Questions on Engine Failure
#1
Burning Brakes
Thread Starter
Questions on Engine Failure
A friend of mine's C6 z06 engine failed. On inspection, it appears engine mount failed and allowed the engine to move enough to pinch off one of the oil cooling lines, thus starving the motor of oil. Connecting rod broke and shot through the block. He has bought a new motor from GM ($12K). A couple questions posed here:
1. Has anyone heard of a failure like this involving a motor mount?
2. Should he have the dropped valve problem addressed (not sure if that was only a problem with a run of motors in the past or an inherent design problem on all ls7 motors)?
Thanks for any feedback.
1. Has anyone heard of a failure like this involving a motor mount?
2. Should he have the dropped valve problem addressed (not sure if that was only a problem with a run of motors in the past or an inherent design problem on all ls7 motors)?
Thanks for any feedback.
#2
A friend of mine's C6 z06 engine failed. On inspection, it appears engine mount failed and allowed the engine to move enough to pinch off one of the oil cooling lines, thus starving the motor of oil. Connecting rod broke and shot through the block. He has bought a new motor from GM ($12K). A couple questions posed here:
1. Has anyone heard of a failure like this involving a motor mount?
2. Should he have the dropped valve problem addressed (not sure if that was only a problem with a run of motors in the past or an inherent design problem on all ls7 motors)?
Thanks for any feedback.
1. Has anyone heard of a failure like this involving a motor mount?
2. Should he have the dropped valve problem addressed (not sure if that was only a problem with a run of motors in the past or an inherent design problem on all ls7 motors)?
Thanks for any feedback.
yes no matter what get the heads fix ASAP I felt like death driving on stock heads. And hmmm rod failure
ans did he not notice low oil pressure or low oil or something
Last edited by 427V8BB; 07-15-2018 at 11:38 AM.
#3
Team Owner
Motor mount failure is common on all vettes bit never heard of it causing an issue besides a clunk .
Yes heads need to be addressed.
Yes heads need to be addressed.
#4
Team Owner
What year is the car out of curiosity? Heads will need to be addressed at some point. Pity he already paid $12K for a stock motor...
#5
Melting Slicks
Member Since: May 2005
Location: Las Vegas Nevada
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St. Jude Donor '08
AHP offers a forged LS7 blueprinted motor with the head fix for $15,000. There are also a number of upgrades available for it also. Maybe you can cancel or return the motor???
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Too-Fast (07-15-2018)
#6
Burning Brakes
Thread Starter
the AHP motor might have been an option but think it is too late for that.
#7
Team Owner
^Yes, new GM heads are still an issue.
#8
My motor dropped a valve and blew up. I'm happy to say that AHP is building my new motor for me with a bunch of great upgrades. Should have it soon can't wait!! It's nice to actually know the person building your motor and also see it being put together by that person.
#9
Pro Mechanic
Pro Mechanic
Heard of engine mounts failing. While I have not heard of engine mount failure causing an engine failure due to pinching-off an oil line but, given how the oil lines are routed and how they might be affected by engine movement, I can see how such a failure could happen.
Should you preemptively remove the heads to assess any potential problem with valve seat concentricity? Well...that's an awfully expensive way to proceed, but if your anxiety about possible valve guide wear is at a very high level, there's no way to accurately determine if there's a problem with seat concentricity other than removing the heads, disassembling them and measuring valve seat run-out.
As for dropping valves, keep in mind that guide wear has to be significant with the engine subjected to fairly severe duty before it will break a valve.
If it were me, I'd put the new engine in then run it 8000-10,000 miles. If you get to that point and the engine is demonstrating symptoms of excessive guide wear, then you can pull the heads, measure the actual guide wear and valve seat run-out then make repairs as necessary.
Should you preemptively remove the heads to assess any potential problem with valve seat concentricity? Well...that's an awfully expensive way to proceed, but if your anxiety about possible valve guide wear is at a very high level, there's no way to accurately determine if there's a problem with seat concentricity other than removing the heads, disassembling them and measuring valve seat run-out.
As for dropping valves, keep in mind that guide wear has to be significant with the engine subjected to fairly severe duty before it will break a valve.
If it were me, I'd put the new engine in then run it 8000-10,000 miles. If you get to that point and the engine is demonstrating symptoms of excessive guide wear, then you can pull the heads, measure the actual guide wear and valve seat run-out then make repairs as necessary.
Last edited by Hib Halverson; 07-16-2018 at 12:34 AM.
#10
Team Owner
Owner may want to throw in some more rigid motor mounts...Hinsons or AMT. If the owner is nervous about this happening again (I'd say odds are equivalent to a being struck by lightening while holding the winning powerball ticket)...he could always upgrade to the ZR1 oil cooler/heat exchanger which eliminates the front mount oil cooler and lines. His new motor will have the bosses in the oil pan for it to bolt up...heck, it may even come with it depending on how the motor was dressed upon purchase. Solves the low oil temp issues on street driven C6Z's as well...that's what I did.
#12
#13
Burning Brakes
Definitely sucks that your motor decided to kick you in the junk. If your car really is modified with heads & a cam I'm not sure how you can point to just the oil though without more information. Just 1 of the breaks unfortunately of modifying your car