How To Measure Jesel Rockers For Pushrod Length Part 1
Wayne Scraba
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When you purchase a new set of shaft rockers from Jesel(or actually, any roller rocker for that matter) it’s a good idea to check how the rocker sweeps across the valve tip. Sweep is established by way of the rocker stand height. And equally important, you have to accurately determine the length of the pushrod. Dollars to doughnuts, you’ll need new pushrods. Once you have the rocker shaft height figured out (another story), you can investigate pushrod length. This isn’t a difficult job, but you will need a set of adjustable pushrod length checking tools to get it done.
Jesel offers three different pushrod length checking tools – two for cup style adjusters and one for ball format adjusters. Other manufacturers offer similar tools. In the photos that follow, I’m using checking tools from Trick Flow Specialties. These particular tools are marked with a laser-etched alignment line. Each full rotation of the adjustable pushrod represents 0.050-inch. As an example, if you have an 8.800-inch checking pushrod and it’s fully screwed together, if you turn it out one revolution for your setup, then the correct pushrod is 8.850 inches (the standard 8.800-inches + 0.050 = 8.850-inches).
If the pushrod length checking tool(s) you use are not marked, then you’ll have to accurately measure the length of the pushrod by way of a large caliper. Calipers that open to 9 or so inches (or longer) aren’t really that common in many enthusiast tool boxes. Finally, for some engines, such as the big block Chevy shown here, you’ll need two tools – one for the intake rocker and one for the exhaust.
For this portion of the article, we’ll look closely at several different types of adjustable checking pushrods in the accompanying photos. One set from Jesel, one set from the “old” Crane Cams (unfortunately, now obsolete) and one set from Trick Flow Specialties. In the next article, we’ll show you how to actually measure for custom pushrods. The reality is, the entire process is not that difficult!
For a closer look at the checking pushrods mentioned above, take a look at the accompanying slideshow:
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I have several different sets of adjustable pushrods in my tool box. Included in the mix (and from the left) is a set from the old Crane Cams. The set in the middle is from Jesel. Finally, the set on the right is from Trick Flow Specialties.
The old Crane pushrod tool adjusts by way of a common 3/8-inch wrench.
This is a complete Jesel adjustment set. Included are two ball adjusters, one cup adjuster and sufficient threaded aluminum tubing to make up just about any pushrod length or configuration you’ll need.
Here you can see how the Jesel setup assembles.
Both the Jesel and the Crane adjustable checking pushrods must be measured with an accurate (large) caliper to determine length. See the text for more info.
The Trick Flow Specialties tool also adjusts, but you really don’t need a large caliper to figure out the length. See the next photo:
As you can see, the tool is laser-etched with a scale. One full revolution equals 0.050-inch in length. More info in the text.
