posted 05-17-2011 11:02 AM                  

If the timing belt lets go while the engine is running, the valves stop opening and closing. Some will remain open and some closed depending on where the valvetrain stopped. At the same time, the momentum of the bottom end (pistons, crankshaft, etc) keeps the bottom end spinning for a while = the pistons keep moving up and down. Since the rest of the valvetrain has stopped, those valves that remain open or partially open will be hit by the pistons in an interference engine.

posted 05-22-2011 12:59 PM                  

quote:

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Originally posted by padroo:
I just finished replacing my timing belt, radiator hoses, heater hoses, oil change, serpentine belt, v belt and fresh antifreeze. Those hose clamps are a real pain. I had to order another 3 jaw puller to pull the harmonic ballancer, I have a stack of 3 jaw pullers but none would fit the tight space to get the job done. Car only has 6900 miles on it and is a 1999. Chaged old rubber parts as an insurance policy even though everthing I removed looked good.

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posted 05-22-2011 08:29 PM                  

This is the procedure to install the timing belt that I used.

Locate the cam gear timing marks and the one on the crankshaft. Rotate the crankshaft to align all three marks. Then remove the tensioner from the engine and remove the belt.

Starting from the crankshaft gear, install the belt working in a counterclockwise direction. Tip: jam something under the belt under the crankshaft gear so the belt will not slip off its gear. Next, go around the drivers side cam gear with your belt. You have to make sure it is tight between the crankshaft and the first cam gear. Tip: Rotate the cam gear just enough so you can get the belt on the cam gear then rotate it back to the timing mark and make sure it is tight and on the timing marks. Tip: This is very high tech, take two cloths pins and clip them to the cam gear to hold the new belt in the cam gear and still tight and on the timing marks. Next install the back side of the belt around the water pump and then to the next cam gear. Using the same procedure of rotating the cam gear slightly then putting the belt on the cam gear then rotating back making sure there is no slack between the cam gear, water pump and first cam gear. Install two more clothes pins to hold it in place. Now look at what you have, all three timing marks should be in time and there should be no slack until you get to the other side of the second cam gear. Install the cam gear around the tensioner and the belt is in place. Take the tensioning device and compress the plunger in a very large vice. There are alignment holes that will line up and I used a small allen wrench to hold the plunger and removed the tension from the vice. Install the tensioner with the two bolts and torque to specs. Remove the allen wrench with force and it will put tension on the new belt for the first time. Check your three timing marks, then rotate the crankshaft two full revolutions and stop the crankshaft timing mark on TDC. The cam timing marks should be lined up also, you are done. If you keep the belt tight and the marks in alignment you will get it the first time. Pat yourself on the back!

posted 05-31-2011 11:05 PM                  

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Originally posted by padroo:
My wife's ex called after we got into this timing belt thing and said his girlfriends 1995 VW Cabrio jumped time and the bill is $2900 dollars. No one ever told them the belt should be changed (ignorance isn't necessarily bliss). It had 80,000 on it. I don't have details about the damage.

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posted 06-03-2011 07:11 AM                  

Besides mileage there is a time factor.
Belts are made of rubber
Rubber degrades and rots

Usual rule of thumb is XXX mileage and/or 7 to 10 years, whichever comes first.

This would make EVERY KAT SOLD now due for a timing belt and tensioner change!
My experience has shown that the tensioner fails more than the belt does with the same disasterous results!

Most of the cars I now specialize in and sell are older Volvos.
Most are 1998s thru 2004 so almost every one of these I buy now I do a belt unless that nice large sticker is on the top f the engine showing it's been already done.
Luckily these motors are easy to do and my cost is only about $275, (incl labor) but most cars are FAR more complicated and more expensive to do.

(My personal jewel. 2000 V70R. VERY rare, AWD, quick, the most comfy car in the world and only 30K original miles.
ECU flash 310 hp. sway bars plus a bunch of other hidden upgrades.
I realize that this probably does not excite anyone here but what the hell!)

This would make EVERY KAT SOLD now due for a timing belt and tensioner change!