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Hey guys! My timing chain snapped while I was on the highway about a week ago so far I have pulled apart the engine and the bottom end looks good but I think I’m gonna need the top end rebuilt I’m wondering if it’s possible to do the necessary repairs at home? I’m replacing the pushrods and valves but what else? Do I need new guides, springs, or rocker arms? What else am I missing, or would it just be better to take it to a shop I am also wondering if I might need new pistons, I think they will most likely be okay but I might as well get more opinions. Pushrods I pulled from the passenger side head
If you remove the oil pan, then you could slowly turn the engine over by hand and carefully examine each connecting rod as it comes into view. Also, if the engine turns over smoothly, that is a good sign. In addition, you could measure from the block deck to the top of each piston at TDC. All of those measurements should be very close to one another. If one piston is indicated to be lower than the others, that is a sign that that connecting rod is bent. All of this is not as good as taking the engine to a machine shop to have them examine it, but it is better than nothing, and maybe that is what you are looking for.
using a dial indicator, you can check the rods. Any rod that is bent will give the piston less lift / height in the cylinder. . Usually best done with two people. One turning and one measuring.
Drop the oil and see if there is a large amount of metal in the pan, if so, I would do a complete tear down.
I wouldn't even think twice about doing a complete rebuild. None of those parts can be trusted after the pistons smacked the valves.
I'd even consider a different engine altogether.
It is unfortunate. As others have wondered - what conditions lead to the chain breaking?
How many miles on it? How do you use your Vette? Stay stock....mild performance build....or RACECAR?
it is mostly stock:
catless speed engineering headers
borla atak catback
summit harmonic balancer
it has 78k miles on it, I recently bought it just about 12 days before the timing chain blew, I used it as a daily with a few pulls here and there. it has fully documented service history and I did multiple checks before buying, it is a healthy car and I’m not sure what caused this
If you remove the oil pan, then you could slowly turn the engine over by hand and carefully examine each connecting rod as it comes into view. Also, if the engine turns over smoothly, that is a good sign. In addition, you could measure from the block deck to the top of each piston at TDC. All of those measurements should be very close to one another. If one piston is indicated to be lower than the others, that is a sign that that connecting rod is bent. All of this is not as good as taking the engine to a machine shop to have them examine it, but it is better than nothing, and maybe that is what you are looking for.
okay perfect, I will do this and post the results, thank you
I wouldn't even think twice about doing a complete rebuild. None of those parts can be trusted after the pistons smacked the valves.
I'd even consider a different engine altogether.
It is unfortunate. As others have wondered - what conditions lead to the chain breaking?
What parts are you referring to specifically?
as for the conditions of it i was at about 70 mph about to shift from third to fourth and it snapped ~4k rpm I wanna say
A timing chain failure at under 80k miles is either a freak event or that thing was run HARD before you got it.
I believe one of two things happened, either GM was cheap and reused a ls1 chain which I have heard is much more prone to breaking, I also noticed that the cam position sensor was chewed up pretty bad and there was a small magnet stuck in the chain, it looks to be a cheap aftermarket one that one of the previous owners installed, I think it’s possible it may have broke and somehow took the chain with it?
(Ps it’s obviously not definitive proof that the car wasn’t beaten on but for most of its life it was owned by one guy 10 years 55k miles, a books worth of service history and after removing the heads everything looks very well maintained)
Yeah, agree that there's no way I would trust those pistons. Rods and crank are probably OK. I'd replace/rebuild everything above the pistons. Another option is to go with a middle aged LS2 take out that hasn't been opened. I've had pretty good luck with those on stock type stuff. Most of the yards will give you a little bit of a warranty. Buy the engine and don't delay putting it back into service. Being in Dallas, you also have easy access to Houston, San Antonio, and Austin yards.
If looking for bigger power, I'd rebuild what you have for sure. Then there's always the iron block option if you're on a tight budget. An LQ4 with your rebuilt 243/799 heads is pretty much an iron block LS2. Add a really mild cam and you're north of the power you had before your LS2 **** the bed. I question whether anyone other than a serious road race guy can feel the extra 100lbs on the front end.
Yeah, agree that there's no way I would trust those pistons. Rods and crank are probably OK. I'd replace/rebuild everything above the pistons. Another option is to go with a middle aged LS2 take out that hasn't been opened. I've had pretty good luck with those on stock type stuff. Most of the yards will give you a little bit of a warranty. Buy the engine and don't delay putting it back into service. Being in Dallas, you also have easy access to Houston, San Antonio, and Austin yards.
If looking for bigger power, I'd rebuild what you have for sure. Then there's always the iron block option if you're on a tight budget. An LQ4 with your rebuilt 243/799 heads is pretty much an iron block LS2. Add a really mild cam and you're north of the power you had before your LS2 **** the bed. I question whether anyone other than a serious road race guy can feel the extra 100lbs on the front end.
My concern is not power at the moment I am plenty happy with how she is
And could you clarify what you said about “Another option is to go with a middle aged LS2 take out that hasn't been opened. I've had pretty good luck with those on stock type stuff“?
Do you mean swapping in another ls2 or just the parts from a junkyard ls2, I was planning on throwing a used set of pistons into it
My concern is not power at the moment I am plenty happy with how she is
And could you clarify what you said about “Another option is to go with a middle aged LS2 take out that hasn't been opened. I've had pretty good luck with those on stock type stuff“?
Do you mean swapping in another ls2 or just the parts from a junkyard ls2, I was planning on throwing a used set of pistons into it
Low mileage, untouched LS2 (complete long blocks or complete engines) shouldn't be hard to find (search corvette crashes on YouTube and see how people wrap these things around poles because they can't drive). Preferably one that has never been modified or rebuilt.
Didn't mention but should be obvious you'll need a timing cover gasket, probably replace the water pump while you're working on it since you're gonna have the motor out anyways, new serpentine belt, new timing set.
Timing chain broke
so far I have pulled apart the engine and the bottom end looks good but I think I’m gonna need the top end rebuilt 
I’m wondering if it’s possible to do the necessary repairs at home? I’m replacing the pushrods and valves but what else? Do I need new guides, springs, or rocker arms? What else am I missing, or would it just be better to take it to a shop
I am also wondering if I might need new pistons, I think they will most likely be okay but I might as well get more opinions.
