British Anzani Racing Motors & History

[Healey75]

When I first started playing with boats and had hair and stuff...nobody but nobody wanted an Anzani engine, you could not give 'em away, we all wanted 'Jonyrudes' because they were quiter and smoother...if only we had known and put 'em in the shed, I guess they are all still in the canal

[SpiritOfSelkirk]

This picture is a typical 1960s British Anzani Mark 2 methanol burning single carb in a full 350cc (not 322cc) displacement powerhead USA Westcoast style (PacMan megaphone pipes) prepared and restored engine. For reasons unknown never clear to me to date when British Anzani came to North America to be raced in methanol aka Alky classes it was in Class B Alky restricted to 322cc whereas other engines like Mercury, Quincy-Mercury, Konig and even the Anzanis American cousin the Harrison were allowed the full 350cc displacements! What was clear was you could push higher compression ratios into Anzani's cast iron blocks you could not do with all the others which were typically aluminum blocks with cast iron sleeves. Anzani compressions would attain up to 14.5 to 1 comopression ratios. Because the block was cast iron you could add as much as 30%+ nitromethane into the methanol fuel mix putting Anzani 322cc engines horsepowers into the 75 to 80 horsepower ranges giving 3.5 to 4 horsepower per cubic inch of displacement. With Anzanis cast iron block and superior metallurgy this nitromethane loading could be done time after time with normal wear characteristics of its type of race engine where other brands of competing engines would destroy themselves running only 10% nitromethane in their racing fuels only for a very short time. When Anzanis did blow up the effect was akin to a grenade blowing up with engine fragments flying all over the place meaning it could injure bystanders.

*One important note is the westcoast style of engine setup abandoned DelOrto overhead fuel bowls leading to a float type carburettor and pressurized fuel tank for a floatless carb with return overflow fuel back to an unpressurised fuel tank that used a OMC typical pulse type fuel pump to circulate the methanol based fuel. The later OMC pumped system was inherently safer leading to less Alcohol fires in raceboats that happened too many times with pressurized fuel tank systems.

Enjoy the picture as it is a one of a kind 350cc British Anzani Alky engine whose speed and power capability against a 322cc Anzani model is presently unknown. What is known is the more displacement the more horsepower, torque and rpm.

[SpiritOfSelkirk]

Do the twin carbs feed just to the inlet ports under the piston skirts? If so, what's been done with the original secondary inlet tract via the crankshaft rotary valve? Strikes me that there could be some conflicts here...unless the crankshaft tract has been closed off somehow?

Twister:

On the 2 carb Anzani engines the big Vacturi carb contributed 3 streams of air/fuel on the one carb. That is one stream to each piston skirt port and a third one down the S shaped rotary valve tunnel as well. When they mounted the smaller Tillotson HL carb on the crankcase opposite the crankshaft rotary valve window they kept the block tunnel port open as well as it was felt the Tillotson HL carb was grabbing more airfuel before the transfer tunnel could do it as well as afterward giving more constant air/fuel overlap flows cutting down on intake pulsations considerably unlike just using a single carb where the spitback would not quit until the engine was above 3,000rpm. Their thinking was correct as the two carb non-hybrid Mark 2 Anzanis were switched to this 2 carb configuration very quickly afterward in the USA Northwest where Anzanis generally stayed single carb into the rest of North America where they ran slower than any comparable 2 carb version the Northwest was running. From there in the Northwest it was not long before they again jumped forward with the 4 carb version.

[SpiritOfSelkirk]

Just another front to side view of a typical Anzani Alky racing powerhead already featured from the carb side previously. The whole assembly of the engine is very clean and uncluttered just as the class A and B Stock gas engines restored by Twister are. These engines aside from the over engineered perennial problematic Lucas magneto were very reliable and extremely powerful. With bell megaphone exhausts the sound is pure "race". If production did not end around 1966 it is just speculation now where the engine could have gone as well in years as well as evolution. Most Anzanis were finished in racing by 1976 due to lack of new and or next generation parts and assemblies. Closing down production of these Anzani race engines was a mistake no different than ending Jaguar XKEs only to reopen the design almost 2 decades later with the Jaguar XK8. By 1983 Anzani was liquidated on gone only to be reborn in the new millenium but where from there only Anzani can answer.

Enjoy this second different view picture.

[SpiritOfSelkirk]

A picture of a typical 2 carb British Anzani class A - 250cc or class B - 322cc outboard racing engine. This is the typical Ron Anderson and Jim Hallum type Anzani conversions that happened in the mid to later 1960s with the typical engines changing to 4 carbs on class A and B engines by the start of the 1970s.

