Tech
S&S 106ci Hop-Up, Part 3
The Screamin’ Eagle Hydraulic Cam Chain Tensioner and High Flow Oil Pump Kit fits ’99-05 Dyna models, ’00-06 Softail models, and ’99-06 Touring models. The late model big twins all now come with hydraulic tensioners. To install the kit, a Spacer Kit, Cam Service kit, and Drive Gear retention kit is also required.
Rolling along into the third installment of improving the performance and durability of our friend Oscar’s ’02 Road King, we are going to follow along as Kevin Feuntes from Los Angeles Harley-Davidson of Anaheim buttons up the bottom end, installs new pistons and cylinders, and tackles the heads. Over the past two issues Kevin has been overhauling the tired 88ci engine and upping the King to a more modern triple-digit displacement. The stock flywheel assembly was out of true so it was swapped with one of S&S’s 4-3/8-inch stroke flywheels ($1,249.95). While the swap obviously required splitting the cases, the new flywheels fit in with no machining required. Some light clearancing was performed in the cam chest area for the new 585 cams that are going to be installed (visit baggersmag.com to fully catch up on the last two articles).
In this article the cam chest area will get upgraded with S&S’s 585 Easy Start Cam kit ($367.95). Intended for large-displacement engines, the 585 cams are designed to deliver strong horsepower and torque through the 2,500-5,500-rpm range. The most unique thing about these cams are their Easy Start feature which releases some compression on start-up making it easier for large-displacement motors to turn over while also relieving stress on the starter and battery. To go along with the cams, the stock cam plate and oil pump will get upgraded to a Screamin’ Eagle Hydraulic Cam Chain Tensioner and High Flow Oil Pump kit ($499.95). One of the most important aspects of this upgrade is the switch from the old-style spring-loaded cam chain tensioners to the newer style hydraulic tensioners. The spring-loaded tensioners have been a big topic of discussion over the years from bike owners experiencing low-mileage wear, cracking/breakage, and/or bits of tensioner material circulating through the oiling system blocking oil passages and wreaking havoc. The hydraulic tensioner pads are comprised of a nylon material, which along with the hydraulic nature of the tensioner support, provides a longer lasting, more durable design while still providing proper chain tension for cam timing. The kit also includes an SE High Flow Oil Pump that provides better oil pressure and scavenging as well as lower engine temps as compared to the stock unit. Backing it all up and providing improved support and oiling is a billet cam plate. Atop the cases Kevin will install an S&S Big Bore kit. S&S offers its 3.927-inch bore cylinders and piston kit ($749.95) as a bolt-on upgrade for 88- or 96ci bikes taking the bikes displacement up to 97 or 106 ci, respectively. Once combined with the 4-3/8-inch flywheels the kit will bump up this bike’s displacement to a more modern 106 ci. It should be noted that we inadvertently transposed the numbers in the intro of the December article; the correct number is 3.927 inch, not 3.972 inch.
Now that you know where we are headed; hold on because here we go.
01 Here’s a comparison of the old-style spring-loaded tensioner (right) and the new hydraulic tensioner (left). On the old style, tension on the cam chain was achieved with a tightly wrapped, heavy-duty flat wire spring. Whereas, oil passages on the backside of the new tensioner allow oil to build up hydraulic pressure and keep tension against the chain. You may also notice the new style has a more durable white nylon pad as opposed to the more brittle orange pad.
02 Kevin began setting up the new billet cam plate by pressing in the bearings for the outer cam journals to reside in.
03 Here we are looking at the left side of the cam plate (the side that faces toward the flywheel), you may notice the outer cam journals reside in two different style bearings, the left ball bearing (front cam) and the right roller bearing (rear cam). The rear cam is under heavier, more angular stresses than the front and therefore needs a more durable bearing to properly support it.
04 S&S’s Easy Start 585 cams feature a spring-loaded compression release built into the heel of the exhaust cam lobes at the point where the valve would normally be fully closed. The raised lobe of the compression release holds the exhaust valve slightly open at cranking speed, which releases some compression making it easy to turn the engine over. Then when the engine starts and the RPM increases, the compression release lobe is centrifugally retracted and the engine runs normally with full compression.
05 For ’02-06 models the SE Hydraulic Cam Chain Tensioner Kit allows for the use of a single row front roller chain (bottom) to replace the stock silent timing chain (top). One of the issues with the stock tensioner and silent chain is that the design of the stock chain has edges to it that could add to the increased wear of the pad.
06 After lining up the timing mark on the cams, Kevin pressed them into the cam plate.
07 He then installed the cam bearing retaining plate followed by the secondary chain tensioner.
08 Kevin then flipped the cam support plate over and installed the snap ring on outer journal of the front cam.
09 Inside the cam chest, Kevin replaced all the O-rings and then …
10 … pulled the oil pump apart so he could properly lubricate it before installation.
11 The oil pump was then aligned on the pinion shaft and slid into the cam chest.
12 The cam plate was then installed along with the support plate bolts. Kevin then used dowels to get the oil pump properly aligned. He then had someone slowly turn the rear wheel while in gear to get the oil pump properly aligned and then he tightened the oil pump bolts to spec.