# Timing chain broke. Boooo!



## svede1212 (Nov 1, 2005)

Went to the doctor today and when I went out in the parking lot and started the car it fired and immediately, went "clang-clang" and quit. Had her towed home and pulled one valve cover off and turned the crank by hand a bit. Rockers did not move. My stock LS1 timing chain broke. I've had the cam in 6-7 years now and I know I should have put in a stouter chain but I didn't. Ziggy is down for the count until I get the new parts and then find out if I bent some valves too. Then the heads will have to come off. Not a good day. 



*EDIT:* Update on real cause post #16


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## silversport (Mar 23, 2007)

I didn't think that was as big a deal on OHV engines...just OHC motors...I'll keep a good thought for no damage...

Bill


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## Rukee (Feb 8, 2007)

Yes it is an interface engine, hopefully you only bent some push rods and not the valves.


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## HP11 (Apr 11, 2009)

Rukee said:


> Yes it is an interface engine, hopefully you only bent some push rods and not the valves.


Pretty sure you meant to say "interference" engine.


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## svede1212 (Nov 1, 2005)

If they were stock push rods I'm sure they'd go first but of course they are chrome-moly. I'll pull the rods out and check those. That's easy. I pulled the fan assembly to turn the engine over by hand. Having a LS1 I'll have the messy job of draining antifreeze out next on the dis-assembly.

This seems to be doctor week (3 docs and dentist for me and a colonoscopy for my wife) capped off by our anniversary Saturday so it will probably be next week before I really get into it. 

I have a Rollmaster adjustable chain set and Melling oil pump coming from Ed Curtis at flowtechinduction with ARP cam and crank bolts.


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## svede1212 (Nov 1, 2005)

Pulled both valve covers and rockers and saw that #1 intake and #2 exhaust valve stems were down a 1/4" more than the others. Pulled the FAST off and I could see down into #1 intake that the valve wasn't seated and the stem was bent. Heads are coming off and going to the machine shop for a rebuild.  

This should be a cautionary tale to not cheap out when building up. I'm getting an adjustable Rollmaster chain set but I could have gotten at the least a stronger LS2 chain for $40 back when I did my cam 6-7 years ago. I'm upgrading the oil pump too now that I'm in there but this is going to cost me at least $500-600 and more if I have a broken piston not to mention a whole bunch of work.


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## danfigg (Sep 27, 2009)

*re*

Is this motor definately a interference angle engine or is it more like the traditional small block. Im trying to see how the valves can hit the piston Does the LS1 have valve reliefs on the pistons. Hopefully since this was a low rpm incident piston damage. Good luck Svede-------Danfigg


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## svede1212 (Nov 1, 2005)

It was at low RPM as it was at start up but it sure did some damage. Even when stock the valves can interfere with the pistons. I went out and looked at my stock 241 heads and the intake valve is only 1/8" in from the deck of the head. Stock cam lift is just under 1/2". Stock pistons are flat top and at the top of the stroke is anywhere from flush with the deck to out of the hole .010". Mine are at the upper limit of .010". I also have larger valves, milled heads and a .612/.600 cam which made it worse. Normally the lift of a cam really isn't an issue as full lift is when the piston is at the bottom of the hole but if the timing chain breaks some valves are left open and the piston comes back up from inertia and smacks them. Really hoping for pistons in one piece and the heads not damaged too badly.


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## Rukee (Feb 8, 2007)

Lets hope it doesn't look like this...


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## svede1212 (Nov 1, 2005)

This is some pretty heavy wrenching on cars for me but I had my son Nick over and he helped with the heads. I'm surprised that things looked as good as they did. There are some divots on the pistons but they don't seem too deep and I think I can smooth them out. I expected the valves sideways and the combustion chambers messed up but just a few valves looked off kilter so maybe just a handful of valves with new seats. Lifters look OK so new pushrods, chain set, oil pump and the head work with new gaskets. The ARP studs have worked nicely for me as this is the second time the heads have been off with them. At the least anti-freeze and crap didn't go down in the holes and will make clean up a lot easier. I only have to pull the back center stud to clear the brake booster.
I still have to pull the timing cover and do the oil pump and chain set.


