Very bad sound in engine...

[bamfordsgarage]

Hello all, my D25 engine developed an alarming sound this morning, all of a sudden and for no apparent reason. I've done some further investigation and would appreciate the comments of Forum members about this dang racket.

Brief clip at: http://img576.imageshack.us/i/xsma.mp4/ or maybe http://img576.imageshack.us/img576/9189/xsma.mp4

Shortly after pulling out of a parking lot only 7.2 miles after a long road trip, all of a sudden there was a loud clattering from under the hood. I pulled over onto a side street and had the car towed home. Between my initial investigation at the roadside and since the car came home, I have run it about 5 minutes total, never at high speed.

The sound is a sharp metal-on-metal one, much like rapping the head with a ball peen hammer.

The sound does not change when individual plug wires are removed. This would seem to rule out rods (and pins?).

The sound is present at idle, speed-up and slow-down. I have not put a load to it to see if there is any change.

I forgot to check oil pressure when this first happened. Later when the engine was started cold it seemed to have normal oil pressure, but I never ran it long enough to get a reading at operating temperature.

The idle drops (missing) when #1, 3, 4, 5, or 6 plug wires are removed. Hard to tell about #2... some times it seems to make a difference, some times not.

Dry compression is 1-68, 2-45, 3-10, 4-72, 5-68, 6-66; Wet is 2-50, 3-40. I didn't check wet 1, 4, 5, 6.

The stethoscope sounds loudest when over the #2 piston.

My brother in law who is an accomplished shade-tree mechanic said the clip sounds like a stuck valve. And to my untrained ear, it does sound like it could be.

Based on the stethoscope and the remove-each-wire test, it sounds like a #2 valve is stuck. But, that does not explain the compression test readings for #3.

The compression test indicates that #3 has piston/ring problems, but that does not explain how removing the #3 wire will not cause the idle speed to drop. I must re-check tomorrow to see if this is actually true.

Anyway, I'm kind of perplexed, but relieved that this is apparently not a bearing problem.

Correcting this problem is #4 on my project list. I hope to get the problem identified without having to do any disassembly — don't want to have it sitting around apart for two months, but would like to know what's what in order to think and learn ahead about the repair.

And if it is a stuck valve, why all of a sudden, after the many millions of cycles these valves completed successfully in the last two weeks?

Whaddaya all figure?

Edited April 25, 2011 by bamfordsgarage
more info

[greg g]

I could ot get your file to open, don't know if the trouble is here or with your host. I got to the Imageshack page but no further.

What is your oil pressure? Low oil pressure usually indicated a bad bearing. In my experience sticky valves do not make a sound, but they are usually accompanied by a missfire or back fire through the carb if its an intake valve. Could it be a wrist pin coming loose? The compression readings seem very low, even wet.

Guess you could pull the head for a look at the top side, and or drop the oil pan for an inspection of the bearings.

Edited April 25, 2011 by greg g

[1940plymouth]

Chris,

I am by no means a mechanic, but the compression does seem low and the noise you are describing sounds like the problem I had last Spring with my engine, I ended up having a wrist pin that was cracked. We dropped the oil pan and low and behold you could see the cracks. Once we pulled the head to remove the piston, connnecting rod and such, the cracks were real noticable. In fact when we removed the wrist pin from the piston, the collar of the piston even was cracked and broke as we removed the wrist pin.

Just my thoughts on the matter,

Bob

[Young Ed]

I would think it very unlikely a valve would stick on a good running engine. Only way I've heard of that is a chunk of carbon breaking off and jamming up the valve. Just to double check put the stethoscope down by the fuel pump. We've heard of a few guys with those making noises.

[Don Coatney]

I could not open your sound clips. From your description here is my best guess of what you will find.

[190bearplace]

If you spin a rod bearing both halves can end up on the top side of the crank. This let's the piston hit the head. Shorting a plug will not change the noise. I think you will find a piston or bearing issue.

[Plymouthy Adams]

Chris, going back to when we started this car after 2 months of just sitting and the extreme amount of low end knocking of the mains I think we have a dual problem. First is Coatneys piston picture..explains the low comprression and the noise..but the other suggestion of the spining bearing..I think that could be the cause of the breaking piston..I am not convinced the bearing if doubled would lend the piston to hit the cylinder head but I am convinced it would easily push the piston past the step in the upper cylinder due to normal cylinder wear thereby a broken piston could be the result of the spun bearing.

