Big problems. Knocking sound. Any ideas?

[BuffaloGuy]

I pulled a heavy load a few weeks ago and the motor developed a ticking sound. In a matter of a few hundred miles it progressed to a very load knocking sound.

I took it into the dealer (about the only fair to good diesel machanic around) and he said it he thought it was bad injectors.

He removed all four on the drivers side, had them tested and found one very bad and two not so good.

We put eight new ones in.

The sound is still there. No change.

The dealer says that I must have got it hot and they think that a piston has shrunk and is slopping around in the cylinder!?

There is zero blow by. They say that can happen as the rings will still seal even though the piston is moving around.

I DID NOT get it hot. Other than the stock h20 gauge I have a EGT and an Intake temp gauge and all three were within range on the whole trip.

I am having a hard time believing this.

When you listen (with a screwdiver to the ear) to the head or the block it's generally quiet. When you listen to the exhaust manifold at #1 and mostly #3 you can hear the noise. The other spots on the manifold are normal.

I'm guessing that I have a bad valve or two. I am going to do a little more diagnostics and make a few phone calls. Any ideas anyone???

This is going to be expensive and I can't make any missteps.

One other item. I was using my water injection set-up with washer fluid (20% methanol). I am fairly convinced that this has something to do with the problem.

I pulled much heavier and harder loads this summer using only water and had no problems. This is the first trip with the washer fluid. When using the washer fliud I can easily tell the difference in power and sound.

Perhaps I bent an exhaust valve?

Ken

[Billman]

Ken

I don't have any answers for you.

Judging from the dealers reply (Shrunk Piston), neither does he...

Best of luck.

[Hye]

When in doubt, I change the oil and filter while trying to figgger it out. Can't hurt, might help free something that's stuck.
Ditto on the luck part.

[Spindrift]

Originally posted by The Buffalo Guy:
One other item. I was using my water injection set-up with washer fluid (20% methanol). I am fairly convinced that this has something to do with the problem.

I pulled much heavier and harder loads this summer using only water and had no problems. This is the first trip with the washer fluid. When using the washer fliud I can easily tell the difference in power and sound.

Perhaps I bent an exhaust valve?

Ken Ken,

What do you mean when you say you could easily tell the difference in sound? I routinely use an 80/20 water-meth mix, sometimes even 70/30...no problem. Once I mistakenly pushed it up to 60/40. WOW! The truck jumped right out of my lap, but I also heard "pre-ignition" that made my knees wobble. Been there, done that, not goin' back.

[BuffaloGuy]

The difference between water and Wal-mart washer fliud can be heard as a little more diesel rattle. Nothing alarming. The power difference is pretty noticable too but not like you described.

The Wal-mart washer fluid says "protection to -20". Bull pucky. I put a jug in my freezer and it frozen hard as a rock at zero.

With this in mind the methanol must only be a 15% ratio.

Have you pulled hard with the Methanol? Like all day with continous injection?

[Spindrift]

Ken,

With the kids and the dogs the furthest I can pull in any one day is 400-450 miles. The trip to WDW is the exception. Anything longer than that and it's time for the kevlar bandana (if you know what I mean). I really don't think the water/meth was your problem, especially if you weren't hearing any pre-ignition. Maybe the wrist pins? But then you'd have bigger problems for sure. On our trips, the WMI system is energized all the time. As you know, that doesn't mean I'm injecting 100% of the time.

FWIW, I'd stay away from windshield washer fluid. There is a small amount of glycol in the fluid (1-2%), which acts as a detergent. Normally, its presence doesn't pose a problem until you allow the fluid to sit in your tank for a while. The methanol will evaporate and you're left with the concentrated glycol - it's sticky and will clog your injection equipment.

The following site should give you a good yardstick in order to evaluate the FP of your water/meth mix:

http://www.methanol.org/pdfFrame.cfm?pdf=FreezingPointsMethanol-WaterSolutions.pdf

[Billman]

Ken

When you overheat an engine that bad, pistons have the tendancy to expand not shrink. If they became out of round, they would scuff the cylinder walls. You might even see piston in your oil pan.

You would probably need to be in the 1500-1600* EGT range though for extended time.

