Project Update 11/4

In between the longest race of the year & a non stop work schedule I managed to make a little more progress on the Car Craft engine build. In the last update I had disassembled the motor & did some checking of critical dimensions. With that complete I was ready to move on.


The next step in the build was the modifications to the block to improve the marginal internal oil system. The oil system was sufficient for stock applications but lack luster for high performance applications so we have to modify it. The oil goes from the pump to the block & up to the lifter galleys through 1/2″ passages.  There is also a 90* corner in there to complicate things. We drill the 1/2″ passages out to 9/16″. it does not sound like much but add up the gained diameter by the length of the passage & it does make a flow difference. We then contour the nasty 90* corner with a die grinder then smooth with a small sandpaper barrel.


The next oil modification is to get more oil to the #4 main bearing. This is done by taking oil from the front of the motor closer to the oil pump & diverting it through the lifter galley above the main journal. We drill & tap the block in these 2 areas to 1/4″ npt & join the two together with a #6 0r #8 braided hose.


Another thing we do to divert oil to the crank is to put a restrictor in that restricts oil to the drivers side lifters. A 3/8 pipe tap run through the journal @ the front of the block (no drilling required) is a perfect spot to use a steel pipe plug with about a .060″ hole in the center. @ 70psi that will still provide plenty of oil to the lifters & valve train.


The final oil mod will be for future use on this budget minded motor. There is a sort of hole in the block on the passenger side bottom of the block. It looks like a locator hole for a machining process but it lines up with the oil pickup. the diameter of the hole does not need opened up but a thin amount of steel needs drilled to break through to the oil pickup passage, The hole is then contoured then tapped for a 1/2″ pipe fitting. There is an oil pan set up that uses an internal oil line that connects to this spot of the block for more direct oiling to the inlet of the oil pump,


That is the end of the oil mods & now the block gets thoroughly. All that drilling & grinding will get metal everywhere. A clean block is a happy block. The water passages on a block often hide a ton of sediment from years of water minerals & rust. A good set of engine brushes make block cleaning a lot easier. This motor had a lot of sediment. It took many times of scrubbing & rinsing to get things clean enough for the next step.


I decided to fill this block more for future use than for the budget build. Filling the block uses a material called “Hard Block”, There are other brands of this material on the market but Hard Block is the most popular. Hard Block is a concrete like material that contains metal filings. The composition of Hard Block is designed to expand & contract with the heating & cooling of the block to hold its strength. Filling the block strengthens the cylinders keeping them rounder for better ring seal & providing lower end block stability for longer bearing life.


The fill is done in 2 steps. One day one bank, the next day the other bank. The filler is mixed with a specific amount of water into a pourable slurry. Like a milk shake. The block deck should be level to prevent a un even fill. There are pretty specific instructions provided with the filler. Follow them closely. Once we are done filling the one side of the block we then bolt a torque plate to the deck surface. A torque plate is used when boring the cylinders to duplicate the cylinder shape when a head is bolted on. Most people do not have AMC torque plates, also known as boring plates. If none are available just bolting a head on will work just fine. Make sure to torque the head to specs.

The next day repeat the process to the other side of the motor. Machine shops will do this for you for a fee of course.


The block is now ready to head to the machine shop & while it awaits its spot in line I will be getting the timing cover/oil pump ready to re install. More to come……

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