How do I choose a pushrod length?
How do I choose a pushrod length?
If the pushrod is too short, the mark will be toward the intake (inboard) side of the valve tip. If the pushrod is too long, the travel will be toward the outboard or exhaust side of the valve tip. An ideal pushrod length will minimize the travel across the center of the valve tip.
How can you tell the geometry of a valvetrain?
Perhaps the most critical measurement during preassembly with regards to valvetrain geometry is the “sweep” of the rocker arm across the top of the valve. “The simplest way to check it is to mock it all up on the motor, and just check how far does that rocker arm sweeps back and forth,” says Hooper.
Which is an overlooked area of the valvetrain for a performance engine?
One of the most overlooked areas within the valvetrain for a performance engine is pushrod length. Veteran enthusiasts may scoff at this because back in the day, you just dropped in a set of stock pushrods, set the lash on that solid cam and went out and made noise.
What’s the best way to check a valve?
A tried and true method of checking sweep is to set up the rocker arm, get a checking pushrod, adjust it down, and mark the top of the valve with a Sharpie. Then turn the motor over and see how wide an area is cleaned up. Ideally, a narrow band should be wiped clean from the Sharpie mark, and it should be mostly centered (see photos).
How do you measure the pushrod length of a valve?
Adjust to zero lash and then create a witness mark by wiggling the rocker across the valve tip. This mark will indicate the rocker’s starting position. A quick way to get close to the proper pushrod length is to first paint the top of the valve tip. Rotate the crank until the lifter is on the base circle of the cam.
Perhaps the most critical measurement during preassembly with regards to valvetrain geometry is the “sweep” of the rocker arm across the top of the valve. “The simplest way to check it is to mock it all up on the motor, and just check how far does that rocker arm sweeps back and forth,” says Hooper.
One of the most overlooked areas within the valvetrain for a performance engine is pushrod length. Veteran enthusiasts may scoff at this because back in the day, you just dropped in a set of stock pushrods, set the lash on that solid cam and went out and made noise.
How is geometry applied to the engine compartment?
Geometry as applied to the engine compartment, of course, is a bit different from those dry classroom lessons. To start at the beginning, “valvetrain geometry” in an overhead-valve engine refers to the job of ensuring the valves, pushrods, rocker arms, lifters and camshaft are all aligned and rolling together with maximum efficiency.
A tried and true method of checking sweep is to set up the rocker arm, get a checking pushrod, adjust it down, and mark the top of the valve with a Sharpie. Then turn the motor over and see how wide an area is cleaned up. Ideally, a narrow band should be wiped clean from the Sharpie mark, and it should be mostly centered (see photos).
