Ticking/knocking after warm up

[PlymCrazy]

Good afternoon and Happy 4th guys. First time caller, long time listener LOL. Hopefully positing this properly and in the correct area. If not please someone let me know.

‘69 Roadrunner 383 I’ve owned for a couple of years now. Toward the end of last season I started to notice a tick/knock after she’s warmed up. More prevalent this season. I suspected an oil pressure issue so I installed some aftermarket gauges below the dash to better observe what’s going on. She only came with a warning light from the factory. On the maiden voyage today she was reading about 80psi on cold startup. After driving for 10-15 minutes the pressure dropped to below 20psi at idle. I’m suspecting a failing oil pump. Any recommendations for the new pump? I see high pressure/volume options and wondering what you guys who may have some experience here would recommend. Any input is greatly appreciated. - Nick

 

[5.7 hemi]

Melling. You can get high volume, high pressure or standard.

 

[PlymCrazy]

Melling. You can get high volume, high pressure or standard.

Is one recommended over another, HP vs standard? I haven’t torn into this motor too far yet to see if any significant upgrades have been done. Not much history info came with the car.

 

[moparedtn]

Gotta ask - when's the last time the oil was changed - with what - and what brand filter?

 

[RemCharger]

Take a REAL good look at the oil when draining. Hope there's no shinys in it.
I would go with a high volume pump.
And some others would go with a standard pump.

 

[5.7 hemi]

I like high volume with a 6 qt. pan.

 

[davek]

does the pressure go up when you give it gas? what weight oil ,when did you change it last? Tick/knock can be the crappy gas now a days,I run super with lucas octane boost.

 

[PlymCrazy]

Gotta ask - when's the last time the oil was changed - with what - and what brand filter?

Oil changed this season within a hundred miles or so. Wix filter, Lucas 10w40 Hot Rod/Classic oil.

 

[PlymCrazy]

does the pressure go up when you give it gas? what weight oil ,when did you change it last? Tick/knock can be the crappy gas now a days,I run super with lucas octane boost.

I run 90 Octane, non ethanol always.

 

[PlymCrazy]

Take a REAL good look at the oil when draining. Hope there's no shinys in it.
I would go with a high volume pump.
And some others would go with a standard pump.

No shiny stuff in oil when changed recently

 

[PlymCrazy]

does the pressure go up when you give it gas? what weight oil ,when did you change it last? Tick/knock can be the crappy gas now a days,I run super with lucas octane boost.

Oil pressure does rise when I rev it. Oil change recently. Lucas 10W40, Wix filter.

 

[davek]

Nick you bought the car like 2 years ago any info on the motor? Might not be oil pump could be rings,bearing. My oil starts at 75 cold and then warm drops to 25 at idle. Then gos up when I start moving again to about 55. No reason to panic remember 10 psi for every 1000 rpm. My engine is at least 15 years old if not longer since rebuild and I will jump on it and its all good.

 

[Don Frelier]

I don't think 20 psi at idle is really low.
Sounds like it's a collapsed lifter.
Is it just in one spot?
There's also been a rash of worn fuel pump pushrods which can clatter as well. If it sounds like the front of the engine that would be another thing to check.

 

[davek]

also is it a tic or knock there is a difference. Could it be an exhaust tic?

 

[moparedtn]

Yep, it's time to identify the exact source(s) of the noise.

 

[1967coronet]

If possible do a phone recording after its warm and making noise.
Hold the phone around the valve covers and then hold it under the pan area.
Post the recording.
Not every time but it may be possible to narrow the problem area down.
20lbs at warm idle is not bad for a stock worn pump and engine.
If you think the sound is up top pull the valve covers and have a look.

 

[PlymCrazy]

Nick you bought the car like 2 years ago any info on the motor? Might not be oil pump could be rings,bearing. My oil starts at 75 cold and then warm drops to 25 at idle. Then gos up when I start moving again to about 55. No reason to panic remember 10 psi for every 1000 rpm. My engine is at least 15 years old if not longer since rebuild and I will jump on it and its all good.

I don’t have the history on the motor. It’s a matching motor and tranny I’ve confirmed. Haven’t torn in too deep to get much info yet either. Still has solid rocker assembly and 906 heads stamped from the era. Checked one side’s push rods and lifters and seem look good. Will check the other side when I get a chance.

 

[PlymCrazy]

also is it a tic or knock there is a difference. Could it be an exhaust tic?

I’ve had exhaust leaks in the past that are consistent with what you’re saying. This is deeper, metal on metal sounding. Also, in my experience, exhaust “ticks” stay the same or improve when the engine warms up from expansion. This sound I’m hearing is non existent when cold but is very evident when the engine warms up. Just opposite of what I’ve experienced with exhaust leaks.

 

[PlymCrazy]

I don't think 20 psi at idle is really low.
Sounds like it's a collapsed lifter.
Is it just in one spot?
There's also been a rash of worn fuel pump pushrods which can clatter as well. If it sounds like the front of the engine that would be another thing to check.

The sound is sort of centralized but difficult to differentiate top/bottom of engine. I’ve checked lifters passenger side via pushrod check. But this is when the engine is cool and the issue isn’t evident at that temp. I’ll check other side when I get the chance.

 

[PlymCrazy]

If possible do a phone recording after its warm and making noise.
Hold the phone around the valve covers and then hold it under the pan area.
Post the recording.
Not every time but it may be possible to narrow the problem area down.
20lbs at warm idle is not bad for a stock worn pump and engine.
If you think the sound is up top pull the valve covers and have a look.

I will try to do this soon