Knocking coming from the engine.

Someone else will have to chime in, but you should be able to slide the converter on the input shaft a little without hurting anything, I'm thinking if you don't do that, it might rub on the bolt pads and make a bunch of noise and you won't be able to hear if it's knocking or not. And by a little I mean like 1/8th, 1/4 of an inch or so is plenty.

 

Bent push rod. Or cracked rocker. If it was a exhaust leak it would get louder as you reved it. It is a light sound so that leads me to the push rod or rocker. It could also be a wrist pin ! when you put pressure on it, such as reving it or under accelaeration, it would go away because you are putting pressure on the piston, but at idle it does not have the same kind of pressure so it would make noise. I don't think it is a death noise though. Save your bucks for a new motor and drive until it breaks.

 

Nerd
The knocking wont stop if you pull the plug wire. This is because you are not putting any pressure on the piston wristpin location. this is why you can hear it at idle but not when you rev it.
Like I said leave it alone and save up for a new motor. You got 1200 miles on the way it is so I don't think it will blow any time soon. Just don't drive it like you stole it!!

 

That sounds exactly like my exhaust leak did. It was more noticiable at idle just like yours. It did not get worse at higher RPM.

Must be my trained ears.

It is not rod knock and does not sound like the flex plate. A bent pushrod of any significance would cause the engine to stumble and cracked rocker arm is doubtful but possible.

Also possible is a rocker stud backing out causing the valve lash to head south but the engine is still smooth so that is also doubtful.

If you have not checked the manifold gaskets they are an easy fix and cheap at $8 for a set Fel-pro MS9275B.

 

May sound crazy, but check out your fuel pump. I have had a couple of cars that sounded like a rod , but was a bad fuel pump. For what it's worth.

 

Here's one for you, 78 Caddy driven very little, (425/turbo400) owned by wife's grandma, Driven only 4 mo in the summer, started one day and sounded like 2 or 3 pistons were going to come out of the block, remember this motor only driven in town Went to the corner garage where the mech (who happened to like& work on Caddys)checked it out he started by draining the oil and then running a magnet on a collapsabile tube and combed the oilpan, no metal of any kind Added new oil and used the carb cleaner that is injected directly into the carb bypassing fuel pump. Ran the motor this way, changed oil 2x again, turned out that there was so much carbon buildup on pistons that there were pieces of carbon flopping around in the cylinder. Runs like a top now..

 

***

 

Ive been reading this and im a little confused , when asked about the flexplate you stated "its not cracked , i ran a compression test and removed plugs , no difference) ? Im not sure what that meant . Ive seen dozens of cracked flexplates , some easy to see and some you can only see when removed . Ive had them cracked between crank hub holes , and have seen the centers almost come apart . What happens when you powerbrake the car ? Also why not unbolt the converter and run the car , should be easy at inspection cover area to do this . Sure sounds like a cracked flywheel to me .

 

Id check the cam ,What year 350 is it,I also had a problem with one.My motor always had a light tap dull in sound.Didn't get louder with revs.Steady knock. Blew it up after 700 miles.Certain year smallblocks had cracking problems in the lifter areas.I read that some where . Take a weekend and diagnose first. Could be a bad guide in the head also Due compression
Also make sure bolts aren't hitting trans.Check flywheell

 

Sounds like a lifter going bad to me.

 

That sure does sound like a lifter. also make sure there is nothing hitting your exhauts like a heat shield.

 

i second the lifter prob, my 355 is doin the same. couldnt pinpoint the noise with the valve cover off, was a lil deeper in the motor. adjusted the noise out the best i could at the rockers, but as soon as you blip the gas and it came back to idle the taps started again.

 

When's the last time you CHANGED THE OIL?

Have personal experience with too many miles, dirt in oil, makes lifter or lifters "click."

Fresh oil changed it to normal.

 

Word to the wise, the sound of a motor problem is not picked up by your video. Those in the know are looking for a whole range of sounds not reproduced by a crappy mic and a computer. I've listened to a thousand engine noises and have listened to yours on a PC with surround & a subwoofer. But there's not enough actual live noise for me to tell anything. The sounds I'd be looking for in person would be described as sharp, and gutteral, and the unique blend of the two would tell me where to look. And that blend may be at the start of the knock, or the end. So take advice that comes from "listening" with a grain of salt.

I especially like that once you mention being a 20 year old girl somebody says "change your oil". If an oil change cures that noise, you got bigger issues than the oil. Thankfully you did not receive advice about the "710 cap"

good luck

 

RE: oil causing lifter noise, bought a brand new GM product and it has 110K, all driven by me, two different times, 30K difference in mileage, let the oil go to 4K between changes and the lifter noise came, changed the oil, eliminated the noise.

Dirt in the lifters.

Nice newer vehicle.

Your mileage may vary.

 

Male or female, makes zero diff. When is the last time the oil was changed?

 

OK, I was not pullin' your chain. Had said GM vehicle in the shop getting a new A/C condenser and they called telling me I've got a bad "rod bearing" car had 50K on it, never abused, it needed an oil change, they chuckled when I said add a filter, oil change, 5w 30, when they started it the "rod knock" went away.

