218 Teardown 218 Teardown



The donor 218. The history of the block is unknown as it was found in the trunk on the 1947 Dodge Business Coupe. An overhaul plate is visible indicating it was rebuilt at some point. Visual inspection reveals no cracks in the water jacket.



The water distribution tube had been removed earlier and came out in one piece. Next we unbolt the head and set it aside.



With the head removed the valves and pistons look good. No ridge was found on the top of the cylinder bores. All the valves are working so tear down should be straightforward.



The cam driven oil pump is first to come off. It is held to the block with two bolts.



It won't budge after unscrewing the bolts. A couple taps with a brass drift punch splits it away from the block case.



Then it just slides out.



The oil pressure relief valve is next. It required a hammer to break it loose.



If you planing on reusing the parts keep them all together. Inside the spring is the plunger which moves in and out based upon oil pressure. Usually you would replace the valve and spring when doing a rebuild.



To remove the timing gears and chain the front vibration damper must come off. This block was a little different in that the pulley, damper and hub were all one assembly. Usually they are three parts bolted together. The arrow points to the hub nut, which has teeth for using a starter crank.



This is one of those jobs an air gun is very helpful and makes quick work of removing the hub nut.



Close up of the hub nut and crank teeth. The truck has a hole in the front grille for a crank starter.



Next a large puller pulls off the hub and pulley.



Arrow point to the keyway which locks the hub on the crankshaft.



Next to go is the timing gear cover.



Again an air ratchet save some time in removing all the bolts.



Off comes the cover, revealing a rusty timing chain and gears.



After removing the three bolts holding the upper timing gear to the camshaft use a screwdriver to break it loose (arrow).



After it pops off the cam you can remove the timing chain.



To access the valves unscrew the bolts holding the valve covers.



Gently use a screwdriver to pry off the cover. You don't want to bend it with too much force.



Using a long screwdriver as a lever I can turn the cam. Note the rusty oil lubrication tube for the timing gears (arrow). Obviously something got clogged up.



In general, the valve train looks pretty good. It is clean with a minimum of rust damage.



You can clearly see the lifters are working. The valve second from the right is fully closed. Next step is to remove the valves.



To remove the valves you need a valve spring compressor. These can be purchase or rented at any auto parts store or tool rental shop.



Before you remove a valve, it must be in the closed position, that is, the lifter is off the cam ram. The valve on the left is fully closed. The arrow points to a lifter fully open. Because the spring is pushed up on the open valve you can't compress the spring enough to remove the valve keeper. The black arrow points to one of the oil return passages.



To remove a valve, first compress the tool so it can slide in under the spring with the bottom on the block. If you do this in the car you should have rags in the valve gallery plugging the oil returns. This will prevent the keepers from falling into the oil pan.



Next expand the tool so it lifts (compresses) the spring up. This exposes the split cone shaped keeper. The arrow points to where the keeper is split and starting to fall off the valve.



Pull out both halves of the keeper off the valve stem. Left half done, right to go.



Once the keepers are out release the compression on the valve spring and lift the valve out the top of the block. You will need to turn the cam so each valve you work on is fully closed before you attempt to remove it.



With all the valves out, next task is to remove the springs.



Using a large screw drive you can easily push them over the tappets. Once clear of the tappets they pop out.



With the springs out position the block on it's side as shown. Pull all the tappets fully up. This will pull them off the cam lobes so the cam can be removed.



Remove the two bolts which holds the cam to the block. The arrow points to the cam thrust plate which should be checked for wear before re-assembly.



Then slide the cam straight out. The thrust plate is clearly visible.



Flip the block back upright. The tappets will fall out of their bores into the oil pan where they can be retrieved when you tear down the bottom end.



Remember when you start the bottom end tear down to mark all rod and main bearing caps.  This #4 rod has been identified with a numeric punch.



Two punch marks were used to identify the #2 main bearing cap.



The other tear down steps noted in phase one were all performed with no problems. After the crankshaft and pistons were removed, the block was cleaned up. All oil galley plugs were removed for cleaning. A gas powered pressure washer was used to back flush the water jacket and passages, as well as clean the exterior of the block. The water jacket had quite a build up of rust and gunk. The block was then taken to a machine shop for inspection and magnufluxing. Also the cam was magnufluxed before being shipped for a regrind. The cam grind will provide a mild horsepower gain plus widen the torque band.



Things went so well during the tear down I should have known the my luck would not hold ! The magnufluxing revealed 6 or 7 cracks in the head area of the block going from valve seat to valve seat and head bolt threads to water jacket passages. In the top photo a rusty crack is clearly visible where an earlier helicoil repair was made. In the lower photo a crack was found stretching between the two valve seats. Look closely just below the black line which parallels the crack. Approximately 5 similar cracks were found some into the water jacket. At some time this block got really hot and is can not be used. Upside to this problem is it was a freebie so I don't loose any money on it. Downside is I still need a block to rebuild.

The new plan is to use my D24 block for Big Red. The machine work on the D24 serial numbered block is finished and ready for re-assembly.