Bent Con Rod?

[AcidicDavey]

Hey folks,

This is my breaker, just curious, do we think this is a bent con rod?

The PCV system is blocked and it started making this noise a couple of days after a remap I'm told.


https://www.youtube.com/watch?v=g_Y9aJTEma0

[Sweep]

Sounds more like top end to me?

[LeeT5]

If a rod was bent then surely it would misfire on that cylinder. Yours, from what I can hear, is not misfiring. There is definitely a metallic noise but as Sweep says, it's more top end.

Think you'll need to do a compression test to at least isolate the problem. It could also be a hydraulic lifter has gone solid or not filling with oil.

[merc85]

Sounds more like top end to me?

Strangely the rods do when they go, not Deep knocking sound.

[merc85]

If a rod was bent then surely it would misfire on that cylinder. Yours, from what I can hear, is not misfiring. There is definitely a metallic noise but as Sweep says, it's more top end.

Think you'll need to do a compression test to at least isolate the problem. It could also be a hydraulic lifter has gone solid or not filling with oil.

2 850's one being AndysR didnt miss fire with there bent rods

[merc85]

Could be a lifter, worth a oil change n filter

[t5 pete]

Yes they don't miss fire with a bent con rod they do have a destintive noise that gets faster as the revs raise

[AcidicDavey]

The car went back to the tuners after the noise started, full service yet noise obviously persisted.

If you listen to the clip again yes there is a lot of what sounds like top end tapping but also under that there is a slightly deeper sound tapping noise, the recording has quite picked that up too well :(

Anyway, I don't have a crane and if anyone wants this bare engine they can have it for FREE if they come and remove it out the top as I still need to be able to roll the car around.

[AndysR]

Sounds rod like to me, as already said mine ran smoothly and perfectly when I bent a rod, you honestly wouldn't have known if you always drove the car with the windows up.

[Biff]

That's a bent rod if you ask me. Memories!
Mine sounded like the little end, had perfect compression & no miss fire. The rod was certainly bent.
Just for interest when people have bent rods which one went? Mine was number 5.

[jamesy12345]

That's a bent rod if you ask me. Memories!
Mine sounded like the little end, had perfect compression & no miss fire. The rod was certainly bent.
Just for interest when people have bent rods which one went? Mine was number 5.

I read somewhere that detonation is most likely to be furthest away from the water pump, within the hottest cylinder, so that makes sense

[Doingitsideways]

I agree Dave. Sounds like a rod.
It sounds deep when the bonnet is down, so not being absorbed by the bonnet insulation = bottom end, but not a deep enough thud to be a thrown big end.

Ah, too much boost, not enough fuel...

Poor thing :(

[mike 850]

https://www.youtube.com/watch?v=URhNeLVb5n8

this was my bent rod