Quick question on "Rod Knock"
Thread Starter
Race Director
Joined: Oct 2001
Posts: 12,832
Likes: 209
From: Canton GA
Cruise-In III Veteran
Cruise-In IV Veteran
Cruise-In VI Veteran
St. Jude Donor '03-'05-'06-'10-'11-'12
Quick question on "Rod Knock"
...What causes it? :confused: I mean, I know what you can do to make it happen, but what in the engine actually knocks? Is it the same as piston slap?
No, I don't have any problems, I'm just wondering. :cheers:
No, I don't have any problems, I'm just wondering. :cheers:
Heel & Toe
Joined: Oct 2003
Posts: 24
Likes: 0
From: rolling meadows IL
Re: Quick question on "Rod Knock" (ShawnZR-1)
Rod knock is caused by spinning the rod bearings(allowing too much clearance).
I did this when I over-revved 3 times.
As you drive the car, you will hear knocking at around 2000-3000 rpm.
It is a non-pleasant and expensive noise.
I did this when I over-revved 3 times.
As you drive the car, you will hear knocking at around 2000-3000 rpm.
It is a non-pleasant and expensive noise.
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Re: Quick question on "Rod Knock" (ShawnZR-1)
A spun/failed rod bearing.
The rod instead of sliding around smoothly on a bed of oil between the rod and bearing/crank begins to slam against the crank directly and may also hit areas of the block if they are in close proximity.
It sounds like a very deep hollow knocking noise low in the engine that varies with RPM.
The rod instead of sliding around smoothly on a bed of oil between the rod and bearing/crank begins to slam against the crank directly and may also hit areas of the block if they are in close proximity.
It sounds like a very deep hollow knocking noise low in the engine that varies with RPM.
Thread Starter
Race Director
Joined: Oct 2001
Posts: 12,832
Likes: 209
From: Canton GA
Cruise-In III Veteran
Cruise-In IV Veteran
Cruise-In VI Veteran
St. Jude Donor '03-'05-'06-'10-'11-'12
Re: Quick question on "Rod Knock" (scorp508)
Ahhh!!!! Thanks guys! That makes sense.
