Mercedes had the 402/403/404/405 series engines from the mid 70s onward. It was a weight optimised naturally aspirated engine family consisting of V6 of 9 liter, V8, 10 up to V12 for special applications. They all shared the 90 degree block angle optimal for the V8
There were later iterations of this engine, 20 years ago a water wagon at a paving firm i worked for at the time, so it must be built 40 years ago. It was the 90 degree V6, they ground the fuel pump helixes so that it idled on 3 cylinders to get even firing intervals at idle. Nonetheless when idling it still hogged like a pig on a cold morning. I think the last iteration of the V6 had offset crank pins because the engine was so rough that it became unacceptable in the early 2000s..
Anyways, when you tried to idle it on a cold morning to warm up
Read more, the other cylinder bank remained cold. It worked but it was an awful engine.