LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

my timing chain broke (pics inside)

Old Apr 19, 2004 | 12:18 PM
  #1  
DansTransAM's Avatar
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my timing chain broke (pics inside)

I have a pretty much stock TA with some bolts on. I have about 150,000 miles on it so something serious was going to give eventually. I was driving around and I geared down and floored. I was turning some high RPM's then it suddenly just cut off. I pulled over and it was turning over too easy so i need it had to be the timing chain. I broke the timing chain in two places. here are some destruction pics:





I also noticed one of the tooths on the smaller gear got chipped off.


When it broke, apparently it slapped against my timing cover. So now i have to get a new timing cover as well.



a lot of metal debris and chain links were at the bottom of the cover:



I have a 94 non-vented opti so I have a couple of questions. Im going to upgrade my timing chain. What do i need to go with to fit my car? I would also like to slip a cam in, since i got everything off but im not too sure if I should since I have 150,000 miles on it and I don't know what parts I need as far as valves and lifters go.

If anything i'll just get another stocker timing chain and go easy on the car.
Old Apr 19, 2004 | 12:31 PM
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With 150k and the potential of some of that debris getting in the motor, I would personally just replace everything with stock parts and save up for a rebuild. Don't forget to change your oil too, preferrably before you start the motor, and after you let it run for a few minutes. Good luck.
Old Apr 19, 2004 | 12:34 PM
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Don't forget to change your oil too, preferrably before you start the motor, and after you let it run for a few minutes. Good luck.
Yeah thats a given. I heard let it run for 10 minutes or so then change the oil?
Old Apr 19, 2004 | 01:44 PM
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Definitely pour oil through the motor and let it drain out, right there by the timing cover, too. There's probably a lot more of debris all over and that's not good.

If you don't plan on doing a lot of modification, just go with a stock replacement.

BTW, hit me up if you need a timing cover.
Old Apr 19, 2004 | 01:47 PM
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I already got a PM from a guy about a timing cover.

Im looking a harmonic balancer as well. When i took it off I noticed a chunk of rubber in the ring on the backside was missing and i could wiggle the metal part with my hands.
Old Apr 19, 2004 | 02:00 PM
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ouch, sorry to hear about that.

was there any piston/valve contact?
Old Apr 19, 2004 | 02:05 PM
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Originally posted by mineralwater
ouch, sorry to hear about that.

was there any piston/valve contact?
i hope not!
Old Apr 19, 2004 | 02:18 PM
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I thought our motors were of the type non-interference? Does piston/valve clearance become a problem when camshafts with higher lift are used?
Old Apr 19, 2004 | 03:57 PM
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Hmm, that looks familiar. I had the same thing happen on my 95 at the roadcourse one day. I was downshifting into a corner (rev matching), hit about 6k rpm (revlimiter at 6500, upgraded cam, rockers and springs), and the engine just died. Broke the stock chain, which damaged the cover, and bent two valves (which left scratches on their pistons).

IMO, now is the perfect time to do the cam and valvetrain while you're in it. If you can afford it, it would definitely be worth it to go ahead and get the heads ported and polished too. If you haven't already removed the heads, you need too as I'd bet that you've got some bent valves. Also, you might as well go ahead and upgrade to the vented style opti while you're at it, and replace the water pump while you're in there. Here's a lift of things I'd do:
vented opti
electric waterpump
double roller chain
cam
1.6 roller rockers
spings
port and polish heads
lifters
pushrods
Old Apr 19, 2004 | 07:03 PM
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Originally posted by LT4Firehawk
Hmm, that looks familiar. I had the same thing happen on my 95 at the roadcourse one day. I was downshifting into a corner (rev matching), hit about 6k rpm (revlimiter at 6500, upgraded cam, rockers and springs), and the engine just died. Broke the stock chain, which damaged the cover, and bent two valves (which left scratches on their pistons).

IMO, now is the perfect time to do the cam and valvetrain while you're in it. If you can afford it, it would definitely be worth it to go ahead and get the heads ported and polished too. If you haven't already removed the heads, you need too as I'd bet that you've got some bent valves. Also, you might as well go ahead and upgrade to the vented style opti while you're at it, and replace the water pump while you're in there. Here's a lift of things I'd do:
vented opti
electric waterpump
double roller chain
cam
1.6 roller rockers
spings
port and polish heads
lifters
pushrods
On an Lt1 with 150k
Old Apr 19, 2004 | 08:05 PM
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if i got to take the heads and intake off might as well stroke it to a 383.

Im putting the chain back on and see if the car will run. Hopefully if it does, im turning it back into my daily driver until I can get some money saved up for a 383. I gotta get that bottom end freshened up before i start putting cams and heads all in it.
Old Apr 19, 2004 | 08:09 PM
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Sorry to hear about that Dan..... you still have got really good life off a stock LT1 chain (and I know you don't ever turn that car up hard ). Hopefully, before too long I'll have a stock LT1 chain to give you if you want it . Take 'em easy man... good luck with the engine.
Old Apr 19, 2004 | 08:28 PM
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Damn dude...I had that happen a few years ago. Not cool.

I went ahead, pulled the motor and re-built it with some goodies.

I had some valve/piston slap

Check your pushrods to see if they are straight, if not, you might have some slap, and the heads will nead to be fixed.
Old Apr 19, 2004 | 08:36 PM
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Built trannies that shift hard and stock chains dont get along well. If you need a timing cover, I've got one off my 94 you can have for shipping cost. Just send PM
Old Apr 20, 2004 | 08:47 AM
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You really need to pull the heads and at least check everything before trying to start it up again. If you got bent valves/pushrods you could do serious piston damage by starting it up after just changing the chain.

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