Engine assembly

The actual assembly took several weeks as I had never seen the inside of a Chevy inline 6 cylinder before.  As I mentioned earlier, I bought 2 engines in the engine parts deal.  One was a 1954 and the other was a 1953.  The 54 had been running in the guy's car while the 53' had been sitting for quite some time.  I wanted to use the '54 because the valve cover was held on with 4 retaining bolts around the rim rather than the 53 and earlier style which was retained with 2 studs that came up thru the center of the valve cover.  Turns out the 54 wasn't the better of the two.  It had been bored .020 over previously and the crank had been turned .020" on the rods and mains.  Plus a couple of rod bearings were scored and failing and the crank would need another grinding.  The '53 engine turned out to be very clean inside and show very little wear.  I decided to use the 54 head on the 53 block.  The block was line bored, bored .030" over for new pistons, and the deck was cut to maximize compression.  New .030 over pistons, Comp Cams hydraulic camshaft, new timing gears, Hastings cast rings and Clevite bearings were added to the shopping list.  The crank was polished and the rods were reconditioned.  The entire rotating assembly was balanced and I carefully cleaned and checked the 53 oil pump for reuse. 

Checking the main bearing clearances is a little tricky on these old 6's.  Shims are used under the main caps to achieve the desired clearance.  I had been warned to keep the main bearing clearances tight to promote proper oil pressure to the lifters.  The main clearances came in at .0018 -.0020 with the shims.  Look closely on the edge of the center main caps and you can see the copper colored shims.

The crank nose was drilled and tapped for a small block Chevy balancer retaining bolt and the camshaft was degreed to 3 degrees advanced using an offset key.  The Felpro gasket set also included a neoprene rear main seal to replace the old rope seal.  Much better leakage prevention with the neoprene unit and much less drag on the crank. Here's the block with crank, cam, rods & pistons and oil pump installed.

These old 6's used an external oil filter system that didn't filter all the oil.  A little research on the internet produced an article on how to modify the block for full flow filtering.  I was a little apprehensive about drilling holes in the side of the block but I did it and it worked!  http://www.stovebolt.com/techtips/full_pressure.htm 

The cylinder head prep was a lengthy process.  The exhaust valves were replaced with stainless ones and new seats were installed to allow running unleaded fuel. (this modification had previously been done on the 216 already in the car).  In order to boost compression, Clifford Performance recommends cutting .100" off the head surface and sinking the intake valve that same .100".  They also suggest cutting .100" off the valve stem.  Take a look at the combustion chamber for this head and you can see why.




If you look closely just to the right of the intake pocket, you'll notice a small circular area.  That is one of 3 plugs that were used to repair a crack we found.  The process is called "stitching" and has proven to be very effective to repair small cracks.  Unfortunately, finding this crack and fixing it caused us to forget to check the rest of the head for any issues.  That came back to bite us in the butt later.

The 54 head had a some light porting done in the intake area to round the area below the valve a bit.  New valve seals were installed and the Comp Cams springs were installed at the specified 1.700" height.  The head was then set on the block and the rocker shafts were installed to check for valve to piston clearance.  In order to achieve proper cam lift and valve to piston clearance, .100" shims were added under the rocker stands and .080" lash caps were added on top of the exhaust valves.   Here's the head installed and the rocker shafts just sitting in place.  You can also see the new holes for the oiling system on the lower side of the block along the oil galley ridges.  These will be clearer in a later picture.

Once the valve train was finalized and the block was masked it was off to the paint booth to add some color.  Here's the before and after pics.

That color was supposed to match the roof of the car but the NAPA paint store didn't have a color chart for the '41 and I guessed wrong.  A second coat of something a bit darker looked better.  Then someone suggested using all stainless steel fasteners to spice things up a bit.  So, it was off to the hardware store and to Duane's private stock for some nice SS bolts.  Add a couple of chrome covers that came with the motor deal, paint the Fenton headers black and bolt on the Clifford polished aluminum 4bbl intake and the little 6 started looking kinda sharp!

Note the 2 blue fittings in the side of the block.  Those are the new holes added for the oiling system filtering.  That little Holley carb sitting on top is a new 390 cfm unit with vacuum secondaries and electric choke.  In order to test run the 235 on the dyno, I had to add a water pump, balancer and thermostat housing.  The ones we used aren't going to be the final units as my generator uses the wide belt (5/8) pulley.  I plan to remove the new water pump from the 216 and I have another balancer from the 53 engine.

The distributor was completely disassembled and cleaned before going back together with a Pertronix electronic kit and a new matching coil.  The "plug" in the #1 cylinder above is a piston stop.  Setting the timing on these old 6's is done thru a hole in the bell housing and, to me, that is most inconvenient.  So, we made a pointer for the front of the engine out of a ss bolt that doubles as a timing cover hold down, found top dead center of number 1 cylinder and marked the balancer accordingly.  I also marked a 36 degrees before TDC mark on the balancer.  The chrome road tube in the picture above (right in front of the distributor) was later removed and replaced with a black one that had a better shape. 
Next it was off to the dyno room to break in the camshaft and see how much HP the little 6 could produce.  In stock form, the '53 was rated at 115hp with a single barrel carb.  I was expecting somewhere in the range of 175 - 180 hp on the new motor.

Note the timing pointer and oil filter system in the top pic.  One of the things stressed by all the old timers is heating the bottom of the intake under the carb to prevent stumbling and poor gasoline atomization.  We ran a temp probe right under the carb during the dyno time and the old timers are right!  The temp drops a lot when the throttle is opened.  Note the water hoses running from the block to the intake and from the thermostat housing to the intake.  Dick added a fitting in the thermostat housing for the hose connection.  These pics were made prior to running during the initial setup.  It was late in the afternoon before we finished the setup and got it running.  When the lower water hose blew off the water pump giving Duane and I a warm bath, we figured that was enough for the first day.  Little did we know, that was just the beginning of several more issues to follow.