493charger
Member
First of all, I'd like to say hello and this is my first post here, so please be kind.
I guess some background info would be helpful. I'm working on an RB 493. It has an Erson hydraulic, flat tappet camshaft. I suspected the lifters to be bad(collapsing), so I removed the top end to inspect the cam and valvetrain. Well, I was almost half way through "running" the cam with a dial indicator when I noticed that the cam seemed to be "walking" a lot more than I am used to seeing. Probably a good 3/16", but I haven't actually measured. Now, I understand that a flat tappet cam "walks" a lot more than say a roller cam would. I also understand how the rotation of the distributor gear creates a lateral force that holds the cam gear bushing back against the block. And that the taper of the lobes and the process of the lifters rotating helps keep the cam from moving around while running. Unsurprisingly, I have read different stories on cam walk. Some people swear it makes no difference because the above processes keep the cam stable. Others seem to think a cam button is a good idea on any camshaft.
I guess I would like to know what is considered an "acceptable" amount of cam walk, preferrably a number if possible, before I take the front of the engine apart. I am used to seeing camshaft end play in the .010-.020 range with roller cams, so forgive me if 3/16" seems a little ridiculous.
I guess some background info would be helpful. I'm working on an RB 493. It has an Erson hydraulic, flat tappet camshaft. I suspected the lifters to be bad(collapsing), so I removed the top end to inspect the cam and valvetrain. Well, I was almost half way through "running" the cam with a dial indicator when I noticed that the cam seemed to be "walking" a lot more than I am used to seeing. Probably a good 3/16", but I haven't actually measured. Now, I understand that a flat tappet cam "walks" a lot more than say a roller cam would. I also understand how the rotation of the distributor gear creates a lateral force that holds the cam gear bushing back against the block. And that the taper of the lobes and the process of the lifters rotating helps keep the cam from moving around while running. Unsurprisingly, I have read different stories on cam walk. Some people swear it makes no difference because the above processes keep the cam stable. Others seem to think a cam button is a good idea on any camshaft.
I guess I would like to know what is considered an "acceptable" amount of cam walk, preferrably a number if possible, before I take the front of the engine apart. I am used to seeing camshaft end play in the .010-.020 range with roller cams, so forgive me if 3/16" seems a little ridiculous.
