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Thread: The Harrison Racing Outboards - Legendary Birmingham Metal Products Alky Outboards

  1. #21
    John (Taylor) Gabrowski
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    Default Harrison Class A Alky Block - Anzani crankcase mounted version

    The following pictures are of the Harrison (HRP) class A Alky block. This particular block was designed to be mounted on a British Anzani class A-B crankcase and tower housing. It was only in these most recent times on this website that I came to learn that Harrison engines though I seen them in the 1960s amongst Anzanis was truly the Britsh engine's American cousin! Both engines shared the crescent shaped exhausts systems leading most onlookers to think the design was so good that 2 different brands of engines adopted similar design technologies or they were the same engine as Anzani that was mistaken and described as a Harrison. Harrison in fact was making aftermarket parts for British Anzani engines in America for quite some time and the name Harrison in the UK was associated with Anzani as Anzani was associated to Harrison in the USA. Kind of confusing but the facts were these engines were awful fast in their time and set records proving that.
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  2. #22
    John (Taylor) Gabrowski
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    Default Why 2 carb inlet holes on the Harrison class A Alky block?

    Why there are there right and left side of Harrison block carb inlet holes for air / fuel? The Harrison engine blocks unlike the Anzani cousin's cast iron loop block is aluminum alloy with ferros (cast iron or steel) cylinder sleeves fitted.

  3. #23
    John (Taylor) Gabrowski
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    Default The Harrison class B Alky engine block - Anzani crankcase mounted version

    The following picture is the typical Harrison (HRP) class B Alky outboard racing block. Only one carb opening on the block though??? The block was cast of aluminum alloy same as its smaller class A version with ferrous metal (cast iron or steel) sleeves. The Harrison was a loop scavenged engine same as its British cousin, the Anzani with some departures and refinements.

    Instead of rectangular or squarish ports the Anzani used through out the engine block Harrison kept to squarish exhaust ports on the inside and rounded the exhaust port to the outside for easier exhaust pipe matching. On the inside the Harrison incoming to cylinder air / fuel transfer ports to cylinder proper were very well rounded and almost twice the size of Anzani.

    Harrison also made a very concerted attempt to angle intake transfer ports upward for the Schnurle effect in loop scavenging that was more effective in charging fresh air / fuel into the cylinder area upward towards the combustion chamber and sweeping out residual exhaust gases better than the conventional 90 degree loop scavenging Anzanis still used quite effectively.

    Bill Tenney must have really kept an eye on Harrison development as his answer to the Harrison refinements to loop charging was to develop the 6 intake port Anzani loop engine that used 2 additional ports to additionally charge air / fuel and sweep out residual exhaust gases from a different angle and perspective. Both Schnurle improvements in the Harrison and the addtion of 2 additional ports to the Anzani by Tenney was indicative or the competitive spirit involved between these 2 competing though related A and B ALky racing engines.
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  4. #24
    Sam Cullis Mark75H's Avatar
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    Excellent posts John! Fantastic pictures!
    Since 1925, about 150 different racing outboards have been made.


  5. #25
    John (Taylor) Gabrowski
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    Default Thanks! Credit has to go to known and to other annonymous providers though

    I would be no where without much of the originating background information you and others posted here to the site on the subject. Other annonymous readers provided me with some of the detailed pictures you see and in others having some of the components allowed me the same privilege. When a body has some of the parts on hand, Tim Chance being able to get Harrison materials directly to examine and speaking to Kay Harrison to compare what they were doing and why plus being able to speak directly to engine developers like Jim Hallum and having Lee Sutter posting here and soon perhaps to Ron Anderson too is bringing what they were all thinking and doing to life even where some have passed away like Bill Tenney. Its a rare privilege to be able to re-construct some history like this for all to see and participate in.

  6. #26
    John (Taylor) Gabrowski
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    Default The typical earlier Harrison class B Alky pistons

    The following picture set is the typical earlier Harrison B Alky piston set. The piston crown is converx but not as much so as Anzani owned to the Schnurle approach to through the port air/fuel transfer. These were the aftermarket pistons intended for Anzani replacements that also became the Harrison piston. Cast with the HRP marque on the underside is also the Lodite casting marque. These piston's skirts were knotched at the intake piston port beneath the carb to create timing overlap to minimize the heavy pulsing waves that cause carb spitback at various rpms that occurr in pistons ports merged into a single barrel carb intake port on the block as the B Harrison was.

    One later innovation not present on these pistons was the use of the Dyke's rings or 'L" rings as they were called that came later. Harrison did use a narrow rectangular racing ring though that was superor to the earlier squarer cast iron rings found on Harrisons and their cousin the Anzani. In the abscence of "L" pressure back type rings compression as all pistons with rings of this nature was brutal and immediate with 14 to 1 compression ratios common and very hard to pull over and start. As time progressed the Harrison pistons saw the addition of the "L" ring on top of the existing rings and then later still the engines would sport a single "L" piston ring per piston only, where the "L" of that ring was as much to control exhaust port timing by its location but also was a pressure back type that made starting the engine so much easier too than the older rings ever allowed.

