefit to this article. And in the communication between the car manufacturer and the owner the issue with timing belt aging is ignored (1998 car, failure in 2005 so failure after 7 years where timing belt replacements are usually recommended on 5 to 6 years). — Preceding unsigned comment added by (talk) 08:35, 13 May 2013 (UTC)

-But has the belt actually been changed?[edit]

A point related to Reference 4, I think, is that an increasing number of vehicles have timing covers designed in such a way that belt inspection is too difficult to be carried out as part of a normal service or pre-purchase inspection.

I don't have figures for the prevalence of this, but I know I've been lied to in the past about belt age, by a seller who was no doubt aware that checking his claim would be nearly as difficult as changing the belt. --Anteaus (talk) 13:34, 6 July 2014 (UTC)

Wet Timing Belt Designs[edit]

Several articles mention that the Ford 1.0 3 Cylinder Ecoboost engine utilizes a unique timing belt design where the belt is actually lubricated by engine oil. I am not sure if Ford (or any other manufacturer) is applying this to any other engines. I would guess that in these cases the timing belt is made from more oil-resistant materials, and may have a different replacement interval. Cascade1988 (talk) 03:41, 10 October 2014 (UTC)Cascade1988