- How do you measure a pushrod?
- Tool steel tip recommendation
- Why change my pushrods from factory to aftermarket
- What outside diameter is best for my engine?
- Why do pushrods fail
- What situation calls for a heavier wall pushrod
- Will Trend stocking pushrods fit guide plate applications
- What is the difference from clearance to taper
How do you measure a pushrod?
Ball-Ball pushrods: Because the through hole radius in the tips can vary in diameter from factory to other manufacturers, it is not advised you measure pushrods by their overall lengths. Instead it is far more dependable to measure at the .140” gauge diameter. Find two washers with .140” diameter holes, place a washer over the ball on each end of the pushrod and measure the overall distance (outside of washers) finally, put the washers together to get the total thickness and subtract that from your measurement. This will ensure you get exactly what you need.
Ball-Cup Pushrods: There are three ways to accurately communicate the proper length of a ball cup pushrod. Over ball measurement is from the tip of the ball tip (lifter end primarily) to the top of the gauge ball set in the cup. If your adjuster is 5/16” and the pushrod cup is 5/16” you would take a machinist gauge ball measuring .3125” and set it in the cup, and measure to the top of the ball. This is an Overball measurement. Overall length would be same as the Overball length less half of the gauge ball diameter. Underball measurement would have the total diameter of the gauge ball subtracted.
When would you recommend a tool steel tip and do you make them for my rocker arm setup?
Tool steel tip: We recommend a tool steel tip for extreme applications. Poor geometry, high RPM, extreme spring pressure or any application where you’re just having a hard time with pushrod tips living. It has been very successful in cup applications as well as big cubic inch pro-modified mountain motors but has been widely used in sprint car applications. We make it in a variety of shapes and sizes and do offer custom tips as well.
Trend Performance aftermarket pushrods are recommended to use on performance applications ranging from mild to wild. The truth is that if you do not have control over your valvetrain it will control you. Usually the last thing looked at is the pushrod but in our findings with the Spintron™ the pushrod should be the first thing in question after an engine build. If you’re pushrods are in question, give us a call!
The grand rule for pushrod diameter is run what fits, we feel the biggest and baddest pushrod will give the best results in real world performance. Outside diameter of a pushrod solely depends on the allowable space in your cylinder head and sometimes the space allowed near the lifter. Some things to question is style of lifter (offset, tie-bar, etc..) Trend performance has a wide variety of diameters and clearances to fit virtually any combination around.
Pushrod failure can be caused by a number of different issues. The biggest issue we see at Trend is lack of oil and poor geometry. Lack of proper lubrication will destroy an engine. Signs of poor lubricity will be shown through bluing or burning on the pushrod tips followed by galling but keep in mind that depending on geometry (rocker ratio, camshaft size, etc..) the oil flow may be blocked when the valve is opened all the way. Trend has a few solutions in this event, so if you think it may be an issue let a Technician know so we can make recommendations.
We typically recommend heavy wall pushrods in high spring pressure applications. Cylinder pressure along with power adders (nitrous and boost) call for a larger pushrod altogether. This is why Trend stocks heavy wall 5/16” pushrods all the way to heavy wall ½” pushrods.
Yes and no. 5/16” and 3/8” pushrods will fit no problem but moving into a 7/16” diameter setup you will need to relay that info to your sales or tech consultant.
A lot of customers confuse clearance for taper. Taper will most likely affect the overall pushrod where a clearance only reaches back from the “ball or cup” to the largest OD of that pushrod. Depending on length and OD of the part the clearance could be .500” to 1-5/8” ramping from behind the ball up/down to the body. Trend also stocks parts double taper but any of our “on the shelf” parts may be tapered.