What Are the Advantages of Automotive Timing Belts？

Timing Belt - Advantages

• Precision registration and timing with no loss of high torque carrying capability
• Minimal vibration and chordal effect
• Positive slip proof engagement
• Wide speed range, especially important when the entire speed range is developed from a single source
• Virtually no elongation (stretching) due to wear
• High mechanical efficiency, as much as 98% when properly maintained. By contrast, chain drives are in the 91-98% efficiency range, while V-Belts average in the 93-98% range.
• Power transmission efficiency is not lost with use
• Clean operation, no need for lubrication
• Reduced noise
• Long, dependable trouble-free service
• Excellent abrasion resistance
• Rust resistant
• Resists chemicals and contaminants
• Increased drive design options
• Weight savings
• Safety issues
• Economical operations:
  • No need for expensive drive enclosures
  • No need for lubrication systems
  • No need for tensioning devices
  • No adjustment needed due to stretch or wear
  • No cost for lubricant or disposal fees
  • No worn sprocket replacement
  • No ongoing maintenance costs for roller chain
  • Energy savings
  • Reduced costs associated with "downtime" on top of lost productivity

Timing Belt - Disadvantages

Our own experience has shown that the timing belt is not perfect in every situation when comparing it against a chain drive. Being able to recognize timing belt limitations helps us to educate our customers in making the right decisions on their particular applications needs.

You will get efficient and thoughtful service from SBT.

• Availability of numerous chain sizes allows for the use of smaller pitch diameters and/or number of teeth while achieving the desired ratio
• Higher speeds and power capacities
• Detachable chain links make installation easier in some instances
• Need for accurate initial alignment of drive components
• No slippage
• Higher drive ratios at shorter center distances
• Lower bearing loads
• Less affected by temperature or humidity
• Less affected by oil and grease

I always hear about the disadvantages of a timing belt and how it is a $300 job every few years or so, depending on miles driven. Other disadvantages include you being stranded with a non-running engine until the belt is replaced or the worst case of an essentially trashed engine from the valves crashing into the pistons or vice versa.

Are there any real advantages to these compared to timing gears or chains? Are they better for fuel economy due to a lighter mass or is there any other practical reason for them besides getting you into the shop for a replacement or worst case a new car if you neglect them?

Conor

Not In My Opinion, Not To The Car’s Owner, Although Some Will Be Offered Here, I’m Sure.

I quit buying cars with timing belts several years ago, right after I wrestled my last one into my 3.5L Intrepid V-6, out in the driveway over a couple of days, purchased and home-made special tools and all.

They’re silly, really.

CSA

This topic has been beaten to death, and the consensus is that if there is an advantage, it really isn’t worth it.

Please see http://community.cartalk.com/search?cx=partner-pub-%3A2yk2yg-lkla&cof=FORID%3A11&ie=ISO--1&q=timing+belt+advantage&sa=Search

I think I am the only person to make a case for the advantages of a belt, and even I realize calling these items “advantages” is a stretch. In the end, the only real advantage is that replacing your water pump at the same time as the timing belt means your water pump will never get a chance to fail, and if you’re lucky, your mechanic might find and repair other items that might otherwise fail or cost you more money as a separate job, like a leaky gasket or seal inside the timing belt housing.

BTW, if you can really find someone who will do a full timing belt job for $300 (with the whole kit, not just replacing the belt), take advantage of that opportunity and thank your lucky stars. On many vehicles, timing belt jobs range from $450 (on my Civic) to $900 (on some minivans). You really should get the whole kit, which includes the tensioner pulley and sometimes other important items, depending on the model.

I see. I have heard timing belts slapping covers before as well as chains on the early ’s Dodge 3.9L V6 engine commonly used in the Dakota. Those Dodge engines all clack loudly at idle and I was driving a friends to get some parts at AutoZone. The AutoZone manager told me that I had a knock like a wrist pin or rod. I told them that they all sound like this and I don’t recall many of these engines catastrophically failing. That can’t be said for other Dodge engines such as the 2.7L used in Intrepids and similar. I am not a huge MOPAR person overall.

