British Anzani A & B Stock & Alky Racing Engines

[John (Taylor) Gabrowski]

These heads lower the Anzani's compression to just about 6 to 1 off the top of the exhaust port. Clearly they were used to test some theory more than likely lots more of nitromethane in the methanol base with higher BTDC ignition timings. From combustion staining, it was tested but the results, good question???

[John (Taylor) Gabrowski]

Anzani engines came from England with nice hard chromed but not balanced steel flywheels with gear type magneto drives screwed on the underside and the marque rope plate on top. You combined their stock weight with what the crankshaft was made of with its heavy center full circe rotary valved cranshaft midsection and you had one bery, very heavy assembly centered in that crankcase, that needed lightening to manage the revs though the powerband easier. Its interesting that only when they took two thirds of the weight off was the first time these flywheels would see a re-balancing and from the drill out points to do so, they were very carefull at that with some very fine rebalancing done.

[John (Taylor) Gabrowski]

It seemed quite reasonable on Roger Wendt's Anzani hybrid that a stronger tower would need to be made up to use a Konig gearcase (earlier version Kong). A complete Anzani powerhead with everything surrounding that case iron loop block, crankcase, crank, rods, flywheel etc. outweighed a Merc 4 cylinder complere with pipes by nearly 2 pounds. Not so with the lighter Harrisons. I has both Anzani and Harrison crankcase nut down stud pattern too. Why on earth they kept all that weight on such narrow clamping systems as original equipment or even when a steel tower with Merc saddle, clamps and co-pilot brake was built and at standard height left you scratching your head? You would think them wide for reasons of weight and the engines power deliveries.

The picture is a real strong, well made thicker wall moly steel pipe tower with Merc peripherals setup for a later model Konig gearcase.

[John (Taylor) Gabrowski]

The aluminum castings done by British Anzani for tower clamps are of a size and quality of large castings found on outboard engines with 100 horsepower ratings. to this period, this poster has never heard or seen a broken transom clamp casting. Stripped clamping bolt threads, lost clamping washers, cracked/broken torque aluminum tower/torque tubes, a few but not a fractured clamp casting.

[bill boyes]

I remember drivng a Anzani B runabout for Lowell Haberman. While testing took a very hard spill. The Tower broke. Lowell got a replacement from Kay H that was a Bronze casting if I remember correctly.

[John (Taylor) Gabrowski]

When it came to the parts for the whole engine, that tower neck was it Achillie's Tendon for cracking/breaking. Funny though some old towers show no signs of ever letting go still and they were heavy run too.

Any pictures of your boat, race or anything related to add to this thread. Please Do???

[Modhydro Steve]

Here are some photos of an earlier Anzani 350 I have. I have found OS pistons for it and will bore it out and get it going in the near future. Note the different gearcase design. This one has the removeable skeg like a Johnson SR/PR foot.

[John (Taylor) Gabrowski]

It sure is wonderful older factory stock version 350 "B".

I wonder if it is an actual near 350CC block or a 322CC block? It is my understanding that there was the larger bore for stock outboard gasoline racing and the smaller bore for "B" Alky.

The gearcase on yours already shows signs of where it was going to evolve and they sure did just that not much later and turned into a unbelievable hydrodynamic wedge design.

The older wider transom clamp set I have here, very much looks like yours in your pictures so I am assuming they must be of that earlier era. I wonder why they went to a narrower transom mounting width as by then they must have already seen increases in power and speed as A and B Alkys on this continent that needed a wider stance to stay put on the transoms.

I hope you get her rolling again as with the thread, the interest in these engines is bringing them out. I am hoping for some action pictures. I have some understanding of where I might get to examine "negatives" film that has been archived for the marine museum people here to develop their displays with. They would not know what to look for where I can and will. Do you have any action photos you can post Steve???

Your submission is great!

[John (Taylor) Gabrowski]

There were some major differences between the "A" and "B" Alky versions of British Anzani(s). Even with those changes, they remained heavy duty changed products.

*One, was the actual cylinder block. It was a different "A" casting from the "B" that still fit directly to the crankcase in common use for "A" or "B" classes but the bore was thinner with the "A" versions maintaining the distances relationships of cylinder to water jacket distances of the larger "B" blocks to similarly disipate heat through water cooling. There are at least 2 generations of "A" class block castiron castings where they are both square exhaust ported at the cylinder wall but the older one goes rectangular outward to the outer flange that would fit Steve's early engine's factory stock exhaust system boltup dead on. Later generations had a square cylinder opening turning round between the cylinder wall to outer flange boltup face best suited for tuned pipes immediatrely but the flange was still 4 bolt rectangle that would fit the stock exhaust manifolds with little or no change to its performance as a stock gasoline fueled engine.

*Another difference was that the piston displacement and smaller but fit a common A and B connecting rod with a shorter wrist pin matching the smaller piston & bore. Both A and B pistons saw "skirt notching" as a third port to create intake overlap increasing the As power in the same way the B engine's power also increased. Two to Four mini drilled added boost ports were also run with success. Original A pistons were two ring but they did everything in terms of numbers and ring variations as they did to the Bs and got corresponding performance increases.

* The cylinders head was a smaller direct match to the "A" block casting and reduced in CCs to match the 250CC bore originally sized to run gasoline but planed off to raise compression to burn methanol based & nitromethane additived fuels wonderfully.

*When it came to the displacement of the gasoline based and jetted Amal Monoblock slide carb which also came in 2 barrel casting sizes for A and B gasoline running, in favour of the high fuel flowing Vacturi butterfly controlled carb for methanol based racing fuels. The carbs huge barrel/venturi that was used on OMCs C-Service engines, you had to machine a smaller sleve to lock into the way larger Vacturin stock barrel/venturi to match the "A"'s block opening resized for the bigger carb which also used a spacer/adapter between carb and block to accomodate the factory's shaped opening that included a consideration for how air/fuel entered the block flowed to the torturous S shaped port from the cast iron block to the crankcase proper and finally to the crankshaft rotary valve.

*The pictures following show some of differences and especially so the evolved gearcase. The props for these engines are absurdly tiny for A and B Stock and later for Alky engines in brass or stainless steels. They will be posted shortly for views. Two differeht gearcase gear ratios were available to make proping the engine interesting between hydros and runabouts and course lengths.

*Exhausts elboes and bells between the A and B Alky versions were all within come common parameters that in relative terms the A versions were slightly smaller and shorter dimensioned than the B Alky versions.

*How much horsepower was dynoed out of a 250CC "A" or 15 cubic inch Alky? About 375-400 horsepower per liter depending on nitro percentage loads increased to the methanol base fuel and lube mixes. On the high end of nitro loads of over 20% is where things started to reach some limits. On gasoline? Steve? Do you have any dynoed, reported or educated guess horsepower figures???

Enjoy some more Jpegs of an "A" Anzani, Alky.

[John (Taylor) Gabrowski]

Final picture - Anzani - Alky A