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post #1 of (permalink) Old 05-31-2002, 12:13 PM Thread Starter
 
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Valve clatter

Hey all, I have an interesting problem. you all know the valve clatter sound when accelerating in the timing is off right? well, I can adjust my timing to get rid of it but it comes back. It seems to be if I set the timing with a full tank of gas, no clatter, but at a half a tank or lower, I get clatter. now if I set the timing with a half a tank of gas, no clatter, but if I fill up, the clatter is back.
I am just smoking some crack thinking that this is related?
any thoughts on why?
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post #2 of (permalink) Old 06-04-2002, 06:01 AM
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Re: Valve clatter

When you say valve clatter, surely you're talking about pinging-knocking-detonation. Valve noise has nothing to do with timing or load.

And if it comes and goes depending on how much gas is in the tank, yes, it's what you're smoking.

Where are you setting the timing? How much do you change the timing to make the noise go away?

Only thing I can think of would be that water in the tank is changing things, but I really don't know why or how.
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post #3 of (permalink) Old 06-04-2002, 09:24 AM Thread Starter
 
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Re: Valve clatter

correct, the pinging-knocking-detonation.
timing is set to about 8*btdc and to make the noice go away, i only have to change it about 2* at most.
thanks
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post #4 of (permalink) Old 06-04-2002, 10:20 AM
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Re: Valve clatter

A 258 at 8 degrees retarded shouldn't knock in the first place. I'm not at all familiar with California engines. Is that the recommended timing setting? My '78 258 is supposed to be about 2 degrees advanced, and runs better at around 8 advanced.

If that is the recommended setting, there must be something else wrong to make it so inclined to knock. EGR valve bad maybe? Vacuum leak? Carbon buildup? Really cheap gasoline?

I suspect that your fiddling with the timing is masking a symptom of a different problem. Once that is corrected the pinging will take care of itself.

I'm sure plenty of guys can suggest other sources of the pinging. Maybe you should put up a new post asking about causes of pinging.
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post #5 of (permalink) Old 06-04-2002, 12:25 PM
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Re: Valve clatter

8 degrees advanced (btdc) like you have it shouldn't produce ping. And for sure, the amount of gas in the tank should have no bearing at all.

Some causes for ping:
Cheap gas, low octane, too much alcohol (Arco)
Over advanced timing:
Too much initial advance
Too much total advance (max about 35 for most engines)
Wrong vacuum to the advance diaphram - doesn't retard enough during hard acceleration.
Carbon build-up - misfires, rich?
Overheating
Plugged exhaust
No EGR when the engine was designed for some
Too lean a mixture - causing high combustion temps



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post #6 of (permalink) Old 06-04-2002, 02:03 PM Thread Starter
 
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Re: Valve clatter

thanks guys, you jogged my brain a bit. I think gas has something to do with it, I had to put cheap ARCO gas in it a couple of times recently. I will try better gas, and see.

I'm not sure how to check the total advance,
but I do think that some of my vacume lines are getting old and I was planning on redoing them, maybe the vacume line to the dist. is bad.
plugs good, exhaust good, egr new, carter carb(sets own mix right?)
thanks for the ideas!!
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post #7 of (permalink) Old 06-04-2002, 05:47 PM
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Re: Valve clatter

i get the same pinging also. i tried the water-down-the-carb remedy to possibly steam-clean the carbon. then i retarded (dist-clockwise) the spark a little, just by ear and that got rid of it. i also buy a higher octane gas. i don't use a timing light much on the jeep.

valves sticking is another issue. i just dropped in new lifters last weekend and remedied that prob.
post #8 of (permalink) Old 06-04-2002, 06:01 PM Thread Starter
 
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Re: Valve clatter

now why would I trust you? you're just a stinky ole surveyor!! lol. How are ya doing?
Valves could be a possibilty, seeing how its kinda intermittend.
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post #9 of (permalink) Old 06-04-2002, 06:17 PM
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Re: Valve clatter

when mine was pinging, it was only when i put a load on it. if i just "cruised" through the gears it would not ping. after i retarded the spark it stopped the pinging. after i did the lifter job, i had some start-up issues. i had to take off the carb and fuel lines to pull the head and manifolds. after re-assembly it started right up and then died. wasn't getting fuel to carb. had to prime carb couple of times to get the air out of line. during this prob, all the new plugs i put in got fouled with a fine black powdery smoot. i [email protected] with the timing to get it running and now it starts and runs great but has slight pinging. i will retard spark and that should fix.
post #10 of (permalink) Old 06-04-2002, 07:54 PM
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Re: Valve clatter

For those that might be interested - Harbor Freight has a cheapie timing light with the advance knob for less than $30, on sale sometimes even less. The first I've seen for less than $100. My Snap-On cost $230 - loaned it out once, never saw it again.

Yes, cheapie Chinese, but it seems to work pretty good, bright, and accurate.

That's what's needed to check total advance, that or a degree wheel.
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