timing belts are crap

Plug

Run_to_da_hills wrote: »

I have a 1939 flathead motorcycle since the 1982 and still have it roadworthy, It has never overheated, siezed or left me on the side of the road with dropped valves. It depends on how these engines are treated, if they are gunned by some moran flat out they will obviously burn out exhaust valves as with any engine if mistreated.

If I was given a bike to travel across the world I would choose this configuration of engine because any back street workshop in India or Pakistan equipped with a vicegrip, hammer and chizel can work on it not like the modern junk that requires a "computer" to get it going.

Are motorbikes on diagnostics aswel? Didn't know that.

unkel

As I think I said in another thread, belts suck

groupb wrote: »

My mx5 has a belt but its a non interferance engine.

Are you absolutely sure? There are versions of the engine of my car that are interference and others that are non-interference

A wise man suggested to me to treat all engines as interference unless you know for sure it is not

Seth Brundle

Plug wrote: »

Once you change your timing belt over your recommend milage then nothing will happen.

That is not true! Belts can go at before or after the recommended mileage!
I connot recall a thread about a timing chain snapping!

Plug wrote: »

I dont think they have a tensioner but they do stretch and thats the sad reality.

Here is the diagram for my timing chain.
It has tensioners as do most chain driven engines.

Anyhow, AFAIK the main reason that belts are used over chains is down to cost!

Plug

kbannon wrote: »

That is not true! Belts can go at before or after the recommended mileage!
I connot recall a thread about a timing chain snapping!
Here is the diagram for my timing chain.
It has tensioners as do most chain driven engines.

Anyhow, AFAIK the main reason that belts are used over chains is down to cost!

I never heard of a belt snapping unless it went a good bit over the milage mark to get it replaced. It probly has happened but I can't see how, this part isin't under extreme pressure anyway.
I would also think the labour replacing a timing chain would be higher.

Run_to_da_hills

zilog_jones wrote: »

What happens when a timing chain breaks in a pushrod engine? I assume it's a lot less likely to happen than in one of those newfangled yokes, due to the chain being a lot smaller.

Are there any pushrods left besides the big american V8s? I know the Ka hasn't had them since 2003, but what about Skoda? Anyone else still living in the past?

There is no timing chain in a push rod engine. Extended rods are used to open and close the valves. Leyland Minis, later Micky Minors and most classic British Motorcycles used pushrods. The only drawback would be if the tappets came so loose that the pushrod popped our or sometimes got jammed and bent if dislocated. In most cases if the push rod gets dislocated the valve would remain shut and there would be no damage to the piston. http://en.wikipedia.org/wiki/Overhead_valve

Seth Brundle

@ plug
http://www.boards.ie/vbulletin/archive/index.php/t-2054901570.html
Im sure there are more but I couldn't be bothered going through them.
http://www.google.ie/search?hl=en&safe=off&client=firefox-a&rls=org.mozilla%3Aen-GB%3Aofficial&hs=8ud&q=timing+belt+snapped+site%3Awww.boards.ie&btnG=Search&meta=

Run_to_da_hills

Plug wrote: »

Are motorbikes on diagnostics aswel? Didn't know that.

Yes unfortunitally most modern Jap would require a computer to get them tuned right. Not long ago I came across a lawnmore with computer management chip built in :eek:

Oilrig

"best 8v engine imo, will do 185 bhp with a few mods"

Not with 8 valves it won't... a genuine 145 is really pushing it, and it gets REALLY expensive if you want reliability...

Belts should be consigned to history IMHO, they came, we tried, they failed.

With modern era engineering and lubrication the old problems with chains are not an issue.

BMW got rid of belts in the early/mid '90's, the logic was that a chain will last the life of the engine - a belt won't.

Chains don't get upset when they're contaminated in oil, they don't ingest stones etc and more importantly nowadays, they cut down on maintenance costs.

