Twin Cam Engine Build Part 4 of 5

We finish the cam plate install and start on the lifters

how to build a twin cam motor

After tightening the two sprockets retaining bolts, place a straight edge over both sprockets to measure if your spacers are in alignment.

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Let's finish the cam installation and move on to the lifters. If you're just now joining us, we're rebuilding the Twin Cam A from a `99 Harley FXDX. After a 100,000 miles of loyal service, the motor had earned a spa day.

After we broke it down, we inspected it, and then sent the lower end to Darkhorse Crankworks (DHC) so its squad of bottom-end experts could rework the tired components. Working with Dave Mackie Engineering (DME), we concocted a solid 107ci top end using bored H-D cylinders and some DME Mega-Sphere pistons, complemented by a DME cam. Both DME and DHC are known for their superior quality and attention to detail, so it was a pleasure to assemble this motor knowing the end result would be a powerful yet balanced blueprinted motor.

how to build a twin cam motor

Pictured here is the correct sprocket spacing with the retaining hardware removed.

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how to build a twin cam motor

Using a JIMS sprocket-locking tool, lock your cam sprockets and torque the cam sprocket bolts.

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how to build a twin cam motor

Next we take a look into the Zipper’s Performance hydraulic cam chain tensioners. We are looking inside to make sure the bore is clean and has no foreign material from production caught inside.

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how to build a twin cam motor

Using a small amount of H-D 20/50 motor oil, we filled up the tensioner pistons.

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how to build a twin cam motor

Install the cam chain tensioner and torque to factory specs.

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how to build a twin cam motor

Since we are using Zipper’s cam chain tensioners, it is recommended that some of the webbing inside the cam cover be removed so the tensioner does not hit the inside of the cover.

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how to build a twin cam motor

You might have to place the cover on and off a few times to make sure you have removed all the material away from the tensioner housing.

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how to build a twin cam motor

Once the cam cover sits flush, install the cam cover bolts and torque to 90 to 120 inch-pounds.

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how to build a twin cam motor

Pre-soaking lifters is always a great idea to bleed all the air out of the tappet body so when starting the motor the lifters will be somewhat oil filled and therefore have less to do when the motor is first fired.

Photo: Hot Bike Staff