    Some later additional modifications were made to the piston to introduce "boost port" openings windows in addition to the big transfer windows that are 180 dregrees apart on each window on the piston's skirt.
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  7. #27
    John (Taylor) Gabrowski
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    Default The Class B Harrison Cylinder Head

    The Harrison cylinder head was typically made from aluminum alloy made hollow for water jacketing through out with head bolting done with appropriate cap bolts and washers and in come cases studs were installed in the block. The head alternatively was also or could be washered and cap nutted down to locked in block head bolt studs.

    The Harrison head was fastened with some differing head gaskets made from sheet metal goods like copper and head gasket cement. There also were head installations using a very strong glue without a sandwiched in head gasket before fasteners were turned on to hold the head covering 2 cylinders down simultaneously.

    The combustion chambers were typically shaped similar and made offset to induce "squish" from the cylinder as a whole off to the side to the small hemi combustion chamber proper to the well proven cousin's design of the Anzani. Where Anzanis had some head leakage problems that required special measures to equalize bolt torque and head to block seal the Harrisons had those problems well worked out and prevelent but never the less there was some minor problems due to the nature of these racing engines though between the 2 cousins, a little different.

    Typically Champion L84R, their A/C and Autolite alternative brands of sparkplugs that were cold heat ranged made for racing spark plugs were the sparkplugs of choice for these engines.
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  8. #28
    John (Taylor) Gabrowski
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    Default The Harrison Cylinder Liner - inovation off the block

    Revolutionary to outboards in particular racing outboards was the introduction of the 2 stroke loop engine by Anzani and out of close grained cast iron to. That made for a very heavy block and it also made for some very difficult machine work to set the block up for racing. Similarly as Anzani wound down operations and production in the mid 1960s and Harrison ramped up to finish using up Anzani components in an engine that evolved into the name brand marque the Harrison, HRP found it had to cast its own blocks which they did of cast aluminum alloy.

    Processes at the time found many on and offshore engine companys casting engines both with liner in situ and later finish machined or liner installed afterward with machine work done before the liner was forced in fit with sealing material to make it impervious to water, air, fuels etc. Harrison installed their liners finished machined as a dry sleeve installation encircled by the machined fit of the aluminum block bored to fit the liners where engines like Konigs later had wet sleeve installations suffering some water sealing problems in the process Harrison did not have. It was typical to have the Harrison cylinder sleeve frozen cold for maximum contraction at hand and the aluminum engine block heated for maximum expansion prior to installation using a press and done quickly before the metals equalized their tempertures locking them together with friction even closer.

    The cylinder map for Harrison made for larger intake ports that were angled, round and at least twice the size of Anzani on the intake transfer ports where on the exhaust ports both engines being cousins to each other were similar and quite squared for a very fast working exhaust port.

    British Anzani engines being cast iron blocked loop engines could withstand huge nitromethane loads in the fuel to compensate for poorer breathing than the Harrison could. Typically a Harrison loop engines with its larger and better designed and breathing Schnurle intake cylinder transfer ports, alloy block and ferrous cylinder liners would not last long where nitro loads were present in percentage done heavily in Anzanis. It seemed each engine traded off something to compete with the other without mechanical failures increasing to get there. The Harrison was truly the modernization of the Anzani on the long term. Where Anzani held kilo and mile speed records going over 100 miles per hour by the early 1970s the Harrisons held competition records where average speeds around the course in competition exceeded 80 miles per hour during the same era.

    By comparisson todays Super E gas modified engines of 49 to 60 cubic inch displacement have hit 70 mile per hour average speeds this year 2007. Harrison and Anzani engines from the mid 1960s had already exclipsed that barrier with less than a third to one half the engine displacements. The key to much of that is engine overall design & metalurgy and most of the rest was superior port design.
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  9. #29
    John (Taylor) Gabrowski
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    Default Harrison Ignitions - They evolved

    Harrison variants were very much indicated by the hardware they carried. On the ignition side there seemed to be evolution going on that went the gamut from using the Anzani Lucas built gear driven magneto when they the Lucases were plentiful to when they became scarce Harrison went to other battery as well as self energized ignitions like Phelon / Repco and so on.

    Featured here is a top part components section of a Harrison self engergizing ignition system for a 2 cylinder racing engine? very much reminding readers of what Konig breakerless ignition systems appeared to be the basis of. Nothing ever stopped Alky racers and developers from taking ideas from each other or adapting from other brands of engines, generally who made better or more readily available parts or products.

    Enjoy the pictures.
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  10. #30
    Sam Cullis Mark75H's Avatar
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    Quote Originally Posted by John Taylor View Post
    By comparisson todays Super E gas modified engines of 49 to 60 cubic inch displacement have hit 70 mile per hour average speeds this year 2007. Harrison and Anzani engines from the mid 1960s had already exclipsed that barrier with less than a third to one half the engine displacements. The key to much of that is engine overall design & metalurgy and most of the rest was superior port design.
    You are comparing gas motors to alky & alky nitromethane motors .... and the Super E rules restrict the motors to many stock parts including standard fishing version carbs ... its not due to magic in the Anzani/Harrison motors, its due to rule restrictions on the larger motors.
    Since 1925, about 150 different racing outboards have been made.


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