Loud Knock After Replacing Intake Manifold

[tdsunderla]

Just replaced Intake Manifold. Started engine and timing was off and engine backfired twice, once extremely loud. Set timing and engine idles fine, but there is a loud knock. Any ideas on the source of the knock? Any help is appreciated.

 

[dhartman]

pray you didn't bend a pushrod.

 

[fast 99]

Carbon, crud or fastener in a cylinder?

 

[GTX63]

Upload a video of your engine running.

 

[SirRobyn0]

Upload a video of your engine running.

This. It's impossible to do anything other than guess without getting to hear the knock.

 

[75gmck25]

Use a mechanics stethoscope or a piece of tubing and listen at the valve cover over each cylinder. I used that method to find out an adjuster had loosened on one cylinder and I was hearing the pushrod clattering.

 

[tdsunderla]

I have got a great video, with the sound, but how do I upload? When I go to attach a file I only see photos.

 

[Dmack]

8 bolts and you can have your valve covers off. Easy enough to see if a rocker broke or pushrod is bent....

 

[tdsunderla]

Attached are pics of what I see…

 

[Dmack]

You can grab each pushrod and see if any are loose. Easier option is disconnect the ign power wire to your HEI (or coil wire for non hei) and have someone crank the engine over while you watch the lifters. If any aren't moving, you have a problem.

If a pushrod is bent and off the lifter, or a lifter came apart or isn't of its bore, you can lose oil pressure.

 

[SquareRoot]

Just replaced Intake Manifold. Started engine and timing was off and engine backfired twice, once extremely loud. Set timing and engine idles fine, but there is a loud knock. Any ideas on the source of the knock? Any help is appreciated.

Are you missing a 10mm socket?

 

[tdsunderla]

Are you missing a 10mm socket?

All 10mm sockets accounted for.

 

[JBswth]

Just replaced Intake Manifold. Started engine and timing was off and engine backfired twice, once extremely loud. Set timing and engine idles fine, but there is a loud knock. Any ideas on the source of the knock? Any help is appreciated.

Get a mechanic's stethoscope and listen all over the engine when it is running, including the crank case and the pan. This will help tell you where the noise is coming from. Hope you didn't bend a rod.

J.B.

 

[tdsunderla]

Get a mechanic's stethoscope and listen all over the engine when it is running, including the crank case and the pan. This will help tell you where the noise is coming from. Hope you didn't bend a rod.

J.B.

Will do.

 

[tdsunderla]

You can grab each pushrod and see if any are loose. Easier option is disconnect the ign power wire to your HEI (or coil wire for non hei) and have someone crank the engine over while you watch the lifters. If any aren't moving, you have a problem.

If a pushrod is bent and off the lifter, or a lifter came apart or isn't of its bore, you can lose oil pressure.

I did pull the valve covers and cranked the engine over and all rocker arms and push rods appeared to be operating normally.