rod knocking?

[Civib2]

okay well when it was drivable it made this weird like zinging noise after everytime i accelerated, like as soon as i let off the clutch it would do it. the dealer diagnoised it as a rod knocking noise. So i pulled the oil pan and i dont see anything, no scraps of metal in the pan or anything like that. the rods all looked okay visually to the eye. and the pistons had no burnouts like holes or anything. So my question is what is defined as rod knocking? and what do you guys think it could be. Because i really am probably going to just drop a new motor in but i want to figure out what went wrong with this one.

 

[BISHILVR]

You have to pull down each rod cap (the two nuts on the bottom of each rod) doing that will let you look at the rod bearings. If there is bronze color showing or deep scrapes in the bearings then thats your boy.

 

[Old Mitsu Tech]

Zinging and rod knocking don't seem to go together. A rod knock is a rapping noise. A main knock is like a lead mallet type of noise. It's deeper and not as sharp sounding. If you are getting zinging I would look possibly for the flywheel contacting the starter bendix? Not sure without hearing it. But that would make more sense to me than a rod knocking. Look around the flywheel/bellhousing area and if possible to reproduce while standing still, use a mechanics stethescope. If not, then use a sound tracer with wireless transmitters to locate. You will want to rent/borrow as I just found out a 4 channel setup is around 600.00 to buy from Snap On.

Good Luck

 

[Civib2]

No well it started as a zinging when it first started, but now it deff sounds like a scraping just ugly sound. if i pull the rod caps off does anyone know the tourqe specs for the 420a for those bolts when i put them back on. Also do you think this sounds like a bearing. all the rods look find could i have knock that is just not visual to the human eye.

 

[Civib2]

its not the tranny or flywheel or clutch, thats what i thought it was at first too but i took it to a tranny shop and they tore it apart and it looked really good for how many miles were on it and everytyhing was in order

 

[BISHILVR]

A bad rod is'nt something that you can see from the outside bro. To get the torque specs just call a dealership and ask someone in service for the info.

 

[Civib2]

No im not looking at it from the outside, i dropped the oil pan i can see the rods and pistons. they all look okay visually to the eye

 

[ndm1]

Did you pull the rod caps of like Bishilvr said?
If so what did they look like? pics?

 

[TOPDSM]

Did you inspect the wrist pin(the pin that holds the piston to the con rod)? cause I had a similar problem with 1 of my cars. The rods and bearings looked fine but the wrist pin had worn out and was rocking on the piston. See if you can rock the con rod or wiggle it if so then inspect the pins.

 

[Civib2]

Okay im dropping the rod caps today and i will also inspect the wrist pin. will iit be ovbious if a rod beaering is bad like metal scratches and moveablility of it?