SBC Camshaft questions

[Sapper]

Okay I have a couple of problems.

I thought that either the cam or the timing set would include bolts and a trust washer. Neither did and now I need to get bolts for the timing set and I also want a thrust washer. Do I need a specific thickness for the trust washer and also a Cam button? I am using flat hydraulic lifters so I am not sure if I need a cam button or not.

How is the cam restricted from moving once installed? Does the trust washer keep it from moving to the rear of the block and then the button restrict it from moving forward too much?

Just as a reference this is a .060" over 400 SBC, (412) with a mild cam.

Should the cam sit flush with the block or protrute slightly? I intalled the rear plug in to the same line as the original one but I am not sure if the cam should sit flush or not?

[Buckshot33]

on an early 400 block all you should need is a a timing set bolt kit from ARP and a cam button. sould be all of like 30 bucks from summit. that engine won't need a thrust washer.the distributor gear keeps it from going too far back in the block. infact, the engine is designed to pull everything back against the distributor gear so it should be fine. IIRC, only the newer roller style blocks need thrust washers/plates or retainer plates.

[Sapper]

Okay then I will remove the thrust washer and put in the cam button. Is there a trick to getting the cam button to stay in place while you put the timing cover on. I already bought both the cam button, and washer which are Comp Cam pieces 201, and 202 I think.

Will grease work to hold the cam button in place? There is no hole in the cam for the button to sit in.

I still have to degree the cam and set the valve lash so it is easy to get at everything.

[Buckshot33]

The button should just fit in the center of your cam sprocket. I have run into some button being too tall, I just milled a little off the top till it fit and didnt push the timing cover out. grease would probably hold it in place. throw your grease in the freezer for a while and get it good and cold, it will be more stiff and easier to work with. What timing assembly are you using?

[Grumpy_old_fart]

Originally Posted by Buckshot33

The button should just fit in the center of your cam sprocket. I have run into some button being too tall, I just milled a little off the top till it fit and didnt push the timing cover out. grease would probably hold it in place. throw your grease in the freezer for a while and get it good and cold, it will be more stiff and easier to work with. What timing assembly are you using?

theres a little locking plate that you get with the button, most of the time. it locks the bolts in place, and the button sticks through it.

[Sapper]

It is a Clevite timing assembly, double roller.

[Black Dog]

With a flat tappet cam on a SBC you do not really need anything to keep the cam from moving forward, and the factory did not use anything. The lobes on the cam are ground so they taper down in diameter (slightly) toward the front of the cam so that the pressure from the hydraulic lifters keeps the cam pushed back toward the thrust washer. The worm drive gear set that turns the distributor also develops a slight force on the cam toward the rear of the block.

A roller cam is a different story, and that is where those buttons and special timing covers are necessary.

[positrack@earthlink.]

Originally Posted by Black Dog

With a flat tappet cam on a SBC you do not really need anything to keep the cam from moving forward, and the factory did not use anything. The lobes on the cam are ground so they taper down in diameter (slightly) toward the front of the cam so that the pressure from the hydraulic lifters keeps the cam pushed back toward the thrust washer. The worm drive gear set that turns the distributor also develops a slight force on the cam toward the rear of the block.

A roller cam is a different story, and that is where those buttons and special timing covers are necessary.

Yup, X2.