Lifter bleed down or stick

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The '74 Dodge has been a terrific runner and driver for the past 3 months I've had it. I've put nearly 2500 miles on it already!

However, I've run into an intermittent problem that occurs only about once every 2 weeks. As most mopar small blocks will, it will run smooth and quiet throughout the day. Then, after sitting overnight, it'll start up with an impressively loud clack/tap that continues for 2 minutes or so before completely disappearing as if nothing ever happened.

Considering how it acts and sounds, and through probing with the stethoscope when it happens, I'm convinced it's a lifter problem.

Now, I'm sure I'm about to speak this forum's foul language (and it's usually foul language in my own book as well), but I think this engine is a good candidate to make an attempt with some sort of cleaning/flushing agent. I know for a fact that this truck sat for a significant amount of time at some point in it's life (it has 70k miles on it now and the last 40k of them were put on since 1978). Peeking through the fill hole in the valve cover, I see no indication of mal-maintenance - no sludge, no buildup. I've filled/drained the oil twice on it already and visually, haven't seen anything abnormal. The motor doesn't use much oil (just an occasional puff from leaky valve seals ) and runs sweet and quietly. Just one lifter seems to have a problem once in a while. And, while I do plan to pull and refresh this motor at some point, now is not the time for me.

Looking for thoughts/suggestions on the topic. Any magic potion worth a shot?
 
You can run 16oz of Kreen from Kano labs for 1K or a can of Berrymans Chemtool fuel system cleaner in the oil for 10-15 min at idle only before changing the oil.
Both work well, the Chem tool was originally specified for this use but people abusing it (driving the vehicle) forced them to remove that recommendation, used properly it will cause no harm.
 
I would first start out with a clean oil / filter change , probably with 100% synthetic oil .

My impression is synthetic oil " cleans better " than dino oil ?

If I am wrong , some one please correct me .

Best of luck , :)
 
Originally Posted By: ARCOgraphite
You sure its not the heat riser valve flutter in the exhaust? - a typical dodge warmup noise?


An interesting thought. I was pretty sure I had isolated it with the stethoscope, but I admit I never checked around the exhaust manifold. Maybe I should wait till the next event and check the valve...

Now, this IS a fairly loud clack when it happens. That exhaust flapper can make that much of a racket?
 
Originally Posted By: emmett442
The '74 Dodge has been a terrific runner and driver for the past 3 months I've had it. I've put nearly 2500 miles on it already!

However, I've run into an intermittent problem that occurs only about once every 2 weeks. As most mopar small blocks will, it will run smooth and quiet throughout the day. Then, after sitting overnight, it'll start up with an impressively loud clack/tap that continues for 2 minutes or so before completely disappearing as if nothing ever happened.

Considering how it acts and sounds, and through probing with the stethoscope when it happens, I'm convinced it's a lifter problem.


Its a lifter, but its not a "problem." My 73 318 ran 436,000 miles until I sold it, occasionally doing that the whole time. Its completely harmless, and I think its caused when a susceptible (for whatever reason) lifter winds up with its valve spring compressed when you shut the engine down. It slowly bleeds down, and on the next re-start it takes a long time to re-fill.

The thing I found that helps the most is to find and use an oil filter with a really good anti-drainback valve. For some reason, Wix filters were much more prone to causing the "empty lifter" noise in that engine than any other brand, despite otherwise being good filters.
 
Thanks for the reply.

I agree with your assessment that it's happening when the engine stops at the position to keep pressure on the susceptible lifter.

In my case, the filter doesn't seem to make a difference. It's made noise with both the Purolator and Wix filters I've had on it (changed the oil when I got it, then again when this noise occurred the first time). I've been running 15W-40 weight in it.
 
Perhaps slightly, but my concern is that it's bleeding down.

Makes little difference to me if it knocks for 90 seconds or 120. I'd rather it be silent!
 
try a thicker oil? A leaky lifter is small potatoes in a 43 yr old engine. Especially a classic like the 360. This is gonna sound crazy. Use a thick oil for an oil change. If it quiets down...If it doesn't quiet down try a load of thinner oil like a 5w20. Maybe 20w50 wont drain past the seal.. or a thinner oil to blow away a chunk of dirt. I would live with it and try to fix it without taking it apart. OR Turn up the radio ! Stuff like this shows character in an old pick up.
grin2.gif
 
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