Help identify noise

[cranetruck]

My multifuel has been making a "clack, clack" noise for some time, perhaps for 6,000 miles now. It comes from the upper portion of the engine and occurs about 3 to 4 times/second at approx 800 rpm. Hard to tell, but could be #5 or #6 piston.
It is more pronounced at low rpms and can not be heard at all above 1,500 rpm or so. Not the clicking sound from tappets.
A bad rod bearing would come from the lower portion of the engine, correct?

The engine has never been overrevved while I have owned it (ten years).
No smoke, no loss of power, starts easy and fuel is regular diesel at the moment.
Replaced all injectors and no change.

What about the rod-to-piston connection, can that bearing make a noise?
Guess it can, but anyway, I'm no expert.

Oil pressure is kind a' low, perhaps 20 psi only and that's on the highway, so that's another project. Oil and oil filters have been changed within the last 3,000 miles.

During my cross country trip many people heard the sound, but had no particular reaction to it. Patrick and Peter gave it a listen when they visited and had no comment as I can remember.

Any input or thoughts would be appreciated.

 

[TheBuggyman]

A bad exhaust leak can sound like a rocker problem but what is funny is that it goes away with rpm. Does this engine have hydraulic or solid lifters? If hydraulic the low oil pressure may cause the lifter not to pump up causing excess clearance at thr rocker which would go away with rpm as the motor moves more oil and builds more pressure.

 

[EZFEED]

Have you checked your valvetrain completley?

It might be a slightly loose rocker or damaged pushrod. Cracked or failing valve springs make noise too. Yank your vavle covers and check each cylinder by hand. Go to TDC and check the rockers and pushrods for play. Watch the springs as they compress too.

If nothing on the top end I say go south and drop your oil pan and get up in there and check for play in the rods and mains. You'd better catch it now because these things only get worse and will lead to a disaster.

If your oil pressure is low then you might be starving your valvetrain. Stuff will go clackety clack when that happens for sure and if you have hydraulic lifters then for sure those will make a clatter. This would make sense being that you stste the sound goes away at higher RPM, that's because you're forcing more oil up there.

This would be a great time to change your rod and main bearings if your crank isn't worn badly or scored. You'll get your high oil pressure back then. Rebuild the oil pump too.

 

[cranetruck]

Thanks, sounds like it all needs to be done, I'm afraid it's gonna turn into a project, no way around it. Gotta wait for better weather....

How much for a new set of valve cover and oil pan gaskets? What's needed to rebuild the oil pump?

 

[EZFEED]

Re: RE: Help identify noise

Thanks, sounds like it all needs to be done, I'm afraid it's gonna turn into a project, no way around it. Gotta wait for better weather....

How much for a new set of valve cover and oil pan gaskets? What's needed to rebuild the oil pump?

I'm new to the Deuce but no newbie to mechanics and vehicle restorations so as far as giving exact specs on the deuce I wont be able to help "at the moment". Once I get mine down from Pineville to my shop I'll be doing a complete rebuild if not a ground up on it.

The only vendor I know with what seems like cheap prices is Saturn Surplus ( http://saturnsurplus.com/ ). They have an engine gasket set for $125 and a valve grind set for $65.
Also you can check with whatever heavy truck or diesel mechanics are in your area to get gaskets for the model engine you have. These powerplants are used in other applications besides military and parts are available. Someone told me NAPA has allot too.
You could go the cheap route like me and just buy a sheet of gasket material from your local AutoZone or O'reilys and set the parts dopwn on them and trace and cut them out. I actually prefer doing this on most things because I can make thicker more heavy duty gaskets for certain parts. You can make your own for a few dollars rather than pay $20 or more for pre-formed gaskets. Just be sure to match or get close to the original thicknesses.

If your going to buy gaskets then I'd at least get a valve grind set to take care of your top end. This will come with valve stem seals, valve cover gasket, head gasket, water outlet, etc. Basically everything for the head on up. The place you buy this set from should have a oil pan gasket set or know where you can find one. Don't pull the head unless you absolutley have to.

