Technical Information

Morel Mechanical Lifters


Information Coming Soon

  • Oil Flow to Push Rod via the Roller Lifter 
  • Weight of Lifters and How it Affects RPM 
  • Lifter to Bore Clearance (Makes the System Work Correctly)  
  • Where to Use "HLT" Limited Travel Lifters 
  • How a Hydraulic Roller Lifter Works
  • Oil Types Affect How a Hydraulic Lifter Operates 

Morel Rebuild Information


  1. Contact one of our dealers to obtain pricing and get the product rebuilt.
    The rebuild price is roughly 50% to 60% of a new price.
  2. We rebuild all mechancial lifters.
  3. We do not rebuild hydraulic lifters.
    The tolerance between the piston and I.D. body is so small, that we found scoring and debris of the body cylinder wall requires too much time to rebuild the hydraulics.                     Note: If your engine has a cam failure or engine failure, the hydraulic lifters should be replaced. The engine should be thoroughly cleaned, including the lifter oil galleys. Just installing new lifters, without proper cleaning of the engine, can cause the new lifters to fail because of dirt and metal debris from the engine failure.

Rebuilding Process

  1. The lifter set is inspected to insure that the parts match up with the part number and description.
  2. The parts are measured to make sure they can be rebuilt. If a lifter body is cracked, we replace it and charge additional for the new body.
  3. The lifters have the fasteners, tie bars, axle clip, axle, needles, and wheel removed. These parts are discarded.
  4. The bodies are examined for cracks or any odd wear points.
  5. The bodies are micro polished, which removes .0001".
  6. New axles, wheels, needles, stainless tie bars, and fasteners are reinstalled.
  7. The assemblies go through final inspection and are shipped back to the dealer.

Installing Rebuilt Lifters

  1. Do not wash in any solvent. Wipe the parts off with a lint free towel.
  2. Use 10W30 oil and lube the O.D. of the body and wheel.
  3. Make sure the lifter-to-bore clearance on cast iron blocks is: .0015" - .0017". On aluminum blocks that oil the lifter (LS Series) the clearance is .0012" - .0014". The aluminum block will have a higher rate of expansion and that is why the clearance is tighter. Both of these measurements are at 70 Deg F.

Adjusting the Zero-lash Setting of the Lifter

  1. I always like using the firing order to set the valves. Put the engine on #1 cylinder.
  2. What we want is the int. and exh. to be on the base circle of the camshaft.
  3. Adjust the rocker until the push rod just starts to get tight while taking the pushrod and rolling it between your thumb and finger. Once you feel drag, this is what we call Zero-lash.
  4. You are now ready to tighten down on the adjuster nut using the following method: It is important to know the thread pitch, in threads per inch, of the adjuster nut, because one complete turn of the nut will move a distance of one complete thread. Therefore, verify the thread pitch of the adjuster nut, because racing rocker manufacturers use different nut sizes and thread pitches. If your adjuster nut is 7/16 x 20 threads per inch, then divide 1 inch by 20 threads per inch.  One complete turn down on a 7/16 by 20 adjuster nut will move .050". Next, divide .050" divide by 4 to calculate the distance for a quarter-turn of the adjuster nut (.050" / 4 = .0125"). For a 3/8 x 24 adjuster nut, the calculations are:     1" / 24 TPI = .042" per full turn and .042" / 4 = .0105" per quarter-turn. Use the chart below to determine how many quarter-turns to tighten the adjuster nut after Zero-lash:      Cast Iron block and Cast Iron Head = .020" - .025"     Cast Iron block and Aluminum Head = .030" - .035"     Aluminum block and Aluminum Head = .045" - .050"
  5. Repeat these adjustments for each cylinder running through the firing order.