I HATE secrets!! I give up (for now) just cannot figure it out...
 


I want to know what makes these lightweight lifters so damn light, almost 30% lighter than stock and they're just not giving up their secret.

I've been over em with a fine-tooth comb and nothing, not one single thing I can put my finger on. In fact if anything they should be heavier due to a few things I'll point out but NO... they're friggin lighter! A LOT lighter!!

They are the same height, width and depth. Their skirt thicknesses are identical. LW ones do have a smaller waist oil groove and a smaller oil port with a "break-in" surface coating on top lobe "wipe" surface but that should increase weight.

Both match the cam lobes' Rockwell hardness rating at 41C. Valve stem pivot mating surface underneath is same length and diameter. There is a small convex relief in the stock lifters underside roof, probably for increased rigidity but thats nowhere near the 30% weight difference.

So I'm stumped but it wont last long. Next time I place an order I'm going to get one extra lifter and it's going under the knife... ok, would ya believe Rotofera cutting disc?

I'll get to the bottom of this. I shall not be defeated by a friggin lifter!! Poor little guy has no idea this is a war he can't possibly win!

Needless description: lifters on right are the LW ones.

 

Lifter dissection...
 

Here's a stock lifter cut open, cleaned and laid out in re-assembled order.

I still don't see where such dramatic weight savings is coming from but there's no denying it's in here somewhere. The lower cylinder in pic has a ball/seat check valve on the spring end and the spring is rated at 7.2lbs at 25% compression and 10lbs at 50% compression.

Dammit, I was hoping to avoid doing the same thing to a lightweight one but this virtually seals one unlucky LW lifters fate.

 

Lightweight lifter secrets revealed...
 


I pretty much gave everyone the answer to the question yesterday when I said it's "all in the shell." All of the weight-savings is accomplished in the lifter shell body.

In the lower chamber that sits over the valve springs the lifters share an idental wall thickness of .034". The dividing wall that separates the sealed upper from the open lower are same thickness as well tho the cylinder flange that the oil-plunger assemblies slide in is facing the upper cylinder in the LW lifter and the lower area in the stock lifter. This makes for a lifter with larger oil volumes.

All comes down to lifter body (shell) thickness. Other than them being the same in both lowers the LW one has a .033" thick wall while the stock lifter has a .061" wall thickness.

Tops are slightly different in that the stock lifters' top is .095" thick while the lightweight top is .080" thick.

Internal components are identical in EVERY way with not even a 1/100 gram difference in the their entire assemblies and are actually interchangeable with each other.

Weights are as follows after ultrasonic cleaning and oil removal:

Stock lifter: 69.1g
LW lifter: 48.28g
Net Difference: -20.82g (30.12% lighter)