KingDeleted

does it sound like an exhaust leak? At any rate it sounds like your going in the right direction. You took something headed for who knows what, and made a running engine again. Does it sound normal under load?

futura1

have not had it on the road yet simply because the "knock" was there right from startup and was right in line with rpm's. In the next day or so i will try to get a better look at the exhaust manifolds, but i think i will try pulling the coils one at a time to see if the "knock" changes or goes away all together. surely it is just coincidence, but the bearing that was gone was on the same cylinder that spit out a plug about a year ago. I had a local mechanic fix that for me. I cant imagine any chips from that procedure causing only that rod bearing to fail. One more thing, oil pressure looks good (gauge, not a light) but also looks suspiciously stable as i go from idle to 2000 maybe 2500 rpm's.needle doesn't appear to move at all.

futura1

after disconnecting the coils one at a time, there was one that made the engine sound much better. i believe i will just go ahead and do all the rod bearings this weekend. Does anyone know how big a risk it is re-using the rod bolts? i would have to order them from summit or someone like that and they are like 130 bucks.
And why would a rod bearing fail in the first place? I don't have a problem doing all the bearings just to be safe, but i am a little concerned that the root cause of the problem may still exist. Thoughts!

KingDeleted

What I heard is that as you pull the coils one at a time, pulling one in particular decreases the pinging noise. I’m thinking there could be a defect is that plug since you stated that it had previous repairs. If she breaks loose consider taking it out half a turn and see if the ticking decreases. I just wondering if that could explain the noise before you go spending 130 bucks on some bolts.

futura1

Not a ticking or pinging sound...it is definately a "knock" .

KingDeleted

Yeah if your going to do rod bearings I would do them all too. Maybe that plug with the helicoil caused the rod bearing failure. What does that plug even look like?

futura1

Not sure what that plug looks like. I will pull it out of curiosity now. They all probably need replacing with 119k on the engine and i dont remember when or if i did them. I am kinda afraid to change them, just due to the design issue with those heads though. will investigate if there is something i can do if i do replace them to maybe prevent them from coming loose and popping out. i would think a thread locker might interfere with the ground and create a weak spark situation.

futura1

Now that i have started to replace the rest of the rod bearings, i discovered that after removing the one next to the one that was totally gone i could see that the crank is wasted. there is a definite wear of maybe .010 inch or more on the crank where the two rods would meet. My guess is the knock is caused by the two rods banging up against each other (more likely just the one hitting hard on that worn area of the crank). Now i for sure would like to find that "pdf" on 5.4 liter engine removal.
Anyone have it ? or know someone who does?

KingDeleted

That sucks

RX1Cobra

That sucks. I'd be looking for a junkyard or reman motor.