383 engine noise question

[buck351]

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 .

Good point. Didn't inspect the springs while I had the valve cover off but it would be an easier fix than a rod. They are the original. Have to pull the cover back off and check. Having never seen a cracked or broken compressed spring I assume it's obvious. I was surprised they didn't replace them. The rebuilder just checked and shimmed them as needed to get the correct tension.

First fuel pump I had do that and I've had the car since it was 1.5 years old. Usually they start leaking gas out the vent hole from diaphragm failure. This one was making noise that stopped after I replaced it. There was a little free play in the existing fuel pump arm that wasn't in the new one.

 

[buck351]

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..

It is synthetic ZRod Amsoil not regular 20W50. Didn't know how 10W30 synthetic would get along with a vintage engine since it flows easier than regular 10W30. For about 40,000 miles before the rebuild I had a different cam and Rhoads lifters which at the time required 20W50, 40 or 50 weight. I ran 20W50 and it was non synthetic. Never checked the pressure back then.

 

[buck351]

if the oil pressure is good, I'm leaning toward piston knock.

I suppose it is good considering the spec pressure from the Dodge service manual was with regular oil not synthetic.

 

[buck351]

Don't know if it related but the engine has a miss when running at >=2000 rpms parked when I'm checking the noise. When the lifters on the passenger side were clacking it was running rough.

 

[buck351]

One thing that's been rattling around in my head is the tapping fuel pump, tapping at the front of the passenger side head and the lifters on the passenger side clacking all started close to the same time. keep wondering if it's not coincidence but some root cause.

 

[bOb shingler]

bad plug wire?

 

[furyus2]

Thanks for this thread. I think it will be very helpful to others. My thoughts are that the cam went flat. Since you say it's missing, and tapping. What happens when you pull plug wires one at a time? Might be time to pull the intake to look at the cam.

 

[buck351]

Thanks for this thread. I think it will be very helpful to others. My thoughts are that the cam went flat. Since you say it's missing, and tapping. What happens when you pull plug wires one at a time? Might be time to pull the intake to look at the cam.

When I changed the lifters all the bottoms had normal wear and still looked like they should. My understanding is if the bottoms of the lifters look normal the lobes should be ok. Missing and light knocking happens at = or >2000rpm.

I took a day off work to check the valve springs and do the dead cylinder test. No broken springs. When I pulled the plug wire on #2 cylinder, which is where the noise is at, the light knocking went away. Not good $$. :-( I have been talking to the people who rebuilt the engine 5 years ago. I have to call them back to talk to the owner tomorrow and see what happens. Not sure if they will offer anything worth while. Other wise I'll have to find some place close to home to take it since it sounds like a pull the engine to fix it. There is a place near that buys/sells classic cars, does mechanical work and body work. They show three babes with grease on under the service tab. If they work on your car I want to watch.

For anyone's curiosity here's the link to the place http://baltria.com/home/

 

[mguner]

Was the engine bored or just re-ringed and honed? It may just be piston slap....

 

[buck351]

Was the engine bored or just re-ringed and honed? It may just be piston slap....

It was bored .30 over with new pistons. Just got off the phone with the rebuilder. Sent them an audio file of the noise for them to listen to it. They will call back after listening to the file. Discussing the noise again with them it's sounding like it is piston slap. Rod bearing he said will be there all the time. They said piston slap will sound like marbles in a can. He said slap is related to scuff/collapsed skirt on piston.

If anyone is curious here's a link to the audio file of the noise called "engine knocking noise": https://onedrive.live.com/redir?resid=6E844A0215278E3A!694&authkey=!AKa5BojAiKwi2Yo&ithint=file%2cwav

 

[buck351]

Place who rebuilt the engine is working on having someone stop by after work on 4/28/16 to check out the noise. It has been ~10,000 miles and 5+ years but they have taken some positive actions so I'll see what they say after seeing it.

 

[buck351]

Well the guy from the engine rebuilder stopped by and listened to the engine. He thinks it's piston slap. Far as I can tell from what I have read its' either that or rod knock. Took a look inside the cylinder thru the plug hole to see what I could see on the cylinder walls. Some vertical lines on #2 cylinder wall in only one area on the knocking cylinder. Couldn't see other side of cylinder to see if there was a mirror image across from the area without putting a mirror on the scope. Didn't want to risk dropping the mirror in cylinder. Sent photos to shop. I did look at another cylinder, #3, that was also down at the same time for comparison. #3 had vertical lines on whole cylinder. Unfortunately I haven't seen open engines to know what's normal so I'll see what the engine shop says. First photo is #3 second is #2.

