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magari
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Broken timing belt

Post by magari »

This was a seriously close call. My wife has been driving my GTV6 and she told me the car was making a funny noise. I started the engine and saw what I thought was maybe a mouse stuck to the timing belt.

Once I tore it down, it was no mouse. So I got to spend yesterday doing the timing belt thing. New belt, water pump, spark plugs / well seals, belts, valve cover seals, and had the radiator rodded. All in all about $450 in parts.

But that's a whole lot cheaper than bent valves. I think the main crank gear skipped a tooth, since both cams were timed together, but were out of time by one tooth to the crank.

I posted some pic's, what an odd break in the belt.

I know there are some people out there who don't use timing belt covers, but I do. So it wasn't a case of no cover and something damaged the belt. This belt and pump had only 3 years and maybe 15,000 miles on it at the most since I did them last too. The pump looked great, and probably didn't need replacing.

One thing that I HIGHLY recommend is the use of anti seize on every bolt that is used for the water pump, including the thermostat housing. When I did my pump 3 years ago, I encountered 4 broken bolts. I fixed them all and used anti seize when replacing. It made the water pump R&R a breeze, with no broken bolts.

I was going to retorque the heads too, but the bolts were so tight I didn't want to loosen them. It was over 100 ft lbs to loosen them, and the torques setting was supposed to be 75 ft lbs. I don't have a problem, so I didn't want to create one.

It runs perfect again. No apparent damage done.
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Doug

1986 3.0 GTV6
1991 Spider
Greg Gordon
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Re: Broken timing belt

Post by Greg Gordon »

It sure looks like foreign object damage, but it's hard to say for sure. Even with the timing belt cover, something could have worked its way in there.

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Re: Broken timing belt

Post by Mats »

Since you could see the timing belt I assume you are running without a cover? I'm going to have to agree with Greg: FOD.
Mats Strandberg
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Re: Broken timing belt

Post by MR2 Zig »

On the V6 you can see the belt and timing wheels from the rear of the engine.

While the covers take care of the stuff coming at the front if something bounced around just right....

I agree that this looks like FOD...a bolt that fell out maybe????

zig
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magari
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Re: Broken timing belt

Post by magari »

When the belt covers are properly in place, you can see the belt from behind. That's how I spotted what looked like a mouse stuck to the belt. It was actually the torn off part of the belt folded over backwards.

The belt actually travels pretty slow at idle, but not slow enough to get a good look. And of course you have no control over where the broken part of the belt stops.

It might have been a small nut or bolt that fell into the belt guard, but I was not missing any nuts or bolts when I took everything apart.
Doug

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1991 Spider
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Re: Broken timing belt

Post by MR2 Zig »

Well then I guess its the "lucky" bounce.

Congrats to the Missus for catching that before you lost the valves

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Re: Broken timing belt

Post by Duk »

Good thing you got that in time :D :D :D
Alfa's and FIAT's realy do suck when it comes to belt protection from little belt fcukers getting in and wreaking havok.
I never realised until I bought a Japanese twin cam engined car. They go a lot further to protect the belt.
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