383 engine noise question

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buck351

buck351

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So I had a ticking lifter on drivers side and decided to just replace them all on that side to make sure I got it. Before I did it I got this louder noise on the passenger side front that sounded like it could be a lifter so I did them all. Ticking is gone but the louder noise is still there in the passenger side front of the engine. Listened around and it's a ticking at the front of the head with more of a loud tapping sound above the fuel pump and on the fuel pump. Same rate at all the locations. You don't hear it standing in front with the hood up until you hit 1800-2000 RPM. Anyone had a loud tapping noise around the fuel pump before? I had replaced a leaking fuel pump about 4 years ago.
 
Can't say that it's your issue but I have seen fuel pump pushrods worn up to a 1/4" over new. I would pull that push rod out and check it. The other thing to remember is if it's that sloppy it's not doing the eccentric on the cam any favors either. Remove the fuel pump and there's a threaded plug on the block you have to remove to pull the push rod out.
 
Dubob said:
Can't say that it's your issue but I have seen fuel pump pushrods worn up to a 1/4" over new. I would pull that push rod out and check it. The other thing to remember is if it's that sloppy it's not doing the eccentric on the cam any favors either. Remove the fuel pump and there's a threaded plug on the block you have to remove to pull the push rod out.
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Thanks for the input I can check that. I didn't say in the post that this just started happening.
 
Breadburner said:
Spun a bearing....
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My understanding is a bad bearing is a knocking sound like hammer on block. This is higher frequency tapping like loud lifter. Maybe I didn't explain it correctly in the original post. Noises can be hard to describe but it's loudest around the fuel pump area.
 
Disconnect the fuel line and plug it . Start the engine. Put your thumb over the pump inlet. The pump will quit working after about 3 cycles.The arm will drop down and so will the pushrod.Noise still there means it's not pump related.
You can do the same test by clamping the rubber fuel line, but it's hard on the line. Old ones can crumble inside and make trouble.
 
AJ/FormS said:
Disconnect the fuel line and plug it . Start the engine. Put your thumb over the pump inlet. The pump will quit working after about 3 cycles.The arm will drop down and so will the pushrod.Noise still there means it's not pump related.
You can do the same test by clamping the rubber fuel line, but it's hard on the line. Old ones can crumble inside and make trouble.
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Thanks. Learned something.
 
I can attest to the lost of fuel pump rod in bb's... Crappy construction in aftermarket parts exist, I have lost two rods where the eccentric side of the fuel pump rod simply wears away. I finally ordered a USA made Hughes version and , no more wear. Installed magnets on oil pan to catch any metal, just in case. Made the noise your talking about, then finally no noise and no gas pumping.
 
61forfun said:
I can attest to the lost of fuel pump rod in bb's... Crappy construction in aftermarket parts exist, I have lost two rods where the eccentric side of the fuel pump rod simply wears away. I finally ordered a USA made Hughes version and , no more wear. Installed magnets on oil pan to catch any metal, just in case. Made the noise your talking about, then finally no noise and no gas pumping.
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Thank you. Looks like I need to pull and check the rod. Have to check paperwork on the rebuild 5 years ago and see if they replaced it or used the original.

Check rebuild paperwork. It's the original rod.
 
Anyone know what the length should be for the rod that rides the cam lobe for the fuel pump? I wasn't finding it in the service manual.
 
It's not the rod. The machined chamfer is still on the edge of the ends. Could it be the pump?
 

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So pumps aren't expensive so i figure I'll put a new one on. So after its together again if it's still making the noise any suggestions on steps to diagnose it?
 
When you replaces the lifters did you break them in again? Its my understanding that new lifters on a new cam need to be broken in.
 
DartVadar said:
When you replaces the lifters did you break them in again? Its my understanding that new lifters on a new cam need to be broken in.
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Existing cam new lifters. Yes broke them in as per manufacturer. Thats when i noticed the one noise was still there which becomes obvious around 1800-2000 rpm.
 
EUREKA!! After replacing the fuel pump the loud ticking noise is gone at >1800 rpm. Four year old fuel pump must have been one from China with a low quality spring. Service manual said for fuel pump noise weak or broken spring. I'm thinking cheap spring got weak after 4 years and < 10,000 miles. I did notice there was a little easy movement on the old one from hand pressure that wasn't there on the new one. I had a really hard time trying to move the new one at all but I could pump the old one some with just my hands.
 
Thanks for posting what you found. Good information to know.
 
So after the winter working on the lifters, fuel pump and master cylinder I went for a test ride today. Although the loud tapping is gone and not at the fuel pump anymore the noise is still there >or = to 2000rpm. Only in the front part of the passenger side head. Noise decreases as you move away from the front part of the head toward the back of the head with a rod touching the head at the valve cover. Lifters have all been changed but when the engine rebuilder did the engine he used the original rockers after checking them. I'm wondering since they are the original rockers if one has worn in the past 10,000 miles causing the noise. Maybe new lifters took up some slack since the ones installed at the rebuild had gotten noisy? Cam lobes should be good since all the removed lifters looked normal where they ride on the cam. Rockers? Rocker shaft? Pushrod?

Just pulled the rockers. Push rod ends look ok and when I had them out changing lifters I rolled them. Second rocker from right, front cylinder, doesn't have full contact with shaft on bottom of rocker like others?
 

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So the noise is not the rocker that had the wear different than the rest. Changed it and the noise is still there. Light knocking noise that I can feel in a wood rod I was using to listen on the head. From what I read light knocking noise at constant rpm is a connecting rod noise. Have to kill the spark to one cylinder at a time and see if it decreases the knock to check for rod noise. This is looking like a major problem $$$$ :-( So much for having the engine rebuilt during the restoration. In hind site should have drove it until it died.
 
What head castings do you have? Possibility of something stuck on top of a piston? Maybe use one of those inspection cams? Haven't lost any tiny screws down the carb?
 
Haven't lost any screws down the carb. Don't know the head casting number but they are the stock ones on a 67 GTS. Started making the noises sometime after last car show last fall. I had mentioned to a fell Mopar guy I've had a slight tic in a lifter, very minor, on the driver's side for awhile an he asked if I had check the oil pressure. I hadn't so I pick up a gauge on the way home and checked it. Spec from service manual is 45-65psi @ 1000rpm. I got 47psi. I decide to check it again since this slight knocking noise could be low oil pressure/flow related. I checked today and it's 43psi at 1000rpm. It was a little over 45 cold and dropped to 43 hot. Also the lifters were making a little more noise than they should be making for hydraulics after warm and the knocking was lower level today that last time. I'm thinking the relief valve in the pump may allowing too much oil to flow back into the pan. Oil pumps aren't expensive and they are external where the filter screws on. Never noticed where they are located, the oil flow path and that the filter actually mounts to the pump. Also running 20W50 synthetic and oil/filter changed just a few months ago after new lifter break-in. I've been running this oil and same brand filter since the engine was rebuilt about six years ago after break in and the noises just came up lately. Anyone have any thoughts? Does my logic make sense?
 
I had 70ish psi oil pressure in my 71 383 cold and hot.. with the original oil pump that I replaced all the O rings in - Mancini has all the O rings needed if you don't want to drop $100 on a new pump..

If you change the pump, change the oil to 10w30.. 20w50 is way to thick..
 
buck351 , had the # 2 cam bearing rotate on a 66 383 , thats showed itself in the cam valley although . bearing had come out a bit . also have you checked your valve springs , could have cracked one and now it broke . i have never had problems with the fuel pumps on my 383's , just my 440's .
 
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