Of course its number 6

[larrym]

Freshened up the bottom end new roller cam and springs this winter, all was good I did have what I thought was not enough preload on one lifter. Was out on the weekend cruising on the highway and it started to back fire through the intake and load and it would do it.


Pulled the valve cover to make sure it wasn't a stuck valve, rolled it over all the valves where moving, pulled the plugs and rockers rolled it over no noise,removed the push rods one at a time and narrowed it down to number 6 intake even with the plug out it sounded like it was coming up the intake. Pulled the intake and head tonight and I can't see anything obvious, no marks on the piston thought the chain might have jumped its brand new double roller, lifter appears fine link is intact pin for roller is fine. Pulled the valve there is some carbon on the back side of the intake valve not much and the seat looks ok.I did pull the cap on the cam sensor it appeared to be in the correct location when I set the balancer 25 degrees ATC. I did use an adjustable push rod to check #6 intake and still got the same sound no preload. Spring looks fine dampner looks fine, I'll pull another intake and compare the size of the seat surface.

Layed a straight edge on all the valves they seem to be the same height any clues?

 

[turbofabricator]

Inition module. Swap it out and see what happens.

 

[turbofabricator]

oops, shoulda done that before disassembly.

 

[kidglok]

X2 for ignition module

 

[larrym]

I had the ECM unplugged and rolled it over same thing then no spark plugs installed and It was still making noise how could that be the module?
The racket was scary when I fired it up again almost thought the valve was contacting the piston that's why I yanked the head in hind site I should have done a compression test with the rockers off or charged the cylinder with air.