I took the front cover off my BBB 455 and found that the cam gear and distributor gear were wore real bad. What would cause this? I also found my cover had a hole in it and had to buy the new TA cover with oil pump and everything installed. Not Cheap!!! I have purchased a new TA-413 cam and steel distributor gear. Is anyone running this cam? How is it? I also got the recommended springs lifters, and keepers. Thank's; Mike
Mike, I've seen this problem many, many times and I'll try to explain if I may. I think most everyone knows that the front cam bearing must be installed ~.125" past flush of the block face. This offset has a very critical purpose as it forms an oil galley that feeds the "centrifical pump"(the off-center hole drilled from the cam to block thrust surface to the back of the cam gear) in the nose of the camshaft that ultimately provides lubrication to the cam/dist gear interface. If the cam happens to move forward, the seal between the cam and block is lost allowing the oil intended for the cam/dist gear to hemmorage down the face of the block behind the upper timing gear allowing the cam/dist gears to run dry. Many factors (both individually and collectively) can contribute to the forward movement of the cam. The most common being to high oil viscosity, with high volume pump being next. Many aftermarket cam lobes are ground without the ~2-3 degree off-parallel to cam centerline that the OEM cams had that provided rearward loading of the cam, then throw on extra stiff valve springs and you can see how problems can arise. A simple fix would be to limit cam movement to .005"-.008" with a non-aluminum thrust button.You can also install a spray nozzel tapped into the oil pump discharge passage to keep things lubed. Most BBB will take a button ~.875" diameter and ~.040" thick depending on the front cover gasket thickness. Hope this helps you. By the way, the cam gear can be replaced (yes I know it's cast intergrally in the cam core) and save one the cost of a new cam and lifters!
Cam gear wear cure To expand on Martian's suggestion, Poston has the squirter you simply drill and tap an 1/8th pipe tap into the oil galley in the aluminum case and insert the squirter it works great. I installed a brass cam bumper which is adjustable but you have to drill and tap into the water pump side of the case and use JB weld to seal. homemade but effective. I hope that JB wled live upto expectations or Mr. Foamy will pay me a visit. Weekender
Mike, I always use a thrust button on all the BBB and if its going to be performance oriented, I build and install my own spray nozzle(less than $3 in parts store for material). One thing I forgot to mention that can cause the cam to move forward can be timing chain/timing gear alignment and parallelism. This is something that really needs to be checked.
Alright then. Thanks for all your help guys (and Martian). I guess I'll have to try this one on my own. Mike
