Solid roller wheel size

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mopardave
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Solid roller wheel size

Post by mopardave »

Looking at the BAM roller lifters and see the have a .750 wheel and a .815 wheel. How do you pick the proper size wheel or does it not make any difference? The lifter with the smaller wheel is less money as well.
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Re: Solid roller wheel size

Post by cgarb »

If you can afford the bigger wheel... Get the bigger wheel. It has a larger axle diameter and more bearings which increase the capacity of the lifter.
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Re: Solid roller wheel size

Post by mopardave »

Ok, just what i was looking for. Their was a thread awhile back about a larger wheel needed for small base circle cams, but not sure that was the reason for bigger wheel. Thanks
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Re: Solid roller wheel size

Post by ClassAct »

mopardave wrote: Tue Dec 22, 2020 8:56 am Ok, just what i was looking for. Their was a thread awhile back about a larger wheel needed for small base circle cams, but not sure that was the reason for bigger wheel. Thanks

Bigger wheel means a bigger axle (it should but not always) and a lower roller RPM for any given base circle, lift and RPM. The bigger the base circle the higher the wheel speed for the above. I never use a chevrolet diameter wheel in a Chrysler. The manufacturers do that to save money.

Buy the bigger wheel.
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Re: Solid roller wheel size

Post by Walter R. Malik »

For what engine ...?
With a big block Mopar you will need lifter bore sleves, (or a small base circle cam core), to run the bigger roller as the lifter roller cut-out will expose the block oil gallery near max lift.
Crower makes a shielded solid roller lifter for the BB Mopar so, sleeves aren't necessary but, it needs a smaller wheel in order to be shielded.
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Re: Solid roller wheel size

Post by panic »

The plot of valve motion vs. cam lobe position is different between .750" and .815". The larger wheel accelerates faster as some points, but the change is not linear, the curve is distorted.
Ask the cam manufacturer.
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Re: Solid roller wheel size

Post by mopardave »

Had the same issue with a sb mopar. Tried comp and crane. Both leaked as the lifter raised opening the oil galley. A morel with a .750 wheel fixed it. I have a non bushed lo deck mopar block. The BAM lifter 2016-16 has a solid body with a .815 wheel.
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Re: Solid roller wheel size

Post by BradH »

B.A.M. Pro series for BBM with .815" wheels on left; IMM's (member ou812) in-house BBM lifters that were based on COMP 892s on the right, which also have .800+" wheels.

Both styles have been used in unbushed blocks with lobes approaching .450", but I believe that's getting into the lift range where bushed lifter bores are needed.

The B.A.M.s are in my RB 452, but this particular block had bronze lifter bushings installed long before I switched to a roller.

FWIW, the B.A.M. lifter bodies measured approx .9038, whereas the COMP-types were more like .9033", IIRC.
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Re: Solid roller wheel size

Post by mopardave »

Hey thanks Brad. Long time no speak. I think my lobe lift is .416, thinking seriously about the BAM lifter. Looking like a nice quality to price lifter.
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Re: Solid roller wheel size

Post by BradH »

The version that uses a bushing instead of needle bearings wasn't available when I bought mine. Even though they are a good bit more expensive, that's what I would get today.
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Re: Solid roller wheel size

Post by mopardave »

A couple yrs ago, Dwayne had a set of the red zones with bushings fail on the Dyno. Not sure what caused the issue, but thought maybe I should just stay with the needle bearing but directly oiled.
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Re: Solid roller wheel size

Post by PRH »

Actually, that customer had them fail in his car.
All 16 had the bushings totally wasted in 200 Miles.

They had started failing pretty much right off the bat, since he said he had to keep adjusting the valves.

Isky replaced them with a version that had edm oiling to the axles, and the upgraded bushing material....... and those were fine.
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Re: Solid roller wheel size

Post by CamKing »

panic wrote: Tue Dec 22, 2020 9:55 am The plot of valve motion vs. cam lobe position is different between .750" and .815". The larger wheel accelerates faster as some points, but the change is not linear, the curve is distorted.
True, but it most cases, it's a minimal change.
It will accelerate the valve a little faster off the base circle, and accelerate(negative) a little faster from max velocity.
Unless the cam was designed to give you the exact curve the engine needs, it's usually not an issue.
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Re: Solid roller wheel size

Post by BradH »

CamKing wrote: Tue Dec 22, 2020 1:59 pm
panic wrote: Tue Dec 22, 2020 9:55 am The plot of valve motion vs. cam lobe position is different between .750" and .815". The larger wheel accelerates faster as some points, but the change is not linear, the curve is distorted.
True, but it most cases, it's a minimal change.
It will accelerate the valve a little faster off the base circle, and accelerate(negative) a little faster from max velocity.
Unless the cam was designed to give you the exact curve the engine needs, it's usually not an issue.
Dug this up from a post here in 2013:

Crane's web site has an article under the Tech section that gives an example of differences in measured lobe duration when increasing roller lifter wheel diameter. Here's what it says:

"Mechanical Roller Lifters with Larger Rollers

Most Crane Cams mechanical roller profiles are designed using a roller diameter of .750". If a larger roller size is used, a duration change will occur. For example, if a .810" diameter roller is used to measure a lobe with 280 degrees of crankshaft duration designed for a .750" roller, an increase of 1.3 degrees will occur at .050" lifter rise. The amount of duration increase will vary with lifter rise, but the total lift will remain the same. The table below shows a typical pattern of how duration will increase using a profile of 280 degrees at .050" and .500" lobe lift.

R-280/500
Lifter Rise Duration increase with .810" Roller
.020 0.8
.050 1.3
.100 1.6
.200 1.7
.300 1.4
.400 0.9
"
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Re: Solid roller wheel size

Post by mopardave »

Thanks for the correction Dwayne. I’ll have to check pricing on the bushed lifters . Brad, looks like the bigger wheel does make a bit of difference. Good info, thanks.
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