Engine Part II (Post # 37)

Last week's posting, Engine Part I, was about the general features of the Alfatross' 1975 cc four cylinder Super Sprint  engine and the differences between it and the more pedestrian engines installed in other 1900 Alfas.  This post is going to delve into the inner workings of the engine and how we're going about making sure that beneath the Alfatross' beautiful skin its beating heart runs strong and true. 

The Approach

The Alfatross was built to race, and we want it to be race-worthy when the restoration is complete. It follows that functionality will be emphasized. Some authorities would say that maintaining originality trumps other considerations, but the 1900 engine has known internal design defects that can be corrected during the rebuild.  My view is that we would be doing a disservice to The Alfatross not to correct these internal problems while we have the opportunity. There are other departures from originality that will improve performance and longevity such as the application of special coatings that reduce friction and even chemical and physical treatments that allow the re-use of original parts which might otherwise have to be replaced. This is where I am relying on the expertise of DeWayne Samuels, who is directing the engine work in Phoenix. The following is a distillation of his various progress reports, broken down by component groups.    

Engine Block

After cleaning the main bores and mating surfaces of the block the main bearing bore diameters were measured and checked for core shift and alignment.   These dimensions tell us how true the crankshaft will run in relation to the cylinders, and also will indicate if there has been any core shifting or problems with the main web or main cap.



The initial measurements indicated that new main studs and fasteners need to be installed first to obtain proper loading during measuring and correction procedures. So the main studs were extracted, measured, profiled, and sent out to a vendor to fabricate new custom-made stud and fastener assemblies.  The threaded female stud bores in the block were also analyzed and repaired where needed.



  The cylinder walls and deck surface were subjected to sonic testing to determine thickness and integrity.  This test tells us the amount of material available for overbore with relation to wall thickness, concerns for cylinder deformation, and cooling/heat transfer.  The results show that the cylinder block assembly has plenty of life left.  

Cylinder Head, Valves, and Cams

The combustion chamber volumes were measured and recorded as were the volumes of the piston domes and valve reliefs.  The valve spring retainer/adjusters could not be assembled without first fabricating a tool.  The cam bearing journals were prepped and measured to determine clearances.  When the camshafts themselves were cleaned and inspected it was apparent that one lobe was badly worn and will have to be repaired.  Additionally, all the bearing journals were pitted.

The cylinder head was disassembled, cleaned and glass bead blasted.  It was apparent that cylinder No. 3 had sustained damage.   Valve seat wear was assessed for all cylinders.  A special tool had to be fabricated to measure spring heights and seat location in the head.

Measuring the piston dome and valve relief volumes.

Pistons and Crankshaft

The piston domes, wrist pin locations and offset, deck heights and pin heights were measured along with combustion chamber molds and volumes.  When the pistons and cylinders were checked for wear, piston no. 3 was found to have irreparable damage.  So the Alfatross is going to get a new set of pistons.   The crankshaft's main bearings had damage attributable to poor lubrication (one of the known design deficiencies of the 1900 engine) in addition to a potential crack.  It may be necessary to send the crank out for nitriding to treat the bearing surfaces.

By the Numbers

The Alfatross' heart is not exotic or complicated, but even a simple engine takes a lot of time to break down into its component parts, and clean, measure, and compare them with the original specifications.  So now we have a lot of "baseline" numbers and dimensions for the main components of the engine, and it is clear we have a lot of work to do. Although I have not yet discovered incontrovertible evidence that The Alfatross was raced competitively, at least some of its previous six owners must have driven it pretty hard, given the evidence of use and minor rebuilding in the past that we have discovered.  The good news is that it looks like the pistons are the only parts that need replacement--so far! 

  

Engine Part I (Post # 36)

Old Business: Brake Time

In my last post I mentioned that the Alfatross' original brake fluid reservoir was something of a mystery: so many fiddly parts . . . what do they all do?  Who made it?  Well-known 1900 guru Peter Marshall saw the post and was intrigued.  He forwarded the image to Don Cross, a colleague and student of the kind of arcane technology found in exotic cars from the 50s. 

The Alfatross' diabolical brake fluid reservoir.  The brass rod and piston on the left are upside
down in relation to the other parts in the photo.

Mr. Cross noted that the reservoir is similar, but not identical,  to those found on Lancia Appias, and wrote:

The system works on the basis that when you pull [the brass rod] up against the pressure of the spring, the suction of the cup will fill the barrel with fluid which will then pump it around the brake system. When the brake system is fully bled and the reservoir full of fluid the rod should be pulled to its fullest extent and should stay there ( if it doesn't - then you have a leak somewhere ). It will over a period of many miles gradually work its way down, but the idea is to keep it fully extended at all times.