Edited April 25, 2011 by Tim Adams

[Jim Saraceno]

I could not access the clips you posted on imageshack either. Maybe you could post it on Youtube.

Maybe this will help...

[TodFitch]

Also near the #2 cylinder is where the fuel pump lever rides on the cam. If one of the springs in the fuel pump broke then the arm won't ride the cam and it will make some noise.

Which brings up the question: Does the noise sound like it is at crankshaft speed or camshaft speed? Might also have a bearing on if it's a stuck valve as that would also be at camshaft speed.

[bamfordsgarage]

Thanks all for the comments thus far.

I cannot get the sound file links to work either, but don't have a YouTube account to post there. Could I e-mail the file to someone with a YT account and they could post it for all to hear?

As near as I can tell (engine is starting cold now) the oil pressure is normal for this engine, which has always been on the low side. Highway oil pressure when hot was just under 40 on the gauge, dropping to near zero at idle. Cold start-up pressure was typically just over 40, and that looks to be unchanged.

Not sure if the noise is at cam or crank speed, but I would guess it is valve speed. It does not backfire through the carb, so that would appear to rule out an intake valve.

We had a possibly-related experience coming home from Lethbridge on Saturday: slowed down near-panic braking to make a turn at the last minute, and a quarter mile down the road got a sharp ticking sound from the engine (but not near as loud as this one). Not audible at idle, but louder with revs and loud when backing off the gas. (Tim, this is what I tried to call you on that day). Limped in to the nearest town on very low revs, tried to sort it out there, thought it had improved slightly, decided to make for home at 20 mph (250 miles!) and found we could gradually increase our speeds before hearing the noise. It came back worse a couple times, and one time the vacuum gauge buzzed violently for a second or two. Thirty miles later the problem was gone and we were able to resume highway speeds.

We had called a car club friend of RobertKB on the cell for ideas, and he speculated it might just be a chunk of carbon come loose in the cylinder. That could conceivably follow from a panic stop... oil piling up at the front of the engine, loading up a front cylinder through worn rings, all that oil loosening up carbon in the cylinder (Jerry remembers his dad pouring ATF down the carb to loosen carbon) and the carbon clearing itself over time. The vacuum gauge buzz could be a little chunk temporarily lodged in an intake seat.

Makes me wonder if this problem just might be back again but worse. I would want to eliminate this problem before tearing into the engine, if only for diagnostics. Hopefully, someone here can post my clip and maybe that will help.

[Plymouthy Adams]

a top end inspection would be quick easy and realtively inexpensive by removing the head only...if carbon..you will see a heavily coked compression area and thus be able to clean it proper..if anything esle say valve, valve seat that may have come loose, busted upper piston lands or a say a piston that is higher/lower in the cylinder at TDC compared to the others could indicate turned bearing etc etc hopefully a good visual could detect this type of problem..

given the number of miles you put on this engine and being a bit tired to start with..oil consumption as high as you stated..it is hard to say how much of a build up you have in the cylinders...when you did the compression test, did you read the plugs, any indicators there?

Edited April 25, 2011 by Tim Adams

[55 Fargo]

Chris, how big is avi file, if less than 4 or 5 mb send it to me, I will upload it to You Tube.

Or if you are using a Windows system, go to programs, select and open windows movie maker, import your video, then save and select for email on left hand side menu.

PM me if you want me to upload it for you, but the file needs to be less than 5 MB for me to handle from my email end.

[bamfordsgarage]

Thanks Rockwood, the file has been sent.

Tim, the plugs looked pretty even, nothing stood out about #2 or #3 (or the others, really).

Disassembly for diagnosis obviously makes sense, but I just do not want to start taking things apart until I am ready to work on the car. I have three projects that ought to come first. Also I would want to round up a replacement head gasket before pulling the head so if things are otherwise OK in there I can get it back together pronto.

Looking ahead, Rockwood and the other Canadians here, who have you found to be decent vendors of parts for the Canadian engines?

[55 Fargo]

Lets try this Chris

[TodFitch]

Based on your most recent post about the symptoms, I think I'd put my money on Don C's post. When I had that happen to me decades ago the initial sounds were at camshaft speed, I guess because it was only making noise on the power stroke.

