Engine knock at idle

[Machspeed]

My friends 89 has a loud knock especially at idle. When you go in for a closer look it sounds like its comming from somewhere very close to that part that opens the secondaries on the rear of the rail, could it be a vacuum leak?

 

[Spin]

how many miles does it have on it?

 

[projectSHO89]

Probably a valve out of adjustment.

When was the last 60K valve adj performed?

Steve

 

[Machspeed]

Car has about 125k, i dont know if the previous owner ever did a valve lash.

 

[Chrisssssssss]

If it sounds like it is coming from the top of the engine just under the valve covers then it is more than likely a valve out of adjustment. Time for a 60K...

 

[sdpatt]

I think without having done the service until 125,000 miles that it is really no longer a "60K." The services involved with the 60K are preventative maintenance activities designed to prevent the type of problem that started this topic. If you can hear a loud knock from a cam lobe striking a shim, the damage is already done. It takes energy to make noise. Hopefully the shim has sacrificed itself rather than damage the cam lobe. After that many miles, you'd be very lucky to if that was the case.