The system is then under some pressure and is sufficient to take up any movement in the system, but not enough to actually extend the brake shoes against their return springs. Gets rid of what I call "stiction."

When bleeding the brakes, keep pulling up the rod to pressurize the system and making sure you keep the reservoir topped up otherwise you will push air into the system. This means it is a one man job bleeding the brakes. Pressing the foot pedal will not bleed the system with this type of arrangement. ( Nobody told me this when I had my first Appia and it took a long time and much frustration until I worked it out).

Thanks Peter and Don!  You have saved me a lot of time and effort.  Hope I can return the favor one day! 

New Business: The Engine



Side view of the 1900 SS 1975 cc engine:  short and tall!  
Alfa Romeo 1900 Sprint, Gonzalo Alvarez Garcia.

Front view of the 1900 Super double overhead cam engine
showing the double chain arrangement.  Alfa Romeo 1900
Sprint, Gonzalo Alvarez Garcia.

Work on the Alfatross' engine continues apace.  As mentioned previously, it is at Standard Machine in Phoenix with instructions to "blueprint" it.  But what are we starting with?  It seems that there were a number of factory engine options for Alfa 1900s.  All the engines were 4 cylinders with cast iron blocks and double overhead cams, but there were important variations.  The basic engine was an 1884 cc version producing between 80 and 100 horsepower, depending on which of the 5 different carburetion options were fitted.  The top engine option was the 1900C Super Sprint with a displacement of 1975 cc producing up to 115 horsepower at 5,000 rpm.  This engine, fitted with a pair of dual downdraft Solex 40 PII carbs and mated to a 5-speed transmission and a 9/41 rear end could take a relatively heavy steel bodied Alfa 1900C coupe to 190 km/h. 

So which engine does the Alfatross have and how do we know?  The first clue is the engine serial number: 1308-01541.  This number falls within the 1900 Sprint Second Series production range for the year 1955. Other evidence is provided by external and internal features present in the Alfatross' engine, including the double chain arrangement used to drive the cams, the dual downdraft Solex 40 PII carburetors with oversized jets, double v-belts on the crank, water pump, and generator pulleys, 4 into 2 exhaust headers, 8:1 compression ratio, electric and mechanical fuel pumps, and cylinder head and cam characteristics.

What Was the Original Configuration Under the Hood?

The Alfatross' engine appears to be largely original with respect to the configuration of the engine matching the specifications published in the literature.  When compared to other restored and "preserved" examples there are intriguing similarities and differences.  Below are photos of the engine rooms of 7 1900C SS Zagatos in addition to the Alfatross'.  Putting aside the various cosmetic differences and focusing on the similarities, all of them have the same basic 4-cylinder layout with tubular headers and black crackle painted cylinder heads and cam covers.  Only one example has the distributor driven off the right cam.  Five engines show either dual downdraft Solex carburetors or the large, flat, heavy steel air filter box appropriate for those carbs.  The two other engines appear to have been retrofitted with side-draft Webers. 

The 7 examples below could be divided into three camps: engines that have been restored to enhance performance, engines and engine compartments that have been restored to present the best appearance, and cars that have not been--and may never be--restored in any way.

Car 01954 has a beautifully finished engine room but non-original carburetors.
Note the unusual distributor location mounted on the right cam.

Car 01941 also has a scrupulously clean engine compartment. Much of this car
 appears to have been "over-restored," but an effort has been made to retain
the appearance of originality under the hood.  Www.hi-think.it/luzzago.

Car 01915 is obviously set up to run in events.  The engine room sports some
retrofitted performance enhancements, the most noticeable of which are
upgraded carbs and wrapped headers. 

Car 01845 is a "preservation" candidate and should have one of the most
authentic and original engines, but the normal shroud over the exhaust
headers appears to be missing.    Octane magazine.

Car 01915 is another preservation class example with an amazingly original and
intact engine room.  Nothing seems to be missing or modified.

Car 01931 appears to have a largely intact engine bay if the air filter box can
be found.  www.kidston.com.  

This image was on the Internet, but there was no information about its chassis
number.  Other than "cosmetic upgrades" the engine presents as original.
Www.ultimatecarpage.com.

My plan for The Alfatross' engine is to maintain an authentic appearance, re-use as many original components as possible, and make sure that when it is finished it runs strong and true.  As new information comes in about how the Alfatross' engine is progressing I will report it in future posts.

