Pond block gallery question

[ToddK]

I have just about finished putting together my race engine, and have a question regarding the gallery plugs at the back left of the block. The block is a Pond aluminium. See the (crappy phone) pic of the galleries I'm talking about.



I know the upper gallery with the brass plug is the main side oil passage. However my question is regarding the lower hole that is not plugged. As far as I can tell, this is a blind hole. Do I need to plug this hole, or can it be left open as it is now?

[ToddK]

I think I figured out part of my question - the lower hole is for the oil pressure relief valve.

Since I am using the oil pressure relief valve in the block, just the one in the oil pump, that would explain why it seems to be a blind hole. So I shouldn't need to plug it - am I correct in my assumption?

[GJCAT427]

Is it drilled from the bottom up through into the oil galley?  Thats were the cast Iron engine relived from thus it held the relief valve and spring in, if I recall right. If its not drilled I would worry about it.

[Barry_R]

Pretty certain its a dead blind hole as supplied.  OK to leave empty.
You will know once you pre-oil it 

[blykins]

It's a blind hole.

Now, on the other hole you have plugged, that hole is meant to get a -6 AN plug with an O-ring.  If you don't have that, you'll get a leak.

[blykins]

By the way, that bottom hole is not even counterbored on the newer blocks:

Look down at the picture in this thread:

http://www.network54.com/Forum/74182/message/1415142238/

[ToddK]

It's a blind hole.

Now, on the other hole you have plugged, that hole is meant to get a -6 AN plug with an O-ring.  If you don't have that, you'll get a leak.

Ah, ha! Probably why the plug is sticking out so far. That is how I got it from the guy who did the build. I will replace it with a plug as you describe. As Barry said, the test will be when I prime the engine.

[blykins]

When you pull that plug out, you'll see the counterbore for the o-ring.  Unless this is a very early Pond block, you will need the o-ring'd plug as I mentioned.

The front 3/8" NPT plug that is to the driver's side of the timing cover needs to be eye-balled to make sure it doesn't protrude too far into the bore.  If it does, it will partially block off the passage that goes to the #1 main/cam bearing, and also to the galley that runs down the side of the block.  If you have a chance, pull the oil filter adapter off and shine a light up into that passage to see where yours sits. 

[ToddK]

I don't have the oil filter adapter on yet, so will check that passage out. Thanks Brent.