Rocker arm totaly loose...

[66 Tiger]

So I figured out today that the strange knocking noise coming from my carb/intake was actually coming from the valve cover.

When I removed the valve cover I found that the rocker arm on the #5 exhaust valve was sort of laying across the stud at a 45* angle. The adjusting nut was still on the stud but very loose.

Upon close inspection everything seemed to look ok - the push rod appears to be straight & the rocker arm dosen't have any visable wear.

My question is do I have any need for extra concern with this other than just re-setting the lash & locking down the adjusting nut? Also, could any damage have possably occoured to the engine?Cam damage? Lifter damage?

I was on the way home when the popping noise initially presented itself so I'd have to say I don't have any more than 5miles on the car - & that was at a " nursed" 2500rpm or less.

I just got the motor put back togeather from a H/C/I, carb & everything else swap & I'm kind of bumed here thinking something might have got f-d up...

 

[D.Hearne]

I hate to be the bearer of bad news, but you could very well have a wiped cam lobe there. I've had two separate engines do the same thing. One lobe. One lifter. Check the intake pushrod on that cylinder. Reset the lash on the loosened exhaust valve then crank the engine with the starter and watch that rocker and valve to see if it's opening like the rest. If it looks like it's not opening fully like the others, you've got a wiped lobe and lifter.

 

[351carlo]

As I said in the other thread, if the lobe wears, a lifter mushrooms, or some other type of wear on the cam/lifter interface, the rocker will come undone. There is no longer pressure being applied on the push rod side of the rocker's fulcrom, as the lash is off so much.

I'm not saying that is the only scenario, because it is easy to miss tightening of a rocker or have some other fluke incident occur. However in my experience this tends to be the answer.

To check this, you have two options. You can take the intake off (I have a dry intake, so I don't mind pulling it and making sure), or you can use a dial indicator as was brought up elsewhere on the pushrod to measure the lobe lift. There should be specs for this online for your camshaft, or you can take the total lift and divide it by the rocker ratio.

For my camshaft:
.570 gross lift intake/ 1.73 Rocker Ratio = .329 lobe lift

What lifters did you use? Did you use an oil additive/what oil did you use for cam break in? What method did you use for tightening the rocker arms?

It's ashame you aren't closer, I'd be glad to give you.

I know it can be frustrating. During 2005, I had one camshaft get shipped and showed up in 2 pieces (DHL: and they gave me the runaround). And then when I went locally and picked up the cam, I ended up screwing up my lash and wiping 3 lobes.

 

[66 Tiger]

This sucks... To be so close to actually getting to take the car out & drive for the first time - I was actually driving the car home from the exhaust shop when this happened & looking forward to putting some miles on it this weekend.

I have had the car since Sep 06 & this would have been the first real drive...

Oh well, enough crying - I guess this is what you have to deal with when doing your own work & using aftermarket parts that weren't originally designed for the car.

I will attempt D.Hearne's approach & pray that everything looks ok after reassembaly.

And thank's for the offer of help 351Carlo - If the above mentioned dosen't look ok, I'll just have to go into this a little more deeper.

351carlo
What lifters did you use? Did you use an oil additive/what oil did you use for cam break in? What method did you use for tightening the rocker arms?
.

I went with the Jegs brand solid lifters. I didn't use any "special" oil additive for the cam break-in, but I did completely coat the cam with some sort of permatex type graphite lube the guy at the auto parts store recommended...

Thanks...

 

[D.Hearne]

Problem with cam break-in now is two faced. Too much lube is as bad as not enough. Too much and the cam lobe doesn't get enough traction on the lifter bottom to spin it in it's bore. That's what happened to my first cam failure. The other was trying to fire it up in freezing temps. Oil was too thick. Then there was a butt-load of bad lifters out there to make it worse.

 

[351carlo]

Problem with cam break-in now is two faced. Too much lube is as bad as not enough. Too much and the cam lobe doesn't get enough traction on the lifter bottom to spin it in it's bore. That's what happened to my first cam failure. The other was trying to fire it up in freezing temps. Oil was too thick. Then there was a butt-load of bad lifters out there to make it worse.

Precisely. I had a similar situation.

If you look at the foot of a properly broken in lifter, there will be a very light neat looking swirl pattern.

If for some reason this doesn't work out, just remember for the future. We all have had bad luck in the past, heck both of us posting here have. We didn't learn it the first time around.

Any other questions feel free to ask. Trust me, I've broken and messed up almost everything imaginable. Just makes it that much easier to do it right the next time around.

AND BTW: I know how you feel. I had my car off the road from JANUARY 06 until just 3 weeks ago. I had the car driving for 6 days before I blew my transmission to pieces. Luckily I knew it was going to break, and was expecting it.