Sunday, May 8, 2016

Building a power plant for the Nautilus, Part 3

I took the crank, rods, flywheel, pressure plate, fan, pulley and pistons to Denver Balancing last Thursday to have them dynamically balanced.  I also left them with the engine case and main bearings, asking that they be taken to Painters Grinding to have case clearancing for the 74mm crank and piston spigots to ensure the dome top piston skirts clear.  I've done a lot of non-precision case grinding here lately, but it made a freaking mess to my workspaces in the garage and the results look a bit amateurish.  The 'D' hole for the breather hole in the engine case for the 1500S was incorrectly done by RIMCO and the metal baffle plate wouldn't set flat on the block.  Also, the immediate shelf area inside the case was not cut through.

I tried to get several shops to handle this entire job for me, but no one locally would.  I finally sent the case off to RIMCO for some work, but they only opened up the top breather hole, and then only just enough for their comfort level.  The pictures here show what I had to do with my new drill press and a hand held Dremel tool to get the results I was after.  It's pretty close to what the factory does with all late '64 and later VW cases.  Why do this?  Because interior case pressures at higher RPMs causes oil burning.  There's a Workshop Bulletin that discusses this, some of which is shown above.  The other recommendation in this Bulletin was to use an improved piston oil control ring, which was actually done already in the NOS 1500s piston and cylinder kit I sourced 12 years ago.  Beyond this, I'm going to use Deves piston rings and that should be yet another improvement and further reduce the potential for oil burning in this higher compression engine.  With Painters finishing up the job with clearancing, I hope the results will be worth both the cost and the wait.  And, help keep my shop clean.  We shall see.

There's been engine progress made with the induction system, too.  I've worked hard to come up with a great set of stock style dual Solex carburetors for the Nautilus' power plant. Along with the dome 83mm 'S' pistons, the Solex PDSIT carbs debuted on the Type 3 1500 S engine at the beginning of the '64 model year.  Most Type 34s received this engine configuration as VW tried to give the car all the performance it could. These Solex carbs are left and right specific and the main carb bodies are stamped with a code that helps identify the engine specification onto which they were originally installed.  For an early '64, I was looking for codes of 5-2 on the right carb and 6-3 on the left.

I let BerT3 in Belgium know what I was looking for and he eventually found a good rebuildable set.  His carb rebuild services include re-bushed throttle plates using Oilite bushings and new reproduction levers in the accelerator pump covers.  I must say his work is outstanding.

As good as BerT3's work was, I did find a little room for improvement.  Maybe I was just being picky when I swapped out used electric cutoff jets with some NOS units and replaced the chokes and choke seals with some NOS pieces.  I also replaced the accelerator pump lever washers and keepers with original parts to help better maintain the original geometry.  I also replaced the drain plugs and idle enrichment screws with some brass pieces I had.  Just because.

These carbs shipped to me with clear zinc plated intake manifolds, but these will be painted with the same high temperature gray muffler paint as the exhaust components before installation.  Or, those particular manifolds won't be used at all because I'm considering dual port heads, with larger venturis in the carburetors.  This will no doubt also require a re-jetting for each carburetor.  I know that all of this is a departure from the originally bone stock configuration I intended for the craft, but these changes will wake up the performance modifications I am installing deep in the engine.  I'll be using VW parts, so I consider the engine modifications a sort of later 60's 'vintage speed' modification that could have been made to result in some real performance gains.  I do realize I'm sort of heading into an odd direction with this restoration, but I've invested in a set of Wide-5 CSP front disk brakes and later stock Type 3 dual master cylinder, so the horsepower increase--while not massive--is coming with an improved braking system.  When VW introduced the 1600 Type 3 engine in the '66 model year cars, the cars also were equipped with front disk brakes.

I confirmed I have the correct air cleaner and air control assembly.  The induction is definitely getting closer to being entirely sorted.

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