Speaking to somebody last night about engines and they mentioned that I should have used a cam button in my engine. It is a 383 small block with a hydraulic flat tappet cam. Is it common to use a cam button on flat tappet cams? Should I have put one in and what could be the consequences? THe cam is a XE274 comp. 230/236 @.050 and .490 lift. THanks

flat tappets do not require a cam button, the slight angle of the lobes keeps the cam from wandering. That being said, i alway use a cam button. The reason being, every cam kit Ive ever bought had one, and by god I payed for it I'm gonna use it.

A properly installed cam button will smooth out the bouncy timing mark when you are adjusting the ign. timing. The cam walking in the motor will make the dist change.It does make a difference. A improperly installed cam button will jam the cam gear into the block and make the gear and block wear. You must set the thrust ( end play) on the cam when you install the button. Some buttons are too short and provide no help and some are too long pushing the gear into the block. Heres how I set mine up. You need to do this without the chain on the timing set. Put the button on and install the timing cover with the gasket. Use a screwdriver to move the cam forward to see how much movement you get.(Use common sense here and don't chip the cam lobe). I fine tune my thrust by bending in 3 places the timing cover to reduce the amount of thrust to what looks pretty good. Im not too picky about being exact on the thrust, Im happy with less than .015.Once it looks good I re-install the chain and timing cover and get my magnetic based TDC tool that has a dial indicator and place itr on the cover with the indicator in the center where the button is. I make sure the cam is all the way back and then I zero the indicator and push the center of the cover in with my thumbs till it stops against the button and it will tell me exactly how much I have. My last by eyeball measured .008 with the indicator. That was good for me.

I used a nylon cam button for my solid roller set up. They are very easy to grind down to get the clearance you need. Also, another alternative to what idunno suggested is to use molding clay on the tip of the button. Just ball up a little piece of clay, stick it on and bolt the cover on. When you take it off just measure the clay thickness for your clearance. I forget, at the moment, what my clearance spec'ed out to be but it only took a couple tries with my grinder.

I originally bought a roller style button but I could not get it to fit in my cam gear. Then I saw the nylon one and it was a snap to set up. Hope this helps.

Jim

In my opinion a cam button on a flat tappet cam is completely unnecessary but will hurt nothing if you feel you need one.
The taper of the lobes tends to "screw" the cam into the block.
This along with the oil pump load keeps the cam right where it belongs.
I do a lot of circle track stuff with a locked distributor & I see absolutely no difference in timing with or without a button.
Just finished two 427 SB flat tappet engines & the timing is rock steady,,, with no buttons.
A roller of course is a totally different animal :D