Same deal happened 40K later, same results. It can happen.

 

I just thought of something. Put some Marvel Mystery Oil in it and see if the noise goes away. Probably 1/2 quart.

 

Not to get too simple on ya but I had a insistant rattle/clicking that I developed on my small block awhile back...

I thought it was something serious and was getting ready to pull the engine for a complete diagnosis when I pulled the dipstick out when it was running and my noise stopped....put the dipstick in and the noise started...

When looking at the dipstick you could see where it contacted the crank...

seems the cheapo mr gasket chromed dipstick tube and dipstik lost its temper and curled up enough to contact the crank ...

installed a new one and problem solved...

tales of the weird I tell ya....I woulda been pissed had I pulled the mill for that....

 

If you need tools I can come help you out with a jack and my toolbox sometime tomorrow. Its kinda late. PM me for my number if you want help.. This is the first I have seen this thread, been busy with my Model A in the afternoons so I only get on at lunch or late at night.-Weeks

 

fuckin hell, i need to check stuff like that....

 

and no, i dont know the water pump joke......

 

To clarify, you have had this problem for 1200 miles and there's 1250 miles on the oil change? Was there a new filter installed? Something could be related, if you're going to mess with any magic mystery oil, I'd urged you to change the oil and filter. If it's not that, at least you know.

Oil / lifters / stuck / noisy = related issues.

 

OK, don't need to hear any jokes! But to the engine noise, if it's a lifter, it's oil related. Rislone, all that stuff, cleans the lifter, clean oil is the answer for that.

The flexplate, the revolution of it would seem to not be same frequency of a noisy lifter.

 

Pull the filter and cut it open. If you see metal you know you need to grind up drier sheets, soak them in oil, and dump the mixture down the carburetor.

Sounds like bearings

 

The flex plate still sounds like the culprit. Check to see where it bolts to the crank. Make sure that it is not cracked from there to one of the round holes.

Turn it by hand and check it real good.

Very common.

 

Hey smartass be helpful or go someplace else. Nerdbynight is at least trying and trouble shooting better then most others I have seen come on and ask for help.-Weeks

 

If you're going to keep it and work on it yourself you need to invest in a decent set of sockets and the wrench to go with them. You can get away with Harbor Freight sockets and cheapo box-ends, but at least get a Craftsman ratchet. A crescent wrench is not going to cut it, you'll round off bolt heads and give yourself all kinds of headaches. Maybe you can hit a used set somewhere to save a few bucks, Craftsman hand tools have (had?) a lifetime warranty so if you buy a set and something's bad just take it in and exchange it.

Just out of curiousity, it runs smooth unless you pull plug wires? I had an old Pontiac that leaked oil and if I didn't pay attention, when it got too low the lifters just wouldn't fill and it would run rough and miss a cylinder or two. The answer was to add oil. You have about 5 quarts in it?

And.. it's not a Fram oil filter is it? (search for Fram oil filters here and you'll have nightmares from the horror stories). Is the oil pressure gauge hooked up and functional? Does it read normal?

Given that it started after changing the oil, an early oil change wouldn't hurt regardless.

I like to pour some oil in the new filter when I put it on, incidentally, just to prevent any possible low oil pressure or air pockets after a change. I never thought to ask if it's a good idea or not, maybe if I mention it here I can find out.

 

Nothing to do with female, engine noises are not easy and to start out with the least expensive / time consuming trouble shooting. If it was on a hoist (safety) you might be better able to tell where the sound is coming from, valley area (lifters) at the rear-most cylinders could sound like it's coming from torque converter area. Listening from top side to under chassis could help pinpoint.

Best of luck.

 

Good morning, Nerdbynight...it's 7:30 A.M. here in Michigan. Sounds like Fuzzy Knight, kickstarts, wallace, and skunx1964 are on the right track with a correct diagnosis. Remember that the valve-train moves at 1/2 the speed of the crank. Judging from your video, (which was an excellant idea, by the way) and my "trained ear"....here boy, that's a good ear...HA!.....................the noise is at a slower speed than the crankshaft, indicating valve-train noise. Or a fuel pump with too much play. (but that wouldn't go away when you rev it) Also, a "knock" usually indicates rod-bearings or a rist pin, and a "tick" would point to valve-train. Sounds like a lifter. Almost any other problem with the valve-train would make it run bad...broke valve-spring or rocker...bent push-rod, etc. If it is a lifter, the engine may run for a long time just as it is, but replacing lifters is not a big deal. Pull the valve cover and take a look for excessive play. Or first, take a big screw-driver and press the handle near or on your ear, while moving the other end up and down the valve-cover...you may find exactly where the noise is coming from. I'm not discounting what others have said, but I'd do at least that before going to the trouble of getting under the car and unhooking stuff. Do your best to pin-point the source of the noise before disassembling anything. Take Weeks46 up on his offer to help...you're gonna make a new friend...way to go Weeks. One other thing...check your oil pressure as a precausion. Sometimes, valve-train noise can indicate low oil-pressure...or low oil! The valve-train seems to always be affected first. Good luck. Rick