Here's a cheapo that just might do the job, perhaps with a bit of customizing:

https://www.ebay.com/itm/Valve-Spring-Compressor-Lever-Type-OHV-OHC-Engine-Seal-Keeper-Removal-Tool-Kit/233005003334?fits=Make%3AMercedes-Benz&epid=27025855898&_trkparms=ispr%3D1&hash=item36402e3246:g:7c8AAOSwLKhb68ok&enc=AQAEAAAB8BPxNw%2BVj6nta7CKEs3N0qUkU51pdX81mect%2FPKmj31s7G18M0tFy5DBNaSZExnpagQMFfkPWwaiLH5DgJdi V2ee7vgwlwZafvNa76yt9GKipFh1ZfJK0tqLuX9gySfH3Jmc1SQF21S5k8ntzM2Jc7X2F3Qp3peA7LlOEC2IPUl4Y3Dds2%2B9zb 3Ta64tfad6vg8nv8VkjHEKvdkePXb79eFGp4DS1j460Vou6%2B1bd%2BBNKiKaHTCyLANIVOe9U6Eq7mXJHeshdtJzH5MXP9Fwax f7zhwzx6tzbTAr5tZY9soZVN2jr703Ejd%2BqaT8wscre6lkg3TPzYw07qkvQ%2Fs31eitrIr8NVta3sMCEQkjeQhw8iVDMH31ez i77Fa4lIKjpk61ENLfLG1bmy2TFlBI%2FOEs8C3KeAWL41slH9GynFt5rfRyaQU9PpR1iseLQUxazu0BcG1awM4kLFH%2FfAmPHM JMhmJpTUGoldiKGxBh%2FS5QyQnh4rcPtGXk8zhXGqBjxCWBtchAEmCVQ6O6GLFWC1lvjxb747AhceKA7veSPlfRrC18qO56vfpg OuRk5eAHKiAlKAVIDRmvLwrpoyNpQvb0p8xt2%2B27l15bJtf05F63kdRi65X0W11WnqFZBtXWm6OKgoG9z1g11Wc3peTqsSY%3D&checksum=233005003334beb8517bca1a4818b89dd08a647ed16e