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GM-Frank, ASE Master Certified
Category: Car
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Experience:  37 Years Automotive Diagnosis & Repair. Experience with all makes and models..
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I have a 1989 ford ranger 2.9v6 has hydraulic lifters with ...

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I have a 1989 ford ranger 2.9v6 has hydraulic lifters with a manual adjustment, there was a bad push rod that was replaced, now all the lifters need to be re-adjusted but I am confused as the the instructions on repair
not sure what this means, how do I know if the tappets are in the base circle area??

"On the cylinder to be adjusted, position the cams so that the tappets are in the base circle area"



The base circle is the area of the cam lobe that is at the exact opposite area of the camshaft as the highest point of lift.

Therefore when the valve is opened all the way, the lifter is sitting at the top of the cam lift. When the camshaft is rotated 180 degrees, it will be at the base circle.

You want to have the cam positioned with the lifter at it's least area of lift or the base circle for your adjustment.

If you have replaced the lifters, be careful, because they want the lash before the 1.5 turn to be at zero before the lifter plunger has begun to move. If the plunger is at the bottom of the lifter already, they your valve will not close after you make the adjustment.

  1. Position cams so that tappets are in the base circle area on cylinder to be adjusted.
  2. Loosen adjusting screws until a distinct lash between roller arm pad and valve tip end can be noticed. Tappet plunger should now be fully extended.
  3. Screw in adjustment screws until roller arms slightly touch valves.
  4. Screw in adjustment screw an additional 1-1/2 turns (equivalent to .070 inch plunger travel into lifter) to achieve normal operating position.




I hope this explains your question.

Any other questions, please feel free to ask

Have a Great Day


GM-Frank and other Car Specialists are ready to help you
Customer: replied 9 years ago.
Reply to GM-Frank's Post: "You want to have the cam positioned with the lifter at it's least area of lift or the base circle for your adjustment"

sorry if i seem stupid, but how do I know when this is?


So as not to confuse you and to make is as simple as possible.

Take off the distributor cap, and adjust the Intake and Exhaust valves of the

cylinder that the rotor is pointing toward.


So bring up number one cylinder while the distributor cap is off and see that the rotor is pointing to the number one spark plug wire tower on the cap.. This will place the number one cylinder intake and exhaust valves on the base circle. Adjust those 2 then move to the number 4 cylinder.

Watch the rotor move as you slowly rotate the engine to where the rotor points to the tower where the number 4 wire is connected. This places number 4 intake and exhaust lobes of # XXXXX cyl on the base circle. Adjust them and then move on through the firing order to number 2 then 5 then 3 then 6.

I hope this helps


Customer: replied 9 years ago.
Thank you, XXXXX XXXXX help alot, I'll go give that a try.
now my understanding is, when it is at this point, loosen the adjuster, then tighten until snug (zero lash) then 1.5 turns more correct?


That is correct.

As you are beginning to tighten to take the lash to zero, be very careful and have that adjustment just take out the play with a light touch. Then do the 1.5 turn.

You got it.