I'm curious to your theory on how your WMI may have had something to do with this...

What makes you think you bent an exhaust valve?

[BuffaloGuy]

Been doing a little more diagnostics. I pulled the belt and ran it. Same sound. I guess that rules out the harmonic balancer.

If I crack the injection lines to #1 or #3 it goes away (pretty much). Still no blow by.

The bottom end sounds fine. The valve covers sound fine.

I visited with another mechanic who is leaning towards the scored cylinder/scuffed piston route.

When the injectors were pulled the #3 injector was wet. I'm betting that I had an injector go bad on the trip and it ruined the piston.

I understand that the piston could be hitting the wall below the rings and thus not damage the compression nor cause blow-by.

I'm leaning towards this prognosis.

Any ideas?

As far as the WMI goes I'm thinking that it may not have been an issue. All the injectors looked like they had been hot at one time. While I'm certain that they hadn't gotten hot since I installed the gauges they could have gotten hot before I installed the gauges (and my other updates). As a matter of fact I'm betting that they probably did get hot by my hand (or foot).

I remember that when I installed my ET gauge I was shocked at how hot it ran. Then came the turbo master and the .... No more heat problems.

So the $10,000 question is: Do I get the motor pulled and have them rework one side or two? Or do I have them just pull the head and try to do it while it's in the truck?

Then, what will it all cost and is it worth it?

Or, should I just lick my wounds and buy another truck (ouch).

If anyone has had this kind of work done on their truck I'd sure appreciate your input.

You all are an unusually great set of guys.

Ken

[Billman]

If a piston were scuffing the cylinder wall below the rings on one side, it would also scuff on the opposite side above the rings. It uses the wrist pin as its axis. They get kinda wedged in the hole.

Also, the piston will show heat on top, around the edge, not necessarily on the lower skirts.

I could be wrong about that one. Gas engines do that.

A better test than compression would be a leakdown test.

[tom.mcinerney]

A compression test should clear up question of a bad valve, and give some idea of ring/cyl condition. Agree w. Billman that leakdown test is more definitive. Both should be done by tech with experience, in controlled conditions.

Leaky injectors DO trash pistons. #1, & #3 cylinders are not the common heat-related failures.

The blocks in these engines can crack on bottom end, that can be terminal. However the block casting material seems to be quite wear-resistant (probably good amount nickel).

An old , high mileage engine is liable to need comprehensive overhaul, and need check web cracking before investing. For an old engine the teardown/inspection might be a waste time+money.

Before opening it up check for cracks from compression chamber-to-coolant...no white smoke (or antifreeze scent in exhaust); no stiff inflated radiator hoses; no bubbles in coolant after startup; no indication of exhaust fumes in coolant reservoir by an emissions analyzer probe.

If this is the new/balanced Avant mill, suggest:
1.) Comp/leakdown test
2.) Pull head(s), inspect bore(s), piston(s)
3.) Pull pan check cracks
...
~) Renew distorted piston or two...
{Also, call Avant, or JK, for their guidance.}

Run it .

Happy Thanksgiving! and good luck--

[ 11-23-2004, 04:54 AM: Message edited by: tom mac 95 ]

[cruzer]

Ken, a couple of yrs ago, my engine got hot on a trip out west. The result of this showed its ugly head about 6 months later. The only mod I had at the time was a banks stinger system(exhaust). It cracked piston #3. Upon tear down, #3 cyldr was scored pretty bad and there was a diviot on the top of the wall toward the exhaust side, but was low enuff that it did not hurt the deck. All other cyldrs and crank all checked out std and no cracks anywhere in the 599 blk. The cyldr was able to be sleeved. I found a master rebuild kit w/mahle pistons on ebay and was able to rebuild the motor for about $2500 which included doing a valve grind and sleeving the cyldr head water jackets. The machine shop I found was familiar w/6.5's and did give me a free used piston. FYI, I opted for mahle 0.010 reduced height because my deck height was cut 0.010". I mention this because less money can be spent. I had the cam checked and I took apart and cleaned the lifters. The machine shop had mentioned that the roller lifters rarely go bad. They were in good shape. I assembled the engine.

