394 valve noise

[Olds64]

Hey everybody. I think I might have posted on this earlier but I have some new information. My 64 98 overheated after I pulled it out of storage a few months ago. After it overheated it started ticking really bad so I had a guy check it out for me since I was on the road. It turned out that it blew an oil galley plug on the drivers side rocker arm shaft (so when it blew the plug it wasn't oiling the top end of the valve train and started knocking). The mechanic ended up putting in a new galley plug for me and said I could limp it home even though there was still valve noise (he said it was a collapsed lifter).

So, now 2 months later I still have the tick and I have done some maintenance to it. The first thing I did was replace the lifters. Unfortunately, that didn't fix the tick. Then I replaced the rocker arms on each side (with older ones that I got off of a parts car that were in good shape). I still have the tick. I did a compression test and I have about 155 psi in each cylinder. I know all of my pushrods are providing oil to the rockers because I watched them move with the valve covers off.

I am beginning to think that I have a bad cam. I read that the original 394 cams wore prematurely and they had to be replaced often. Could this be my problem? Or maybe I jumped a tooth on the timing chain... HELP!

[Olds64]

Oh yeah, I haven't seen any babbit or metal in my oil. And there is no water in my oil either.

[88 coupe]

Assuming the tick does not come and go, and it is not an exhaust leak:

........ (he said it was a collapsed lifter) ........

Did he explain why he thought so?

........ The first thing I did was replace the lifters. Unfortunately, that didn't fix the tick.. ........

OK. He didn't know why he thought so.

........ Then I replaced the rocker arms ........

How much wear on the shafts/rocker mating surfaces. Wear will be on the bottom of both.

........ I did a compression test ........

Good thing to check periodically, but cylinder pressure is not related to valve lash.

........ I know all of my pushrods are providing oil to the rockers because I watched them move ........

Assuming, by move, you mean rotate, it only shows oil is being supplied, from the lifters, to the bottom of the pushrods, and the tops are getting oil from the rockers.

The oil supply to the rockers is from the main journals, via the block, heads, stands, and shafts.

Simple way to isolate the offending valve. While the engine is idling, you can put a finger on the pushrod end of a rocker, and feel any excessive valve clearance. Even simpler: With the engine off and the lifter on the heel of the cam, you can feel any thing over zero clearance.

........ I read that the original 394 cams wore prematurely and they had to be replaced often ........

I read a lot of things. Some of them are more true than others.

........ Could this be my problem? ........

Taking the statement at face value, how could you, or anyone on an internet message board, know if it applies in your case?

Regardless, a worn lobe would lift the valve a shorter distance, resulting in a loss of power. It would not affect valve lash.

........ Or maybe I jumped a tooth on the timing chain

Valve timing cannot affect valve lash.

Norm

[88 coupe]

Originally Posted by Olds64

Oh yeah, I haven't seen any babbit or metal in my oil. And there is no water in my oil either.

I would not expect to see any unless there was another, unrelated, problem.

Norm

[Olds64]

You know I thought it could be an exhaust leak. I need to get down there and check; however, I doubt that is the problem since I did blow out an oil galley plug. I see where the mechanic sweged a new plug into the rocker shaft. I know it isn't the rocker shafts, they are both in decent condition. I also know that it isn't a lack of oil to the rocker arms because when the engine is running I can see oil ooze out from underneath each of the rocker arms. Plus, I made sure all of the oil galley holes in the rocker arm shafts were good.

I guess it is probably a worn cam lobe. I can go back in and check the lash the way you mentioned. That is a good idea. Too bad you can't set valve lash on an Olds.

BTW, if my cam lobe is worn then wouldn't I see the metal in the oil? It would have to go somewhere wouldn't it? That is why I mentioned I didn't see any metal in the pan.

[Olds64]

Anybody else have any pointers? Is there a better way to id an exhaust leak besides just starting the car, looking around, and crawling underneath it?

[88 coupe]

Originally Posted by Olds64

........ I thought it could be an exhaust leak ........

Reread the first line of my first post. Eliminate it as a cause, first.

........ I doubt that is the problem since I did blow out an oil galley plug ..........

You said, it overheated. Not related to a missing oil plug, but could be related to an exhaust leak.

........ I also know that it isn't a lack of oil to the rocker arms ........

If any valve train damage occurred, it would have been during the time of the loss of oil delivery. Under that scenario, when the mechanic capped the leak the loss was restored, which is what you see now.

Have you checked your oil pressure with a accurate gauge?

........ I guess it is probably a worn cam lobe ........

Are all the valves all opening to the same height? If one was not, would it affect the valve lash?

........ Too bad you can't set valve lash on an Olds ........

That would be another (unrelated) topic.

........ if my cam lobe is worn then wouldn't I see the metal in the oil? ........

In the case you described, wear would not make shavings/grindings.

........ I didn't see any metal in the pan.

Did you see a rough surface (as if it had been ground) on any of the lifter surfaces?

Norm

[88 coupe]

Originally Posted by Olds64

........ Is there a better way to id an exhaust leak ........

If it gets louder as the engine works harder, it is likely an exhaust leak.

Norm

[Olds64]

Hmmm... thanks for the tips. Here is some more info.

You said, it overheated. Not related to a missing oil plug, but could be related to an exhaust leak.

I think I know why it overheated. When I was driving it on the highway it slipped out of gear and started over revving (my tranny is bad). I didn't have any noise before it overheated so I know it wasn't an exhaust leak that caused it to overheat.

Have you checked your oil pressure with a accurate gauge?

No.

Did you see a rough surface (as if it had been ground) on any of the lifter surfaces?

No.

If it gets louder as the engine works harder, it is likely an exhaust leak.

Well, the noise is definitely louder as I approach the tranny's shift point. It seems quietest at about 40-45 miles per hour. The engine also doesn't seem to be working very around that speed in that rpm range.

Hmmm... Well, I will look into it again on Saturday. I will keep everyone posted. Thanks for the tips.

[88 coupe]

Originally Posted by Olds64

........ (my tranny is bad) ........

I still don't do trannys. http://www.urbandictionary.com/define.php?term=tranny

........ I didn't have any noise before it overheated so I know it wasn't an exhaust leak that caused it to overheat ........

Overheating could cause an exhaust leak at the manifold. Rare, but possible.

Norm

[Olds64]

[59-59-59]

This may work, and it may not..but 95% of every 371 / 394 Olds I have ever had with lifter ticking came from dirty oil I had. I changed the oil and filter and the ticking noise was never heard again. Try this first before tearing half the engine apart.. Its cheap and it may work

[88 coupe]

Originally Posted by Olds64

........ That is why I mentioned I didn't see any metal in the pan.

I would be very surprised if he did not change oil, when he replaced the pan.

Norm

[Olds64]

I have changed the oil twice since it started ticking.

[big-al-D-88]

You guys are great with the comebacks!