Plug

kbannon wrote: »

@ plug
http://www.boards.ie/vbulletin/archive/index.php/t-2054901570.html
Im sure there are more but I couldn't be bothered going through them.
http://www.google.ie/search?hl=en&safe=off&client=firefox-a&rls=org.mozilla%3Aen-GB%3Aofficial&hs=8ud&q=timing+belt+snapped+site%3Awww.boards.ie&btnG=Search&meta=

:eek: gutted to him but at least ford paid for the damage. I wouldn't think it random snapping is common though.

Run_to_da_hills

Oilrig wrote: »

"best 8v engine imo, will do 185 bhp with a few mods"

Not with 8 valves it won't... a genuine 145 is really pushing it, and it gets REALLY expensive if you want reliability...

Belts should be consigned to history IMHO, they came, we tried, they failed.

With modern era engineering and lubrication the old problems with chains are not an issue.

BMW got rid of belts in the early/mid '90's, the logic was that a chain will last the life of the engine - a belt won't.

Chains don't get upset when they're contaminated in oil, they don't ingest stones etc and more importantly nowadays, they cut down on maintenance costs.

Ford had a serious problem with timing belts snapping in the 1.9 diesel blocks they were using around 1989. Rather than do a major recall they kept on producing this engine and offered a heavily subsidised timing belt replacement service every 40K, Im sure any Ford mechanic could do them with their eyes shut!. They have learned their lesson and have fitted timing chains in all their mark 6 & 7Transits!

crosstownk

Belts v Chains. It makes no odds to the average punter. Belts are cheaper to design and install, but require periodic replacement which costs the customer over the ownership period. Chains which are more expensive to install at factory level cost the customer at the point of vehicle purchase but have less maintenance from there on.

Both need tensioners. Belts use the pulley tensioner and chains use a static 'plate' type tensioner. Lada Rivas were well known for needing tensioners as the chain used to cut into the tensioner in a big way.

Ultimately a chain is better, imo. It is less inclined to just snap without warning - a chain will make a racket if the tensioner goes wrong which will give the driver some warning - assuming the driver is listening......

I'd favour a chain, but I would have to say that belts are almost as good nowadays.

As for the noise argument, I'd be inclined to agree that belts are, by their nature, more noisey. But modern technology and soundproofing techniques make this point irrelevant.

bushy...

Chains are also used to vary timing ( on purpose) , some porsches , audi etc use basically tensioners at each side of the chain , by taking slack from one side or the other they get a few degrees +/-.
Unless someone has a good new idea , sidevalves are for old things & cement mixers etc , pushrods can perform well, Mercedes used carbon fibre ones to show off at one stage.

zilog_jones

Run_to_da_hills wrote: »

There is no timing chain in a push rod engine.

The timing chain in my pushrod Fiesta would like to have a word with you

Even the WP article you linked says they can have chains:

...a pushrod engine has the camshaft positioned next to the crankshaft and can be run with a much smaller chain or even direct gear connection.

Oilrig

"Ford had a serious problem with timing belts snapping in the 1.9 diesel blocks they were using around 1989" IIRC this was down to incorrect tension - the dreaded whine of death...

"The timing chain in my pushrod Fiesta would like to have a word with you" Brings back memories

crosstownk

Oilrig wrote: »

"Ford had a serious problem with timing belts snapping in the 1.9 diesel blocks they were using around 1989" IIRC this was down to incorrect tension - the dreaded whine of death...

"The timing chain in my pushrod Fiesta would like to have a word with you" Brings back memories

The rattling noise from those Ford pushrod engines would put me off buying one . OHC is so much quieter.

Run_to_da_hills

zilog_jones wrote: »

The timing chain in my pushrod Fiesta would like to have a word with you

Even the WP article you linked says they can have chains:

I would not be familiar with this engine, It probably has a small chain in place of the normal timing gears. The large majority of pushrod engines would have operated their pushrods directly from geared driven cams and followers.

Oilrig

"The large majority of pushrod engines would have operated their pushrods directly from geared driven cams and followers."

