I posted on here a few days ago with the problem of a flat cam lobe. Basically I could run the rocker arm down to the pedestal and still lift the pushrod up and down. Could not remove the lash from it. Lkely scenario was flat lobe. Well, tore it apart tonight to get ready for the new cam coming tommorow and discovered that: The lobe in question looks fine The lifter for that lobe looks fine The cam, after removing the sprocket, but still tight with the retainer bolts moves at a minimum 1/4" perhaps 1/2" With a finger down the lifter bore I can feel the edge of the lobe. It appears to not be perfrctly centered. My question is, what happened? I started to adjust the lash due to excessive valvetrain noise and I did find this one cylinder WAY off the lash specs but all else now looks to be ok. Also, the oil pan (inside) had a slight layer of milky oil, kinda of thick. I know that is typical of a head gasket but I was running terrific before I pulled it apart. Perhaps assembley lube? Motor has less than 1000 miles and sat in the paint shop for several months. Ideas? Now that I have a new cam on the way I don't want to drop it into another problem. Sorry for the long post, been a frustrating evening.
If the lifter and lobes are OK, I would look at either a rocker stud coming out (pressed in studs can & do come out), rocker arm damage, pushrod damage. That's about all I can think of other than maybe one pushrod was shorter than the rest? A little bit of "milk" in the bottom of the pan is usually normal for an engine that sits for a long time. Condensation builds up and drips into the oil. First time you get the engine up to operating temp (180 deg. OIL temp) it will evaporate pretty quickly. As for the lifter not being centered on the lobe, that is normal. They are designed that way so that the lifter will spin as the cam turns. This is what wears the face of the lifter and the lobe on the cam evenly. If it ever stops spinning in the lifter bore it usually wipes the cam. Roller lifters can't spin in the bores or lots of carnage will result usually. Frustrating evening? I can relate. Engine teardowns after "problems" are always frustrating, especially if you can't find a cut-and-dried cause. Kind of like dads 347 with the thrust main gone. We're still beating our heads against the wall trying to figure out what caused it.
Sounds like you didn't take the cam out yet. If that's the case, the lobe may be wiped. Take it out and compare it to the rest. I recommend when you put it back together with the new cam that you use Rotella oil for the first couple of thousand miles.
Cam IS out. I checked all that prior to pulling it out. Rocker arm is fine, pushrod is ok, screw-in stud is still screwed in! Errr..
Do your valves have the lash cap on them? The lash cap will wear out and leave you with a lot of noise and a headache trying to find it. Check your other valves and see if they have a cap that lifts off. If so then replace ALL of them. If one is worn out they all have the same number of strokes on them.
Ok, you have way too much lash, The cam is good, the lifter is good, the pushrod is good (right length and not bent), the rocker is good, the valve is good and the springs are not broken. There is nothing else left - did you use a micrometer to check the cam? Did you inspect the inside of the lifter? (where the pushrod rides?) It has to be broken or the lobe is bad. It isn't magic - it is just a car engine
Check for a bent valve. If that valve appears shorter than the rest, that is what it is. We ran into this same scenario(loose lash) on a buddies Mustang last fall, and it was a bent valve. The valve to guide clearance was too tight causing it to hang open when it got hot then the piston smacked it. It had plenty of piston to valve clearance.
Paul, I agree. It is something simple that I am just missing. I am having the cam lobes miched today for lift. By eyeing it though, they looked ok. Frustrating. Although, I think I will hold off installin the new cam I just bought untill I fiqure it out. Scott
just ideas... is there something behind the cam preventing it from seating in all the way? is there any way that the cam is incorrect and therefore not allowing the lobes to line up correctly. i suppose it is likely that the cam lobe in question was made incorrectly? can you buy a new cam and check to see if it seats correctly,? and then go from there? good luck..
Are they the Stock Ford valves? They are machined 3 piece. The tip of the valve may have come off. Usually you will find the piece, looks like a small watch battery. The milky stuff if not water may be the metal from cam or lifter. Take a magnet through it an see if it sticks to it. Good Luck
I appreciate all the thoughts. The cam is the same one I have ran for over 20,000 miles over the last 20 yers. Nothing changed there. The heads are new Edelbrock RPM's, the tips are there. I am dropping the old cam off at the shop in the am and they will mich it to see if it is flattened at all. New cam sitting here right now in my office but I think I will wait until I solve a bit of the mystery before I drop it in. The milky stuff is for sure water, but it is not much and easily could have gotten in there last week when I noticed a few intake bolts loose. Not a big concern for me right now. I really doubt it is the head gasket or anything worse. Let all know soon..
If the thrust plate bolts on, the cam will be located where it needs to be once the timing chain is installed.
