SuperH Heads

SuperHank · May 18, 2009

I rebuilt the heads on my SH 2 years ango and I have not put many hours on since. During the rebuild the machine shop operator noted that there was a hole in a copper by pass tube that went over the top of the heads. It is part of the lube set up and I could not id it. Since he seemed to know what he was doing I let him braze the hole shut. I just read that the hole may be part of the oiling system of the head. I am having more work done on the SH and will have the hole opened. Have I damaged the heads? Any other in put from you guys on how this works will be appreciated

rustyfarmall · May 18, 2009

That tube is part of the engine/crankcase ventilation system. It has nothing to do with oil. The hole is SUPPOSED to be there.

Anonymous-0 · May 18, 2009

Dear Rusty,
Which way is air traveling in the vent tube going to the air cleaner? Is this a filtered inlet or is there suction on the tube? Why is there another breather tube on the side of the block?

Anonymous-0 · May 18, 2009

There is a slight vacuum on this tube as it leads to the inlet pipe on air cleaner and as an engine will normally have more blow by than the amount of air passing through the tube you still need another vent for crankcase. Breather on side has a filter element in it also (chore boy) to keep the dirt out in case there would be a reverse flow. When the 460 and 560 came out they also had a vent tube to air cleaner from valve cover, but soon learned it just lead to more build up inside air cleaner inlet pipe and took it off and plugged hole at air cleaner and valve cover.

Wayne in MN · May 18, 2009

Air flow:
from the governor to the head, through the valve & rocker arm area, out of the head & into the air cleaner.
Air flow is restricted by size of brass fittings in the head.

SuperH Heads

SuperHank

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rustyfarmall

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Anonymous-0

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Anonymous-0

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Wayne in MN

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