Bent Exhaust Valves?

[D-dub]

Hello Team~ new to this forum but have learned a ton about my recently purchased 2000 LS V8. Bought it not running helping a college student pay for school. Would start but not run well at all. Checked all cylinders. 1-2-3 | 5-6-7-8 all have 125+ compression. No 4 however nothing. Put air on the cylinder and discovered the exhaust valves are staying open. Pulled the RH VC to discover that the secondary chain had lost it's master link (I'm assuming previous owner had the work done-he didn't have any details for me). The tensioner looks new (the new style) so I am assuming whoever worked on it replaced the tensioner and the chain, but didn't fasten the master link properly and when the engine was started, the chain link flew and the chain came apart. (No, haven't found the back side of the link yet)

Ordered a secondary chain (no master link) from Christopher on ebay and it came yesterday. After inspection, looks like when the timing chain broke it bent cylinder 4 exhaust valves. The other valves appear okay as does the heads and cam shafts. Took a gooseneck video cam into the cylinders and the top of the piston looks fine.

Question: can I remove the RH cyl head without removing the front engine cover to replace the two exhaust valves? Not positive that it's the problem, but when I turn the cam over, the number 4 valves do not move - the cam isn't making contact with the shims.

Learning as I go as this is a very unique engine. Thinking of replacing the secondary chain and just replacing the VC and getting it running enough to sale. Any thoughts/guidance would be much appreciated. Not really looking forward to removing the front engine cover and have to rent the timing tools and reset the timing. More than I really bargained for. Anybody else face this problem. The vehicle only has 107,303 miles. Interior/exterior in great shape. Thanks in advance.

 

[grizzlyls]

Really, everyone with a pre may 2001 built LS faced these problems. Mine only had 100k on it pristine highway miles (Senoir Citizen original owner) and I was the SECOND replacment of the chains. Christopher sells the best he can, but really what it boils down to is bad design being replaced with bad design.

Having said that, the master link meant a replacement once, as you know, but really proper replacement of ALL the chains is like I did - buying the POST may 2001 chains and tensionors all around (yes and the sprockets).

IMO sell the car as a parter, or leave the work to someone that has an interest in rebuilding this engine right (like I did) but thats pricey.

 

[D-dub]

Really, everyone with a pre may 2001 built LS faced these problems. Mine only had 100k on it pristine highway miles (Senoir Citizen original owner) and I was the SECOND replacment of the chains. Christopher sells the best he can, but really what it boils down to is bad design being replaced with bad design.

Having said that, the master link meant a replacement once, as you know, but really proper replacement of ALL the chains is like I did - buying the POST may 2001 chains and tensionors all around (yes and the sprockets).

IMO sell the car as a parter, or leave the work to someone that has an interest in rebuilding this engine right (like I did) but thats pricey.

Thanks for the input grizzlyls. I am debating whether to do a full "chain job" or not. I will keep you posted.

 

[RigsLS]

V8 Secondary Timing Chain Tensioner Replacement.pdf

 

[oddball]

Front cover has to come off for the head to come off. Well, if you want the front seal to ever seal again.
Sometimes a lower part of the piston can break when it hits a valve - I had the oil ring land break off of a piston that hit an intake valve. So a full inspection may be worthwhile before throwing much money at it.
Another option is getting a junkyard motor that doesn't have any apparent damage, replace the chains and swap. Of course, engine R&R isn't exactly easy on these things, but you're well into the realm of hard work regardless.
These were really nice cars and I still enjoy driving my 2002, but this is a really tough situation. I don't think there's any way to get your time or money back out of it.