Guess you're used to bigger diesels?

groupb

unkel wrote: »

As I think I said in another thread, belts suck



Are you absolutely sure? There are versions of the engine of my car that are interference and others that are non-interference

A wise man suggested to me to treat all engines as interference unless you know for sure it is not

Thats what I've read in the repair manuals , but now you've got me worried. I rarely change gear below 5,500RPM unless I'm around town.(its not a muppet motor).Anyway I'm off to read the manual again.

Senna

2 things, I've a non-interference engine (3sge), but i've been told that this isn't a guarantee, if it snaps a high revs, it can still do damage. Is that true?

also, i had a K11 micra, it had a timing chain, but Nissan still said it should be replaced every 60k miles. Is this just there way of getting out of responsibility if it snaps?
but I never did replace it, had 130k when i sold it:D

groupb

Phew! just checked the net and yep mk1 1.6 mx5's have a non interferance engine according to the mx5 clubs , but thanks anyway. Better to be sure before I visit the red line again.

Run_to_da_hills

Oilrig wrote: »

"The large majority of pushrod engines would have operated their pushrods directly from geared driven cams and followers."

Guess you're used to bigger diesels?

Yup,:) I served my time as a mechanical fitter with the Irish Lighthouse service, mostly stationary diesel gen sets and small marine. ie Lister/Petters, Ruston Hornsby, Yanmar, Cummons and after that worked on marine in the States. The only small stuff would be my own transport ie transit van and bikes.

groupb

Run_to_da_hills wrote: »

Yup,:) I served my time as a mechanical fitter with the Irish Lighthouse service, mostly stationary diesel gen sets and small marine. ie Lister/Petters, Ruston Hornsby, Yanmar, Cummons and after that worked on marine in the States. The only small stuff would be my own transport ie transit van and bikes.

So did I. Left in 98'. I miss playing with those listers. Now exposed to the world of belts and chains.

Run_to_da_hills

groupb wrote: »

So did I. Left in 98'. I miss playing with those listers. Now exposed to the world of belts and chains.

I left in 89 on a years leave of absence and never went back I learned more about playing cards on the Conningbeg when we should have been ripping those listers apart

kona

Oilrig wrote: »

"best 8v engine imo, will do 185 bhp with a few mods"

Not with 8 valves it won't... a genuine 145 is really pushing it, and it gets REALLY expensive if you want reliability...

Belts should be consigned to history IMHO, they came, we tried, they failed.

With modern era engineering and lubrication the old problems with chains are not an issue.

BMW got rid of belts in the early/mid '90's, the logic was that a chain will last the life of the engine - a belt won't.

Chains don't get upset when they're contaminated in oil, they don't ingest stones etc and more importantly nowadays, they cut down on maintenance costs.

your right 180 is a bit much it will run more than 140bhp, a 1275 A-series block can be bored and stroked to about 1526cc
add a 290degree race cam, a crossflow head, webber carb, turbo charge it and run about 10psi, it will be pusing 160bhp, a shot of nitrous would push it up to 180.
sure you wont be able to drive it on the road, and you will be tearing it apart no end, but it will do it.
the A-series will reliably push out around 110bhp.

but still amazing power range in the A-series 30bhp to 160bhp. designed in 1952 revised in the 80s and ceased in 2000

Stephen

Senna wrote: »

also, i had a K11 micra, it had a timing chain, but Nissan still said it should be replaced every 60k miles. Is this just there way of getting out of responsibility if it snaps?
but I never did replace it, had 130k when i sold it:D

Funny that, nissan did seem to have massive problems with the Almera eating timing chains every 40k or so!

