Engine Noise Knocking - need help diagnosing - Valves??

solracem · July 19, 2016, 10:29 AM

Hey Everyone - so, I've ran into another headache with my project and would like your opinion in diagnosing the noise. Please take 15 seconds to watch the video link below and let me know your thoughts.

https://www.youtube.com/watch?v=VXbnyA1w78k&feature=youtu.be

This is an 1989 Fleetwood Bounder class A RV on a Chevy p30 chassis with a carbureted quadrajet 454 7.4L BBL Engine

My thoughts are that I need a valve job. What do you guys think??

kenwautoone · July 19, 2016, 10:43 AM

First things first: STOP driving it.That sounds way more like very expensive engine noise.im sure you made sure there is oil in it.Does it have oil pressure? I would remove oil filter and cut it open to see what else is in there besides oil.submit pictures here.lot of knowledge on this site.... Ken

Surfinhurf · July 19, 2016, 10:52 AM

Doesn't sound good, Sounds like a rod bearing. Drain the oil and look for shinny flakes, then take the pan off and check rod bearings. If you drive too far you will take out your crank.

Good Luck
Hurf

legomybago · July 19, 2016, 11:00 AM

Ouch! Run her till she blows!!! Just kidding.....Valves tick, that's not a tick. That is a solid sound....Hopefully it's just a cat caught in the fan W%

Rickf1985 · July 19, 2016, 01:21 PM

Noises over the computer through you tube are very hard to place. It sounds like a main bearing but could also sound like a blown out muffler. As was asked, did you check the oil and does it have oil pressure? Is a muffler blown out? Does the noise get louder under acceleration and does the knocking get faster with faster engine speed and slow down to a slow knock at idle? Can you make a video from outside at idle walking around the front to the side?
It does not sound good but I want to make sure it is engine and not exhaust. Exhaust is not going to cost you thousands of dollars.

I am thinking if that is a rod or main then by the time you read this it will have let go if you kept driving.

Froggy1936 · July 19, 2016, 04:50 PM

!-!Shut it off From all the noises I have experienced, That is a Rod bearing noise And if it breaks you will have major damage , Though the crank may already be unsaveable without a regrind Frank Sorry

Rickf1985 · July 20, 2016, 06:34 PM

I am still waiting to hear back, I am not convinced that was a rod. It was not consistent. It was single, double, single, rattle, double. Just like a blown muffler. Just too hard to tell in a you tube video. And it seemed too loud, more like from outside than under the engine cover.

lemortede · July 21, 2016, 11:10 AM

I am of the same thought as you. My first thought was a rod, but the more I listened the more I started wondering about a really bad exhaust leak.

solracem · July 21, 2016, 12:13 PM

Hey everyone thanks for taking the time to help me.

I still don't know what the problem is. I did change the oil to 15/40 with lucas stop leak in it. When I drained the existing oil I put a magnet inside the pan but there weren't any metal shavings on it. A buddy is suggesting buying a crate engine. I'm just not too sure what to do. Do you know of any way I can diagnose if it's a blown muffler?

The engine does start up. I had to get it back to the storage place yesterday. I drove it slow and got it there. I'm getting a lot of smoke out of one muffler. The noise did occur but it's not constant. Only if I'm accelerating and even then only sometimes.

I figured if it were a rod or bearing it would have seized up and not started again. Any suggestions?

If I were to buy a crate engine, any suggestions on where to buy it from or not to buy it from?

normthenomad · July 21, 2016, 02:23 PM

Do you have oil pressure? To determine lower end [ crank/rod ] problem remove dog house start the engine and put it in gear, apply a little throttle to it while applying the brake. If it makes a low frequency knock it's the crank/rod bearing. Make sure you have oil pressure when you start it if not shut immediately. I suspect a sticking valve is the problem since you're not finding metal in the oil.

Rickf1985 · July 21, 2016, 03:55 PM

As I posted in the PM to you it would help to have a video of it idling from the outside. The smoke could indicate a holed piston from a dropped valve. Is it missing on any cylinders? The muffler check, just climb under and look at the mufflers, if it is blown out you will see it.

W%

Is your "Buddy" going to pay for the crate engine and swap it for you? More accurate diagnosis is needed first.

And I and several others have all asked about oil pressure, DOES IT HAVE OIL PRESSURE?

?

solracem · July 21, 2016, 09:01 PM

Hey everyone - so, it looks like the oil pressure is good. I tried to get the gauges in the video below as well.

You'll notice the smoke only comes from one side. Also, I rev the engine a couple of times but, no knocking noise. It only seems to happen when I'm actually driving.

As for the buddy with the crate engine idea - he thinks since I bought the RV from someone who let it sit for 6 years and only started it once every month or so but, never actually drove it that since they sit, the oil pressure drops and creates metal on metal contact while the oil pressure builds again. He thinks this probably wore the engine out and thinks we'd be throwing a lot of money at it chasing problems. In the long run he feels I'd be better off just doing the crate engine now. And, yes, he'll help me install it but, of course all of this costs money.

So, long story short, I rely on this thread and the advice that all of you give me and then show him so that I can make a more informed decision.

