Shortly after finishing with the machining process of the cylinder; Ronald proceeded with the installation of the valves, valve springs and associated parts.
When rebuilding the cylinder head of an M88/S14 and S38 engine, it is advisable to replace all the exhaust valves, as these have a hard life due to thermal stress. I know of at least another M88/3 and two other S38B36 engines that recently broke down due to a burnt exhaust valve. It is therefore of the utmost importance to calibrate and if necessary adjust the valve-clearances of these engines at least once every 10k km or at least once per year.
Although the old stud-bolts could were still usable, I replaced all of them to secure a reliable long term fit. They also give the freshly rebuild cylinder head a much better appearance.
It was not really necessary to replace the intake-valves, as these are not submitted to high thermal stress. But at 35% of the nett-price of an exhaust valve, replacing these is IMHO a no-brainer.
The following picture shows a randomly selected combustion chamber with the new valves that are properly seated in the valve seats. The smaller diameter valves are the exhaust valves (32,0mm), the larger diameter valves are the intake-valves (37,0mm). Please not the small clearances between the intake valves. The diameter of the valves is the same for the M88/3, S38B35 and S38B36. The S38B38 has intake valves with a diameter of 38,5mm and 32,5mm for the exhaust valves reducing the clearance even further.
Even though the engine of #231 already had the dual valve-springs installed with the goal to reduce the risk of a break, this cannot be totally eliminated. The risk of a cracked valve spring is typically caused by metal-fatigue that becomes a determining factor for engines that are used at high engine speeds for sustained periods of time. That is the reason why I replaced all valve springs with new parts. The following picture shows the outer and inner valve spring. Please note that the M88/3 uses smaller diameter springs then the S38 variants.
Next to the valve-springs, I also replaced the spring-pockets, spring plates and valve collets for the same reason as mentioned before. The following picture clearly shows the inner-and outer springs with the spring plate. Also visible are the valve-stem seals.
Ronald temporarily installed the camshaft-house onto the cylinder-head to enable him to set the valve clearance to the specified range by using the initial shim-thickness of 3,75mm to 3,80mm as used during the factory assembly a long time ago.
Last but not least a picture from the cylinder head placed onto the engine block. Please note that this is not a permanent install as some timing-chain guides still need to be installed.
The rest of the work is simply assembling the remaining parts. In a week or two the engine shall be ready.