Problem, spun rod bearing?

[Jeff822]

Well, lately my boost has been spiking crazy high and not staying at its set boost, i turned it down a lot and now it holds at 11psi. After i did that my car was smoking a lot at idle, thought it was maybe just from running way rich from it being tuned at 18 psi and only running 11. But heres the deal i drove the car about 10/15 mins to the store and when i turned the car off the turbo timer was still running and i could hear a tapping which sounded like it was coming from the bottom end on the passenger side of the motor with the hood closed, it didnt sound like lifter tick it wasnt as fast. My car has very low compression less then 100 in all cylinders but its still running, a lot of people told me it could be the piston rings but i had a problem before that with my car smoking a little bit after idle and thought it was the HG or valve seals. Any help is appreciated. Thanks, Jeff

 

[andymoraitis]

Jeff,

Does the sound happen while driving or only at idle? Usually, rod knock from spun bearings starts to make itself known around 2500 RPM and continues from there. Sounds at idle are generally confined to issues with a rocker that's fallen off or a collapsed lifter.

The best way to tell is to run the motor to the point at which it makes the sound. While holding it at that RPM, have a friend remove and replace spark plug wires one at a time. If the noise goes away, it's a rod bearing issue. If the noise continues, it's more likely something in the head.

I'm crossing my fingers (and toes) so please let us know what you find.

Andy

 

[Jeff822]

Thank you for the help. It's weird because it happened when the car was already hot and being shut off, when i came back out from the store it wasnt doing it when i started the car. A friend of mine said that it couldve been a rod bearing that had already been destroyed and fallin back into place, if i can keep the car running untill some family members pay me back i will buy a rebuilt 6 bolt for the car. Im hoping for the best. Thanks again, Jeff

 

[95talon_in_ma]

Thank you for the help. It's weird because it happened when the car was already hot and being shut off, when i came back out from the store it wasnt doing it when i started the car. A friend of mine said that it couldve been a rod bearing that had already been destroyed and fallin back into place, if i can keep the car running untill some family members pay me back i will buy a rebuilt 6 bolt for the car. Im hoping for the best. Thanks again, Jeff

If a rod bearing was destroyed, it can't fall back into place...That's just plain crazy...

A rod bearing will make noise at idle when it's completely spun. But it's very loud and (I think), unmistakable on a completely spun bearing. Literally like someone is taking a hammer to your hood.
I do agree that when they start to go, it's a faint noise that starts above 2k. But eventually will work it's way to idle and be very loud.
I have a truck that has a wrist pin knock, which is similar to the noise of a bearing starting to go, but not as lous as a spun bearing. It will make that noise for years...

Sounds to me like it was "dieseling". That happens when your timing is to advanced and when you shut the motor off, it actually goes in the opposite direction before shutting off. I'm not sure how much tuning you did, but if the timing is advanced both from the sensor and mechaniclly, I'd look there.....

Good luck!

P.S. Family never pays you back. That's really crazy.......

 

[Blocking_Da_Sun]

You Spun a rod bearing man. Drop the oil pan and look at the metal shavings and look for play in the rod caps/bearing. See if the crankshaft is in spec if it is you might just put new bearings in all 4 and take it to town. If its bad take your crankshaft get it resurface and put oversize bearings on it. To prevent this use thick oil and a better cooling system. Good Luck