Tech / General Engine Is your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!

Enigne knock

Thread Tools
 
Search this Thread
 
Old 03-30-2014, 05:28 PM
  #1  
Senior Member

Thread Starter
iTrader: (2)
 
Mirror Image's Avatar
 
Join Date: Mar 2003
Location: Birmingham Alabama
Posts: 859
Received 5 Likes on 5 Posts
Car: 1991 Firebird convertible
Engine: LQ4 ls 6.0
Transmission: 4L60E
Axle/Gears: 342 Limited slip
Enigne knock

I have a SBC 377 and over reved it today and now I have a knock but only at idle and it is a solid knock not a tapping my oil presser gauge reads 20psi at idle it has a scat forged crank and the crank was ordered with the right main journal so I didn't use spacers any ideas what it could be
Old 03-30-2014, 07:20 PM
  #2  
Moderator

 
AlkyIROC's Avatar
 
Join Date: Jul 1999
Location: 51°N 114°W, 3500'
Posts: 17,120
Likes: 0
Received 123 Likes on 104 Posts
Car: 87 IROC L98
Engine: 588 Alcohol BBC
Transmission: Powerglide
Axle/Gears: Ford 9"/31 spline spool/4.86
Re: Enigne knock

Spun rod bearing or bad wrist pin is the most common source of a knock.

Main bearings don't knock. Spun cam bearings don't knock.

Getting a knock after over reving the engine could still be a failed rod bearing (stretched rod bolts). You could have floated the valves and at least one is now bent.

Doesn't really matter. If your engine has a knock, it will need to be stripped down for repair. The longer you put it off, the worse the damage can become.

Pull all the spark plugs to see if one is damaged.
Old 03-30-2014, 07:31 PM
  #3  
Senior Member

Thread Starter
iTrader: (2)
 
Mirror Image's Avatar
 
Join Date: Mar 2003
Location: Birmingham Alabama
Posts: 859
Received 5 Likes on 5 Posts
Car: 1991 Firebird convertible
Engine: LQ4 ls 6.0
Transmission: 4L60E
Axle/Gears: 342 Limited slip
Re: Enigne knock

Yeah wrist pin is what I was thinking would it still have good oil presser if it was a spun bearing the engine only has 25000 miles on it
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
RedLeader289
Tech / General Engine
10
05-28-2019 01:47 PM
bigjay89gta
Engine/Drivetrain/Suspension Parts for Sale
12
10-15-2015 08:04 AM
efiguy
Engine/Drivetrain/Suspension Parts for Sale
0
09-27-2015 01:30 PM
spartanreaper
Engine Swap
12
09-25-2015 07:22 PM
MSgt Luttrell
Tech / General Engine
3
09-05-2015 11:28 AM



Quick Reply: Enigne knock



All times are GMT -5. The time now is 08:00 AM.