There was a discussion on another site about .700” lifter wheel versus .750” lifter wheel because the pressure angle is lower with the larger wheel. The pressure angle difference that a .025” change in the lifter wheel radius makes is very small. If you calculate the difference in the two wheel sizes on our Cam Motion lobe that is 224 at .050” and .370” lobe lift, which is about as aggressive of a hydraulic lobe we would recommend using on this engine, the maximum pressure angle for the .700” wheel is 22.36168 degrees and the same lobe with a .750” wheel is 22.79817 degrees. It is measurable but hard to say it is significant. The pressure angle is only one of the factors to use when choosing the best lifter for your build. The smaller wheel diameter allows the lifter to have a full round body all the way to the bottom of the lifter which allows for more surface contact with the lifter bore below the oil band and much more support for the axle. Also the axle is swedged to prevent them from spreading. The open forks required with .750” wheel can sometime spread out with higher loads. The aluminum blocks are not as hard as the iron blocks so I think the extra surface area would give you better support on the higher lobe lift cams because of the smaller base circle sizes required for more lobe lift. We sell both Johnson and Morel.

 

Great info. Now does your personal car have Johnson's or Morels?

 

My personal car is a G35 but I am going to trade it off soon for a Vette. The new toy will have a (Stage II Titan) (not listed on the web yet) Cam Motion cam with Johnson lifters

 

It was actually a rhetorical question, but thanks.

 

Hmm, I replace a ton of .700" wheel stuff with Morel .750" stuff and issues seem to go away. At give lift rate the encapsulated stuff will grap the lobe. Just had a customer with an LS doing this.

I have not seen a spread fork on a Morel hyd roller in the 11 years I have sold them.

 

If anything the larger wheel will turn slower and will allow better oiling with less stress/heat on the axle.

 

Johnson has a lot of spintron testing on why they chose the .700" wheel.

With the hydraulic ramp rates and spring pressures available on the LS1, either design would be fine. I think both brands higher end hydraulic roller lifters can withstand over 800lbs of open pressure.

I had Morels. Sold them. Now I run Johnson.

 

Another thing is Morel does not use a swedged axle assembly to secure the axle in place. Swedging axles means the ends are left soft so that one can press fit, distort the ends, to hold the axle in place. All of Morels lifters including the street series lifters have a case hardened centerless ground axle that held in the body by "wire lock" clips. No distortion of the axle is needed to secure it.

I called a couple of friends over the hill in NC and we spoke about loads based on wheel diameters. If small changes in wheel diameters did't make a huge difference we would not have evolved from .700", .750, .810, .820, .850" diameters.

I think the key in selecting lifters is to base the decision on a product that can live in the enviroment you put it in.

 

The Morel lifters are some of the best lifters made I did not think I was beating them up. Larger wheels are better no question about that. Forked lifter are in all engines with the most HP highest lift cams. 1200 pounds spring presser crazy RPMs. I just said I like the .700 wheel because of more support in the lifter bore being the block was aluminum. If I had a steel block it would not matter to me if I had the fork lifter or the hooded wheel. Most of the cams that people on this site are buying are street cams so if it’s for the street I think the .700 are fine.

 

Is .750" the largest wheel they're making for the .842" lifters, or are there larger?

 

.750 is the largest for the .842 body for automotive. Some motorcycles have a .842 body with a 1.00 wheel.

 

Good to know, thanks.

 

Great information Kip. It would be interesting to know what lobe lift that maximum pressure angle is reached?

 

Good question Martin. Lift can have an effect on the presser angle higher lobe lift means it has to go quicker. This is how lifter presser angle is effected the most. Here are a few rules that apply for this type of application. If I make a lobe for a LS1 it has a 2.156 cam bearing diameter. If I make a lobe that is .360 lift with 236@.05 the base circle should be 1.435 that leaves .005 lobe tip clearance. The presser angle will be 19.94 for this lobe. Now if I make the same lobe 236/360 with higher acceleration the presser angle will go up to 20.26 depending on how much more acceleration I give it. So next lets say I took the same lobe the first one 236/360 for the LS1 with a base circle of 1.435 now I am going to put it on a Small Block Chevy 402 it will need a smaller base circle diameter than a STD SBC so the rods will not hit with the extra stroke . When I take the same lobe and bring the base circle down to 1.068 to fit the SBC the presses angle goes up to 23.15 because of the base circle diameter verses the roller wheel size. One more thing I will get into later is radius of curvature What does that mean? It will take a wile.