What is this noise?

[v8power]

Re: What is this noise?

warning signs! maybe, but mine was fine when i shut it down and started missing and ticking the next time i started it.

As for running it longer to see if it goes away is not a good idea, a dry lifter, like i said will only take a few seconds to pump up. the video was long enough to do that.

If there was water in the cylinders when you fired it up and it did bend a rod, running it will only damage it further.I f the rod is bent it could cause the piston to hit the head or damage the cylinder wall.

Pistons not true to the bore will do lots of damage.

 

[v8power]

Re: What is this noise?

I just thought of something.

look at the harmonic balancer, i dont know if they were used on boats but some cars have balancers that are steel in the center with a rubber ring around them with the belt pulley around the rubber. Ive heard them when the rubber tears, they sound like rods nocking. Take the belt off and try to turn the balancer by hand, if the outer grooved belt ring turns but not the center then it is broken.

 

[FreeBeeTony]

Re: What is this noise?

When I was a kid I had a '75 Monte Carlo (loved that car!).....anyway, 1 morning I started it up and had the same noise.....thought I had a spun bearing, actually lifted the engine, removed the pan and replaced the bearings while the engine was still in the car.....I was much younger then. After all was put back together I started it and still had the same noise!!!

Someone told me it might be a stuck lifter.....I removed the valve covers and poured Marvel Mystery Oil down the push rods and let it soak overnight, next day I started it and the noise was lessened and after it ran for a while the noise was gone......

Not sure if this is the same problem but it brought back some memories.

Good luck.

 

[fishinpa]

Re: What is this noise?

From the sound of the video it surely sounds as though you have a valve train problem!

dragging a cylinder or two wont idle and making it run ruff along with the accompanying clatter.

if you can run it with the valve covers of it is easy enough to tell by ear and using your hand on the rockers ,to tell if any are too tight or too loose.



Hard for anyone to tell without seeing and testing it hands on ! to be 100% sure what all has been or is being damaged.


You may not find a loose pushrod ,it sounds as though something is Very tight..

fish

 

[kwoolard]

Re: What is this noise?

Here is my plan:

1) Take the port valve cover off and do a visual inspection

2) If everything looks ok, crank the engine over with the starter (ignition grounded) and see if i can locate the clatter in the valve train

I would like to run the engine as you state to see if I can locate the noise that way, but with the heat exchanger and cooling hoses off, how long can i run the motor and not burn up the exhaust flappers for rubber boots? How messy (oily) is this going to be? Do I need to get some of those clip on oil shields?

3) If that test shows a stuck lifter or valve, i'll spary some MMO on the valve train parts and let it soak overnight and run the test again.

4) If nothing noticeable, pull the exhaust manifolds and spark plugs and run a compression test. This would possibly tell me if I have a bent rod, correct?

5) If compression is good and valve train has been ruled out, then it could possibly be rod bearing or main bearing.

Another thing i've thought of, is if i can possibly run this motor and the noise is still there and it is not valve train related, couldn't i pull one plug wire at a time to isolate the cylinder making the noise? If the noise goes away when the plug wire is pulled, wouldn't that indicate a rod bearing?

Any comments on this plan?

 

[fishinpa]

Re: What is this noise?

You need manifolds and water to engine to run it !

not too messy if you dont Rev the engine...
Which you Must not do in your current state , idle only and would not run it longer than it takes to find the noise !
Very short run time !


your noise is most likely going to be apparent whether or not your plug wires are on or off..



and yes a compression test should always be the first thing when having mechanical problem !

compression test before anything can ( may) isolate which cyliinder your problem is in without actually running the engine and worry of further damage.


fish

 

[kwoolard]

Re: What is this noise?

Got the port valve cover off and again didn't notice anything unusual. All rockers are tight, valves and pushrods are all working, at least normal to me anyway.

I bumped the engine multiple times to check each valve, lifter and rocker and everything seems fine in the valvetrain.

I cranked the engine over multiple times and could not reproduce the engine noise at cranking speed. I did however notice something that I'm not sure if I've noticed in the past or if my ear is just paying attention a lot more. But it seems like when cranking the engine over the starter changes tones as if it is cranking a dead or low compression cylinder.

See video below:

Engine Cranking

I'll be running a compression test next, weather permitting.

What do you guys think? If it was valvetrain related shouldn't it show up when cranking?

What are your opinions on the cranking hesitation / tone change?

You'll also notice at the end of the video that when trying to crank it over again I just get clicking in the relay. The starter was rebuilt just last year, so I guess it is probably the solenoid/relay mounted on the manifold.

Thanks!

 

[victorc1]

Re: What is this noise?

That doesn't sound good at all, did you check to see if there is water in the oil pan? What year is the motor, could be the bearings.

 

[v8power]

Re: What is this noise?

well, im outta ideas for now. I will post again if I can think of anything else.

 

[Grumman59]

Re: What is this noise?

Oil pressure was at 40 psi.

Well, that's encouraging. I can't imagine it would be a rod bearing in that case. I mean for a rod bearing to make that much noise, I'd expect to see a marked reduction of oil pressure.

But I agree about the dead sounding cylinder upon cranking. Maybe a broken or cracked piston. At least, if it's that, the crank will likely still be OK. Anyway, a compression test will reveal a damaged piston.