If you drop your oil pan and find that you have play in one of your rods then you will pull the head and use the new head gasket. Be sure to purchase a set of rod and main bearings and piston rings. There's no sense in rebuilding only one piston, you'll have a rough running imbalanced engine this way if the rest are worn and getting some blow by.
Get ready because I bet the rod and main bearing set will be a couple hundred or more bucks but the cool thing is you'll get peak oil pressure again.
The oil pump I presume is in the pan on these trucks. If it's an external pump then it will be allot easier to work on. It's just a deal with two gear looking impellers inside of it. One of these are driven by a small shaft that is run off a 90 degree helical gear set on the cam (In gasoline engines this would also drive the distributor). There will be a gasket where the pump mounts to the engine and an there will be a gasket on the pump itself where it breaks apart. Check the little gears inside the pump and ensure that they are not excessively worn or the housing is not excessively worn. I haven't got a clue as to what the gear mesh is but it shouldn't be too, too loose. Clean the oil pickup tube and screen and reinstall and you should be back in buisness!

Everything above can be done with the engine in the truck (in-frame) but if when you pull your mains and rods you find the journals of the crank are scored or excessively worn then you'll have to pull the engine and do a complete rebuild. There's where I'd be starting to hunt a new engine or crank.

 

[EZFEED]

SWEET!!!!!!!!!!!! You guys really do have everything here!!!!!!!!!

Here is the manual you need bubba!!!!!! It's in the TM section of this site!!!! I'm printing one as we speak!

TM 9-2320-361-34
http://www.steelsoldiers.com/index.php?module=pagesetter&type=file&func=get&tid=1&fid=file&pid=76

This gives you everything including torques and assembly/dissasembly instructions with pictures!!!!! Kinda like a MV Chiltons manual!

 

[OPCOM]

I thought the ticking was two separate ticks of the same type, instead of one. I hate to say that, but I surely do not know where it is coming from. If I recall it was there after the fuel was shut off and also while cranking so maybe it is a valvetrain thing. The mention of low oil pressure bothers me. I hope it is nothing so serious as an impending engine rebuild.

 

[mo-mudder]

Could it possibly be an injector? I know on other diesels whgen an injector is getting ready to go, it can start making some funky noises. You might want to try the ol' yardstick test. Fire it up, and put one end of the yardstick on the injector or line close to the injector, and the other end on/in your ear, depending on the size of your ear. That may explain why it goes away at higher RPM's. It's getting more pressure and more cycles.

 

[WillWagner]

Bjorn, These engines have a different head gasket than other engines I have been around. There is a groove or sipe from the fire ring to the outside of the head gasket right under each exhaust port. If the gasket is blown, it will make a very noticable tick tick tick, mostly at idle. It goes away at higher RPM. You can check it by putting your finger right under the exh. port, and have someone start it. You will feel the leak. Mine leaks at the #1 cylinder. I thought I had a ticker in the overhead. The intake valves on all cyls. had .050+ clearance! After the valves were adjusted, the noise was still there, but not as bad. That's when I found the leak. I read somewhere that's how these engines are designed, something for hydraulic lock and not bending the rod if this happens. Still bugs me though. If you had a rod bearing failure, upper or lower, the engine would have a very noticable and LOUD double knock and the engine wouldn't stay together much longer after you heard the noise. If it was making the noise when you were out on the left coast and you drove it back, it's not a rod faliure.

 

[JDToumanian]

I got to hear the sound... My memory goes fuzzy VERY quickly (lead poisoning?), but I recall thinking it had to be either an injector nailing or a rod knocking. At the time I thought it was probably an injector (coking from SVO?), but if they've all been swapped out... I'd be surprised if the valve train could make that kind of noise but it couldn't hurt to check.

I like the idea of an inframe... the prospect of pulling an engine would cause me to lose a lot of motivation. At least multifuel parts are cheap compared to other comparably sized engines. If it's determined to be rods, I'd probably do the inframe before the opportunity is lost (see pic)...

Jon

 

[Armada]

20 psi oil pressure on the highway!? What is it at idle Bjorn? I think 10psi is the min. at idle according to the manual. That would have me worried. When cold, my oil is at 60 psi at idle. When hot, it shows 30psi at idle and 60 highway. That is, if my gage is calibrated correctly.
Good luck fellow brother of green (tan) steel. Hope it's a minor issue.

 

[houdel]

Don't know about the price of an oil pan gasket but I got a set of valve cover gaskets off Epay for $12.29 including shipping. You are welcome to these gasket for what I paid plus shipping to you. Personally, with the low oil pressure you describe, my first choice would be to replace at least the rod bearings, and since you have the engine torn down that much I'd replace the mains at the same time.