Enjoy the picture.

[SpiritOfSelkirk]

Another Anzani variant but this one is from eastern Canada. It is a class A - 15 cubic inch (250cc) which Instead of using a main Vacturi A0-500 carburator in combination with a smaller Tillotson this variant used one Tillotson HR and one HL Alky carb with the HL located on the other side of the crankcase where they never put them before. How well this variant worked is unknown though the block and internals saw normal racing wear associated with a 9,000+ rpm spinning 250cc Class A hydro or runabout methanol (Alky) burning engine spiked with nitromethane for greatest horsepower possible.

Enjoy the picture. This engine is presently undergoing restoration.

[SpiritOfSelkirk]

This was a cache of Anzani Mark 1 and some Mark 2 parts run as Alkys that were recovered and put in the hands of a USA restorer for future collaborations on getting more of these early loop scavenged engines restored. There are transitional parts in evidence as well as well worn parts telling the onlooker that what was here was campained hard as a racing engine. In the jumble was the first Anzani expansion chamber exhausts systems that were run circa 1965 in the USA midwester area. Until I saw them again just almost two years ago the first places I saw them used was at Detroit Lakes and Winona, Minnesota. They were an oddity making the race engine rather quite in a sea of sound. All other engines were nealry all open pipes. What design specifications were used then are unknown and world wide were still in their infancy with tremedous amounts of cutting and pasting.

Enjoy the jumble picture.

[SpiritOfSelkirk]

The following is the complete block found in the jumble of parts, in this case an Anzani 322cc methanol (Alky engine) with its standard float type Vacturi A0-500 (OMC sourced) carb fuel above from 2 remote DelOrto fuel bowls that mimiced an overhead fuel tank the carb was originally set up for. Some engines were fuel hungry enough to require as many as three of the overhead fuel bowls. These carb and fuel bowl arrangements were typical of all North American Anzani racing engines in both class A and B save for the Northwestern states that converted using a flow through and excess fuel return to fuel tank recirculating fuel system very prevelent in most other pumped fuel Alky engines.

Enjoy the picture.

[SpiritOfSelkirk]

The following picture is that of the comparable exhaust systems of the 1950s into the 1960s and 1970s very much used were the crescent shaped megaphones. The other set was the circa 1965 Bill Tenney built first design type of expansion chamber exhausts they referred to as "rams horn bounce pipes". They understood what was a work in these new systems being sonic pressure waves, the mathematics was primative and the pipes worked when once understood better by the 1970s proved too much for Anzani engines crankshafts. It was much easier and safer on the engine to increase the nitromethane in the fuel mix at times over 30% of content in the methanol base that to harness the supercharging effects of the "rams horn bounce pipes" returning an 8 pond per square inch rise in cylinder pressure where the compression ratio was already 14 to 1 true (top of the exhaust port opening to top of the cylinder bore TDC). As a result kilo records of over 90 miles per hour for the Class A and over 100 miles per hour in the class B engines were all done with lots of nitro and open pipes.

Enjoy the picture.

[SpiritOfSelkirk]

WATER INJECTION: A very interesting email arrived this morning from Alan Ishi who started racing in North America's NOA about the same time I switched from a pitman to a hydro racer about 1965. About the time that exhausts were changing in the sport like the switch from megaphone open pipes to expansion chambers were first being experimented with in boat racing, water injection first appeared. It was during this period that the Northwestern Anzani racers, those record seekers and record setters first started to water inject Anzanis open pipes while dynoing the engines to cool off the pipes from the inside and out. It was soon discovered that the water would alter the engine's powerband causing faster accelleration as the the water entered the elbo through a sprayer opening before the pipe flair section outward. It made the engine respond faster as if the pipes were lengthened increasing the powerband where in fact the pipes were fixed length and tapered. The talk got around to more racers about water injection and before you knew it everyone with megaphone open pipe exhausts and even emerging expansion chambers systems were trying it too. Eventually Quincy Welding featured it as a modification to their Flathead that was used extensively to racing amongst an ever larger Konig of Germany engines onslaught.

*Of some interest is that the United Kingdom during the WWII were first in experimenting with water injection in supercharging of military aircraft engines of various types that also caught on in that industry that eventually went world wide as well in general use where supercharging aircraft engines was involved. Water injection was used as an anti knock agent and system effectively raising fuel octane to produce useable power in higher altitudes with piston engines.

Future pictures about this subject and other exhausts development in racing outboards in general are in the eventual posts for readers here amongst other differing racing outboards.