Here is something interesting 648 & 678 cid straight inline 6 cylinder engine.
06-30-2014 | 07:37 PM
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From: ocoee florida
Here is something interesting 648 & 678 cid straight inline 6 cylinder engine.
Excerpts from: KERMATH- A TRUE CLASSIC By Jim Aamodt
Originally published in "The Boathouse".
Buzz words, such as "Overhead Cam," "4 Valves Per Cylinder Hemi-Head," "Dual Ignition,"
and "Dry Sump Oil System" are all contemporary terms for high performance engines. The
Kermath "Sea Wolf" and "Sea Raider" Marine Engines began production with the above features
in 1926!
Kermath Engines introduced the overhead valve (and cam) leading to the "Sea Wolf" Series in
1926. It surprisingly incorporated many of our contemporary design items. Let's consider how
the Kermath Company formulated those designs.
The overhead valve ("Sea Wolf" type) was introduced in 1926, sharing the oil pan, oil reservoir,
distributor, pistons, and crankshaft of their flathead 150 H.P. predecessor. The new engine was
initially rated at 150 H.P. at 1800 RPM, displacing 648 cubic inches. A later 1928 version, the
"Sea Hawk" was rated at 175 H.P. Late in 1928, the 5" bore was retained, with the stroke
increased to 5 3/4" to produce the 200 H.P. 678 cubic inch version. Within a few months, the
slightly higher compression 225 H.P. version was marketed, which is the highest production
model (through 1943) and known, as the "Sea Wolf'.
The earliest 678 cubic inch engine, I have seen, used dual 11/2 " Schlebler S Models, and later a
Holley DDV-5 downdraft unit. The stabilization of design to twin updraft carburetors occurred
after 1930. Initially they were 1 7/8" and later became 2" Strombergs. The addition of an oil
cooler also appeared about 1927. Later engines also used 1 7/8" Zenith updraft dual carbs.
The "Sea Raider" V12 Series was added in the 1930's. It was simply two six cylinder Sea Wolfs
sharing a common crankcase, thus becoming a 1414 cubic inch V12! Originally rated at 300 H.P.,
most units sold in the 1930's were 450 H.P.
The early 1940's saw the stroke of the "Sea Wolf' six cylinder increased by 1/4" to produce the
275 H.P. "Sea Raider 6" The V12 was also stroked to 1560 cubic inches and became the "Sea
Raider 12 " up to 580 H.P. Counterbalanced crankshafts, internal rod oil passages, and several
minor changes also occurred in the late 1930's.
Chris Craft, Sea Lyon, Garwood, Mathews, and many other builders utilized Kermath Sea Wolf
engines. One of the largest supporters of Kermath was John Hacker. Hacker Craft Boats used the
200 H.P. and 225 Sea Wolf in their 26' through 30' runabouts, and promoted the 450 Sea-Raider
in their 33' models. John Hacker always preferred engines designed for marine use, and avoided
earlier aircraft conversions, and in small~r boats, automotive conversions. He also designed two
450 H.P. Sea Raiders into his famous Tahoe boat, "Thunderbird."
The Kermath Company was a great company with a tremendous contribution to pre-war engine
design. We will certainly remember its popular phrase, "a Kermath always runs."
http://www.offshoreonly.com/gallery/...ath_engine.jpg
Originally published in "The Boathouse".
Buzz words, such as "Overhead Cam," "4 Valves Per Cylinder Hemi-Head," "Dual Ignition,"
and "Dry Sump Oil System" are all contemporary terms for high performance engines. The
Kermath "Sea Wolf" and "Sea Raider" Marine Engines began production with the above features
in 1926!
Kermath Engines introduced the overhead valve (and cam) leading to the "Sea Wolf" Series in
1926. It surprisingly incorporated many of our contemporary design items. Let's consider how
the Kermath Company formulated those designs.
The overhead valve ("Sea Wolf" type) was introduced in 1926, sharing the oil pan, oil reservoir,
distributor, pistons, and crankshaft of their flathead 150 H.P. predecessor. The new engine was
initially rated at 150 H.P. at 1800 RPM, displacing 648 cubic inches. A later 1928 version, the
"Sea Hawk" was rated at 175 H.P. Late in 1928, the 5" bore was retained, with the stroke
increased to 5 3/4" to produce the 200 H.P. 678 cubic inch version. Within a few months, the
slightly higher compression 225 H.P. version was marketed, which is the highest production
model (through 1943) and known, as the "Sea Wolf'.
The earliest 678 cubic inch engine, I have seen, used dual 11/2 " Schlebler S Models, and later a
Holley DDV-5 downdraft unit. The stabilization of design to twin updraft carburetors occurred
after 1930. Initially they were 1 7/8" and later became 2" Strombergs. The addition of an oil
cooler also appeared about 1927. Later engines also used 1 7/8" Zenith updraft dual carbs.
The "Sea Raider" V12 Series was added in the 1930's. It was simply two six cylinder Sea Wolfs
sharing a common crankcase, thus becoming a 1414 cubic inch V12! Originally rated at 300 H.P.,
most units sold in the 1930's were 450 H.P.
The early 1940's saw the stroke of the "Sea Wolf' six cylinder increased by 1/4" to produce the
275 H.P. "Sea Raider 6" The V12 was also stroked to 1560 cubic inches and became the "Sea
Raider 12 " up to 580 H.P. Counterbalanced crankshafts, internal rod oil passages, and several
minor changes also occurred in the late 1930's.
Chris Craft, Sea Lyon, Garwood, Mathews, and many other builders utilized Kermath Sea Wolf
engines. One of the largest supporters of Kermath was John Hacker. Hacker Craft Boats used the
200 H.P. and 225 Sea Wolf in their 26' through 30' runabouts, and promoted the 450 Sea-Raider
in their 33' models. John Hacker always preferred engines designed for marine use, and avoided
earlier aircraft conversions, and in small~r boats, automotive conversions. He also designed two
450 H.P. Sea Raiders into his famous Tahoe boat, "Thunderbird."
The Kermath Company was a great company with a tremendous contribution to pre-war engine
design. We will certainly remember its popular phrase, "a Kermath always runs."
http://www.offshoreonly.com/gallery/...ath_engine.jpg
06-30-2014 | 10:14 PM
#3
Thread Starter
Banned
Joined: Dec 2011
Posts: 117
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From: ocoee florida
I first saw this motor in 1950's wood boat in Lake Dora. I did a little research the motor had to down draft carb and the boat look like it came off the show room floor. Big cubic inches not a lot of horse power just interesting something with that amount of cubic inches was made back then for boats.