 

[Cptkid570]

Re: What is this noise?

Maybe you are getting your starter issues from your battery dying out? Charge your battery up real good. I'm sure it's taken a beating from all the cranking witout a charge.

 

[FreeBeeTony]

Re: What is this noise?

Might want to try cranking it w/o the plugs installed after the battery is charged.......will spin faster and you might hear something different......just a thought.

 

[fishinpa]

Re: What is this noise?

Would be very interested in Compression test on all cylinders

The cylinder or cylinders with the low readings should reveal info for your next steps in correcting your problem.

It appears a lifter or lifters are not bleeding off ( remaining too tight) keeping the valve or valves open.
dirt or other foreign matter in lifter , or a lifter mechanical malfunction.

Too tight making knocking type noise /

Loose lifters or rockers will Clatter, not make the knocking type noise you are experiencing, more of a clicking type sound.

backfire from carb can also indicate and verify valve timing incorrect, if lifters are not bleeding off they are changining the valve timing hence making the rough idle and the symptoms of hard starting and making the god awful noise !


fish

 

[kwoolard]

Re: What is this noise?

The battery was 100% charged the night before and it is a fairly new battery. I was experiencing the starter hesitation with both batteries that I tried.

Fish, I'm still a little confused as to how too tight of a valve or a lifter not bleeding off would create this loud knocking noise. It seems that if it is too tight there would be no clearances anywhere in that part of the valvetrain mechanism to create a noise. I guess if you could explain that a little more in detail I may gain a better understanding.

One other thought I had was that a valve is stuck open with say a piece of carbon betwen the seat and the valve and the noise is coming from the rocker tapping the top of the valve stem. I don't know, just grasping at straws right now.

A compression is definitely on order, hopefully I can get that done before the weekend.

 

[fossill]

Re: What is this noise?

Valve train/ lifter noise I would say from previous experience.
Starting up an engine and letting it idle every week is not good for it. Drain a liter of oil off and put in a liter of Dexron III ATF and let it run for a while. ATF is very high detergent and should help clean a sticky lifter due varnish or the like.

 

[kwoolard]

Re: What is this noise?

Someone else has told me that running it every week or every other week on the muffs is not good as well. Although I keep it running at 1500 rpms for at least 30 minutes. I will do a compression test, and if everything is good there, I guess i'll button it back up and run some ATF through it to see if it clears it up.

Are you sure running it like that until it clears up will not hurt anything?

Is everybody ruling out a rod bearing? One mechanic told me that a rod bearing wouldn't spin or break like that on an initial start up and that is was also more than likely in the valve train.

Seems like if it was a rod bearing I would hear it knocking while cranking.

 

[lowkee]

Re: What is this noise?

I'm looking forward to seeing the compression test as well. I also agree on removing the plugs. The hard-working starer sounds will overpower most engine issues. removing the plugs will make it both spin faster and spin way quieter. Once the plugs are out, I would also spin it by hand (grab the belt and yank), as your hand will detect even slight binding where your ear may not.

 

[fishinpa]

Re: What is this noise?

A rod bearing has its own unique sound!
granted we are working on this engine from hundreds of miles away and using video and sound from the same to determine likely issues, the video is decent and the sound from the video is pretty clear.

A vave (stuck open ) from carbon would leave that rocker arem and pushrod excessively loose creating a loud clatter ,like when adjusting valves engine running and you back off the retaining nut !

IF the lifters are not bleeding off you are running those cylnders like a Solid lifter setup only tighter, there is no cushion on the affected portion of the valve train !

with no cushion you are applying to much pressure on the lifter,rocker arm,camshaft lobe ,valve tip and pushrod.
with pressure and rotation at speed the output becomes an evident hamering type sound.

hydraulic lifters rely on the spring the small bleed holes and the oil to cushion the force applied to the valve train.

It has been my experience that when you have this particular sound coming from your engine that the above malfunction is usually the problem or at least part of it.

generally in this situation too much speed applied to the engine and it will/ bend pushrods , drop a valve or valves,break valve springs etc.


fish

 

[fishinpa]

Re: What is this noise?

Someone else has told me that running it every week or every other week on the muffs is not good as well. Although I keep it running at 1500 rpms for at least 30 minutes. I will do a compression test, and if everything is good there, I guess i'll button it back up and run some ATF through it to see if it clears it up.

Are you sure running it like that until it clears up will not hurt anything?

Is everybody ruling out a rod bearing? One mechanic told me that a rod bearing wouldn't spin or break like that on an initial start up and that is was also more than likely in the valve train.

Seems like if it was a rod bearing I would hear it knocking while cranking.

-----------------------------------------------------------------------------------------------This is most likely not just going too clear up, unless you are Very Lucky !

Yes running it like this for a prolonged period will surely cause more damage than you want!

Most of this you are not going to be able to determine by simply turning the engine over or by cranking with the plugs out.

these types of problems are heard at rotating engine speed /ie: engine running.


fish

 

[fishinpa]

Re: What is this noise?

http://www.youtube.com/watch?v=zkPqrNblYks&feature=related

Just a decent lil bit of how your lifters should work without writing a book on it ! lol




fish.