Old yes. But stupid too?

sloinker · Sep 30, 2020

I have a question and don't slap me down too hard. On a RB what keeps the camshaft from slipping forward and out of the bearings? Distributor gear, timing chain....I know some cam's from differing makes/applications utilize a retainer.

GrabberOrange69 · Sep 30, 2020

Essentially it’s the lifters on the cam lobe. They drive the cam into the block but the cam is stopped when the cam timing gear hits the block facing. It’s due to the slight angle ground into the cam lobe.

A roller cam is not ground with the slight angle on the lobes, as you don’t want/need the lifters to rotate, as on a flat tappet. On a roller, you need to run a cam button in front of the cam timing sprocket to prevent the cam from walking forward.

R413 · Sep 30, 2020

The angle the lobes are cut pushes the cam rearward. There is a thrust surface on the front of the block and the back side of the cam gear.

Roller cam loves are cut straight so there is a cam button the rides on the timing cover to push the cam rearward.

sloinker · Sep 30, 2020

Makes sense. Thanks.

Don Frelier · Oct 1, 2020

It's not a bad question at all.

Remusa12 · Oct 2, 2020

Do small blocks need a cam button or can they use the factory cam hold plate they seem to have.?

451Mopar · Oct 2, 2020

As mentioned, the cam lobe taper against the flat tappets.
I also think the oil pump gear may push the cam back also?

toolmanmike · Oct 2, 2020

Remusa12 said:
Do small blocks need a cam button or can they use the factory cam hold plate they seem to have.?

Cam plate is all that's needed for the most part.

GrabberOrange69 · Oct 2, 2020

Remusa12 said:
Do small blocks need a cam button or can they use the factory cam hold plate they seem to have.?

Anything with a factory cam holder plate (small and big block Ford, LA mopar, for example) don’t need a cam button. Engine families without a cam holder plate (Small block Chevys, BBM, etc) will need a cam button with a roller cam.

The cam plate does have to be compatible with the steel roller cam, just like the distributor gear.

Nate S · Oct 3, 2020

Interesting. I always thought it was the 20 horsepower that gets transmitted to the oil pump through that 90 degree gear.

Old yes. But stupid too?

sloinker

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GrabberOrange69

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R413

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sloinker

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Don Frelier

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Remusa12

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451Mopar

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toolmanmike

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GrabberOrange69

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Nate S

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