Valve / lifter rattle

Hey Guys, I know that this has been covered in a few topics and I've read through most of them. Being that my query is slightly different I though I would post a new one.

my bravo is a 2004 b2600i manual. 130,000klm on the odo.
So my problem is that at cold starts i have a valve rattle until oil pumps to the top end. This is fine i can deal with as i know the 2600i are known for a bit of valve noise. My real problem is when Im driving/cruising at 100klm/h(60mph) and then place my foot down in 5th gear at approx 2,800rpm to 3,500rpm i get valve/rattle type noise from the engine.

Has anyone else experienced this. It doesn't occur in 3rd/4th at high rpms at the same speed. only in 5th under load and light acceleration. Like going up a slight crest.

Any info would help.

Going to change oil and filter to see if that helps.

Thanks

The valve tick is oil pressure related. So at higher rpm, pressure rises.
My 2600i only ticks on start up, or if the oil level gets low. Check the dipstick first.

Also, detonation can sound like valve noise. You might want to double check your ignition timing and/or run a higher octane fuel.

I was thinking detonation as well due to happening under load. Oil level and condition is fine was just going to do the change to eliminate that out of the equation.

Thanks

You have carbon built up on the piston crowns and that is taking your compression higher. This can and does cause detonation. You can try running a can of seafoam in the gas and see if that doesn't take care of the rattle. Depending on how bad it is it might take a second dose. Some garages offer a fuel system service that ties in a chemical directly onto the fuel rail and that might be a good option for a stubborn case.

ran some injector cleaner through the engine and cleaned the throttle body. changed the fuel to a 95ron and no longer pinging. just poor fueling i think.

I had the same problem with my b2600i. All it took was a bottle of Lucas oil stabilizer. 11 bucks and no more rattle