well happened this morning after a 60-130 pull! heard a bang inside engine then tak tak when idling and more in higher rpm (i wont go over 2000rpm for safety )
maybe a bad lifter or twisted rod ! engine does not misfire and oil pressure is good ,my log show no knock when i did the pull!
maybe it has to do that last night i raised my rev limiter to 7200 rpm....not looking good
i knew soon or later this would come at that power level !
the good news is engine run fine and no hole in my block!
cant wait to see the rod shape...
i will update with picture the damage when i open the engine !

 

Bummer man.

Well atleast you get to do an engine build thread now!! Hopefully you get it up and running soon!
Scot

 

very sorry to hear this. i think of these things since my limiter is at 7200 also. i like to visit there but not stay for very long for fear of detonating it lol. yes, it looks like another engine build thread. good luck.

add: yes, re power level. you're at that next step up that i believe is just outside the "sweet spot" for these motors. this may be *more* evidence of that.

 

"Another engine build thread?" Yikes, that's a little concerning.

Have there been other incidents of 996tt engines needing a rebuild? Are these rebuilds due to running these engines excessively? Or is it due to the OP raising the rev limiter? I thought the Mezger engine was robust and reliable?

 

These engines are incredibly robust and reliable. I am right at 100 track hours on mine with a 7200 redline with pretty much each shift right around the 7k mark. I am in the low 500whp range on stock internals. I think once you cross the 600hp threshold your reliability starts decreasing correspondingly. A good tune with adequate fuel margins has a lot to do with it also in my opinion. My gearbox is also at a 100 track hrs with just one 3rd gear synchro change. I firmly believe the transmission cooler has helped in my case. I plan on a precautionary rebuild to strengthen both this winter.

 

Sounds like denonation. Were you running on meth at that point? Btw who tuned thr beast ?

 

they are as far as i know. but it's really easy with these motors to add on just enough power to stress the internals beyond what they were built for. so, then you re-build. it happens.

i am very mindful of that, and have opted to stay just below that power "threshold" that pwdrhound mentioned. again, i think 550 is the sweet spot and anything beyond that, and you're "pushing it". but ya know, you take your chances.

 

Sorry to hear but some of us warned your earlier in the thread. My limit is 1.5 bar on race gas let alone 1.8 bar on pump and meth. But that's me.
Good luck
Markski

 

it might be a lifter as you raised and hit the rev limiter, happened to me once on the stock block, rods were fine when we inspected them... the problem gone after 10 minutes running at idle, hope this is it for you too

 

^ it may be dumb question.. but isn't there any way to check this ( rods/lifters) without opening up the motor!?

 

^record the sound and do a frequency analysis

 

thx guys for your input i apreciate !

heres a good sound clip from cab thx for input
!


so maybe a lifter or rods ,ims etc.. who knows! will tell you the TRUTH when i get there ! so now this bring me to a new step , new project and fun putting down my engine and learn more etc... !
will update later guys

 

Came up private for me.

 

^fixed

 

from what I could hear, sounds like a damaged rod to me...
if you record a sound bite at a known, constant RPM(rev's per second is what you want), pull the bite apart and look for how many times a second the noise occurs...rod/bottom end noise will appear twice as quick as a top-end failure