I suppose a piston pin knock is a possibility. IF you suspect this to be a possibility, you need to pull the heads and oil pan anyhow, might as well go for a full in place rebuild - main and con rods, ream the sleeves, new piston rings and pins. However, piston pin knock is pretty rare, I'd go for the bottom end rebuild first. If that doesn't solve the problem, at least you have 1/2 the job done. You'll still have to pull the oil pan again, plus the manifolds and heads and then go for new rings and piston pins, but I suspect the bottom end rebuild will solve your problem.

 

[red devils dude]

bjorn go too a Hercules Engine Components dealer they can get all the parts for the LDT engine price's are pretty good too.

 

[cranetruck]

Don't know about the price of an oil pan gasket but I got a set of valve cover gaskets off Epay for $12.29 including shipping. You are welcome to these gasket for what I paid plus shipping to you. .

Thanks Lee, PM me the total with your address, my zip is 24120.

 

[cranetruck]

Did some preliminary pressure testing the other day and starting the engine at 30°F produced a pre-filter pressure of 95 psi!! It dropped to about 60 after 5 minutes with the engine rpm at 1,400 and later settled at a low of 25 psi, which seems to be a problem for me.
The dash gauge indicated 45 psi to start and later settled at about 20 psi, again my problem. In any case, the filters were most likely bypassed at startup, with a pressure differential of 30-40 psi. Currently, I'm using 15W30 oil. Checked one of the oil filters and it looked clean, it should, they only have 1,000 miles on them.

Today I removed the pressure regulator assembly from the engine (suggested by Patrick) and it was not a pretty sight..... One plunger was "frozen" and the other spring and plunger were covered with crud (piston cooling valve). Almost looked like old gasket sealer, silicone like.
It was the "early" style so I went ahead and cleaned up the regulator from my parts engine, which is the newer style.

Looking forward to testing it, but the wind is picking up, so it'll be tomorrow probably. I don't mind the cold, it's the wind that's nasty to deal with.

 

[ken]

Have you ever done a valve clearence adjustment? If so were #5 and or #6 looser than the rest? I'd also do a compression test. Because my gut tells me the #5 or 6 piston could be wore and mabye "slapping" in the bore. Is there any way you could shoot a video and post it so mabye we could hear it?

 

[cranetruck]

Installed the oil pressure regulator this morning. Couldn't wait, no wind so the 19°F didn't feel too bad.
Took about 15 seconds to start the engine and 10 more for the oil pressure to begin to register.
The gauge was installed in the oil sampling port and showed 70 psi max while the dash gauge indicated 50. A delta of about 20 psi across the gallery with cold oil.
After 10 minutes, the dash gauge showed 35 and the pressure at the oil sampling port 40, a delta of only 5 psi. Engine temp was now 76°F on my digital thermocouple meter. Ambient 19 degrees and fuel temp 23.

I increased the rpm from 850 to 1,400 and after 1/2 hour the oil pressures seem to stabilize. Both gauges showed about 18 psi with virtually no difference between them, perhaps 1 or 2 psi.
Engine op temp was now 138°F. fuel temp 33°F.
Engine was shut down.

Gauge was installed in pre filter port.
Engine started immediately, about 3 seconds to 22 psi on the pre filter gauge and about 12 psi on the dash gauge, a delta of about 10 psi across the filters.

Readings didn't change much and the engine shut down again after 10 minutes.

Observations:
Replacing the oil pressure regulator did not effect the low pressure problem, which wasn't expected. I'll start the engine again tomorrow after another cold soak so that I can monitor the pre filter pressure.

I removed the pre filter gauge momentarily right after the engine was shut down and noticed a gurgling suction of air through the port as the filters were draining.
No oil drained out, only air sucked in. Perhaps the oil drains via the oil cooler after all, somehow enough sucktion is created to pull the oil out of the filters.....interesting.
If this is true, then it doesn't matter if the filters are mounted upside down or not and a preluber would work also (discussed in the "Check valve for oil filters" thread).

 

[Stretch44875]

More good info...

Dennis

 

[OPCOM]

Dang you worked on that in the c-c-c-old s-s-s-snow!!! It was worth a shot, with the low pressure. I'm sorry it was not the fix. Well I guess the ersatz P*S MAG cartoon I made isn't needed, but here it is anyway. Sorry, I just couldn't resist after looking at the TM drawing.

 

[JDToumanian]