Cheap way to find if loose timing belt trashed engine?

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#1

Apparently the tensioner on my lower timing belt died, with the possibility that the engine is now trashed, because it’s interfering. The garage says they can’t determine if the valves crashed without about $800 worth of labor to tear the engine down. (But they’ll buy it off me for $80.) Isn’t there a cheap way to find out if the valves crashed?


#2

One of my pet peeves (I have many) is when a shop says that an engine must be diassembled to inspect for valve damage when something like this happens. Not.
Several things can be done.

Remove the valve cover or upper belt cover, set the cam lobes on No. 1 to where both valves are closed (or should be if they’re not bent), remove the No. 1 spark plug, and apply compressed air to the cylinder. Intake valves are the ones that get bent so if there’s a problem you should hear air hiss out the intake.

With the valve cover off look at the valve lash on a cylinder (No. 1 with both lobes allowing the valves to be closed for example) and note if the lash (clearance) is excessive. A bent valve will not close of course and this in turn means the lash will be excessive.
Hope that helps.


#3

That does make a lot of sense. Thanks! I’ll be taking it up with the shop in the morning.


#4

I can speak in defense of the shop that tells you they cant determine the exact level of damage without a teardown (but not 800.00). Yes valves will be bent but you dont know if the cylinder head is damaged beyond repair or if a piston is broken. You can bet for sure there is some damage.


#5

Replace the belt and tensioner and try to turn the engine over by hand. If that goes OK, try to start it…If that goes OK, run a compression test.


#6

Granted, a complete analysis could not be done without at least a partial teardown but the way I read this is that they’re wanting 800 bucks to simply determine if the valves whacked the pistons.

This can be easily determined with very little tear down of anything. If it’s then determined that valve damage exists then it’s decision time as to whether to spend some fairly serious money on the car or not; all without running up a bill just to be told that it’s junk.

Just wondering if the car in question is a free-wheeler that they’re offering 80 bucks for…


#7

Where is this $80 car? I might be interested…

I’m also curious what kind of car this is. Lower timing belt? Huh?

If they are unwilling to test the engine in the manner suggested by our friend from Oklahoma, find another shop ASAP.


#8

Ok, first of all, I mis-spoke: Timing chain. Second, it’s a 2002 Chevy Tracker, 4 cylinder, 4wd, with about 100,000 Michigan miles on it. Lost a bit of power pulling into a grocery store parking lot, starter just spun when I came out.

Greenville.


#9

Why don’t you consider the problem is with the starter? Timing chain events are more than a loss of a little power.