Problems with a very noisy hydraulic tappet James Clydesdale contacted the V8 Register saying "I have problems with a very noisy hydraulic tappet in my RV8 and wonder if somebody could point me in the right direction regarding this. Would appreciate any help or advice or perhaps guidance to a company or professional who could make it good". Tony Lake and Victor Smith provided a response. (July 2024) The article covers the need for regular oil changes, preliminary checks on tappet noise, inspecting the hydraulic cam followers or tappets and the options of replacing them. Article Posted: 240723 Hydraulic tappets on a Rover V8 engine The Buick derived engine produced by Rover was a key feature of the MGBGTV8 and MGRV8 models with the sophistication of hydraulic tappets which are self-adjusted by pressurised engine oil. The purpose of the hydraulic tappet is to provide maintenance free and quiet operation of the inlet and exhaust valves. It achieves this by utilising engine oil pressure to eliminate the mechanical clearance between the rockers and the valve stems. During normal operation, engine oil pressure present in the upper chamber passes through the non-return ball valve and into the lower, high pressure, chamber. When the cam begins to lift the outer sleeve, the resistance of the valve spring felt through the push rod and seat causes the tappet inner sleeve to move downwards inside the outer sleeve. This downward movement of the inner sleeve closes the ball valve and increases the pressure in the lower, high pressure chamber, sufficiently to ensure that the push rod opens the valve fully. As the tappet moves off the peak of the cam the ball valve opens to equalise the pressure in both chambers which ensures the valve closes when the tappet is on the back of the cam. See the full article