Timing Belt Replacement

Retired VIP wrote:


There were also cars built in the 1990's that used chains where the chains often failed sooner than timing belts needed replacement, for example the Saturn S series which had so many chain failures that they were being replaced as preventative maintenance. Instead of a repair costing $100-200 (typical timing belt replacement cost when the dealer has a service special) you were paying upwards of $750 for a chain, tensioner, etc. It actually was "the engine lasted the life of the timing chain." However if the owner heeded the warning signs of chain problems, they were okay (increased noise). The problem is that many drivers don't realize there's a problem when they drive the car every day and the noise increases just a tiny bit at a time.

There are advantages to belts as well. They are quieter. They are more reliable for long runs (typical in many engines these days), and they are less expensive to replace.
Actually what would be good is to buy vehicles with non-interference engines.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Exactly how does such an engine differ from the other type?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

An interference type motor is one where the pistons and valve can collide in the event of a timing belt/chain failure. A non-interference engine is one where these parts do not run into one another.
As a general rule of thumb, if the compression ratio is high, then the pistons and valves can run into one another; if the compression ratio is low, then these vital parts will not get in each others space.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jeff Strickland wrote:

They can put relief divots in the pistons for the valve edges to clear, but my understanding is that that causes emissions problems.
Funny how in "the old days", compression ratios were a lot higher, and I don't remember this interference being a problem. Maybe it wasn't a problem because the cams were driven more reliably (short chains or gears, pushrods/not overhead cams), so we were not aware of the interference as a problem in and of itself, though technically the engines were interference design?
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

The relief in the tops of the pistons can sometimes creat hot spots at the edges, which can cause knocking/pinging. The relief isn't there in case the timing belt/chain breaks; it is there because the angle of the valves prodruding into the combustion chamber would strike the piston under normal operatng conditions.

Back in the old days, if the timing chain broke, major engine damage was often the result, but although there were exceptions, cars often didn't last 200,000 miles, so some other failure retired the car before the timing chain broke.
--

Ray O
(correct punctuation to reply)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I do remember the old push-rod engines would 'float' their valves if you over-revved them. It would often result in bent valves or cracked pistons. Miss a shift and you got an expensive lesson in performance shifting.
Jack
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Retired VIP wrote:

Ahh! There you go. So maybe they were in fact interference, but since we didn't have timing belts to break, the average driver wasn't forced to be aware of it. But yeah - now that you mention warnings against floating the valves, that does have a familiar ring to it.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jeff Strickland wrote:

It is very common in cars these days for the water pump to be driven by the timing belt (or chain as the case may be). Two of the three cars I presently own (Chrysler 2nd generation LH cars are that way - one with timing belt, one with timing chain).
It bugs me that they did that with the engine that has a timing chain, because otherwise the timing chain could be expected to be undisturbed for the life of the engine. AS it is, just changing the water pump is a semi-major operation running $600 or $700 - and the common logic is that while you're in there expending all that labor to get to that pump, you might as well replace the chain (and of course the tensioner pulley), since the labor for doing that is free. But, likewise, on the engine that has the timing belt, the water pump is routinely replaced at the timing belt change interval of 105k miles (because of the labor).
The pressure on the auto manufacturers is high for very tight integration of the components - driving the WP with the timing belt or chain is tighter integration.
Bill Putney (To reply by e-mail, replace the last letter of the alphabet in my address with the letter 'x')
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jeff Strickland wrote:

It's very common on Hondas. I know the Neon did this as well.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

We had this discussion before...
According to Gates' web site, an example of Toyotas with a water pump that is driven by the timing belt: 95-04 Avalon 83-01 4 cyl Camry 88-04 V6 Camry
You can go to the web site, look at the automotive timing belt replacement guide, and look for vehicles with the # sign, which indicates a water pump that is driven by the timing belt.
--

Ray O
(correct punctuation to reply)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Ray O" <rokigawaATtristarassociatesDOTcom> wrote:

But those who know just enough to be dangerous can't help themselves.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Jeff Strickland generally posts useful information although they are sometimes IMO a little overly complex. If there is a shortcoming in the information he posts, it is that some of it tends to be more applicable to BMW's and Jeeps than Toyotas, or that the assumption is that everyone does it the same way as BMW and Jeep.
--

Ray O
(correct punctuation to reply)
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message

Not exactly.
I assume that if one understands the concepts, he can work through the particular arrangement he migh tfind on his own car.
My experience is more in US domestic products, but I find that while the parts might change, the stuff those parts do remains pretty much the same. The physical arrangement changes a little bit, but the concept remains constant.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
"Ray O" <rokigawaATtristarassociatesDOTcom> wrote in message

You've ruined Shmuckland's exquisitely stupid generalization. Nice work.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

You're a complete idiot. He did not ruin anything. He gave three specific examples of the answer to the specific question asked. I have not encountered these three engines, so I have never encountered a water pump drivne by a timing belt/chain.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

And yet, you made a pretty definite statement about the RARITY of belt-driven water pumps, as if to say that if you haven't seen something, it barely exists.
"I have never seen a waterpump driven that way, they have always been driven by a fan belt or the serpentine belt. It is far easier to drive a water pump from outside the motor than from inside, this would make it very rare to drive a water pump by using the timing belt."
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

So?
Three of hundreds, perhaps thousands, of engine designs is rare.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Jeff Strickland wrote:

Driving the water pump from the timing belt is now the rule, rather than the exception.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Where do you come up with three?
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
On Sun, 08 Jun 2008 19:07:44 -0500, aarcuda69062 wrote:

(It's called Phat Phingers...)
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.