Rod knock?

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bengill
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Rod knock?

Unread post by bengill » Fri Nov 17, 2017 10:00 am

So I started up my car after a couple of months where I hadn’t driven it. Now I know that the lifters bleed down during that time. But even after letting the car warm up and stuff like that, I heard this sound which I think sounds a little like a rod knock but I’m not sure. I don’t see any sort of Blue smoke or anything like that. What do you guys think?

https://www.youtube.com/watch?v=uNx_7KkLJPM&sns=em





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azdave
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Re: Rod knock?

Unread post by azdave » Fri Nov 17, 2017 10:59 am

I only hear the typical lifter ticking like you get when a Corvair sits for a long time. I've had that last for several miles of driving and then never hear it again for months and months on cold starts.
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terribleted
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Re: Rod knock?

Unread post by terribleted » Fri Nov 17, 2017 11:01 am

Certainly valve train noise, like a rocker tapping from a weak, maladjusted, or not fully pumped lifter (could other uglier things as well of course like sticking valve dropped seat, bent valve, etc.). How long did you let it idle (sometimes a weak lifter may take a good bit to pump up properly...I have let cars that sat for a very long time run upwards of 30 mins 4-5 times before they shut up...and they were good after). I would run it for 20-30 mins and then let it get stone cold (next day) do it again. Perhaps drive it some as well. If it persists then valve cover removal for investigation and repair or adjustment may be in order.
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bengill
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Rod knock?

Unread post by bengill » Fri Nov 17, 2017 6:01 pm

I let it idle for about 15 minutes I’ll do it again tomorrow


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64powerglide
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Re: Rod knock?

Unread post by 64powerglide » Fri Nov 17, 2017 6:50 pm

Sometimes you need more RPM than just idle, I have one that drains out sometimes & I have to drive it 5 miles at 35 to 40 MPH before it loads back up. Other times it pumps up in a few minutes.
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Nickshu
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Re: Rod knock?

Unread post by Nickshu » Sat Nov 18, 2017 6:50 am

Once you have ruled out the lifters you can find a rod knock by grounding out each spark plug with a test light, one at a time. If the noise changes on one you found the location of your problem.
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bengill
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Re: Rod knock?

Unread post by bengill » Sun Nov 19, 2017 10:57 pm

Drove it over the weekend and it quieted down. So all seems well


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Re: Rod knock?

Unread post by bbodie52 » Mon Nov 20, 2017 12:58 am

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Re: Rod knock?

Unread post by terribleted » Mon Nov 20, 2017 8:09 am

bengill wrote:
Sun Nov 19, 2017 10:57 pm
Drove it over the weekend and it quieted down. So all seems well


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Very good! It would not be a bad idea to perform a running valve adjustment at some point just to make sure that the valves are evenly adjusted. If the offending valve is a touch looser than the rest it could explain why it wanted to make noise longer than the rest. Even adjustment is best for the engine anyway and doing this adjustment is not very involved. When you do this you can also see if any rocker nuts have lost tension (I have found some that do not have proper tension with the rocker stud making changes in adjustment over time possible). Any nuts that do not bind to the rocker studs properly should be replaced.
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bengill
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Rod knock?

Unread post by bengill » Mon Nov 20, 2017 10:17 am

Time is my enemy hahahaha. Might be driving down to mels vair shop in San Jose if he’s got time and I’ll let him just go through it


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