On Head Tester
Frequently Asked Questions
Q : What makes the Buxton Engineering on head valve spring tester better than the rest ?
A: Other on head testers on the market measure the down force applied directly over the spring. (see fig below) What they don't measure is the upward force applied to the push rod side of the rocker arm.
This upward force counteracts the downward force. The end result, can produce false readings of as much as 100 lbs. depending on the rocker arm length and design. Our patented design combines both forces to give a very accurate reading.
Q: Other manufacturers advertise .XX% accuracy. Is this true ?
A: Yes and no. The load cell or measuring device may be accurate within .XX%, but the unit as a whole is not. We have done a substantial amount of testing, and our unit is a true 2%. On a 300 lb. spring that would only be +/- 3 lbs.
Q: Will your tester work on stud mounted rockers ?
A: Yes, it will work on shaft or stud mounted rockers.
Q: I don't have much space between the valve cover rail and rocker arm. How much space do I need ?
A: The rocker arm latch has a very thin profile. You only need about 3/16ths of an inch.
Q: Will your tester work on offset rockers ?
A: It will work on offsets as much as 1", depending on the manufacturer of the arm.
Q: Is the adjustment on the tester for different rocker ratios ?
A: No, the adjustment is for the rocker arm pivot length. (the distance between the shaft or trunion and the roller tip) For example on a small block Chevy you can have two different ratios but they both will have the same pivot length.