With the help of TDP, I was able to build a stonger 6.5td. All spent was about $6200, which includes all the mods listed below, rebuilt pump w/new head and rotor, plus new rad and oil cooler.

The way I looked at it was, My truck w/blown motor was worth about $1500, if you could find somebody to buy it.(I'm sure the market ain't great for a truck w/a blown 6.5td.) plus $6200 for the rebuild and maybe throw in a couple $$=$8000+. I shopped for a truck $8000-12,000. All I found were newer higher mileage junk. I also went to a Dodge dealer. I wanted the truck but not the payments. I knew what I had and it would have a new motor. I did shop for motors too.
I also talked to & asked a lot of questions w/ TDP
advertisers and I determined what I needed/wanted. I purchased most of the performance items from Kennedy, who was the most helpful, when I could get a hold of him.

Good Luck, I hope your problems are not so severe.

Happy Thanksgiving, Ken

PS, if you do rebuild don't forget to port match
intake and cyldr heads. there's a lot of material to be removed there.

[ 11-23-2004, 06:55 AM: Message edited by: cruzer ]

[BuffaloGuy]

Looks like the solution is to pull the head on the drivers side and checkout all four.

Can this be done with the motor in. I'll bet that I'll also need to replace a piston or two. Can this be done with the motor in or would it better to just pull the whole motor?

I'm paying someone to do this? What's the cheapest route to go? What should a job like this cost?
Ken

[john8662]

I think its been said here before, its best to pull the engine to inspect everything. It all depends on how deep you have to go into the engine. If you have to pull the pistons, you'll definitly want to pull the engine. Pulling the head will only reveal a washed piston, then you'll be pulling the pan and wishing you'd pulled the engine. I'd only work on the engine inside the truck if it were just head gaskets.

Are you taking it to a mechanic you know and trust or a dealer? Alot of where to take it has a bearing on how much..

ALso, is your noise you're hearing just like mine, or louder or different?

[BuffaloGuy]

John,
I listened to all of your sound clips (with the speaker to my ear!) and yours sounds a whole lot like mine. Mine is a little louder and more regular. However, yours sounds like mine did a couple of hundred miles ago.

I think were both in the same or similar boat.

I think your right about pulling the engine and looking it all over. I am going to get some estimates to do that.

I have the dealership and have just found another good shop that can do this kind of work. Actually, there are lots of very good mechanics around here but not many want to fool with pick-ups, especially 6.5's.

How about if you and I keep in touch on this page? We could share info. Two heads are better than one.

Here's how my crime scene went:

1. The local mechanic turned up my IP when installing my new motor and didn't tell me until months later.

2. I had overheating problems due to the IP being turned up and cooked the injectors but didn't know it.

3. I finally did all the mods that I learned about on the Diesel Page.

3. 30,000 miles later one of these injectors finally got bad enough that it ruined a piston while I was pulling a big, all day load.

What I learned so far:

1. I should not have used this local guy to install my motor (I've got several other reasons too!)

2. I should have installed gauges at the time the motor was installed.

I hope this helps some other poor soul who reads this.

Good Luck!

[ 11-24-2004, 06:52 AM: Message edited by: The Buffalo Guy ]

[Kennedy]

Washer fluid reminds me of Lawrence Welk :D

For future reference, any race shop should know where you can get methanol, and it should be pretty reasonably priced. I still prefer air/air personally.

If a piston were slopping, it should have blowby. Rings cannot seat well when they are not square in the bore.

I'm wondering if the block/crank aren't broken. I think I'd be inclined to remove the engine and tear down/inspect it. If need be, the outlook on long blocks has improved and we can usually get them in a few days.

Ther's also the potential for collapsed lifter etc.

[Billman]

What about the rocker arms. I remember reading about these cheap clips under the valve cover.

I've never had my valve covers off so I'm not too sure where they are/what they do.

[john8662]

The Buffalo Guy,

yeah, we'll compare notes till either one of us reveals the problem. Its interesting that your sound is very similar to mine, same clink just more consistant. Either my noise is getting to be more consistant or I just listen to it more (probably both). I can't do any more tearing down right now, as I am going to install a new injection pump, dual idler gear set, new rear main seal, and stud girle kit in my 86 6.2, so I just hope the 6.5 keeps running while I get my 6.2 running right.

