Head oil drain passages

[mkodama]

Just in case anyone was ever curious to see a picture of the terrible path that oil has to take returning from the heads to the crankcase. Additionally, (not pictured) there is a passage on each head connecting to the timing cover, but oil can go both ways so it’s not always a drain. First picture is the upper pan, viewed from the top. Second picture is the block, viewed from the bottom.

[NoHaveMSG]

Those aren’t the only areas it drains back from.

[mkodama]

Originally Posted by NoHaveMSG

Those aren’t the only areas it drains back from.

No, that’s it. Where else do you think it’s draining?

[NoHaveMSG]

Originally Posted by mkodama

No, that’s it. Where else do you think it’s draining?

I guess I shouldn’t say not all the head drains since we are excluding head to timing cover. Some of the area’s you have marked are not head drains. There is one on each case half to a chamber that goes into the upper drain pan, and then down to the lower. Here is a video I did years ago on it.

[mkodama]

Originally Posted by NoHaveMSG

I guess I shouldn’t say not all the head drains since we are excluding head to timing cover. Some of the area’s you have marked are not head drains. There is one on each case half to a chamber that goes into the upper drain pan, and then down to the lower. Here is a video I did years ago on it.

I mentioned the head to timing cover passage in the first post, which you might have missed.

I just watched your video and there are a few confusions.

The “head drains” you refer to are coolant inlet to the block.

The large port pointed at and referred to as “straight through this baffled passage” is also coolant; this is the coolant thermostat bypass.

The coolant bypass port was mixed up with the front crankcase ventilate system.

And you also include the front and rear crankcase ventilation drain tubes, which are correct, though I wouldn’t call them head drains passages like what this thread was about.


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[NoHaveMSG]

Originally Posted by mkodama

I mentioned the head to timing cover passage in the first post, which you might have missed.

I just watched your video and there are a few confusions.

The “head drains” you refer to are coolant inlet to the block.

The large port pointed at and referred to as “straight through this baffled passage” is also coolant; this is the coolant thermostat bypass.

The coolant bypass port was mixed up with the front crankcase ventilate system.

And you also include the front and rear crankcase ventilation drain tubes, which are correct, though I wouldn’t call them head drains passages like what this thread was about.


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I was reading on my phone so I may have missed it at first.

That one is not coolant. The one next to it is. Blow air through it, it goes strait to the oil pan. I can do this tomorrow and show you.

[NoHaveMSG]

Originally Posted by mkodama

I mentioned the head to timing cover passage in the first post, which you might have missed.

I just watched your video and there are a few confusions.

The “head drains” you refer to are coolant inlet to the block.

The large port pointed at and referred to as “straight through this baffled passage” is also coolant; this is the coolant thermostat bypass.

The coolant bypass port was mixed up with the front crankcase ventilate system.

And you also include the front and rear crankcase ventilation drain tubes, which are correct, though I wouldn’t call them head drains passages like what this thread was about.


Sent from my iPhone using Tapatalk

You are right on the passage below the cylinder. That is coolant, don’t know how I missed these were not sealed from the jacket.

The one on the top of the block is not coolant though, the one next to it goes straight to the water pump. This one goes to the baffled passage and the cover isn’t even fully sealed from the timing cavity with a drain hole back to the pan.