Adjustable push rods
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From: N. Atlanta Burbs
Road Master
Joined: Jan 2006
Posts: 1,221
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From: Chester NY
Adjustable Pushrod
Installation Instructions
Proper pushrod adjustment is often overlooked as an important procedure but many times it can mean the difference in having a quiet running engine or a hammering valve train. Not to mention that improper adjustment can lead to poor running conditions and in some cases catastrophic failure. Here are some helpful specs and detailed instructions.
Popular Pushrod Manufacturers Threads Per Inch:
Revolution Performance Chromoly – 32 tpi
Jims Pro-Lite – 24 tpi
Slim Jims – 32 tpi
Andrews – 28 tpi
Andrews – 32 tpi
Crane New Time Savers – 28 tpi
Crane Old Time Savers – 24 tpi
Crane – 32 tpi
H-D – 32 tpi
S and S – 32 tpi
Screaming Eagle – 32 tpi
Rivera Taper Lite – 40 tpi
Rev Tech – 36 tpi
Pushrod adjustment procedure for the following tappet brands:
Revolution Performance Hydro-Rev (All)
Jims Powerglide
Comp Cams Hydraulics (All)
S and S Hydraulics (All)
Crane Hydraulics (All)
The whole idea in adjusting pushrods is to set the tappet plunger in approximately the middle of its range. Most lifters range is .200" from top to bottom so approximately .100" of depression is ideal.
Start by rotating the engine over until the front two cams are on their base circles (be careful the engine is not in the overlap cycle).
You have to make sure that the pushrod adjusters are exposed at all times. An easy way to accomplish this is to bend a paper clip into a hook on one end and connect a rubber band to the other end. Stretch the rubber band up and connect it somewhere in the rocker box area. You can even do this to all four tubes before you start.
With the lifters on the base circle and the pushrods installed, extend the pushrod until zero lash is achieved. This means that there is no up or down movement but the lifter plunger is not depressed.
Make sure that the jam nut is loose and mark the pushrod with a marker so that you easily see when a full revolution has been accomplished.
At this point refer to the manufacturers specs for threads per inch and use this as a reference. Insert a decimal between the threads per inch number and that is how many full revolutions or turns that the pushrod needs (i.e. 32 tpi = 3.2 full turns).
You absolutely need to make sure that the lifters are bled down before rotating the engine over or valve damage can occur. This process can take anywhere from 5 to 15 minutes. You should be able to rotate the pushrods with your fingertips and feel a slight drag on them.
Repeat this process on the rear cylinder and replace the clips. Our pushrod tube clip installer makes this process a snap.
Pushrod adjustment for Jims Hydrosolid Tappets:
The Jims Hydrosolid Tappet is unique in its design in that it has approximately half the amount of plunger travel than most lifters. This design characteristic means that you must take the normal adjustment specs (32 tpi = 3.2 full turns) and reduce them by half. For example, if you would normally adjust the pushrod out 3.2 full turns you would now only extend it 1.5 turns or run the risk of holding the valve open. Other than this unique feature the process for adjustment is identical to a standard lifter.
Installation Instructions
Proper pushrod adjustment is often overlooked as an important procedure but many times it can mean the difference in having a quiet running engine or a hammering valve train. Not to mention that improper adjustment can lead to poor running conditions and in some cases catastrophic failure. Here are some helpful specs and detailed instructions.
Popular Pushrod Manufacturers Threads Per Inch:
Revolution Performance Chromoly – 32 tpi
Jims Pro-Lite – 24 tpi
Slim Jims – 32 tpi
Andrews – 28 tpi
Andrews – 32 tpi
Crane New Time Savers – 28 tpi
Crane Old Time Savers – 24 tpi
Crane – 32 tpi
H-D – 32 tpi
S and S – 32 tpi
Screaming Eagle – 32 tpi
Rivera Taper Lite – 40 tpi
Rev Tech – 36 tpi
Pushrod adjustment procedure for the following tappet brands:
Revolution Performance Hydro-Rev (All)
Jims Powerglide
Comp Cams Hydraulics (All)
S and S Hydraulics (All)
Crane Hydraulics (All)
The whole idea in adjusting pushrods is to set the tappet plunger in approximately the middle of its range. Most lifters range is .200" from top to bottom so approximately .100" of depression is ideal.
Start by rotating the engine over until the front two cams are on their base circles (be careful the engine is not in the overlap cycle).
You have to make sure that the pushrod adjusters are exposed at all times. An easy way to accomplish this is to bend a paper clip into a hook on one end and connect a rubber band to the other end. Stretch the rubber band up and connect it somewhere in the rocker box area. You can even do this to all four tubes before you start.
With the lifters on the base circle and the pushrods installed, extend the pushrod until zero lash is achieved. This means that there is no up or down movement but the lifter plunger is not depressed.
Make sure that the jam nut is loose and mark the pushrod with a marker so that you easily see when a full revolution has been accomplished.
At this point refer to the manufacturers specs for threads per inch and use this as a reference. Insert a decimal between the threads per inch number and that is how many full revolutions or turns that the pushrod needs (i.e. 32 tpi = 3.2 full turns).
You absolutely need to make sure that the lifters are bled down before rotating the engine over or valve damage can occur. This process can take anywhere from 5 to 15 minutes. You should be able to rotate the pushrods with your fingertips and feel a slight drag on them.
Repeat this process on the rear cylinder and replace the clips. Our pushrod tube clip installer makes this process a snap.
Pushrod adjustment for Jims Hydrosolid Tappets:
The Jims Hydrosolid Tappet is unique in its design in that it has approximately half the amount of plunger travel than most lifters. This design characteristic means that you must take the normal adjustment specs (32 tpi = 3.2 full turns) and reduce them by half. For example, if you would normally adjust the pushrod out 3.2 full turns you would now only extend it 1.5 turns or run the risk of holding the valve open. Other than this unique feature the process for adjustment is identical to a standard lifter.
Wow, I did not think this was a hard question. The difference is:
28TPI 5 turns after zero lash is .179in
32TPI 5 turns after zero lash is .156in
From what I read this is almost significant. ;-)
But if your trying to find bottom and look up, its special
...gene
28TPI 5 turns after zero lash is .179in
32TPI 5 turns after zero lash is .156in
From what I read this is almost significant. ;-)
But if your trying to find bottom and look up, its special
...gene
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