<VV> Camshaft wear.

[Richard Suckow]

In over 40 years in the parts business I have seen a lot of camshafts in various states of damage. I agree that the first 5 minuets are very important. however the 5 minutes before that can make or breake a good cam! you must prime the system be it with a bearing leak detector ( preassurised tank,) or with a 3/8 drill wnd adaptor to driive the oil pump. also Sealed Power states in bulletin DO NOT wash a new camshaft as you will wash off the special molybdenun disulphide surface treatment which is applied after the cam is flame hardened and parkerized. this coating aids in the brakeinond or mating of the shaft and lifters. also it wont hurt to add a can of GM EOS to the initial oil fill. also bulletin 172 titled the wear problem on camshafts and tappets states.  the taper on the camshaft lobe is between .0007 and .0002 across the face of the lobe. the mating face of the lifter is ground with radius or crown of .002 high spot in the middle of the lifter. this places the load on the camshaft slitghtly downhill if you may from the highest point on the lobe and moves the point of contact or load away from the edge of the cam thus spreading the over more of the face of the camshaft. it also enables the camshaft to spin the lifter as it rotates. if you use a used liftter on a used cam or even on a new cam it will usually be worn enough that It will move the point of contact to the edge of the cam lobe and cause spalling or in severe cases I have seen the cam worn down to nothing and the lifter worn clear through the bottom. in fact one that sticks in my mind was a sb chev thet wore through and then the lifter came apart and broke the cam. the breake in procdure that I used was the following. use lots of a good assembly lube the more the better on anything that moves ( moly based of course) be sure of all adjustments prome the system with a mechanical gauge, when you strt it it set it to about 2000 -2500 rpm check for leaks etx. watch the temp gauge, as it warms up crack the throttle every few min or so DO NOT LET IT IDLE AT ANY TIME. about every 10 minutes adjust the high idle down by 150 rpm until you are down to about 1500. It is important to change the speed fairly often as when you do this it directs the oil to different parts and places inside the engine. I generally do this for about a two hour run in period ending up with an idle speed of about 900 rpm. if it is a mt corvair I  then  cool it down and remove it from my stand. install it and take it for about a 60 mile drive or so. In 40 years using this procedure I have never had a camshaft or engine failure of any kind. I will say that I have a out here that someone else built that I have ben chasing a valve train noise in, that I finnaly traced too valves hitting pistons due to a sheared crank key at timing gear. now to build a plate to try and save the gear. 

Dick Suckow
ssuckow at bmi.net