Body Building (Post # 35)

With so many sub-assemblies like the brakes, wheels, lights, instruments, wiring, steering wheel, and running gear already complete or nearing completion, the four 800-pound gorillas still in the room with the Alfatross are body/frame work, interior work, paint, and engine. These are tasks I do not have the tools or experience to tackle so they will have to be done by someone else, somewhere else.  Because I want to reassemble the Alfatross myself, it will be necessary to find a competent shop willing to restore and paint the Alfatross, then ship it back to me.

Young Guns Designs, Phoenix AZ.  Young Guns.

Last week Tyler Tibbits, CEO of Young Guns Designs, flew up to Santa Fe to see the Alfatross for himself.  Wheel man Randy Davis and I met Tyler back in March while on a trip to Phoenix to check up on the Alfatross' engine (see "The Alfatross Meets the Phoenix" April 23rd post and www.younggunsdesigns.com)  Tyler and John Pollock, his business partner, gave us a quick tour of their facility which included an upholstery section, woodworking shop, design studio, metal fabrication area, body shop, and paint booth.  I was immediately impressed by how clean and orderly everything was kept.



The Young Guns fabrication area, see from the mezzanine.
 Young Guns.

We also saw examples of what their painter, Frank Bennett, could do: everything from ghost-striped and flamed resto-mod hot rods to electric guitar bodies to motorcycle tanks and fenders to gas pumps and even refrigerators (the 1950s refrigerator in the lobby painted in flawless Gulf Racing Team Powder Blue and Marigold Orange stole the show!).

The Aluminum Body

Of particular interest to me was Tyler's training and experience in shaping aluminum and steel. The Alfatross' hand-made aluminum Zagato body is what makes it rare and valuable.  Fortunately, it is in pretty good shape, but during soda blasting I discovered there are problem areas that will require the touch of an expert.  So I watched with great interest  while Tyler poured over the Alfatross for hours from stem to stern, locating problem areas, photographing them, and making notes.

Tyler checks the symmetry of the driver's door against the flat plane of the floor.  The body work gorilla looks on, suspiciously.



Tyler examines one of the trouble spots on the Alfatross' bum: the place where
the bodywork comes closest to the road--and consequently takes a beating!



A long crease in the aluminum body just behind the left front wheel well.  The
 cavity behind it is for the dual exhaust pipes.

The aluminum body has numerous flaws, some of them from the day it was built!  There are small cracks, shallow dents, little dimples, scratches, and weld scars, but fortunately very little corrosion.  The restoration work needed is not extensive, but it will be tedious!  The body is what most people will appreciate and judge the restoration by, so it has to be right!








From the bottom side of the hood it is easy to see the
welds in the 6 separate pieces used to make the
aluminum skin.  The steel frame around the perimeter
and under the openings for the scoops shows as
dark gray.




Removal of paint and filler during soda blasting revealed this
crack in one corner of the square-section tubing framing the
hood.

The Steel Chassis

Of greater concern to me than the aluminum is the condition of the steel chassis, particularly the floor pan under the rear seat where there are numerous pinholes, and one spot in the lower rear corner of the left front wheel arch where there is corrosion on the frame.  Whereas aluminum corrodes lightly, steel eagerly turns back into its natural state: iron ore. Like cancer, it has to be cut out and replaced.  This is easy enough when the affected panel is just a flat sheet spot-welded around the edges, but if you add stiffening corrugations ("beads" in body-shop speak) and weld a bunch of other pieces to it top and bottom, repair can get really complicated!


Repair of rust damage to the Alfatross' steel frame is one of the larger gorillas in the room.

Trouble spots on the Alfatross' soft underbelly.  The three upper and one lower circles draw attention to areas where the floor pan has rusted through.  The two central circles are brackets that will need straightening and re-welding.  

The corrosion area at the lower back corner of the left front wheel well is one
of those difficult repairs: it involves several different pieces of steel, difficult
access, cutting, fabrication of new panels, bead rolling, and welding. 

At the end of the 12-hour day, Tyler "did not see anything that is outside our skill set."  Which I took to mean he wasn't scared, yet.   Young Guns appears to have the expertise, facilities, and enthusiasm to tackle three of the Alfatross' most formidable gorillas: body (and chassis), paint, and interior.  And they just added another 5,000 sq ft of workshop space!  And they are not that far away--about a day's drive and only an hour's flight time.  Could we have a match?  We'll soon know . . . .



The rotisserie enabled Tyler to check the Alfatross' frame and body, interior
and exterior, in detail.  If we agree to do business we will have to figure out
 a way to ship the Alfatross to Phoenix while still mounted on the rotisserie,
which is 19 ft 2 in long!