There's a rattling sound coming from what I think is the R side valve cover, or more accurately coming from underneath it. It comes and goes, but it sounds like a loose object bouncing around. It's gotten progressively worse, and used to only happen on startup so by the time I started and got under the hood, it was gone. Now it seems to be pretty consistent to when I'm driving. I've tried revving in park with the hood open, but it doesn't make the sound then. Short of something obvious (like a foreign object inside), what should I be looking for that's causing the noise in the valve-train?

Loose Rocker. Remove the Valve Cover and investigate. You need to find the issue BEFORE IT BREAKS. If it's a sticking lifter, bent push rod, or loose rocker nut / stud, it will only lead to ENGINE DAMAGE. AND STOP REVING THE ENGINE TILL YOU FIND IT !!!!! In FACT, I wouldn't drive it myself till I knew FOR SURE what it is. PERIOD

OK - sounds scary! My 78, 350 has similar symtoms. But, the tapping, clicking noise is now very slight and only occasionally at about 1300-1500rpm when you are driving. Never does it when cold. One more thing. When I start it hot there is a puff of smoke from the exhaust and a few seconds of stumbling before the engine catches and runs OK. Someone with more knowledge than me said "worn valve guides". Is it now time for some serious mechanical work?? If so, what?

Suggestions would be much appreciated. I do not have tools or mechanical skills. But I do have a very good mechanic friend who works on my El Camino.

At this point, I would agree with your friend. Sounds like your describing a slight TAPPET / Lifter noise that goes away after the lifter pumps up. How many miles on the Engine?. When was your last Oil Change? You might think about changing the Oil and substitute 1 quart of Oil with a quart of Lucas Oil Treatment to assist in quieting down the clicking. The puff of smoke I would also agree sounds like guilde / seal leakage. Not a huge issue untill it gets to the point that it starts to foul your spark plug or plugs. Again, these are just a guess at this point.:dontknow:

Just pulled the cover off, nothing obviously loose. Pushrods still can be spun by hand, but no end play in the rocker arm.

I'm out of ideas. There's no signs of abnormal wear on any parts, nothing is obviously loose, no obvious foreign objects. Unless it's deeper in the cylinder head, like a bad valve, or something external like a loose exhaust clamp.

Thoughts? Ideas? Comments?

If the rocker arms are lashed properly, my guess would be a sticky lifter. There are several oil additives that can treat sticking lifters, Lucas and Justice Bros., just to mention a few. Follow directions and give them a try, you could get lucky...

Is there a way to test the lifters without tearing down the engine?

Could it be a heat riser valve? Not sure if you have but it would be in the exhaust manifold.

http://elcaminocentral.com/customavatars/avatar13975_1.gif (http://elcaminocentral.com/member.php?u=13975)Buffalo Dude (http://elcaminocentral.com/member.php?u=13975)
I think you should be OK then. In all probability it's most likely a sticky lifter. Try the Oil Change with an additive as suggested.:beer:

Some people swear by Marvel Mystery oil for unsticking lifters.

Doug

For the money and the effort, just try an oil additive. If it doesn't work, then you can tear into the motor. Try easy first, again, you may get lucky...

Some people swear by Marvel Mystery oil for unsticking lifters.

Doug


I DO
When MAMA ain't listenin. It's a MYSTERY how well it works. :poke: Great for Air Tools also.:secret:

being as you have the valve cover off- take a straight edge- ie a 2 or 3 ft long steel or aluminum ruler and lay it across the tops of the studs that hold the rocker arms- i recently found a pulled stud on a 305 that was making the noise you describe. i was able to tap the stud back in with an aluminum block and a small hammer- i then drilled the stud mount and put in a small roll pin. so far so :sleeping:good- good luck.

I took a peek underneath, and this is what I found:

http://i5.photobucket.com/albums/y155/buffalo_dude/IMG_2845.jpg

http://i5.photobucket.com/albums/y155/buffalo_dude/IMG_2848.jpg


Some of the teeth look like they have some minor wear on the engine side of the flexplate. I took it to a shop to see what they think and the guy at the shop said it was most likely the starter gear flopping loose and rubbing on the flexplate, causing the rattling. What do you all think?

That is possible. But what concerns me with your Photo is the scrape marks on the flex plate it's self, ABOVE the Flex Plate Ring Gear. The Starter gear in NO WAY will make contact in this area.
You may, or should investigate this further. Maybe a cracked Flex Plate?:dontknow:

i agree with larry on the ring gear . the top photo at the bolt looks like it may have a crack in it . quick way to ck for cracked flywheel is take a wrench and tap the flywheel it should ring like a tuning fork if good . good luck

I'll definetely check out the flexplate in detail. I hate that this is such a frankenstein engine, and I don't really know what it's got or what's in it.

As far as starters, I'd like one of the mini high torque starters. I think they make a cool sound when they start, and I'd like a little more clearance from the headers. Recomended brands? I think most are inline mount, but the one that's on there is staggered, will that be a problem?