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TWIN-CAM FACTS SHEET
This is an overview on the Harley Davidson Twin-Cam engine. This engine came out in 1999. The first engines were known as the ALPA or A engine. In 2000 the BETA or B engine was introduced. This engine is used in the Soft-Tail models and has a balancer to help eliminate vibration. The 1999 and some 2000 engines had defective cam bearing and there was limited factory recall.
CYLINDER HEADS
The casting of the cylinder heads stayed the same from 1999- 2004
? The intake valve diameter is 1.840
? The exhaust valve diameter is 1.570
? Stem diameter is .312
? EVO valve spring Pac
? EVO guide seals
? EVO valve guides
These castings had a small exhaust port
2005 cylinder heads castings
The major difference on these heads
? 7mm valve guide stems
? 7mm valve guides - note EVO guides fit these heads
? Updated valve guide seal - note updated
? Bee- Hive valve springs
? The intake and exhaust valve same diameter
These casting will fit 1999-2004 engine and casting have small exhaust port.
2006 cylinder head casting
The major changes on these heads
? These heads have symmetrical intake ports
? The exhaust ports are large
? The intake ports have a raised floor
? Valve, guides and seals are the same as 05
These heads need different intake flanges to mount on earlier engines
CYLINDERS
The cylinders over the years have stayed the same. In 02 the casting numbers changed.
These cylinders can be bored out to a 95 kit. Note the only difference from a factory 95 big bore kit is the bore diameter. Everything else is the same.
PISTON KITS
The stock piston is a cast piston that is fitted at .0007 clearance. These pistons are Teflon coated.
Screaming-Eagle offer many piston combination on big bore kits from cast- forge and various compression ratios.
Note determine cam choice/ to match compression ratio. On our home page we a compression calculator to assist in piston and cam choice
CAM CHEST
All Harley Davidson Twin-Cam engines come from the factory chain driven. In 06 on the DYNA model only, they changed the cam chain set up. They went to different chain set up and a hydraulic cam chain tensioner. In 07 all of the Harley Davidson Twin-Cam engine converted to this set up. Note this new set up can be installed in 99-06 engines.
1999 Cam chest data:
? Cam chain are the multi- plate HI-VO chain
? Outside rear cam sprocket was keyed to rear camshaft
? Rear camshaft had roller bearing
? Inner cam bearing were junk
? Spring load cam chain tensioners
The factory recall include changing the following:
? New camshafts with spline drive on rear cam
? New inner cam bearings
? New cam plate with needle type rear bearing
? New splined rear sprocket
? New cam chains
? Update lifters or the “B” lifter
? Updated cam tensioners
? Updated oil pump
2000-2006 Cam chest data
? The cam chains kept getting more polished to eliminate tensioner wear
? New material was used to eliminate tensioner wear on rubbing blocks
? The Beta or “B” engine has oil screen in crankcase and a oil passage for balancer tensioners
2006 DYNA and 2007 Cam chest data:
? Single roller cam chain inner and outer
? New style cam chain sprockets
? Hydraulic cam chain tensioner
? New designed oil pump
? New designed cam plate
Oil pump data:
? 1999 oil pumps had no wave washer to separate the supply and scavenge side of pump gears
? 2000 oil pumps were change and had wave washer
? 2001 the Beta or “B” pump were introduced and used on both the Alpha “A” and Beta “B” engines
Hydraulic lifters
? 1999 “A” lifters were used for short time
? 2000 The “B” lifter was introduced and still used.
Cam chest service tips:
? The ten cam cover screws are longer in length, note do not use these screws on cam plate. You can damage lifter bores
? On cam plate where dowel pin are, watch your torque pressure when you tighten these screws.
? Replace cam chains when you change cam tensioners, we also recommend polishing cam chains, it helps eliminate tensioner wear
? Inspect cam plate for wear on oil pump surface and crankshaft bushing wear
? Check crankshaft run-out if over .004-.005 you have a twisted crankshaft. Crankshaft needs to be replaced or re-trued.
? Always center oil pump to crankshaft, this can be done two ways:
1. Use EVO tappet block alignment pins
2. Rotate engine and torque oil pump to crankshaft as engine is rotated
ENGINE CRANKCASES
? 1999-2002 all Twin-Cam engine both Alpha “A” and the Beta “B” engines used Timken Bearing on the sprocket side to position crankshaft in crankcases
? 2003-present Twin-Cam engines use a centrical bearing on both sides to position crankshaft. The torque of sprocket bolt centers crankshaft in engine cases.
? 2006 DYNA has a redesigned set crankcases
? 2007 Twin-Cam crankcases both Alpha and Beta are redesigned. They have a non-Timken bearing.
CRANKSHAFTS
ALPHA “A” type
There are two type of Alpha crankshafts
? 99-02 Timken bearing crankshaft
? 03-06 non-Timken bearing crankshaft
NOTE: these crankshafts are currently non-rebuild able
You can use either crankshaft in all Alpha- models years
? 06 Dyna crankshaft
? 07 Stroker Crankshaft
BETA “B” type
There are two types of Beta crankshafts
? 00-02 Timken bearing crankshaft
? 03-06 non-Timken bearing crankshaft
Note: these crankshafts can be used in all 00-06 engine crankcases.
? 07 Stroker crankshaft
BETA BALANCER ASSEMBLY
? 00-02 balancer parts were all the same. This balancer set up used roller bearings in support plates
? 03-06 balancer parts were updated. The sprockets were changed and a centrically bearing were used in support plate.
NOTE: 03-06 balancer assembly can be used in 00-02 engines
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