small ports on either end of block?

[mini64]

putting my block together. on either end of it are small, slightly smaller then 1/2" ports that connect to the pushrod holes (if we had pushrods). what is supposed to be in these- a small freeze plug? they are not threaded like the threaded holes further down for the main oil gallery. if i remember right on the formula ford blocks one of these had a ball pushed in it, but i dont remember one on the other end.

[billwill]

Sounds like holes for core plugs.

So called because the holes were originally the support pegs made of the same sand as the CORE of the mould into which the alloy was poured to form the cylinder head or steel to form the block.. The CORE is the shape of the water chamber. It is made of baked sand and has to be supported in the correct place for the metal to flow around it.

After the metal has cooled the core is broken up with a wire rod through the holes and then finally washed out of the cylinder head or block, leaving a water chamber with holes in the sides. The holes are then filled (after machining) with either screwed brass plugs or a slightly domed disk of steel which is put in place & then hit in the centre of the dome with a hammer. This flattens it and it spreads outwards to jam in and seal the hole.

Same principle applies to the oil vapour chambers, which since you say it connects to the push rod chamber, seems to be what you have there.

[garyeanderson]

putting my block together. on either end of it are small, slightly smaller then 1/2" ports that connect to the pushrod holes (if we had pushrods). what is supposed to be in these- a small freeze plug? they are not threaded like the threaded holes further down for the main oil gallery. if i remember right on the formula ford blocks one of these had a ball pushed in it, but i dont remember one on the other end.

open in front

core plug rear

Gary

[CBUEB1771]

a small freeze plug?

Small freeze plugs go into these bores as shown in Gary's shows photos. I wish I could help with an explanation for the existence of these bores. The new Ford Racing blocks retain this feature. Interestingly, AX blocks from South Africa take tapered pipe plugs rather than the freeze plugs.

[Elan45]

On pushrod motors, this bore in the front of the block is part of the oil return system from the head. After lubing the rocker arms and valve stems, the excess oil
runs down the pushrod bores to lubricate the tappets from above. The front half of the block then drains from the tappet area out this hole and down the front of the block. At the rear, IIRC, oil drains down through a hole below the breather (on a pushrod) and below the rubber head/ block interface tube on a twin-cam.

On a twin-cam motor, I believe the front cover blocks this rudimentary oil passage, but there should be no harm if it were left open.

Roger

[CBUEB1771]

On pushrod motors, this bore in the front of the block is part of the oil return system from the head.

Doh, I forgot that on a push rod motor the oil return passages are full of cam followers. Thanks Roger.