Rattle from top end

[benjy]

Hi. Had to replace the HG on an M50b25. Afterwards there is the most horrible rasping rattle from the topend as the engine returns to idle from being rev'd. It sounds like its coming from the inlet cam. Could this be a knackered lifter?
Im going to check the cam timing in the next day or so, just waiting on the great British weather! Thanks in advance for your help.

[MR 325]

Probably lifter noise. What oil do you have in it?

[Stu]

Is it a "tick" or a rattle like shaking a box of marbles?

tick--> lifter(s) not pumping up
rattle--> VANOS unit

If it happens when revving down (from say 4000 rpm to idle)...probably the VANOS unit. Put your hand over the hump on the valve cover where the unit is and see if you can feel any vibration when the engine comes down to idle

[benjy]

Its a non-vanos:up: Its a metallic rasping rattle. Almost like something thin is loose and vibrating at high speed, if that makes any sense
Oil is fully synth, 10w-40 IIRC

[Stu]

Its a non-vanos:up: Its a metallic rasping rattle. Almost like something thin is loose and vibrating at high speed, if that makes any sense
Oil is fully synth, 10w-40 IIRC

I thought of asking if it was VANOS or non-V but the symptoms seemed textbook for a noisy VANOS unit. I'm out of ideas...anyone else?