[T120]

Hi Chris,What is your vacuum gauge reading at idle?

[40phil41]

Lets try this Chris

Works O.K. for me Fred. I'll let those more in the know do the diagnosis

Phil

[Dodgeb4ya]

Kinda sounds like a ring/ring land let go and is on top of the piston banging against the head-sounds too fast for a valve train noise.

[RobertKB]

Chris, I have had good luck getting parts from this fellow in Coquitlam. Phone him and ask for Ron.

His prices are good and shipping is reasonable. I know there are other good suppliers as well.

Rovon Auto Parts

640 - Porter Street

Coquitlam, BC V3J 5A7

Canada

Phone (604)936-9312

Fax (604)936-4997

Collector Auto Supply is very good also and in the Okanagan area. http://www.collectorsautosupply.com/

[bamfordsgarage]

Hi Ralph, the idle vacuum is 13-14 psi. We are at 2,200'.

Thanks for the tips Robert. I'll give them a try.

[Don Coatney]

Having heard the sound clip it re-inforces my original thought.

7-8 years ago I was sitting at a stop light two miles from home and my original engine started ticking same as yours is doing. On the drive home the ticking subsided as the broken ring and piston were digested by the valves. If you had a spun bearing your oil pressure would be zero at all times.

On another note I find it interesting that you did not carry a head gasket with you on the road. I carry one with me tucked under a blanket on my rear window package shelf. You can pull the head in a half hour or less.

[bri12905]

I think far too much unnecessary and basically unfocused speculation has gone into this problem. Just look at what's stated:

- Very low compression indicates very badly worn cylinders/rings/pistons and/or valves and a very unhealthy top end. Unlikely to be valves, because serious missing is not reported;

- Almost non-existent oil pressure at hot idle - indicates a very unhealthy bottom end. This engine is past its sell-by date and is due for a complete rebuild.

When I worked as a mechanic in a Chryco dealership in Calgary when these engines were in their heyday we initiaslly diagnosed engine condition by checking oil pressure at hot idle. If it was down as low as 20 -25 psi, we would refuse to do any engine work - especially valve grind or re-ring without a complete teardown. Wth compression as low as shown we would have insisted on a teardown before any work or take it away as is.

Sorry to appear negative, but this is reality.

[P-12 Tommy]

It doesn't sound like bearings to me. I'd pull the head if it were me. Like Don said, it would only take a half hour or so to pull it. Or maybe a broken valve spring or keeper came off?

Tom

Edited April 25, 2011 by P-12 Tommy

[55 Fargo]

I think far too much unnecessary and basically unfocused speculation has gone into this problem. Just look at what's stated:

- Very low compression indicates very badly worn cylinders/rings/pistons and/or valves and a very unhealthy top end. Unlikely to be valves, because serious missing is not reported;

- Almost non-existent oil pressure at hot idle - indicates a very unhealthy bottom end. This engine is past its sell-by date and is due for a complete rebuild.

When I worked as a mechanic in a Chryco dealership in Calgary when these engines were in their heyday we initiaslly diagnosed engine condition by checking oil pressure at hot idle. If it was down as low as 20 -25 psi, we would refuse to do any engine work - especially valve grind or re-ring without a complete teardown. Wth compression as low as shown we would have insisted on a teardown before any work or take it away as is.

Sorry to appear negative, but this is reality.

This of course is sound advice you have given, but I know lots of the Guys have engines that have oil pressure when hot at idle speed in the 20-25 psi range, and all without any real consequential effects.

My engine runs 50-55 psi on highway, especially with oil not too hot, on hot days, oil pressure will drop to maybe 30 psi, at idle.

I would expect as you worked at a Chrysler dealership, selling the complete job, as in total rebuild, would have been the company bottom line of the time.

Others have had engine problems, where they completely rebuilt engines, some have just done a patching up, like 40Plymouth did with His engine, all keep running, as long as there not pushed too hard.

[Plymouthy Adams]

selling the total job was not for the benefit of the mechanic and dollars in his pocket for the job..the known fact that in a tired engine that may have worn mains and tired valves that the increasing of the upper cylinder pressure will play havoc on the lower end if left untouched..so to avoid accusations from a customer on a less than proper engine repair...they were better served leaving the engine status quo