engine noise

[jaswalters]

I have a 63 avanti that mostly sits in my garage. I start it every two to four weeks. It has recently started an annoying habit of making a lot of clattering noise that sounds like it is coming from the valves. This only occurs after the car has been running a few minutes. I have good oil pressure and compression.

A friend says that I need to use oil with Zinc additive due to the age of the car. Anyone think this is the root of this problem?

[mfg]

The zinc additive is a good idea for any 'flat tappet' equipped engine. But I don't think that's the problem here. More than likely your Avanti engine needs a valve lash adjustment. That probably hasn't been done in a long time. And Avanti 'R' engines, with their performance camshaft, need this attention more frequently than a normal Stude V8. (As the engine warms up the valve lash increases)

[Gunslinger]

How long since the valves were adjusted? It could a combination of valves out of adjustment, timing being off, buildup of debris on the pistons effectively raising the compression and insufficient fuel octane. That doesn't even take into account the fact that if the engine has never been apart, everything internally is over fifty years old with unknown condition.

Depending on how old the gasoline is in the tank, you might do well to add some isopropyl alcohol dry gas and run it out and fill with fresh fuel.

While adding a zinc additive might not hurt, it likely won't make a difference either. The whole zinc/motor oil debate is overblown in most cases.

Without knowing everything about the engines history, I would start by pouring a can of Seafoam into the carburetor and through the main vacuum line from the brake booster into the intake. That will clean the internal passages of the intake and the combustion chambers and smoke up the neighborhood. Follow it up with new spark plugs, points and condenser properly adjusted and valves adjusted. Basically, a complete tune-up.

If that doesn't solve your problem, then you might need to look further into the engine.

[PackardV8]

Your "It has recently started an annoying habit of making a lot of clattering noise that sounds like it is coming from the valves. This only occurs after the car has been running a few minutes." is too vague for any real diagnosis. Is it an ignition miss? Is it at cam or crank frequency? Is the volume correspondent to RPM? Does it get louder the longer you run it? Does the noise only occur after the choke has pulled off? Does the noise ever go away?

FWIW, I had a similar problem and it turned out to be just old gas. Now, before beginning any troubleshooting on a stored Stude, I drain the tank and fill with fresh fuel.

Your results may vary, but in fifty years, I've never had any magic elixir poured in the carb or the gas tank or the oil pan solve any problems. Have had a few which made them worse.

jack vines

[jaswalters]

Thanks for the comments. i do have old gas in the tank. i think I'll start there.

[fred88]

As said, a little vague to warrant a diagnosis, but start with the noise as "valve clatter", pull the rocker covers and check for oil on the rocker tips, if there adjust valve lash. If there after lash adjustment, get a wood dowel, hold against engine and against ear in different spots to try and locate the source. If possible hold against the timing cover, if it seems to be coming from there check that fuel pump mounting bolts are tight (mine likes to loosen up) sounds like a tappet noise as the lever starts to slap the fuel pump cam. Having good oil pressure at the gage means little if a passage has clogged in the crank and the bearings are starving for oil. Pressure is being "read" off the oil passage in the right head near the oil pump main outlet. rest of motor could be staving for oil.

I'd try the Seafoam treatment or if your feeling daring, pull the air inlet if supercharged, or the air cleaner. Get an old Windex spray bottle, fill with plain water, and while running at a fast idle (1200 RPM +/-) spray the water over the primaries till it stalls. Let sit, restart and repeat. Look for a lot of black carbon coming out exhaust along with a white cloud of water vapor. Works as well as Seafoam, just cheaper.