need help assessing damage after t-belt failure

[rossb]

So basically my timing belt snapped. Now i know very little about engines(i think that is all about to change ), so I took some pictures so you guys can help me figure out what all i need to do. The tops of all the pistons have little dings in the from the valves(I think) as seen circled in the pics below. Is this normal? Also the cams are still in so I don't know if all of those are bent or just open or what ever. I know i need new valves at least, but what about pistons?

 

[knochgoon24]

You definitely have a pile of bent valves.

 

[4pistons]

Remove the cams keeping track of the cam caps then pour some solvent in each of the ports then look to see if any is leaking past the valves. Those are the ones that are bent and will need replacing.

The small dings in the piston tops shouldn't affect or damage anything. Turn the engine over by hand while checking each cylinder bore for damage or scuffing.

If you don't know anything about engines I HIGHLY RECOMMEND getting it done by a reputable DSM shop. The 4G63 is NOT a beginners engine... especially the valvetrain/timing belt/tensioner assembly. If you get it wrong you'll be right back where you are now. ....g'head... ask me how I know!!!

Rick - '91 GSX 5 timing belts in 10 years!!

 

[rossb]

Remove the cams keeping track of the cam caps then pour some solvent in each of the ports then look to see if any is leaking past the valves. Those are the ones that are bent and will need replacing.

The small dings in the piston tops shouldn't affect or damage anything. Turn the engine over by hand while checking each cylinder bore for damage or scuffing.

If you don't know anything about engines I HIGHLY RECOMMEND getting it done by a reputable DSM shop. The 4G63 is NOT a beginners engine... especially the valvetrain/timing belt/tensioner assembly. If you get it wrong you'll be right back where you are now. ....g'head... ask me how I know!!!

Rick - '91 GSX 5 timing belts in 10 years!!

Thanks for the helpful reply! I wasn't going to attempt a timing job myself. What I plan on doing is replacing everything that needs replacing, and then taking the car to a shop for just a timing job.
Another thing is, something had to seize for the belt to snap the way it did. I'm thinking it was maybe the oil or water pump. Is there any easy way to test to see if they are still functioning properly?

 

[architechnik]

The water pump would not effect the timing belt. It's run off of the auxiliary/alternator belt.

If the belt snapped clean in half, then you might have had the oil pump seize, but that's a big maybe. If that was the case, you may have damage to the bearings, as they would not have been lubricated. Since the balance shaft is run off of the oil pump, you may have had a balance shaft bearing go bad, which in turn would stop the pump (and subsequently the belt).

To check it, grab a wrench and start turning the oil pump sprocket (the little one next to the main sprocket toward the rear of the car). It should spin, in a lopey fashion, as the weighted balance turns in the opposite direction. If it doesn't turn at all, or is too easy to turn, then there is something wrong and you'll need to dig in under the pan.

 

[4pistons]

As "architechnik" said it's unlikely that something siezed. If something did you'd have the belt actually snapped or lots of teeth sheared off it. And you'd have bigger problems than the bent valves.

Do you have the timing cover completely off?? A couple things to look for...

The small balance shaft belt is notorious for shredding and wrapping itself around the crank sprocket and timing belt.

The timing belt tensioner may be wasted and allowed the belt to slacken and skip some teeth.

Replace all the belts, and the tensioner, and the pulleys to be sure you've eliminated the problem. Oh yeah, change the water pump while you're in there too, ### you don't want it failing right after you've had everything replaced!

Rick - '91 GSX

 

[rossb]

When i mean it snapped, it snapped. Here is a link to the pic. I haven't gotten it completely off yet.

 

[Kastigir]

As "architechnik" said it's unlikely that something siezed. If something did you'd have the belt actually snapped or lots of teeth sheared off it. And you'd have bigger problems than the bent valves.

Do you have the timing cover completely off?? A couple things to look for...

The small balance shaft belt is notorious for shredding and wrapping itself around the crank sprocket and timing belt.

The timing belt tensioner may be wasted and allowed the belt to slacken and skip some teeth.

Replace all the belts, and the tensioner, and the pulleys to be sure you've eliminated the problem. Oh yeah, change the water pump while you're in there too, ### you don't want it failing right after you've had everything replaced!

Rick - '91 GSX

Not to threadjack, but this is EXACTLY what happened to my T-belt. Guess I should check the oil pump, as the balance shaft belt is intact?

A snapped belt sounds like a faulty or old T-belt.

 

[blackGSX2g]

Do not be daunted by a timing belt job. If you follow the instructions and double check your work, it is not difficult for the mechanically inclined (since you obviously were able to take off the cylinder head).

How many miles were on that timing belt? Do the front BS, oil pump, crank/cams turn ok? Chances are if it is just a high mileage belt, either the BS belt snapped to take out the timing belt, or the timing belt just went past it's useful life.

As far as your pistons, I'd take a dremel and lightly grind down the sharp edges on the pistons as they would create hot-spots in the combustion chamber. Make sure you clean up all the shavings afterwards. Other than that, the pistons should be fine.

 

[DSM1G90]

looks like the belt snapped down at the crank sprocket. The area above the tear doesn't look too good either - like some stress wear and age.

Yea, I'd just call the same - clean up the pistons, check the bores, get the head redone and you're back on the road.

...and pull the cam sprocket cover off from time to time to check to see how the belt is doing afterwards ... Simple preventive maintenance is your best friend in this area.

 

[97 4G63]

Bent valves for sure just take off the oil pan and see if you have any metal shavings.
Also turn the crank and oil pump by hand if it's hard to do then you might want to take a look at your bearings.
Also make sure to pull the lower timing cover and take a look a the blance shaft belt.