Cam Thrust Button

[petieg383]

I'm replacing the gear drive in my 440 with a Cloyes 3045 double roller timing chain. I'm sick of the whining, and that's just from me. Hehe. It's a 3 bolt style setup obviously. The cam itself is a flat tappet style and relatively stock.

My question is do I really need a thrust button? There was one on the gear drive setup. The new timing chain set didn't come with one. The old button isn't the right size so I'd need to find/order one.

Thoughts? Opinions? I'm sure better safe than sorry is the way to go but I've never had to run one on my other cars previously, although they weren't Mopars.

 

[440+6]

Most say it's not necessary because the cam is being pulled back by the oil pump gear, but it's good insurance to keep the cam from walking, I have one on mine.

 

[lewtot184]

no need for one.

 

[moper]

You need one for a gear drive, and for a roller cam, mainly because both have a very small window that the cam has to fit in terms of end play. With a std flat tappet there is a much wider spec and the cut of the cam's oil pump drive gear keeps the camshaft in spec on it's own.

 

[Hemirunner]

Just be aware that any time the cam moves forward or backward in the block, you're ignition timing is changing with it.....

 

[Darthomas]

If oil pump and dist shaft gear has in-out endplay, there's also more ignition timing variation. This can happen if the spacers on the distributor's shaft permit too much movement. I've added washers to sloppy distributors and it really cleans up the higher rpms, much smoother.

 

[lewtot184]

i've been thru the thrust button on flat tappet cams before and have found the only real need for a button is if cam walk is suspected.

 

[moper]

i've been thru the thrust button on flat tappet cams before and have found the only real need for a button is if cam walk is suspected.

Yup.

 

[petieg383]

Thanks for the replies everyone. I'm thinking it's going to be OK without it. I've never run one before, and this engine has very few miles on it and ran well prior to the gear drive to timing chain swap. I appreciate the info.

 

[mentor70]

you will be fine.

hydraulic and flat tappet cam lobes are ground to push the cam to the back of the block, and to make the lifters rotate on the lobes for longer life.
roller cams dont live in that world of engineering, and thus need a cam button.

 

[383man]

Most dont use a cam button on the flat tappet cams. I dont use one on my eng and my timing is very solid. You should not need it unless as was said where you have a cam walk problem which you should not have with the flat tappet. Ron