1969cutlazz

Working on my engine rebuild tonight. Installed my new camshaft. Question: Is there a cam retainer that goes on and bolts in to the oil plugs on each side of the cam by the timing gear? I'm pretty sure theres not. When I tore down the engine back in the spring I bagged and labeled everything and dont see a retainer and don't remeber one being there, but I just want to be sure. Its a 1972 Oldsmobile 350 block NON diesel.

svnt442

Nope. No retainer.

Funkwagon455

Cam is retained by the extension on the top timing gear bolt...

Run to Rund

Cam has the gear and the fuel pump eccentric on it; loctite and torque the bolt to 65 ft lb. The tab on the eccentric goes into the cam gear hole for the pin on the cam.

citcapp

While we are on this subject. I have noticed that a few companies make a bearing that fits over the hub of the bolt and rides on the timing cover that is supposed to help with cam walk and prevent wear to the timing cover. I am replacing the timing cover on my current 455 build and am wondering if this bearing is worth the effort. The existing cover does have wear in this area and yet the cylinder walls are within stock specifications so the wear seems to the cover seems excessive. Thoughts anyone

1969cutlazz

Thanks for the replies. Appreciated much.

InfoJunkie

If this is the thing your inquiring about, it's a chevy thing.

svnt442

That's called a cam button. And as stated that's a Chevy thing.

From what I have heard (and I don't know how true it is) Oldsmobile engines don't require one because of the reverse rotation of the distributor "holding" the cam back.

Someone please confirm or deny this.

joe_padavano

You are exactly correct. The helical gear on the distributor imparts a load to the drive gear on the cam, and depending on the direction of the gear teeth, that force can be either forward or backward in the block. In the case of an Olds motor, the force is towards the back of the block. The cam already has a flange on the front end of it to locate it in the block and react this force from the distributor gear.

Red71

yes I agree with all of this and some blocks will get a worn spot from that flange
and the cam being pulled inwards. There are roller shims for this, and I have seen
cam buttons used on Olds engines. i believe the theory for this is when the engine
is under DE- acceleration the cam trys to push forward.

citcapp

Thanks for clearing this up.

Run to Rund

You can also buy or make a brass shim to go behind the thrust area of the cam where it contacts the block. Unless the block is worn, don't do it without machining the same thickness from the cam's thrust flange, so the lifters will contact the same place on the lobes as they were designed to do. Out of at least a dozen blocks, I have only seen one with wear on that surface. I used to shim the bolt so it was close to the cover, but don't bother any more. You could machine the end of the bolt and use a brass cup plug on it to get about .010" or so clearance to the front cover, but as stated above, it is probably not worth the trouble.