Billman,

Yes, the rocker arm shaft retainer clips could be the problem. Thats another world of work, gotta remove injection lines to get those. But very possible, the clips either break, or just barely hang on causing problems.

[BuffaloGuy]

If the problem was in the rocker arm assembly I would expect to hear some noise through the valve cover. However, all sounds good there.

Ditto with the bottom end.

I guess I'll be pulling the motor and going through it. bummer.

[sidedump]

A friend of mine has a 944 turbo and heard that the blocks were so strong that even with the 120k miles on it the cylinders walls should still have hone marks in them. Wanting to find out w/o removing the head. He had a large animal vet make a house call with his flexable wand type video camera. The Vet put the wand down through a spark plug hole into the cylinder showing every thing including the hone marks.
Might be worth a try.

[BuffaloGuy]

Great idea!

[JohnC]

My $.02

Piston slap sounds sort of like a hollow knocking sound. It is usually most noticable under deceleration or that window between engine driving truck and truck driving engine. Less noticable under load. A piston that's only 5-10 thou loose will knock but won't rock enough to affect ring seating, so compression and blowby may still be reasonable.

A leaky injector can cause a piston to crack, which can sound similar. Some cracked pistons have been known to go a good long time "undetected". (I've had a unexplained tick in cylinder #5 for 100,000 miles. One of these days I'll get to the bottom of it... :rolleyes: )

Lacquer thinner or blow torch fuel is methanol. (Methanol is another word for Methyl Alcohol) Available at any hardware store. Very corrosive, though. I used to run 50% methanol in a water injection system on a gas engine, but it kept killing the pumps...

All the things you can take out to put a camera or boroscope into go into the precombustion chamber. You'll have to get/look through the hole in the chamber to see anything...

[ 11-24-2004, 12:33 PM: Message edited by: JohnC ]

[sidedump]

I forgot about the cups. Sorry,

[john8662]

Another question for ya about the knock, as mentione before with my sound, it pretty much goes away after 750 RPM, I don't hear it at all. Only at the 500 RPM or so idle does it really get after it. I also don't hear it first thing in the morning, I only get the noise after the engine is fully warmed up. Does your sound happen all of the time though out the RPM band or is it just at idle and Hot verses bone cold?

[BuffaloGuy]

Mine had some of the come and go traits but now it is all the time and very noticable. It is even harder to start and smokes much more and a lot longer than it used to. This tells me that something has changed the compression of at least one cylinder.

It looks like I will be biting the bullet and tearing into it. I'm betting that it is a collapsed lifter or a damaged piston. I'm hoping that the block and crank are OK.

If yours comes and goes it could be a wrist pin is slightly warped. You might have something slightly different wrong with yours but I suspect you'll have to do about the same to check it out and get it fixed.

[john8662]

So its all of the time, hot or cold huh. Mine is just when warmed up, its does it all of the time when hot now, and the tones of the "clank" are changing and getting louder and making weider noises. I took off the serpentine belt and ran it to narrow out accessories, its definitly something internal. The only last thing external it could be might be a cracked flex plate. But I had this noise in the past, just not as noticable before the injectors, and I had looked into the flexplate scenario.

Its just annoying how one can take care of and baby an engine, and still have it fall apart :mad:

[JohnC]

Originally posted by john8662:
[QBI only get the noise after the engine is fully warmed up[/QB]Probably not piston slap, then. As the engine warms the piston clearance decreases and slap decreases with it.

[LucasEnglish]

When I first put my water on I messed with washer fluid and varying amounts. I ran as much as I could until I heard the pre-ignition. I talked to Bill Heath,and he said he ran a 6.5 towing with WI and alc that was pre-igniting. He said that one of the wrist pins went flat from all of the extra pressure. If you had a loose wrist pin it would definitly sound like a loud knock.

[BuffaloGuy]

Well, wrist pin it is. We pulled the pan and #3 rod is way loose at the wrist pin. That's the hole that had the bad injector too. I've got chunks of metal in the oil pan.

We're pulling the motor and will be looking over the crank bearings very closely. Any other things to check? I don't want to be throwing good money after bad.