I'm not sure exactly when the change occurred, or why. But in the 60s the front rocker shaft support with the different top was kind of an oil dump. It was open to let any remaining oil at the end of the shaft dribble out. By the early 70s that front support was the same as all the other supports, and the only way out for oil was through the regular little bleed holes along the shaft. What was this change all about?
A few years ago I pulled the original head off my 200. While it was convenient, I made a couple improvements to the oil flow path up to the head, as depicted in the "Book". I used a necked down head bolt in the back where the oil comes up around it, and deepened the little passage in the head where the oil crosses over to the bolt hole. It's a fairly subjective metric, but I think I can hear more oil dripping down from the head to the pan right after shutting off the engine now than before those changes. And that implies more oil flowing up to the head while running. I didn't notice any apparent change to the oil pressure by the dash gauge.
Now I'm getting close to done on a big log/big valve head I've been working on. Wherever I can, I've been easing the oil flow path to the rocker shaft. Nothing radical, just smoothing and slightly enlarging passages here and there. But I had a worrisome thought the other day. Is it possible to divert enough oil flow to the head that you could starve the crankshaft of oil? Or is there plenty to go around, with the split between upper and lower engine not much changed by a little easier path to the top?
A few years ago I pulled the original head off my 200. While it was convenient, I made a couple improvements to the oil flow path up to the head, as depicted in the "Book". I used a necked down head bolt in the back where the oil comes up around it, and deepened the little passage in the head where the oil crosses over to the bolt hole. It's a fairly subjective metric, but I think I can hear more oil dripping down from the head to the pan right after shutting off the engine now than before those changes. And that implies more oil flowing up to the head while running. I didn't notice any apparent change to the oil pressure by the dash gauge.
Now I'm getting close to done on a big log/big valve head I've been working on. Wherever I can, I've been easing the oil flow path to the rocker shaft. Nothing radical, just smoothing and slightly enlarging passages here and there. But I had a worrisome thought the other day. Is it possible to divert enough oil flow to the head that you could starve the crankshaft of oil? Or is there plenty to go around, with the split between upper and lower engine not much changed by a little easier path to the top?
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