I appreciate everyone's advice and help on this. It's definitely been a challenge but, your input has made this much more understandable and easier for me.

https://www.youtube.com/watch?v=o_-yXr8lFys

Rickf1985 · July 23, 2016, 12:13 PM

Ok, Your buddy needs a little education on how engines work, oil pressure drops at idle and goes up with RPM. Sitting makes no difference. I have run engines that have sat for 50 years with not a problem. In your case you have a problem but I am not sure it is all that serious yet. You need to take the passenger side valve cover off. It sounds like you have bent or broken a push rod or rocker arm. The chirping sound is a little disconcerting but you have oil pressure, ( I could not really see it but will take your word for it). You do have a miss on the right side and if it lost a rocker arm it could be pulling oil past a worn valve seal into a dead cylinder hence the smoke. You do have an exhaust leak also, sounds like more than one. The loud knocking sound may have been the push rod hitting the valve cover, you may even have dents in the cover over the one that went. But pull that passenger cover and lets see what you have. Look at it this way, if the engine has to come out this stuff all has to be done anyway. If you have the relay mounted over and behind the alternator be sure to disconnect the batteries before starting this job. A stray wrench hitting a terminal will make things real exiting.

legomybago · July 25, 2016, 10:13 AM

Definitely some exhaust issues going on there....You need to get under the rig and use a stethoscope or a wooden broom handle, hold it to your ear and start listening to different areas of the motor. You'll find that sound somewhere more prominent on the engine, and it will give you idea where to start looking. You mentioned that it doesn't make the REALLY bad knocking sound until you put it in gear? Check the torque converter bolts!! There is no way to diagnose what you have going on over a youtube video.

tmsnyder · July 26, 2016, 07:59 AM

It sounds like something banging on something, or an exhaust leak. It's definitely something stupid, crawl all over that engine and look. Is it an AIR pump going bad? You could take the belts off one by one and see if the noise goes away and narrow it down one by one.

Your friend is wrong, I've started up a chevy v8 that sat for 25 years with no problems.

tmsnyder · July 26, 2016, 08:00 AM

you can also find exhaust leaks by feeling around the connections and pipes carefully, you'll feel them puffing at your fingers.

tmsnyder · July 26, 2016, 08:05 AM

Listening to the last video, pull the belts and start the engine. If the noise is gone then it's one of the belt driven things on the front of the motor.

FN Duck · July 26, 2016, 06:45 PM

Sounds a tad tinny ... â˜º..You might want to check your torgue converter. Easy enough to do .... Visual, check bolts and flex plate . Torque converters will swell up due to pressure and may distort from excess .....

solracem · August 01, 2016, 10:58 AM

Well everyone, looks like I found some problems... Did a compression test and everything read fine except for one cylinder. Can you guess which one??

Here's what I've found so far.. So, question is.. Should I have it rebuilt or buy a crate?

kenwautoone · August 01, 2016, 12:04 PM

This is one of those crossroads of live! No matter which path you go down,it s going to be very expensive.you really have decide how much you like this RV.no matter what you ,you never recoup that dollar amount,but if you love it...... well ....good luck.....Ken

tmsnyder · August 01, 2016, 12:08 PM

What did you end up finding? Looks like a bent push rod, did a valve stick?

solracem · August 01, 2016, 12:17 PM

Hey Ken - I took on this project not really knowing what to expect. However, now, I'm committed. I've replaced appliances, sealed the roof, replaced pretty much the entire fuel system, got the generator going, added several extras, and a have a ton of hours in research/labor. I'm already at a loss. And, I won't find one in as good of shape as this one for the cost of a rebuild or a crate. So, might as well keep it going...

Not the smartest financial decision but, once it's finished I'll know it's reliable and will feel accomplished rather than defeated.... For whatever that's worth i??

solracem · August 01, 2016, 12:23 PM

Quote from: tmsnyder on August 01, 2016, 12:08 PM
What did you end up finding? Looks like a bent push rod, did a valve stick?

Yep, bent push rod, found the lifter floating around in there, and the the rocker arms were loose.

Rickf1985 · August 01, 2016, 12:25 PM

Ok, So you found exactly what I thought you would find, The lifter does not look bad from that picture. What does the base of the lifter look like? Is it dished or worn through? Rocker arm broken? If lifter is good and rocker arm is good buy one pushrod for a few bucks and put it back together and start it up. Put the box end of a big wrench over the rocker arm and see if the valve will operate, if it goes a bit and stops make sure the piston is down on that cylinder. As long as that valve goes down alright then I say put a pushrod in it and fire it up. The smoke should go away as it burns the oil out of the cylinder.

The lifter floating around is not good since you would have taken a BIG hit on the oil pressure but try it and see what you have. A LOT cheaper than a crate engine.

Why did you take the carb off?

tmsnyder · August 01, 2016, 12:29 PM

Is valve stuck, or can you press on it (with a lever) and move it?

You pulled the intake manifold to get the lifter out? Anything wrong with the lifter?

I think you're going to get off cheap here, if the valve is free just replace the push rod. If it's not, you'll have to pull the head and see what's going on with that.

The push rod is missing a round tip, where did that end up, in the oil pan? Put a magnet on the drain plug and see if you can recover that after you put it all back together.