The Eagle SIR connecting-rod caps are torqued to specification with a feeler gauge fitted tight between the caps to prevent bearing damage during tightening. The rod bolts can also be tightened to spec with a bolt stretch gauge and recommended on performance applications. Now's your chance to make sure the connecting rod is centered on the piston. If the rod is installed right, it will be centered, if not, the rod is installed incorrectly.
Now we're over the top of the hill, so to speak. The Comp Cams' camshaft is now installed after a liberal coating of assembly lube. We don't use any fancy tool to install the camshaft. Once it's close to the final bearing saddles, a 5/16-inch Phillips head screwdriver works nicely. Insert the screwdriver in one of the cam gear threaded holes, and the cam can be handled quite easily.
We line-up the timing marks on the cam, crank gear, and the Comp Cams high-tech race roller timing chain, and gear set is installed. The cam gear bolts were torqued, and the engine was rotated...oh no! The engine rotated a turn-and-a-half and came to an aburpt halt. The number-two connecting rod was hitting the camshaft. This is a common concern on stroker engines with 3.750 cranks and 6.0-inch length connecting rods and must be dealt with or catastrophic engine damage can result.
Before we can check the cam timing, the engine has to be able to turn over two revolutions without obstructions. We removed the number-two piston and connecting-rod assembly for minor machining. The shiny spot was ground on a bench grinder, removing just enough material off the connecting rod to provide 0.050 clearance between the connecting rod and camshaft. This is not enough metal removal to be of concern regarding the engine balance unless you plan on revving past 10,000 rpm.
Checking camshaft-to-connecting rod clearance is absolutely necessary on cylinders 1, 2, 5, and 6 on these stroked engines. We use a modified feeler gauge and fit it between the rod and cam. We had to remove all the aforementioned connecting rods and pistons to machine for proper 0.050 camshaft-to-rod clearance. Always check this clearance when assembling a stroker engine. If the cam touches the connecting rod, your stroker will become a boat anchor. In our next installment, we will finish the engine build.
|Engine Build Specifications|
|Piston to cylinder wall clearance|
|Piston ring gap|
|Top ring: 0.022|
|Second ring: 0.025|
|Main bearing clearance|
|Journal 1: 0.002|
|Journal 2: 0.0015|
|Journal 3: 0.0015|
|Journal 4: 0.0015|
|Journal 5: 0.022|
|Rod bearing clearance|
|All connecting rods|
|Connecting rod side clearance|
|Piston-to-cylinder deck clearance|
|Both cylinder banks average|
|Camshaft (Lingenfelter PN 74219)|
|Specs||1.5 ratio rockers intake/exhaust||1.6 ratio rockers intake/exhaust|
|Gross Valve Lift||0.525in./0.525in.||0.560in./0.560in.|
|Duration @ 0.006 in.||280 deg./280 deg.|| |
|Duration @ 0.050 in.||219 deg./219 deg.|| |
|Lobe Lift||.0.350in./0.350in.|| |
|Cam Lobe Center||112 deg.|| |
|Intake Center Line||108 deg.|| |
|Valve Timing @ 0.050 in.||open/BTDC||close/ABDC|
|Intake 1.5 deg.||37.5 deg.|
|Exhaust 45.5 deg.||-6.5 deg.|