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## BWinc (Sep 21, 2005)

Other than fixing whats broke and new oil pump, going to do anything else while you have it apart?


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## svede1212 (Nov 1, 2005)

That's the saddest part. All this work and it's eating up all my money just to get it back where it was performance-wise. The chain and oil pump will be an upgrade tho and I'll be able to degree the cam properly with that chain set. Just doing dot-to-dot like the first time I may (or may not) have been leaving HP on the table.


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## svede1212 (Nov 1, 2005)

Got the call from the machine shop. 4 bent valves and 5 more that aren't 100% true so they are replacing them. Everything else on the heads including the seats are perfect so the heads won't cost a fortune. It's still going to be an expensive repair overall with all the parts involved. If I wasn't going the work myself it would easily be over $2,000 though.


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## BWinc (Sep 21, 2005)

Thats some damage for just a start attempt. I have an LS2, but I'm going to opt for a heavy duty chain if I do a cam swap.


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## svede1212 (Nov 1, 2005)

Here's the culprit. Adding up the parts needed (oil pump was just an upgrade) to fix this and I'm at close to $1,000. The head work was $380 to replace the nine valves, clean up and check everything as well as measure my combustion chamber CCs. $100 for gaskets, $300 for chain set, oil pump and crank bolt, $140 for pushrods (just because), oil, filter and coolant another $50. I'll re-estimate having a shop do this at $3,000. i'm going to have to fish around in the oil pan for one pin and two side links from the chain that are missing. They say a chain is only as strong as its weakest link and in this case the weakest link was indeed the chain.


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## svede1212 (Nov 1, 2005)

Just an update. I found out several things and none of them good. It turns out my engine had a LS2 chain. The chain broke because a Lunati link bar lifter failed and locked the cam shaft. We believe that the pin that holds the roller tip slid out a bit and was smashed into the lifter bore when the cam came around. That also trashed the cam and it looks like the roller tip wrecked the cam position sensor. 

The top of the lifter is totally jammed in the block's lifter bore. I don't know how bad the bore is. I'm going to have to pull the engine out over the winter and see if I can save it or if I need to get another short block. Very sad day. I'ts going to cost $2,000-$5,000 from my estimate to get the car back running.

I have parts all over the garage as I kept having to dig deeper into the engine. At least it's close to winter and I park it anyways but soon it will be too cold to work out there.

Short story one Lunati link bar lifter with 5k miles on it wiped out the engine. I replaced them last year just so I wouldn't have lifter problems. Money badly spent.


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## johni53 (Feb 10, 2010)

svede1212 said:


> Pulled both valve covers and rockers and saw that #1 intake and #2 exhaust valve stems were down a 1/4" more than the others. Pulled the FAST off and I could see down into #1 intake that the valve wasn't seated and the stem was bent. Heads are coming off and going to the machine shop for a rebuild.
> 
> This should be a cautionary tale to not cheap out when building up. I'm getting an adjustable Rollmaster chain set but I could have gotten at the least a stronger LS2 chain for $40 back when I did my cam 6-7 years ago. I'm upgrading the oil pump too now that I'm in there but this is going to cost me at least $500-600 and more if I have a broken piston not to mention a whole bunch of work.


Can only imagine how much it would have cost had you sent the car to be repaired. Triple? Good luck on the repairs, watch your knuckles.


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## silversport (Mar 23, 2007)

ouch...will keep a good thought that the bleeding has stopped...thanks for sharing with us...a wealth of knowledge...

Bill


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## BWinc (Sep 21, 2005)

Daaaaang.


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## bigdeezs (Jan 2, 2014)

Wowwww that sucks. Sorry to hear. Did you ever get the motor pulled out...whats the verdict on needing a new shortblock?


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## BWinc (Sep 21, 2005)

Is Ziggy back up?


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## SIXO GTO (Nov 7, 2013)

WOW Just saw this post  sucks svede , so sorry to hear about Ziggy hope he is back up & running soon 2 more weeks till mine is out of winter storage for good . thanks to you ive had great success in a few upgrades over the winter Just suspension but so worth it !! Once again I wish you luck in getting him back in good health . & since I am planning a cam upgrade over the 2014-2015 storage I would like your opinion on what & what not to replace , I definetly will not skimp on parts after you nitemare !!


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