I got home and looked it up. There is some defect where the chains on the 3.9L slap against the inside of the timing cover and clack at idle/no load. They solved in the later '90’s and you can refit the older trucks with a timing set from the newer models if you like but most people just drive them.

Contact us to discuss your requirements of Automotive Timing Belts. Our experienced sales team can help you identify the options that best suit your needs.

Additional reading:
Are You Overlooking These Signs of BMW Suspension Wear?

Anyway, I am all for the chains myself as they seem to last the life of the vehicle. I was curious if the lower rotating mass of a belt might have increased response or mileage.

Conor

I’ve heard people say they’re quieter, but never the manufacturers. Usually it’s someone offering an explanation for why they’re used.

Bottom line; they’re cheaper. Fortunately, I think customer dissatisfaction has led to manufacturers not using them as frequently. It seems that everything new has chains.

Cwatkin, your comment about the greater mass is insightful. It’s true that lower mass needs less fuel to get moving, and since engines accelerate often in normal driving that would make sense.

Its purely cost. When they were first used, new car buyers kept their cars about 3-4 years and the belt would last 4 years, so belt replacement was not a concern to the new car buyer. The manufacturer doesn’t make any money off the second owner so they are not concerned.

A first owners started keeping their cars longer, the manufacturers began increasing the life span of the belts through better materials. As long as the initial purchaser traded the car before the belt change was due, it was not a concern for the manufacturer.

It finally became a concern for the manufacturers when their customers began to hold onto the car for 10 years. Belts can be made to last that long by using more composite materials and silicone rubber, but it appears that it is cheaper to use a chain rather than upgrade the belt materials.

I have heard the “quieter” argument in relation to timing gears. My parents had a Pontiac LeMans V-8 that had nylon timing gears. The timing gears failed and steel replacemetn gears were installed. I couldn’t hear any difference in the engine sound. The Chevrolet my dad owned had some kind of fiber composition for the timing gears. Again, the argument was that these fiber composition timing gears were quieter. Chevrolets of this vintage with the “Stovebolt” 6 engines were known to have timing gear failure. Fortunately, these engines were not interference engines. The tappets in these old Chevrolet engines were often so noisy that any noise of the timing gears was drowned out anyway. r
Both the Toyota 4Runner V-6 we own and the Toyata Sienna V-6 we own have timing chains and I haven’t been bothered by noise from this set up.

I recently got a Geo Metro 1.0L 3cyl for gas mileage and it has a timing belt. The job on this takes like 1-2 hours to do by myself. That is a $35 kit with Gates belt, new timing seals, a tensioner/idler, etc. I went ahead and replaced the water pump which was also $35 at the same time.

Now these little cars are essentially the modern day VW bug if you can consider something 20-30 years old “modern” and are super easy to work on. Everyone says, “I bet that is a pain to work on with lots of small/tight spaces.” It is actually like working on an old pickup under the hood as it is easy to do just about anything. I can change an entire engine by myself in like 4 hours without a hoist. All I need is a car jack and a metric socket set!

Conor

A timing belt has its drawbacks but also some great benefits. A V engine with overhead cams, especially dual overhead cams, is much cheaper to manufacture but it is also much cheaper and simpler to repair than the chain drive model. Ford Windsor V 8s were notorious for tossing chains at 80,000 miles with manual transmission and 120,000 with automatics and even that simple, non interference engine required longer to replace the chain than a Hyundai, Mazda, Toyota or Nissan V-6 T-belt. And a Mazda 929 was an easy 2 hour job.

And let a Toyota R-22 chain slip while the head is off. That slip will cost you dearly. And BTW, check the flat rate time to replace the timing chains on a Jaguar 4.2L or Mercedes V-8.

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