British Anzani A & B Stock & Alky Racing Engines

[John (Taylor) Gabrowski]

From these previous pictures is a Red class A Alky block that had the extra 2 ports added to one cylinder only and not the other. Clearly it was run that way for a longish time and for some benefit as other blocks had 2 extra ports per cylinder added and that was for the Anzani A. The Anzani B Alky block seems even more extreme with added ports.

The fire clearly got hot when the castiron Anzani loop block with its exhaust plugs to keep the exhaust square going into the megaphone exhaust pipe melted and spread out into more of the exhaust port.

[John (Taylor) Gabrowski]

This perfectly otherwise servicable class B Alky block shows a different port of one extra hole on each corner the castiron block. If one could commen on the quaility of the cast iron block loop castingings cutaways was the flawless castiron castings that they were of an iron called at the time I understand as "gutter iron)", done very precisley and they even cast in flow angles of attack for later port machinng after casting. Between the air/fuel cooling of the ports, the water jacket penetration was also excellent for a cooler running engine even on gasoline, so the last word in cooling was not always lauminum alloys of the day either.

[John (Taylor) Gabrowski]

Making a 125CC Anzani from a damaged block and crankcase section from the worst of the damaged part was the original intent until a machinist lost his mechanical grip on the aluminum crankcase part being macine cutaway, tossing it on the floor and cracking it near irrepairably so. Still a good example of casting technologies.

[John (Taylor) Gabrowski]

This half of the pipe set were both garage fire over heated and warped similary with the aluminum from a melted cylinder head dripping on to the pipe brace support collar and staying there. That fire must have been heartbreak for some many ideas, engines and parts of which considerable was saved.

[smittythewelder]

I wasn't pulling your leg, John. You asked why some tuners preferred steel pipes over aluminum. I don't know their thinking, but here's my guess:

Heat transfer: aluminum has, what, twice the thermal conductivity of steel (I don't have my Machinery's Handbook here)? Anyway, an aluminum pipe will draw heat out of the exhaust gasses faster than a steel pipe. Acoustics: What happens to the speed of the acoustic waves when the medium they pass through is cooled? It gets slower. To the slower-moving waves, the pipe then looks longer. To what effect? It moves the tuning of the pipe to lower rpm ranges. This is why some guys have water injection into the pipe; it makes power at a much lower rpm for getting on-plane, or coming out of a corner. The upshot is that, theoretically anyway, if you want an aluminum pipe to act like a given steel pipe, it needs to be a little shorter and maybe smaller diameter. And if it gets splashed with water, an aluminum pipe might change the wavespeed dramatically.

Sled racers think it's important to keep their pipes at a fairly constant temperature, and experiment with thermal wraps. Car guys believe that keeping the exhaust system hot means that the exhaust gasses have more energy and are more quickly cleared out of the system, lowering back-pressure, so they use thermal wrappings, too. I wrapped the headers in an old van just to keep the engine compartment cooler. But these wraps don't like to get wet, so I don't think they'd work on raceboats, unless there is something new available.

[John (Taylor) Gabrowski]

I asked them at TSR why they did not make pipe formulas for powerboat racing loopers, as they say they don't, but really they do for Loop Charged engines its just that they want or provide software for pipes that warm up and remain constant too for the very reasons you are citing. Makes a good pipe run all over the place like spaghetti because of the water splashing on to the pipe throws the tuning all over the place as it is based on a number of factors that can't be changed on the run from water splashing or hosing on different parts of pipe surface and that to them means any and all. Otherwise their formulas by reputation seem first rate.

When I was in Florida I saw what was either a Yamato 350 or 500 Alky 4 cylinder early version with dual and wrapped expansion/stinger pipes. Were they, the pipes heavier than normal from the wappings? You bet they were and that kind of overhang feels heavy handling too boot. The other key is how to angle them away from the engine like Konig plus so if you spin the Anzani cast iron block side forward that is extra length and weight considerations perhaps would be taken up and easier dealt with too?

[John (Taylor) Gabrowski]

By Sunday this week, I will be streaming a whole load of Jpegs pictures of finer parts, variations of some others, steering systems etc. to fill in a lot of gaps. Is there anything readers may specifically want to see in particular that so far has not been shown and I am working my way towards them?

[John (Taylor) Gabrowski]

One picture shows the original steering bars for British Anzani, I don't know if they ever got beyond those originals, they were pretty basic!

It was not long before adapters came along the use that nice chromed and custom bent/angled Mercury Outboards Steering Bar we see or own on all the Mercurys from KG throught to H series engines.

[John (Taylor) Gabrowski]

From the pictures the pistons come up very high. The circumference dome to skirt edge comes dead even with the top of the cast iron engine block. The slightly hemi-domed piston crown actually penetrates to the combustion chamber where it compresses the air/fuel/lube mix from the cylinder, to lesser combustion chamber to the major chamber where a cold racing Champion or Autolite would ignite the by then very turnbulent mix.

Original Anzani piston rings were good cast iron, there being 2 of them from the factory. Later with a concern that the top ring of the 2 rings installed and not the piston crown was actually controlling the timing, so a new modification came out where a single "Dykes or "L" ring groove as added above the 2 original rings further down the skirt and that Dykes - L ring was installed so that its top lip was dead even level with the outside edge of the hemi piston crown to ensure the piston crown was doing/meeting the actual exhaust port timing.

That 3 ring (1 Dykes L ring and 2 standard rings) system was overkill and perhaps even adding too much friction heat to the engines, so custom blanl pistons were machined with a single top ring grove for the installation of that single Dykes or L ring by itself, with a ring gap near to 0 inches as far as ring gaps were concerned. These were a very successful new piston ring application with a couple of caveats. One was that you had to make sure your exhaust ports were nicely radiused to prevent ring shear. The other was to ensure you knew how much time was put on the rings through engine operation as Dykes or L rings upon combustion force their out edge against the combustion chamber doing one real tight seal. Let one or both caveats go and the rings would get thin and even sharp enough to catch on the exhaust port and out the engine through the megaphone a section of that ring would go, sometimes with surprising little damage but there were times that it was cylinder and port re-conditioning, a new piston and new ring. Those that kept a keen eye, and logged their engine books had engines that went the distance on wear and tear with hardly an incident.

[John (Taylor) Gabrowski]

Where Bill Tenney retained the installed Vacturi's coated cork float with fuel inlet needle and seat that was fed the methanol/lube/nitromethane fuel mix from one to three over flywheel offset mounted DelOrto remote fuel bowls pressure fed fuel via a crankcase pressurized raceboat in hull near transom methanol racing fuel tank - Racers like Hallum, Anderson and Sutter used a very simple OMC remote fuel pump that took its pressure pulses from the crankcase, fed a revised Vacturi that no longer had the float, needle and seat to where fuel was raised in the fuel bowl proper and spilled over through a height bleed off system back to the non-pressurized fuel tank.

Both floated and floatless systems were popular but the later floatless were found less troublesome and more reliable that also allowed Messers Hallum, Anderson and Sutter to add as few as one extra carb to the Anzan for a total of 2 to where as many as si5 Tillotson HL self pumping carbs were added strategically to that one big Vacturi for a total of 6 carbs feeding just 2 cylinders! The picture depicted is still a single carb floatless system, very simple and very reliable.