How To Measure Jesel Rockers For Pushrod Length Part 2

Wayne Scraba

20 Jan 2022

Click Here to Begin Slideshow In our last issue, we checked out several different pushrod length checking tools – a set from Jesel , an older (obsolete) set of tools from the late Crane Cams and finally, a set of checking tools from Trick Flow Specialties. There are others available, but this is what I have in my tool box. This time around, we’ll go right into the checking process. Anyone can do it. Here’s the Jesel method for measuring pushrod length: Starting with cylinder number one, rotate the engine until the intake lifter is on the camshaft base circle. This is opposite from full valve lift. Assemble the adjustable checking pushrod to the approximate length. Install the pushrod on the intake lifter and bolt the rocker arm to the rocker stand. Inspect closely for any interference the pushrod may encounter with the cylinder head and correct as necessary. For the more common cup style lash adjuster style, set the rocker adjuster one full turn down from the fully seated position. For ball style adjusters, set the top of the adjuster flush with the adjuster nut. Next, screw out the ends of the adjustable pushrod until they make contact with the adjuster. Select a feeler gauge blade that is equal to the cold lash specification for your camshaft. Insert it between the rocker arm roller tip and the tip of the valve. Tighten the adjustable pushrod. Remove the rocker arm and inspect the pushrod. With the TFS style of pushrod, you can count the number of turns (on the etched scale) the adjustable pushrod has made, or how many turns it takes to go back to zero. This allows you to determine the correct pushrod length. As a heads up, I also make it a practice to measure the “gap” in the adjustable pushrod. Add the “gap” to the closed length of the pushrod and you should come up with same dimension as you have with the number of turns on the scale on the side of the pushrod. This is just a good double check. At this point, you can repeat the process for the next pushrod in the cylinder. Some folks measure one intake and one exhaust and call it a day. I prefer to measure each pushrod. As Jesel points out: “Due to variances in engine machining processes and camshaft grinds, it is not uncommon for pushrod lengths to vary from one bank to another or from one cylinder to another.” Keep that in mind when ordering pushrods. Something you must always consider with a checking pushrods is that they are not sufficiently strong to allow you to rotate the engine with them installed. Case-in-point are the springs used on the engine shown in the photos. Each has a seat pressure of 270 pounds and an open pressure of 775 pounds. As you can well imagine, that sort of pressure will mangle an adjustable pushrod if you attempt to rotate the engine. In the end, dialing in the correct length pushrods for your engine isn’t really a difficult job. It just takes some time along with a couple of inexpensive pushrod length checking tools. For a closer look at the process, check out the accompanying photos: ### Sources: Jesel Valvetrain Innovation 985 Cedar Bridge Ave. Suite 2 Lakewood, New Jersey, 08701 PH: 732-901-1800 Website: https://www.jesel.com Trick Flow Specialties 285 West Avenue Tallmadge, OH 44278 PH: 888-841-6556 Website: www.Trickflow.com Click Here to Begin Slideshow

How To Measure Jesel Rockers For Pushrod Length Part 1 — Click Here to Begin Slideshow In our last issue, we checked out several different pushrod length checking tools – a set from Jesel , an older (obsolete) set of tools from the late Crane Cams and finally, a set of checking tools from Trick Flow Specialties. There are others available, but this is what I have in my tool box. This time around, we’ll go right into the checking process. Anyone can do it. Here’s the Jesel method for measuring pushrod length: Starting with cylinder number one, rotate the engine until the intake lifter is on the camshaft base circle. This is opposite from full valve lift. Assemble the adjustable checking pushrod to the approximate length. Install the pushrod on the intake lifter and bolt the rocker arm to the rocker stand. Inspect closely for any interference the pushrod may encounter with the cylinder head and correct as necessary. For the more common cup style lash adjuster style, set the rocker adjuster one full turn down from the fully seated position. For ball style adjusters, set the top of the adjuster flush with the adjuster nut. Next, screw out the ends of the adjustable pushrod until they make contact with the adjuster. Select a feeler gauge blade that is equal to the cold lash specification for your camshaft. Insert it between the rocker arm roller tip and the tip of the valve. Tighten the adjustable pushrod. Remove the rocker arm and inspect the pushrod. With the TFS style of pushrod, you can count the number of turns (on the etched scale) the adjustable pushrod has made, or how many turns it takes to go back to zero. This allows you to determine the correct pushrod length. As a heads up, I also make it a practice to measure the “gap” in the adjustable pushrod. Add the “gap” to the closed length of the pushrod and you should come up with same dimension as you have with the number of turns on the scale on the side of the pushrod. This is just a good double check. At this point, you can repeat the process for the next pushrod in the cylinder. Some folks measure one intake and one exhaust and call it a day. I prefer to measure each pushrod. As Jesel points out: “Due to variances in engine machining processes and camshaft grinds, it is not uncommon for pushrod lengths to vary from one bank to another or from one cylinder to another.” Keep that in mind when ordering pushrods. Something you must always consider with a checking pushrods is that they are not sufficiently strong to allow you to rotate the engine with them installed. Case-in-point are the springs used on the engine shown in the photos. Each has a seat pressure of 270 pounds and an open pressure of 775 pounds. As you can well imagine, that sort of pressure will mangle an adjustable pushrod if you attempt to rotate the engine. In the end, dialing in the correct length pushrods for your engine isn’t really a difficult job. It just takes some time along with a couple of inexpensive pushrod length checking tools. For a closer look at the process, check out the accompanying photos: ### Sources: Jesel Valvetrain Innovation 985 Cedar Bridge Ave. Suite 2 Lakewood, New Jersey, 08701 PH: 732-901-1800 Website: https://www.jesel.com Trick Flow Specialties 285 West Avenue Tallmadge, OH 44278 PH: 888-841-6556 Website: www.Trickflow.com Click Here to Begin Slideshow

With the Jesel rocker setup, install the rocker arm stands first. We’re assuming you have the stands set up to the correct height.

Rotate the engine until the intake lifter is on the camshaft base circle.

With a cup style adjuster, set the adjuster one full turn down from the seated position.

Install a checking pushrod and screw out the ends of the pushrod until they lightly contact the adjuster.

Insert a feeler gauge set for cold lash based upon your cam specifications. Adjust the adjustable pushrod ends until lash is obtained. Remove the rocker.

Count the turns on the index mark on the adjustable pushrod. If you don’t have an indexed pushrod, measure the overall length.

This was mentioned in the text, but it’s worth repeating: I also double check the length by measuring the gap on the adjustable pushrod. Add it to the fully tightened checking pushrod length and you’ll arrive at the correct pushrod length.

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