Roll With It – Convert a Flat Tappet Camshaft to a Roller
After we feel like it’s pretty close, it’s time to install the camshaft sprocket with the button in place. Then, we install the outer plate on the timing chain cover with no gasket or sealant. We tighten all of the countersunk allen head bolts.
Using a long screwdriver, we carefully pry against the camshaft lobes to move the camshaft forward and backward. If the camshaft does not move, you should remove more material from the nylon button. COMP Cams suggests setting the endplay between .005- and .010-inch, using a dial indicator to measure front to back movement of the camshaft.
After the endplay checks out within COMP Cam’s spec, we remove the outer timing chain cover plate, and then prepare to install the timing chain. We are installing the camshaft “straight up” meaning that we are using the “0” on the crankshaft sprocket, and lining it up with the dot on the camshaft sprocket.
Now is the time to break out the red Loctite for the three camshaft sprocket bolts. This is the only time you should need Loctite thread locker during the roller conversion process.
We torque the three camshaft sprocket bolts to 25 lb-ft and double check that our dots are still lined up and there is no binding in the chain.
A thin layer of high temp RTV silicone is applied to the outer timing chain cover plate before final assembly.
The 10 countersunk allen-head bolts can be installed for the last time. Don’t forget to install the flat plug in the center of the cover, which is the access hole for the dial indicator while checking camshaft endplay.
Two pointers are included with the timing chain cover kit—one for a small balancer and one for a large balancer. Choose the appropriate pointer for your application and install it using the two supplied bolts.
Also supplied in the timing chain cover kit are low profile bolts, which are necessary for proper clearance between the timing chain cover and a short water pump. We remove the standard hex-head bolts and replace them one at a time with the new hardware to offer a little more clearance.
The COMP Cams 853-16 retro-fit hydraulic roller lifters are the key to this conversion, as they offer a link-bar design to slide directly in place of the original drop in flat tappet lifters.
After applying installation lube on the rollers, we dropped the lifters into the bores. Take note that the link bars are pointed toward the lifter valley, and not toward the block.
When switching from a flat tappet camshaft to a roller, it is important to change the fuel pump pushrod to a bronze-tip unit, like this 4607 pushrod from COMP. Any COMP Cams camshaft with a part number that ends in “-8” or higher requires a bronze-tip or roller tip fuel pump pushrod because of the billet steel construction.