And speaking of timing belts... My ould fella had a brand new Volkswagen Derby around 1980 or so and its timing belt snapped within a couple of thousand miles. Did some pretty nasty damage to the engine too.

galwaytt

Plug wrote: »

Ok see the first black thing I think there is a tensioner on the left of that but maybe I'm wrong, you can see the same thing on the third black thing.
Anyone know what the black things are called?

trying really hard to i.d. that engine, it looks like a bike engine, running hivo timing chains, dry sump ?......and being a 'simple' v-twin......mmmmmmmm

Anyhoo, the 3rd item your referring to, is also a tensioner, this is because the engine you're looking at has two timing chains - left and right cyls are controlled separately - that's too long a run for a single chain. If you look carefully at the crank, you'll notice one chain behind the other. So, yes, if you need to strip l.h. one..........you have to strip r.h. one as well.

As for the whole tb vs chain thing: belts are used for cost and - noise. Current noise levels mean everthing is open to diagnosis for sound levels. That's why BeeEmm use composite cam/ valve covers on so many engines - it dampens the sound. And why your engine is completely covered in plastic covers these days. It's getting to the stage you do roll past the sound test in neutral, at tickover, and still be worried about passing the test !

The other is weight and space. You can loop belts into much smaller radii than chains - witness VAT 1.8t. Belt from crank to cam, and chain from cam 1 to cam 2. To make 'twin-cam' style chain would be too big/heavy(inertia)/too much space. VAG used the best of both, keeping the tb (relatively) un-serpentine, by running to a single pulley, and letting chain do the rest of the work.

This also allows, btw, convenient variable valve timing.

My 968 has a belt tb, and cam 1 to cam 2 is by chain. The tensioner on the chain in the head is actively adjusted whilst the engine is running, to change cam timing. By varying the 'length' of chain (for want of a better word) between the two cams, by pushing the tensioner in/out, you change the valve timing duration.

Yes the Mazda '5 has a non-interference engine - you can snap as many belts as you like, the valves won't hit the pistons....... + 1 for Mazda. I don't see why everyone else isn't doing it.

And it's not just a mileage thing - belt's life is expressed as mileage (for simplicity) or AGE. Rubber perishes. That low-mileage, pristine, garaged car, is just as, if not more likely, to break a belt than a well used one........

Seth Brundle

galwaytt wrote: »

trying really hard to i.d. that engine, it looks like a bike engine, running hivo timing chains, dry sump ?......and being a 'simple' v-twin......mmmmmmmm

If I'm not mistaken, its the S85 V10 from the M5 and M6.

This thread has reminded me of one time marshaling at Rallycross in Mondello and Dermot Carnegie's focus was having technical gremlins all day. Eventually (at the last corner) there was a noise and he coasted to a halt so myself and another marshal went over. All Carnegie could say was "theres a 10 grand anchor for you"! Timing belt snapped.

groupb

Run_to_da_hills wrote: »

I left in 89 on a years leave of absence and never went back I learned more about playing cards on the Conningbeg when we should have been ripping those listers apart

Spill timing and bumper clearances. I think I'm still deaf from the noise in that engine room. By the way , it must have been the only deck of cards with 5 aces.

Biro

Oilrig wrote: »

"best 8v engine imo, will do 185 bhp with a few mods"

Not with 8 valves it won't... a genuine 145 is really pushing it, and it gets REALLY expensive if you want reliability...

Belts should be consigned to history IMHO, they came, we tried, they failed.

With modern era engineering and lubrication the old problems with chains are not an issue.

BMW got rid of belts in the early/mid '90's, the logic was that a chain will last the life of the engine - a belt won't.

Chains don't get upset when they're contaminated in oil, they don't ingest stones etc and more importantly nowadays, they cut down on maintenance costs.

Someone should tell Toyota that... when I had the celica I was told the timing chain was getting rattly, 84k miles on it only... Toyota garage recommended changing it, at a cost of €900...

Run_to_da_hills

groupb wrote: »

Spill timing and bumper clearances. I think I'm still deaf from the noise in that engine room. By the way , it must have been the only deck of cards with 5 aces.

We can still put in a substancial claim for deafness , the Lanbys were worse. Were you there when W.O B was left out on the lightship during a tea break and rowed ashore on an inflatible life raft? (this was when they used the disk for the launch i.e. pre mobile phone days.)