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Found my answer.....thanks very much...........Need HELP on 383 cam install hydraulic flat tappet....END PLAY?

FASTEDDIE1960

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Hi Folks, working on my 1970 Roadrunner installing new cam....just wondering is there no way to set the cam end play? I have it installed but has about 1/4" back and forth end play? is this normal.....I did a few of these back in the late 1970's but can't recall if this is normal or what...Any help greatly appreciated. Thanks Very Much
 
With the distributor drive in place, there shouldn't be much end play at all.
 
With the Helical cut auxiliary shaft installed and the rotation of the engine, the camshaft is always thrusted against
the block. The Auxiliary shaft turns the distributor and the oil pump so it can't have any front and backward movement.
 
Theres only "play" or clearance one way..... it is determined by the upper cam sprocket when bolted in place.
 
The cam bearings would have to really be worn out to allow any wobble to allow the cam to move.
 
The lifters are supposed to always be pushing the camshaft towards the rear of the engine. So if the lifters are sitting on the correct position on the cam with the upper cam sprocket also riding against the block you should not have to be concerned with any forward motion.
 
The lifters are supposed to always be pushing the camshaft towards the rear of the engine. So if the lifters are sitting on the correct position on the cam with the upper cam sprocket also riding against the block you should not have to be concerned with any forward motion.
 
thanks very much, that is what i needed to know..amazing how much stuff you can forget over 50 years.
 
With the Helical cut auxiliary shaft installed and the rotation of the engine, the camshaft is always thrusted against
the block. The Auxiliary shaft turns the distributor and the oil pump so it can't have any front and backward movement.
perfect.....thanks very much
 
The lifters are supposed to always be pushing the camshaft towards the rear of the engine. So if the lifters are sitting on the correct position on the cam with the upper cam sprocket also riding against the block you should not have to be concerned with any forward motion.
My understanding is that it is the taper in the camshaft lobes that the lifters ride on that pushes the cam rearward.
 
My understanding is that it is the taper in the camshaft lobes that the lifters ride on that pushes the cam rearward.
The lobes on a flat tappet cam, solid or hydraulic, have a taper, and the lifter bottoms have an arc.
End result is the cam being pushed to the back of the block, limited by the cam timing chain gear contacting the front of the block. That, and crucial lifter rotation.
Roller cams have no taper, so most use a button of some sort to limit for/aft movement. Theoretically it should not be necessary, the distributor drive gears are also supposed to be driving the cam to the back.
I put a button on my rollers anyway.
 
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The lobes on a flat tappet cam, solid or hydraulic, have a taper, and the lifter bottoms have an arc.
End result is the cam being pushed to the back of the block, limited by the cam timing chain gear contacting the front of the block. That, and crucial lifter rotation.
Roller cams have no taper, so most use a button of some sort to limit for/aft movement. Theoretically it should not be necessary, the distributor drive gears are also supposed to be driving the cam to the back.
I put a button on my rollers anyway.
thanks very much
 
We don't worry about endplay with flat tappet cams. The lobe taper helps keep the cam in place
 
For everyone that might be thinking the meshing of the oil pump driveshaft gear and cam gear push the camshaft toward the rear of the block, it's actually the opposite....
That helical gear action pushes the camshaft forward. That's why non-tapered lobe cams (roller cams) use a thrust button between it and the timing chain cover.
At least on B/RB Mopar engines, anyway....
I used to have a yooboob video proving this, but it has apparently gone away...those bastards!
 
For everyone that might be thinking the meshing of the oil pump driveshaft gear and cam gear push the camshaft toward the rear of the block, it's actually the opposite....
That helical gear action pushes the camshaft forward. That's why non-tapered lobe cams (roller cams) use a thrust button between it and the timing chain cover.
At least on B/RB Mopar engines, anyway....
I used to have a yooboob video proving this, but it has apparently gone away...those bastards!
Easy way to find out
Put a cam in the block without a timing sprocket or a block plug at the back, put in an intermediate shaft with a gear.... and turn it with a bigass screwdriver in the direction of dist rotation..... and see which direction the cam goes.
Test would work on small block or big block.
 
Easy way to find out
Put a cam in the block without a timing sprocket or a block plug at the back, put in an intermediate shaft with a gear.... and turn it with a bigass screwdriver in the direction of dist rotation..... and see which direction the cam goes.
Test would work on small block or big block.
Yup. I did that a few years back, and video'd the results of the cam moving out the front of the block.
Maybe I deleted the video? I'd much rather blame the yootoob bots though!
Cam button use
 
I hate to beat this drum again, but the direction of rotation drives the cam towards the back of the block because of the
direction of the helical cut auxiliary shaft. The taper on the cam is to "spin" the lifters so they wear evenly, not push the cam
back. I will guess that that oil pump takes a fair amount of power to turn thus trying to slow down the cam resulting in the
thrust rearwards. I am not in the camp that believes a cam button does anything to keep a cam from jumping forward!
Again, if the cam moved forward for any reason, the auxiliary shaft would shear because it's fixed in a bronze bushing
driving the distributor and oil pump. A 440 turns clockwise facing the front of the engine, right? Look at the helical gears
and tell me which way it thrusts the cam.
20240406_180432.jpg
20240406_180910.jpg
20240406_183836 (1).jpg
 
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Since the oil pump drive/distributor drive turns COUNTERclockwise, it sure looks like if anything, it pulls the cam forward.
 
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