A Little Shack - Most Popular Harley Davidson Engines Comparison Chart

Model	Knucklehead	Panhead	Shovelhead	Evolution	Twin Cam 88
Years Produced	1936 to 1947	1948 to 1965*	1966 to 1985	1984 to 1999	1999 to Present*
Models Available	1936 - 1952 ---61” OHV EL 1937 - 1942 ---80” UL 1937 - 1951 ---45” WL 1941 - 1947 ---74” FL 1942 - 1945 ---45” WLA Army, XA 750cc Army	1948 ---------74” FL Pan 1949 - 1957 74” Hydra Glide 1952 ---------45” K 1954 ---------55” KH 1957 - 1971 55” XL Sportster 1958 - 1963 FL Duo Glide 1965 - 1970 FL Electra Glide	1970 - 1971 - XR750 (1972-80 = Aluminum, 1981- ? engines only) 1971 - 1980 - FLH1200 1971 - 1972 - FX1200 Super Glide 1972 - 1976 - XLH, XLCH 1000cc 1972 --------- Sportster 1974 - 1980 - FXE 1200 1977 -----------FLHS 1977 - 1979 - XLT 1977 - 1978 - XLCR, FXS Low Rider 1978 ----------FLH80 1979 ----------FLH80 Classic, FXS 80, FXEF1200, Fat Bob 1980 ----------FXWG Wide Glide 1980 - 1982 - FLT Tour Glide, FLHS, XLS, FXEF80, FXB Sturgis 1981 - 1986 - FLT Classic 1982 - 1985 - XLS Roadster 1982 ----------XLHA, XLSA 1982 - 1983 -FXR, FXRS Super Glide II, FXSB Belt, FXRT Tour Glide (shovels) 1983 ----------FXDG Disc Glide 1983 - on-----FLHT, FLHTC	1984 - FXST 1984 - FXRDG – only year 1986 - FXR – re-introduced, FLST Heritage Softail 1987 - FXLR Low Rider Custom 1988 - FXSTS Springer Softail 1990 - FLSTF Fat Boy 1991 - FXDB Dyna Glide Sturgis 1992 - FXDB Daytona Dyna Glide – only year 1992 - FXDC Super Glide Dyna Custom 1993 - FXDWG Dyna Wide Glide, FXDL Dyna Low Rider 1995 - FXSTSB Bad Boy, FLHR Road King	In its first year, the Twin Cam 88 is on all the Touring and Dyna models, with the Softails following later.
Displacements	1936 Series E Displacement 61 ci Bore 3 5/16 inch Stroke 3 1/2 inch 1941 Series F Displacement 74 ci Bore 3 7/16 inch Stroke 3 31/32 inch	E Series Displacement 61 ci F Series Displacement 74 ci	XLH & XLCH (Sportster) Displacement 55 ci In 72 the Super Sportster had 1000cc All other models had standard 74 ci powerplant untill the introduction of the 80 ci	Displacement: 80 ci Bore: 3.498 inch Stroke: 4.250 inch	Displacement: 88 ci 1450cc Bore: 3.75 inch Stroke: 4.00 inch
Compression	Available in Low, Medium and High	Available in Low, Medium and High		Compression Ratio: 8.5:1	Compression Ratio: 9.0:1
Head Design	Whereas the flat head engine had the intake and exhaust valves on opposite sides of the combustion chamber the valves in the knucklehead were moved to the top of the combustion chambers.	The panhead didnt change much from the knuckle in internals. But it came equipped with aluminum heads.	Larger aluminum version of the Sportster head, with the same hemispherical combustion chamber and valve angle	New aluminum heads designed to decrease oil leakage while utilizing side-squish combustion chambers and flat pistons	Aluminum permanent mold with 85cc bathtub combustion chamber
Cylinder Design	Cast Iron	Aluminum cylinders have a lip on top of the barrel that fits into a recess on the head			50% more fin area for better cooling. Constructed of aluminum high-pressure die cast with cast in Spiney-Lok cast iron liner.
Case Design	Introduced in 37 the recirculating dry sump oiling system. Later models included centrifugal bypass oil pump.	Revised crankcases and cylinders feed oil internally to the heads and return internally to the cases. In 1955 Harley modified the pans by installing a quieter more efficient lower end. In 65 they were the first HD's to have electric start.	Later introduction of rubber mounted engine	A new lower end designed for electronic ignition for better spark control to meet emissions, something the shovel couldn't do anymore.	Twin ge-rotor, dry sump, internal oiling imported from the Sportster. Now uses an O ring instead of paper gasket on the base to cylinder. Stronger crankcase mounts. Counterbalanced crank to reduce the classic vibration.
Fuel Delivery	Linkert carburetor on later models	M-74B 1 1/2-inch Linkert carburetor on 74 ci		Keihin carb, EFI was introduced in 95	Carb or EFI
Transmission	61ci E models had separate 4sp trans constant mesh. Optional three-speed and three-speed-with-reverse transmissions with sliding-gear first on early models. All later Models were 4sp with optional side car gearing.	Both E and F series were available with either hand or foot shifted 4sp transmissions	Late introduction of 5sp trans on FLT model.	By 1991 all models featured the 5sp transmission	Within the transmission housing lies a new shift mechanism that delivers low-effort, clunkfree gear changes
Other	The knucklehead motor was the first of the overhead valve motors and succeeded the side-valve flathead (although the latter continued in production throughout the knucklehead era and beyond).	Basically the knucklehead lower end with a new top end with hydaulic valve lifters and aluminum cylinder heads FLH motors are fitted with Victory camshaft that has a higher lift		To this point the Evo was the most radical departure in engine design for HD In 1992 belt drives were standard on all models.	Twin cams with chain driven spring loaded tensioners Now the Twin Cam has surpassed the Evo in a departure from the design norm. Supposedly only 21 parts are common to the Evo, however, a press release states that fewer 18 parts are shared between the engines
Spotter's Guide
Special Notes	* Main production models, does not include specialty models such as WL etc. The knuckle received it's nick name by the appearance of the heads which look similar to the top of a hand.	*Panheads had the longest production run of any Harley motor to date, lasting 17 years. The first Sportsters, introduced in 1957, were panheads. See the notes on Shovelheads as to why the shovel was not considered the longest production run. Received it's nick name due to its valve covers look of an upside down cake pan.	*There were two versions of the shovel: the generator or flatside shovel, and the cone motor shovel. The flatside shovel, was produced from 1966 to 1969. A generator was mounted ahead of the front cylinder, giving the motor a relatively flat look. Generator shovels are also referred to as "pan/shovels," because the the lower end is the same as a panhead.		*The Twin Cam is also referred to as the Fathead in some circles.

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