Honda Going Back To Timing Chains?

Tmning chains seldom wear out, seldom break, and seldom cause your valves to turn into interesting forms of dramatic scuplture.

Belts on the other hand...shrug..thats what they generally do if you dont replace them regularly. With some effort, cost and down time.

Gunner

I've lost the belt on a Civic and the chain tensioner idler on a CB350. In both cases there was no significant damage to the rest of the engine.

A year ago I replaced the timing belt on the 91 Ranger and knocked loose at least one well-concealed electrical connector plus sucked some air into the valve lifters by turning the camshaft backwards slightly. Getting it going again took probably three days work, spread over a year and including machining more custom tools and parts. A helpful mechanic with access to a paid site printed out a wiring schematic that was much more useful than the one in my Ford shop manual since it wasn't spread across a dozen pages and cluttered with all possible options.

jsw

On Sun, 06 Jun 2010 04:35:44 -0700, Gunner Asch wrote the following:

And since most new engines rely on interference fits for the highest performance, a slipped or broken belt means a new engine. I'll bet they went back to chains to be able to do the "100k warranty" thing.

P.S: I disabled my gmail filter once again, so I see you once again, mon.

-- It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change. -- Charles Darwin

Probably for the same reason they use thin oil and roller rockers etc.

- less friction. Here's a good read on the tech that's required to get top fuel specifics.

Wayne

And that replacement is a $700 job at the dealer. Our new Kia Sorento uses a chain also, and that is the motor destined to power other models. I just replaced the belt on our Sedona, what a huge job, it's easy to see how they charge $700. Good riddance to timing belts.

Subaru went to a timing chain on their 6 cylinder boxer. Speculation is that it cut about 2" off the length of the engine and let them shoehorn it into existing body styles.

I think it is more likely because people are pissed about timing belts. They have been around long enough that a big group of people have found out that a $39 tune up is required at a 100,000 miles, but a $600+ timing belt is required at 60,000 miles. And when the belt brakes, it causes major inconvenience. I do not think anybody makes an interference fit motor anymore, as they had to warrantee replace a bunch of motors. People find out a motor requires a $700 fix at 60k miles, they go to the competitors car.

Years ago, I was touring a Saturn dealers service facility while negotiating the purchase of my current vehical. The salesman wanted to impress me that they could service my vehical, I saw a mechanic that looked like he was changing out a timing chain/tensioner.

So I asked him what is wrong with this car, he said, they didn't change the oil often enough.

I will not buy an car with a belt driving the cam shaft. I still remember the periodic working on a buds Fiat X19.

Belts are fine when it is easy to change them out.

Wes

-- "Additionally as a security officer, I carry a gun to protect government officials but my life isn't worth protecting at home in their eyes." Dick Anthony Heller

In article , snipped-for-privacy@Gmail.com says..

I remember when they first appeared. Ford of England used them on the BDA engine (Belt Drive series A). My first one was on a Pinto 1600 engine.

The belt could be changed in 10 minutes. First, the engine was not sideways, so you could get at it. Second, it wasn't even under a cover. Third, you did not even have to remove the crank pulley.

Then they added a belt retainer under the bottom of the belt, so you had to remove the crank pulley to slide the belt out. Then added complex dust covers. Then they made the belt drive other things, like water pumps. Then they put them on front wheel drive cars where you had to remove all kinds of things, including the two or three piece front engine mount, which uses 4" long bolts and there is only 3 7/8" of clearance between the engine and inner fender.

I just did the one on my Kia Sedona, and the basic job was going fine, it was as straightforward as any I have done. Then I removed the four 4" long motor mount bolts. And the mount didn't budge. Nada. After searching on online forums, I discovered there is a fifth motor mount bolt that comes from the front, sideways to the rest of the bolts. It is not mentioned in the repair manual. This requires that you remove the alternator. Which requires the radiator to be moved forward. Which requires the upper front cross member removal and part of the intake air duct and loosening the air condioner lines and stretching them to the max to allow the passage of one alternator bolt.

That one stupid extra motor mount bolt doubled the time required to do the job, and no other car I have done has had a bolt needed in that location.

snipped-for-privacy@citlink.net wrote: ...

