VCCA Home Forums TECHNICAL - GENERAL Mechanical - Engine, Trans, etc straighten a camshaft?

I have a L79 PN 3863151 camshaft with about 3 thou runout. in my engine with fresh cambearings it turns by hand but not freely. I read some info on the internet saying to support it on v blocks,find the LOW spot and strike it with a bronze tipped chisel/ hammer adjacent to bearing area. Has anyone done this and is this the correct method? how hard and how many times? was hoping to find a youtube on this....

There is some rather limited instructions for straightening a camshaft in the shop manuals.
Probably a task best done by a machine shop - if you can find a good one.

Assuming you have a surface plate, the v blocks and a dial indicator on a mount and a brass hammer...You could always take a shot at it...Be careful, one blow at a time...Check it again...Nothing...? Strike it once more a little harder...3 thousands is only the thickness of a sheet of paper...If you decide to leave it to a machine shop, call around to some automotive machine shops...Call and ask...I would skip over your typical machine/job shop...Good Luck

I have known of crankshafts straightened using a press. It will have to be pushed past the .003 as it will rebound. You might want to check with a shop that advertises cam rebuilding (usually grinding).

The camshaft is a forging and will break very easily if pushed too far. A .002" runout is acceptable so very little tweeking is necessary. When I was in the parts Dept. a new cam fell out of the cardboard tube that they came in and hit the floor. It broke in half just like that. Caused by yhe vibration....and hitting with a hammer could have the same affect.

I agree with Chev Nut,use it as is.They break very easy!!!

All true...And, the term "blow" was a bit harsh...Once bent in one direction, attempting to bend it back the other way could spell disaster...

As Gene pointed out, .002 is acceptible. Someone on here should know if maybe .003 might not also be OK.

????

I'll bet not very many cams get checked this close when these ol' engines are rebuilt. Who knows?

A friend building a 50s flat head V-8 sent his original cam in for a regrind, shortly after got a call from the machine shop that the cam broke when it hit the floor falling out of the shipping box. I was surprised that they are that fragile.

I agree with Gene on this one, take it to a auto machine shop. Or get a NOS one (that hasn't been dropped. If it has, you may need to take it to the shop too).

Charlie

I worked at a plant that made 12 cyl air cooled diesel engines that had a cam 5' long, and straightened them in a cam press. From this experience may I suggest that you support the cam at each end on a block of hardwood, turn the "bow" to the up position, and use a crow bar or pinch bar and wedge the one end under something solid and high enough so that it rests approximately horizontal with the cam under it acting as a fulcrum. Press down on the other end of the pry bar slightly at first and just keep working it with progressively more pressure until the bow is gone. You have a lot more control of the straightening process that a wack with a hammer. Good luck

From Gene's earlier post, he only need to get .001 out of it to bring it into acceptible .002 spec. That ain't very much!

I know nothing! However, for being .001 out of spec, (if it were me, and it ain't!) I'd coat it well with a good cam prelube, install it and run the heck out of it.

"To each his own" - - -