Engine cases, new old, the good,bad,ugly and T4

Going to put out some helpful insight for both new engine cases, used cases and type 4 case here. Lots of years and tears to find and refine these finds.

For starter we will talk on the new Mag cases from Motorav. New cases have not been overheated, abused, or seen a lot of stress like a used case. Magnesium is the same martial used in factory cases. Mag dissipates heat much faster and more efficiently than aluminum. This is why it was chosen for vw engine blocks. Then engines we build with mag cases do not have to run and external cooler but it is never a bad plan and is cheap insurance. Now even though these cases are new they are not bolt on ready. It is very important to blow threw all of the oil passages, it has been found that some times they are not all correctly connected.If so the plug or plugs must be removed, passage drilled to the correct depth and reinstalled. The case savers are also installed higher than the deck witch I totally do not under stand, so they need to be milled down and clean up with a tap. These cases normally come with uneven decks I have seen as much as .010 tho side to side and .004 cylinder to cylinder. so It is best to deck them right out of the gate. For some reason the case 3/4 side is .003 taller than the 1/2 side. This .003 side tolerance can also be seen on the older autolinea Mag cases. In addition they have a much taller deck then old factory cases. Used cases normally see some where between .035 and .049 thou deck heights with a 69mm crank. The new Mag cases are more in the .065 to .080 deck range. This is nice for when you are building a stroker makes it easier to come up with a good deck with out shims. If you plan on building a stock 69mm stroke you will need to deck the case lower to come up with the correct deck around .040. New cases do come with better rear main drains and a few updated features, yet they do need to be baffled for case pressure and better oil drain back. Much like in the factory Bentley going from a 1500 to 1600 you are shown to enlarge the baffle hole from 13mm to 15mm. I like to make about a 17mm air passage, with a little bit of a labyrinth to control the oil splash off of the cam gear. There is also 2 tangs on the bottom of the engine case that must be milled off to fit a sump. The newest versions of the Moto Rav can not be cam hoover modded there is not enough meet to connect them unfortunately,This to me is a huge bummer.

Aluminum cases are a huge improvement to Vw engines. They are so much stronger, weighing about 10-14lbs more.They have more added material and the metal itself is stronger.These cases can take 400hp and last a life time. With every thing there is a down side, these cases hold heat in more than the mag. This is why I always recommend running and external cooler with them. My personal bus engine is in a aluminum case with almost 5o,000 on it showing no signs of wear. In reality I have found no real differences between Autolina, EMPI or CB aluminum cases. All are good, they too need air baffled, the decks seem to be much better. These engines can also be hoover modded with out issues. You CAN NOT run a standard aluminum crank pulley on these cases, They will tear up the revers grooves on the pulley and sometimes friction weld the pulley to the case. Always run a steel pulley or a sand seal front pulley. In my opinion I prefer sand seal pulleys on every build!