 

[mguner]

I vote for piston slap. From what I see this was a re-ring in a somewhat tapered bore. An old school refresh that works but sometimes is a little noisy. Many in the old days would intentionally put engines together loose in this fashion to reduce friction and haul A$$! They do make a little rattle at idle though. Many engines with forged pistons will also make the sound when cold because of the extra clearance needed for the different expansion ratio of the forged material. If the pistons are of factory design and were put in backwards (which was also a common speed secret) the slap is worse. The indicator will be the location of the "notch" that usually goes to the front of the engine will be at the back.

 

[buck351]

I vote for piston slap. From what I see this was a re-ring in a somewhat tapered bore. An old school refresh that works but sometimes is a little noisy. Many in the old days would intentionally put engines together loose in this fashion to reduce friction and haul A$$! They do make a little rattle at idle though. Many engines with forged pistons will also make the sound when cold because of the extra clearance needed for the different expansion ratio of the forged material. If the pistons are of factory design and were put in backwards (which was also a common speed secret) the slap is worse. The indicator will be the location of the "notch" that usually goes to the front of the engine will be at the back.

Rebuild was .030 bore with new cast pistons, rings, bearings, new cam, new lifters, valve job etc. I'm leaning toward piston slap since #2 doesn't have the vertical lines around the entire cylinder.

 

[txstang84]

It is synthetic ZRod Amsoil not regular 20W50. Didn't know how 10W30 synthetic would get along with a vintage engine since it flows easier than regular 10W30. For about 40,000 miles before the rebuild I had a different cam and Rhoads lifters which at the time required 20W50, 40 or 50 weight. I ran 20W50 and it was non synthetic. Never checked the pressure back then.

First, I'm inclined to agree with mguner's assessment of the noise...probably just some loose tolerances if your oil pressure is adequate and you've run down the other likelihoods (lifters, fuel pump, etc.)

The reason I quoted the above statement is because of my own potential misunderstanding. If I understand the rating of oil viscosity correctly, the brand and type don't matter because they're formulated to operate under the viscosity rating on the bottle and the API service rating on the back (I think they're up to SN now). The viscosity of the oil used needs to match the engine build though...thicker oils will create more demand on the oil pump and driveshaft and probably shouldn't be used unless the engine needs it. Thinner oils create less drag but aren't well-suited for large bearing clearances because the volume required to hold the wedge would kinda defeat the purpose of using a lower viscosity oil in attempt to reduce parasitic losses.

 

[buck351]

I've noticed it knocks for a short time when started then stops when oil pressure comes up then is fine while idling. Well it's in the shop and they will probably have the engine out next week. Once the engine builder gets it apart I should know what's up.

 

[mguner]

I built a few "loose" engines with the pistons in backwards and they would make a kind of hollow knocking sound until they warmed up and the pistons expanded a bit. Looking forward to the report.

 

[buck351]

They have the engine apart and suppose to take photos for me. #2 cylinder has bad rod bearing plus two other rod bearings are showing wear. They think some of the bearing material from #2 got carried over to those other two rod bears causing the wear. They said there is also a scratch mark on two main bearings so machine crank and bearings. They disassemble the entire engine and it will get cleaned first. One thing that still sticks in my head is two years after the rebuild I dropped the pan to address a leak and noticed the oil shield for the front bearing had a hole worn in it. At the time I didn't know what that piece of sheet metal was so I sent a photo of it to the rebuilder. He told me what it was but he didn't seem real concerned about the metal that worn off and went into the oil pan. Other than the oil pump which only has a screen on the suction side I would think the filter should have kept anything bigger that 25 microns out of the rest of the engine. Unless less than 25 micron particles could have worn the bearings.

Update:
They didn't take photos but are suppose to save the bearings for me.

 

[buck351]

In reference to oil viscosity The 1967 Dodge Service manual oil viscosity recommendations are attached in the screen grab file from the service manual. I only use the car spring thru summer to early fall.