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"timing chains seldom ..." - you must be out of your mind - timing chains always wear out, taking the larger gear with them - I've had to change them on my 38 plymouth, 36 cadillac, 59 cadillac, and twice on my 51 dodge - newer ones hold up better, but they still go bad - and they are much harder to change than a belt - I've seen plenty of catastrophic timing chain failures but the usual failure is not that the chain breaks, rather that it stretches and cuts the teeth off of the cam gear.

even more nonsense - any performance motor will be an interference fit motor as you call it - how could it not be and get decent compression - econobox motors for little toy cars don't need the performance and can afford the extra clearance but check ANY car you consider to be high performance - BMW, Audi, Corvette, Porsche, Lotus, Ferrari, Bentey, you choose -

those cars you named, probably none have a rubber timing belt, and when you figure a $800 tune up for the Porshe etc. they are not in the same league of the cars we are talking about. the econoboxes pocket the pistons, etc, so if the belt breaks the valves do not hit.

Maybe you should have changed the oil more. The only street car with a timing chain failure I have had in 50 years was a Chevy Luv P/U. And that was a tensioner failure.

I replaced the timing chain in a '66 GTO YS 389 V8 engine because the timing was off. If I had waited, it would have broken. I replaced it with a double roller sprocket racing chain. It was a quick job, in spite of one of the Woodridge keys falling into the oil pan. A bent hanger and 30 seconds of fishing dragged it out. It took under a half hour, and most of that time was spent scraping off the old gaskets.

That's the only one I've replaced, and I've driven a lot of high mileage vehicles.

Belt guards serve a valuable purpose in keeping crap and stones etc away from the belt. More than a few cars without covers have found this to their cost. On a well designed engine they are quite easy to remove, I've mainly done a few FIAT/Lancia twin cam engines and they were quite straight forward, the Lancia Delta having the least clearance in the engine bay and so being the most trouble for that mm or 2 clearance isse.

On Sun, 06 Jun 2010 20:54:18 -0400, DT wrote the following:

You often wonder if the suits forced the engineering team to futz one up so the dealerships remained busier, don't you?

-- It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change. -- Charles Darwin

From 1996 - The Designer The designer sat at his drafting board, A wealth of knowledge in his head was stored. Like "What can be done on a radial drill, Or a turret lathe or a vertical mill?" But above all things a knack he had, For driving gentle machinists mad. So he mused as he thoughtfully scratched his bean, Just how can I make this thing hard to machine? If I make this perfect body straight, The job had ought to come out first rate. But it would be so easy to turn and bore, That it would never make the machinist sore. So I'll put a compound taper there, And a couple of angles to make them swear. And brass would work for this little gear, But it's too damned easy to work I fear. So just to make the machinist squeal, I'll have him mill it from tungsten steel. And I'll put these holes that hold the cap, Down underneath where they can't be tapped. Now if they can make this, it'll just be luck, Cause it can't be held by dog or chuck, And it can't be planed and it can't be ground, So I feel my design is unusually sound. Then he shouted with glee, "Success at last! This goddam thing can't even be cast!" Gerry :-)} London, Canada

my 911 has a timing chain - actually two of them, but it does have a rubber cogged belt to drive the power steering pump. However, my 944 (in fact all

944s) have a "rubber" timing belt - of course it's not rubber really, but it's the black flexible stuff - the 944 uses two of them, one for timing and water pump, one for balance shafts - I change them at 30K intervals. Audi TT has "rubber" belt also, only one - the manual says the change interval is "120,000 miles" - but that's a mistake, they forgot to change from KM to miles - major lawsuit as virtually every belt broke before the change - in my case, only 16 of 24 valves destroyed. so, no, in this case you are wrong - performance cars use timing belts, they use them because they are lighter, have less inertia, and are quieter than chains. But, with the cost of labor, and so many folks not knowing which end of a screwdriver is which, I can see why cheapie cars aiming for reliability might go back to a chain.

That said, the $800 tuneup cost on a 911 is mostly the labor to get at the plugs - I work pretty fast and it takes four hours to get there, then about

5 minutes to change 12 plugs, then four hours to put everything back - mostly you have to do things like remove mufflers, sheet metal, etc - it isn't as annoying as on a cheapie car because the instructions tell you what to do, and it's all pretty reasonable, just tedious - no like those vegas where you had to remove a wheel and drill a hole in the fender..... >