Timing Belt Broke, need opinions

[AliceCooper]

Hey guys I was on my way home from class doing 60mph on the highway when my timing belt broke completely. Didn't put the clutch in right away because I was more like "what was that" until I noticed all the lights on and my rpm dropping. So I got it towed and now I'm looking at my options. My mechanic friend is doing a leak down test, which I am sure will say the valves are shot. But I am wondering about my pistons. This has to be a reliable car. I am wondering if the pistons should be replaced or if they don't have to be. I don't want to take any chances with one of them blowing up while driving because I don't have the money to do another tear down, let alone barely enough for this one.

 

[Jon91TSi]

Hey guys I was on my way home from class doing 60mph on the highway when my timing belt broke completely. Didn't put the clutch in right away because I was more like "what was that" until I noticed all the lights on and my rpm dropping. So I got it towed and now I'm looking at my options. My mechanic friend is doing a leak down test, which I am sure will say the valves are shot. But I am wondering about my pistons. This has to be a reliable car. I am wondering if the pistons should be replaced or if they don't have to be. I don't want to take any chances with one of them blowing up while driving because I don't have the money to do another tear down, let alone barely enough for this one.

Typically unless a valve snapped off and made a huge gouge in the piston they will be fine. I have worked on 3 cars in the past 4 months that all had a timing belt failure, I de-burred the pistons, had the head re-surfaced, installed new valves, guides, and seals, and put the car back in service. Remember to use an OEM or better quality timing and balance shaft belt, change it every 60k and you'll be fine. You really won't know the extent of the damage until you get the head off. Good luck.

 

[Morphius]

You should put a new belt on it before doing anything. Make sure it's timed correctly (belt wise) and see if it runs. You may have lucked out and it's fine. Otherwise if you do a leak down, you're for sure going to continue to do more damage to the valves rotating the bottem end with out the cams following along.

 

[Jon91TSi]

You should put a new belt on it before doing anything. Make sure it's timed correctly (belt wise) and see if it runs. You may have lucked out and it's fine. Otherwise if you do a leak down, you're for sure going to continue to do more damage to the valves rotating the bottem end with out the cams following along.

The easiest way to check quickly if there is damage is to pop the valve cover off and see if the rockers have jumped off and are laying in the oil galleys in the head. If they are it means the valve spring is compressed (valve is bent) and the valve spring could no longer hold the rocker in place.

 

[AliceCooper]

Thanks for the quick replies. Not too sure what to do, seems like a gamble to me on whether or not to replace the pistons. If the only way to tell is to take the head off, then I think I might scrap it. The paint is now oxidized and the turbo is beginning to go out. Taking the head off will cost me money so I think I will cut my losses. Thanks guys.

 

[BogusSVO]

I would agree with both Jon and Morphius...

Pull VC... Jumped rocker?
No= Install timing belt, do Leak down test.
Yes= Pull head.

Ill keep an eye on this thread to check on your updates

**EDIT**

Alice... alot of 4g63 engines are running with dinged pistons from broken timing belts.

But odds are you bent valves, and cracked guides. That is common, and since you were running 60mph....I would bet the same has happened to your head.

 

[AliceCooper]

I would agree with both Jon and Morphius...

Pull VC... Jumped rocker?
No= Install timing belt, do Leak down test.
Yes= Pull head.

Ill keep an eye on this thread to check on your updates

**EDIT**

Alice... alot of 4g63 engines are running with dinged pistons from broken timing belts.

But odds are you bent valves, and cracked guides. That is common, and since you were running 60mph....I would bet the same has happened to your head.

I'll post back what happened to it. But with the way the car is now, I'm not sure I want to invest the amount of money that it is worth. I'll let you guys know. Thanks for the input.

 

[Jon91TSi]

I'll post back what happened to it. But with the way the car is now, I'm not sure I want to invest the amount of money that it is worth. I'll let you guys know. Thanks for the input.

I would also add that it doesn't take that much know-how to pull the head and re-assemble once the machine shop finishes with it. This will save you a significant amount of money if you are willing to tackle this yourself. It's nothing to be afraid of, you have a great group of people here to help you along the way as well as great sites like vfaq as well.

I wouldn't part with the car over a broken timing belt, but that's just my .02

 

[AliceCooper]

I would also add that it doesn't take that much know-how to pull the head and re-assemble once the machine shop finishes with it. This will save you a significant amount of money if you are willing to tackle this yourself. It's nothing to be afraid of, you have a great group of people here to help you along the way as well as great sites like vfaq as well.

I wouldn't part with the car over a broken timing belt, but that's just my .02

Only reason I'm leaning towards parting with it is because the tranny is going out, turbo is throwing tons of oil, and my paint is super oxidized. I'm planning to part with it down the road anyways so why use up more money and risk not making it to school. I just have a lot of thinking to do .

 

[BogusSVO]

You can grab a used head off the classifed for $200-$300 shipped

gaskets, oil & filter, antifreeze, a full timing belt kit, is appox another $300

The info you need to put it all back together is here on the fourm.

 

[billyt]

BogusSVO! on call!! -by the way thanks for all your help in the past!

 

[TexasTurbo]

Go ahead and get yourself a new tensioner and pulleys with that new tbelt.