4720 engine noise

Monte Tractor · Aug 13, 2025

This is my first post here. I am having trouble with the engine on our 4720. It will miss one number one cylinder and while activating the loader joystick to the end of cylinder stroke to relief pressure. The power steering does same. I have removed the intake manifold. The noise is a popping sound coming out of the number one intake port. I do not know where the timing marks are. I removed number one injector and found TDC with a dial indicator on the number one piston. I made my own marks on the front pulley and timing cover. I then adjusted valves to .012, they where very close already. With number one at TDC I adjusted 1 and 2 intake valves and 1 and 3 ex valves. One engine revolution and set intake valves on 3 and 4, and ex valves on 2 and 4. I did stand on the brakes and it was quiet. I am getting ready to dyno it just to make sure. I m curious about valve timing specs and the procedure to do it. Even the location of timing mark for TDC would be helpful. Thanks for now!!!

JTKub · Aug 13, 2025

I'm probably misunderstanding, but if it was a valve timing issue, you'd have issues on all cylinders. Can you fit an endoscope cam down through the injector port to get a look around the suspect cylinder?

Monte Tractor · Aug 15, 2025

I am actually thinking a particular cam lobe worn down. Like number 1 intake ramp eroded away. Working now on fabricating a compression tester adapter. There are about a hundred thins, it seems going on around here. This ranks somewhere towards the bottom half. THANK YOU FOR YOUR REPLY.

Harry in Ky · Aug 15, 2025

Monte Tractor said:
I am actually thinking a particular cam lobe worn down. Like number 1 intake ramp eroded away. Working now on fabricating a compression tester adapter. There are about a hundred thins, it seems going on around here. This ranks somewhere towards the bottom half. THANK YOU FOR YOUR REPLY.

I know I'm dense, but your logic here escapes me. Do I have this right? Engine has a miss. (mostly cylinder #1) You checked valve adjustment and it was not off by much? You hear a popping sound from the #1 intake manifold off. This is running or just cranking it over? Either way, that sound more like a valve seating (or not) issue than it does a cam lobe, lifter or other valve train related problem.