Valve rocker loose, bad lifter?
 

Hi guys,

I have a question, a couple of days I started hearing a ticking noise under the valve covers, so today I decided to dig into it.

After taking the covers off I found one rocker really loose, I checked the following things:

- Nut was tight (I had adjusted them all about a month ago and added the nuts with the locking allen bolts from Crane Cams)

- Stud length as exact the same as the other valve of the same cylinder (heads are the reworked original '77 L48 boat anchors, lengths of studs were about 1.315 inch)

- Rocker seems OK, nothing noticeable there to see

So this leaves me with the lifters (hydraulic Crane Cams, in the car for 6-7000 miles street driving). How can I find out whether this lifter is broken, stuck?
Are they usually stuck all the way out, because that would have put even more load on the rocker, instead of making it looser?
Can it be stuck all the way in as well, there should be a spring keeping it up right? When I look down under the intake I can see both inside lifter bodies up against their retainer ring?

Any ideas what this loose rocker can be, except from me screwing it up when i adjusted them, but it should have made a noise right away them, not 4 weeks later?

Any help/advice would be greatly appreciated, and let me tell you that this forum is the easiest and best way to get that as there aren't that many Chevy-engine experts to be found in Belgium?

Thansk a lot, see ya, Sonny

did you also replace the cam? perhaps you have worn down a cam lobe? why did you put new lifters in to begin with?

When you say it was loose, how loose was it? A few extra thousands' could make it tick...

While it certainly is possible the lifter has collapsed, after operating normally for this length of time, it would probably require an oil restriction of some sort to this particular lifter to cause it. Of course if and or when the restriction passes, the lifter could quickly return to normal.

One other thing that is possible is that the stud is slowly pulling from the head as it is only pressed in. While it isn't very common in an otherwise relatively stock engine, it could happen.

What I would recommend is that you try to determine that the lifter is getting oil. You can do this by removing the valve cover and with the engine running, see if oil is coming out of the push-rod and onto the rocker arm. (Most good auto parts places sell a set of clips that you attach to your rocker arm to redirect the oil so you don't get a big mess doing this.) If you have good (the same as the others) oil flowing into the rocker arm and you are convinced the nut has not backed off, I would simply readjust that lifter and button it back up. If you do not have good oil flow, you can try removing the lifter, disassembling it to clean any debris out and reassembling it and putting it back in. Check again for oil flow and if no change, try installing a new lifter... or a known good one, just to verify oil flow.

If the stud is pulling out, you will soon encounter the problem again. At the first sign of ticking, verify it's from the same one and then you'll need to look at either pinning (not my preferred method) the studs, or having the heads modified for screw-in studs.

Good luck and let us know how it turns out... GUSTO

yes, I should have said that above as well, it was a cam and lifter package that I added when I overhauled the engine. I added it to wake the engine up a bit. Can a lobe go bad in a say 150-200 miles, as that's all I did in the last month after I adjusted the valves, and at that time the engine ran fine.

Sonny

Yes you certainly can. A friend just built a very nice 383 for his 78 SA and installed a CC that wiped a lobe in about the same amount of miles. When he checked with CC they told him he used the wrong oil for break-in and that's why the lobe was wiped. In his case however the symptoms were much worse than a loose rocker arm.

You can check the lift on that lobe and compare it to a couple other of the same lobes (exhaust or intake). Use a dial indicator and you should be able to verify the integrity of the lobe pretty quickly. In my friends case he also found metal in his oil. You could check this by tearing the filter open or even swirling a magnet around in the oil. His was very obvious.

One other thing to do would be to remove the lifter and examine the face of it. If there is a problem, you should see evidence of it in the face of the lifter.

Good luck... GUSTO

Thanks for the advice!

One thing I noticed yesterday when taking both rockers (stamped ones) off of cyl 6 is that the cup that's in the rocker under the nut is thinner on the one with the loose rocker then the other one. I couldn't see any different signs of wear on both though, so I don't know whether this has always been that way, or not ??

I have readjusted the rockers yesterday (I put the loose one with the thinner cup on a different valve) and will start up the engine today to see if I indeed have oil through the pushrod, and if the pushrods come up about the same heigth to verify the lobes on the cam.

I'll let you know the result...

Sonny

lets hope its a bad rocker.

Hi guys,

I think the problem is solved :)

I have replaced the worn rocker and the ball and adjusted them again. I was able to spin the lifter around in its bore with a screwdriver, so I think this one is fine as well.

I started up the car and she runs like a swiss clock again :thumbs:
All rockers are getting oil and seem to work fine.

I think that particular rocker has been without oil for a while (maybe some dirt in the lifter) and the ball had started wearing causing the rocker to get loose.

I haven't been able to take the car for a ride, as just when I was finished a thunderstorm came over and it started raining :rolleyes: that will have to wait for tomorrow.

On a sidenote, if this solves the problem, it was probably the cheapest fix ever in 4 years ownership, as the "new" (used, as that was all I was able to get on such a short notice, shops aren't so easy to find here) rocker has cost me ......... 2 euro = 3 dollar :D :D :D

Thanks all for the good advice, I have no idea what I would do without you guys...

See ya, Sonny :cool:

good job!!