Timing Woes

Grizsk

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Hey guys,

I'll cut right to the chase.

2002 LS8 sat for a month, and when I went out to start it the battery was shot. It was replaced by the previous owner with a non-vented version, so I picked up a factory battery from the dealer and replaced it.

Then the drama.

The engine was turning over, but not firing. CEL and charging system light. It didnt sound much, if any different when cranking than it did when it was in perfect working order. I began my research and tried the usual unplug the MAF, check fuel pump etc. After a few attempts, I had it towed to my mechanic. He swiftly confirmed fuel, spark, air and compression, and I immediately feared timing issues.

We proceeded by removing the valve covers, low and behold, I was told "the secondary timing chain jumped bank 2." I should note that there are no codes stored on the PCM whatsoever. Mechanic suggested that perhaps changing the battery may have cleared any sort of system cache.

This is where I need your help. Neither of us know all that much about the LS. From what I've read, some say valve/piston damage is a worry, others seem to experience only a rough idle with a slipped chain and that damage is usually seen with a broken chain. I'm currently waiting on confirmation of whether there is any such damage.

It's a bit of a cliffhanger, but I'll post up any new information I recieve. If theres no damage I'm considering a timing system refresh with new chains and metal tensioners.

My question to you is, what are your thoughts? Knowing all that I do thus far, how would you proceed?

I appreciate any input, bearing in mind that I am aware of the fact that if there is valve damage, I'm looking at a replacement motor or a rebuild.

Thanks for reading my novel.
 
You need a new "mechanic." He should know this stuff. Would you go to a surgeon that had never operated on a human before?
Broken chain = certain valve/cylinder damage.
Skipped chain = possible valve/cylinder damage.
It's possible to verify that there is or isn't damage without removing the head (with a borescope).
 
Would slipping a tooth cause the engine not to fire? I've read conflicting reports on the matter.

P.S. I'm not communicating directy with the mechanic, but through shop staff
 
I agree with Joe,

That said, I've owned an 02 v8 with a BROKEN secondary chain (bought as a parts car). I replaced it and it ran better than any other 1st gen I've ever driven. Ran and sounded brand new, no signs of any problems. plenty of info here on replacing it, and one good write up with pics (IIRC).
 
Would slipping a tooth cause the engine not to fire? I've read conflicting reports on the matter.

P.S. I'm not communicating directy with the mechanic, but through shop staff

No, and typically it should still start, but idle very badly. Are you trusting this guy's diagnosis, or did you see for yourself that both cam flats did not line up?
 
I agree with Joe,

That said, I've owned an 02 v8 with a BROKEN secondary chain (bought as a parts car). I replaced it and it ran better than any other 1st gen I've ever driven. Ran and sounded brand new, no signs of any problems. plenty of info here on replacing it, and one good write up with pics (IIRC).

Well, then it must be possible (but I would bet unlikely) for it to break without damage. Maybe it broke while you were trying to start it, or at least while it was only at idle, or the cam was turned to have the exhaust valves mostly closed at the moment that the chain broke?
 
The person I'm working with is a good friend whom I trust completely with any of my vehicles. That being said, I have not seen with my own eyes the flats not lining up, but I was told that they do not. I'm not sure how far the chain jumped, but either way, I got some more news.

2 valves on the passenger side are confirmed to be badly damaged, thus leading me to believe that no matter what, there's probably piston damage from the impacts. I am now entertaining the idea of a new-to-me engine.

I'm up in British Columbia, and I was choked when that never fired 3.9 was sold up here and shipped down south across the border a couple weeks ago. I called the dealer, $8300 CAD for a brand new motor. Sounds like that motor that was recently sold went for about $1800 USD. What a steal.

That being said, is anyone aware of any 3.9's available anywhere near me? I can't find a damn thing anywhere near me without opting for an entire LS to swap from. G-Rell I'm assuming based on the fact that your parts car ran like a dream, your broken chain didn't result in damaged valves/pistons? Has anyone ever recovered an LS in my situation without swapping in a new motor or restoring the spent one? From what I hear a used motor is cheaper than a rebuild. Thoughts?

