I have started the process of LE head and cam install, but just before I was under the car and heard a very faint knocking or ticking noise come from the rear of the block near the bell housing. It is not severe and may even be the roller rockers, but I cant quite tell.

It is most noticable under the car at the back of the block at idle. When it is reved it does not get any louder. Even when driving and hammering on it no knocking sound. Cant hear it at all up top with the hood up. I had the rod bearings go out on my Jeep, knocked very loud while driving. Definitely does not sound like that.

78K on the clock and good oil pressure. Is this faint knocking sound normal when you are under the car? Could it be my RR's or am I on the way to bad rod bearings? Again it is not loud or violent, not like a hammer against the block.

 

Dont know yet, plugs come out tomorrow. I did have a tiny leak at the driver side collector, very tiny.

 

I was about to say exhaust leak maybe. Possible drivetrain issue. TOB makes noise sometimes.

 

TOB less than a year old.

If it were rod knock could you hear it with the hood up at idle or revved up? Again I hear nothing but normal RR noise on top.

 

I have this same ticking, and i saw that your car is also an M6. I just started to think it might be something in my clutch or tranny, though unlikely. It is starting to worry me.

 

I gotta go with TOB as well. I have replaced mine several times and none of them have lasted very long (I'm not easy on them though.) If the ticking goes away when you push in the clutch then that's your culprit. If not then I can't help you. Best of luck and I hope its nothing serious.

 

If it were the throw out bearing the sound would change if someone were to depress the clutch while listing beneath the car. If is is a bottom end bearing it would get louder with more rpm. That's my experience with rod bearings. My #8 plug was completely loose where you could see exhaust blowing past the threads but I don't recall hearing a noise from it. Time will tell on the noise; I hope it's not the worst case.

 

Can flywheels crack like flexplates?