73-87chevytrucks.com

73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: dirtysentra on August 26, 2011, 06:06:14 pm

Title: tapping sound not sure what it is
Post by: dirtysentra on August 26, 2011, 06:06:14 pm
I was cleaning my carb earlier, since I just got the truck and it was filthy.  After I got done, I now hear what kind of sounds like a lifter tapping but more solid, louder.  Revving it up a bit makes it go away, just does it at idle.  Could crud have come loose in the carb and jammed something up somewhere else?
Title: Re: tapping sound not sure what it is
Post by: 1979C20 on August 26, 2011, 06:57:40 pm
Where is your oil level and what is your oil pressure? If you oil level or pressure is low the lifters could rattle, but you migh also have a loose rocker arm and you just never heard the sound befote. Or, it could be your pcv valve rattling. Pop the pcv out of the valve cover and see if the rattling goes away.
Title: Re: tapping sound not sure what it is
Post by: dirtysentra on August 26, 2011, 07:48:39 pm
Oil pressure about 18psi at idle.  I'm gonna change it tomorrow, but its up to full.  I may seafoam it then change it.
Title: Re: tapping sound not sure what it is
Post by: zieg85 on August 26, 2011, 07:51:04 pm
Depending on what you mean by cleaning... You could have dislodged a piece of carbon which can sound hairy until it passes...
Title: Re: tapping sound not sure what it is
Post by: Blazin on August 27, 2011, 01:14:17 am
If its carbon get the motor some what warmed up. Take a squirt bottle and fill it with water, rev the motor up to about 1500, 2000 RPMs. While its running spray a light mist of water down the carb. Keep it running while doing this.