P.S. I'm one of the rare few willing to dump an insane amount of cash into this thing to keep it running (although not quite the $8300 the dealer wants for a fresh part)
 
do you have junk yards up there? if so, start calling around until you find one with an LS or two, from the same gen, and still have their motors... I'm sure the price will be much better than $8300
 
I've called 6 yards in BC none of which have any Gen1 LS's. I'll be calling around for the next few days on my spare time to see if I can source one. I found a gentleman parting out a Gen1, but of course, the drivetrain was already gone. Does anyone have input on scooping a motor up off Ebay? There are many available, but I'd like to avoid surprises and Ebay seems sketchy to me. Not to mention the fact that I'm then looking at shipping the motor up across the border.

Ebay Canada does not have a single listing for an LS engine of any sort. They do, however, have listings for passenger side cylinder head w/ valves. Would it be worth my time to look into replacing that part? Or would I still be better off replacing the motor in your opinion?
 
I would suggest that you check what the extent of the damage is first. You may be able to rebuild what you have. I have seen other interference engines lose a timing belt at idle and just bend a few valves and have a couple of dents in the pistons. The owners have been able to get away with a few new valves and labor for a valve job. I have also seen what happens when mechanical timing goes awry at 7500+ rpm. Take apart what you have and determine what can be saved. Whatever you buy used should be checked and/or refreshed anyway. Most places that warranty a used part will replace the part itself but shipping and install/deinstall/reinstall labor won't be covered. Warranty (used parts) usually gets voided if the part doesn't get installed by a certified mechanic.

car-part.com lets you search continent wide network of automotive recyclers.

Also check local machine shops. A head rebuild may be cheaper than cost of a used head, for example.

There was a machine shop selling rebuilt ls engines on ebay. Just over $3k if I recall.

Good luck.
 
Jumped chains tend to not cause damage because after a long time of ignoring warnings, the chain jumping a tooth makes the engine run so poorly the owner finally gets it fixed. If they ignore it, it just increases the odds of the chain jumping further and/or breaking, which is when the real damage will occur.

I got an engine on eBay. It was on the high end at $1100. Other options included $500 chipped from eBay and $300 at a local junkyard, all with unknown miles. Your options are still limited to eBay and junkyards. That's not going to change.
 
I was experiencing rough acceleration around 45-65 MPH, and after a bit of research and figured it was misfiring. Could that have been a symptom of, say, a chain slipping one tooth, only to further slip and cause the real damage?

I've located a 3.9 right here in BC, just waiting for monday morning to find out mileage. Is there anything I should be asking when it comes to this particular motor? I will also be sitting down with the most reputable machine shop around to discuss my options for replacing the bent valves and fixing any piston damage. I'll post prices as soon as I get them
 
Little bit of an update.. That engine I found has 76,000 miles on it, which, oddly enough, is about 76,000 less than the existing one. He's asking just under $700 USD and will ship it to my trusted mechanic to install for cheap, he's only about 2 hours away. I've pretty much decided to go this route as opposed to repairing, so what should I be looking out for? Are there any common issues other than COP's, plastic tensioners and valve cover gaskets? What else should I have done while I'm in there?
 
... and I was choked when that never fired 3.9 was sold up here and shipped down south across the border a couple weeks ago ...

Close ... it was actually from my source out of Mississauga Ontario and it was purchased and send down south some time last year, it was recently re-discussed in a thread that come back on the matter.

I'll make a call and see if there are more kicking around the region. Story actually goes that the CDN market received dedicated warranty replacement motors, they are still hidden away LOL.

GLWR, glad to see a salvaged motor going to good use. Many good low mile motors end up getting crushed in yards.
 
Does anyone have any idea as to what I should be paying to have my old engine removed and the new one put in? I've got quotes ranging from $560 to $1400 USD. I need some insight from someone with experience in the matter.. I want to get this done right the first time.

Is it more or less a plug and play situation or do I need a dealer to get it done properly?
 

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