|April 2000 Tech Feature||www.virtualindian.org|
|Home / Features / Inside the Ace|
#1 (last month) gave
a very brief overview of the history of the Ace motorcycle, and briefly
examined some aspects of the Ace engine. Part #2 this issue will explore
some of the oiling system, the crankshaft, the pistons and conrods. Some
discussion will be directed towards a chronology of Ace parts and models.
To the casual observer, most Ace motorcycles in the years 1920 through 1927 all look the same. But a detailed examination will reveal a host of yearly changes, to the point where very little of the 1920 model will even fit the 1927 model. Some discussion of the various models and parts would thus seem to be necessary.
But first, a word on the Ace parts numbering system, and many models of similar looking bikes.In the beginning, there was the Ace in its startup year 1920 and there was the letter A. So it was logical they went together. All Ace parts for the year 1920 are prefixed with the letter A, as are all Ace engine numbers (perhaps). The first part in the Ace parts book is A-2000 Crankcase Upper, and numbers for the 1920 year range from A-1200 (Oil Pump) to A-3037 (Generator Belt Hook). Plain numbers under 1000 are used for nuts, bolts, screws, washers, keys, cotter pins, rivets, etc. The bikes and parts for 1921 were as for the 1920 year, so retain the A-prefix letter in all respects.
When some mechanical changes were made for the 1922 Model Year, the system adopted for the new parts was that the letter B prefixed the same part numbers. So the new inlet manifold was B-2300. The 1920 inlet manifold was A-2300, so only the prefix letter changed for a new part, and the number stayed the same. New for 1922 pistons were B-2005, new Schebler carburettor was B-2301,etc.
When the Ace Sporting Solo was announced in December 1922 for the 1923 Model Year, the prefix letter for the parts was C, but the engines retained the B codes. So the new high-fin cylinders were C-2003, new aluminium pistons were C-2005-C, new inlet and exhaust tappets were C-2053, new oil breather was C-2265, etc.
The 1924 prefix letter was D, and some examples of new parts were new piston pins with floating brass end-caps D-2010, new camshaft centre bearing D-2025-C, new Gas Tank and toolbox complete D-1555, new fork spings and rebound springs D-2889 and D-2890, etc.
The Ace Motor Corporation went into liquidation in early 1924. Following much financial wrangling, it restarted Ace production as The Blossburg Corporation in 1926, so there was no 1925 production at all, as far as can be determined from this remote point in time. There was no code for the 1925 year, being completely omitted from the system.
The 1926 production year code was logically an E. Parts introduced for this year were minimal, but a noticeable change was the one piece inlet manifold and 4 cage inlet valve assembly E-2300 and new Schebler carburettor E-2301, Schebler number DLX25.
Big news for the 1927 model was the switch to pressure oiling lubrication, with a host of detail changes to permit this change. And a large number of other changes. A major development though was the purchase of the ailing Ace concern by the giant Indian Motocycle Corporation. While the 1927 year would have been year code F, Indian Motocycle changed the system slightly by prefixing the F with a V. So the 1927 year code for the Indian Ace was VF, and literally hundreds of new VF part numbers were introduced. Examples include new pressure feed upper crankcase VF-2000, pressure feed lower crankcase VF-2001, drilled crankshaft VF-2032, etc
For 1928, the previous Ace part number system was completely overhauled. The previous Ace part numbers became "factory numbers", and Indian initiated a new system of part numbers commencing AA1 for the flywheel, AA150X for the upper crankcase, etc. Engine codes used a CA prefix. Items such as nuts and bolts which were common with other Indian models adopted their existing Indian part numbers. For example, the cylinder stud nut lock washer, which had been Ace number N214, became Indian P/N 19B114S, same as for other Indian models.
To recap :
An Inspection of the Ace Crankshaft and Lubrication System.
Ace4 - Splash Oiling
The Ace4 engine 1920 to late 1926, immediate ancestor of the Indian4, utilised "splash oiling" for the engine. The Indian4 by contrast was a pressure-oiled motor, a system of lubrication used to this present day. The basic description of the Ace4 engine was a 4 cylinder engine, at first of 75 cubic inches, and later at 78 cubic inches. The undrilled crankshaft used 3 main bearings, and 4 separate journals for the four cylinders. The gearbox also used plain bearings, and also relied on splash oiling. So what is splash oiling ??
In the splash oiling system, oil is whipped up by the crankshaft and conrods rotating around and dipping into the oil troughs. Oil is splashed everywhere inside the engine, and trickles down into oil collection holes and thus lubricates the bearing surfaces. Sounds precarious, but was standard automotive practice on the majority of motor vehicles of the times. It worked - probably as long as there is no prolonged high speed running... Roads were mostly rough dirt tracks in those days, so high speeds were rarely even contemplated.
Contrary to popular belief,
while oil is stored in the deep and handsome aluminium sump,
the splash oiling occurs in oil troughs located immediately
under the crankshaft. In effect, a second pool of oil is held up under
the crankshaft, and this pool is maintained and replenished by the oil
pump. The oil in the base of the sump is only maintained as a cooler resevoir
of oil to draw from - the externally finned sump assisting with the cooling. The
inside of the sump was not finned at all, but is divided
into 3 main compartments - engine, clutch and gearbox. The sump is not
a structural part of the engine assembly - it just bolts up from underneath,
to retain the oil.
Oil splashed up into the cylinder bores would lubricate the pistons. A number of pistons had been available over the years. First for 1920 was a cast iron piston of diameter 2.7" diameter (no details known). Next was a 2 ring cast iron piston of 2.75" nominal diameter for 1922 (?), the rings were 3/8" in width. Later followed a 3 ring cast iron piston for 1924 (?), (2 ring and 3 ring cast iron pistons compared) the 3rd (lower) ring being an oil scraper ring of sorts. Not shown is the Ace aluminium pistons fitted as standard in the engines for the Ace Sporting Solo Model - this performance model with the lowered handlebars had been available since January 1923. Finally, a view of the Ace cast iron piston compared to a later Indian4 aluminium piston - the Indian4 has thinner rings, more rings, bigger wrist-pin, taller piston and is cam ground.
Thanks to Per Erik Olsen of Norway for
the spare crankshaft images,
Eagle-eyed readers will have observed that the cam, valves, valve gear and combustion chambers have not been discussed. Maybe next issue...
1926 Ace engine
1920 Ace parts list
1922 Ace parts list
1928 Indian Ace parts list
Ace sump with oil tray