617 weird behavior diagnoses - Page 4 - PeachParts Mercedes-Benz Forum

leathermang · #46 11-12-2014, 02:54 PM

Lucas said he would avoid using air...
let me say that with a little more emphasis...

On a diesel... due to how close the piston gets to the valves ... there is NO reason to use air to keep the valves in place while doing work on the valve stems. The valves can rest on the top of the piston while springs, rotators, valve stem seals are addressed.

and it introduces DANGER which Lucas mentioned.... not only the possibility of causing the engine to turn fast at a point you are not expecting it to...catching a finger in a belt or fan blade.... as Vstech has warned about also...

Air can be used to check blowby... but that should be done with the piston at the bottom of its travel..... but even that allows the possibility that a head gasket leak will allow pressure to get to an adjacent cylinder...

I had not even thought about the fact that an accidental movement of the crank MIGHT BE IN THE WRONG DIRECTION..... which can mean a skipped sprocket on the Injection pump... The FSM says do not turn the engine backwards ( except for a short distance which I probably should not even mention )....

Lucas · #47 11-12-2014, 03:20 PM

Question. To get piston at bottom where should the cam position be? After exhaust stoke and cams lobes evenly opposing rocker arm assembly's?

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leathermang · #48 11-12-2014, 03:28 PM

Depending on what you are wanting to do....
I think trying to use the cam lobe position is a dangerous shortcut....
what are you wanting to do ?

Lucas · #49 11-12-2014, 03:33 PM

Double check my rings on cylinder #2 before dumping money into a head. I was thinking about removing glow plug from that cylinder, cranking with the oil fill u latched and sitting there, and seeing if it dances less. But a burnt valve, bad guides and seals don't really help in that determining something. I think.

Edit: I should pour oil in and test compression again, shouldn't I? Don't know how I forgot that.

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leathermang · #50 11-12-2014, 03:41 PM

Be sure to crack all the fuel lines if you pour oil in for a wet compression check...
Forget about that dancing cap thing... you have nothing to compare it to... it is a worthless test unless your engine blows it into the underside of the hood....
and never turn your oil fill cap upside down ... that allows oil to run under the gasket... then when you put it back on the valve cover... it runs runs down and looks like it came from the blowby...
How did you measure your pistons and now worry about the rings on number 2?
You might consider taking your car to a real pro on Injection pump calibration... in case they did not match that up to the 240 specs of your bores....

Lucas · #51 11-12-2014, 03:47 PM

Ahhhh. Old motor had 240 Pistons. My new one is an original untouched 220. I disassembled the old one.

So crack all the lines? For the purpose of not starting? Or should I be concerned about residual fuel? I use a remote switch to crank it with the gorilla knob pushed in.

I've been considering going into the injection shop after all this. Pop testing my injectors and dialing in the pump. I have a good one around here with a mercedes guy that works there. It would suck to get a drippy injector and blow it all.

Hijacking all the threads. Lol. I need to go work on some other stuff.

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OM617YOTA · #52 11-13-2014, 09:22 AM

Thanks for the help, folks.

The engine ran BEAUTIFULLY for several thousand miles before this started up, I would think compromised valve springs would have shown up immediately?

Smoke is the same. Constant gray at idle, blue when cold started, good cloud of blue when given throttle the first time, which clears and goes gray. Lately, when I'm really on the throttle and revving it hard(freeway onramp or such), I've noticed some serious black smoke at heavy throttle that gets even thicker for 1/4 second or so after I let off the throttle?

Greazzer rebuilt the injectors not once but twice. Could I have done something to screw them up again?

Stretch · #53 11-13-2014, 09:33 AM

Quote:

Originally Posted by OM617YOTA

... Could I have done something to screw them up again?

I don't think you've done anything to bugger up the injectors - you're great mate!

barry12345 · #54 11-13-2014, 10:20 AM

Quote:

Originally Posted by Lucas

Question. To get piston at bottom where should the cam position be? After exhaust stoke and cams lobes evenly opposing rocker arm assembly's?

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The intake valve cam lobe of the cylinder in question will be just letting the intake valve close totally after opening it when rotating the engine in the right direction.. There is very little overlap cam wise to consider.

barry12345 · #55 11-13-2014, 10:31 AM

Quote:

Originally Posted by OM617YOTA

Thanks for the help, folks.

The engine ran BEAUTIFULLY for several thousand miles before this started up, I would think compromised valve springs would have shown up immediately?

Smoke is the same. Constant gray at idle, blue when cold started, good cloud of blue when given throttle the first time, which clears and goes gray. Lately, when I'm really on the throttle and revving it hard(freeway onramp or such), I've noticed some serious black smoke at heavy throttle that gets even thicker for 1/4 second or so after I let off the throttle?

Greazzer rebuilt the injectors not once but twice. Could I have done something to screw them up again?

No the injectors have just been removed from the list of possible issues as you have had them checked. Somehow I missed this had been done. So you should totally discount them at this time as having any bearing on the problem. A little confusion with two cars being discussed on the same post now probably got to me.

As for the original posters car. It was running beautifully and this suddenly started is signifigant. Something has suddenly failed. How many total miles on this engine would you guess? Superficially it sounds like more than one problem is present.

Some symptoms make me think possible head gasket if not turbo seals. While others do not. I just cannot seem to get my head around the issues presented properly. Unless something has possibly been accidentally added to the original problem of the sudden eruption of the heavy smoking. Was it the first observation of a problem being present? All the symptoms described or only the smoking? There is no insult intended here but instead an attempt just to get to the bottom of the problems one way or another the easiest way. I am just an average at best fairly simple guy so keep that in mind. The last time I thought I was right the wife corrected me.

I would chase down the heavy blue smoke issue first though. Fixing it might eliminate the other seemingly separate issues in some ways . I wish our esteemed Mr hunter could have the time to post an objective opinion. He has explained that he is busy but suspect he still finds time to scan the threads from time to time.

Lucas · #56 11-13-2014, 10:54 AM

Quote:

Originally Posted by OM617YOTA

Thanks for the help, folks.

The engine ran BEAUTIFULLY for several thousand miles before this started up, I would think compromised valve springs would have shown up immediately?

Smoke is the same. Constant gray at idle, blue when cold started, good cloud of blue when given throttle the first time, which clears and goes gray. Lately, when I'm really on the throttle and revving it hard(freeway onramp or such), I've noticed some serious black smoke at heavy throttle that gets even thicker for 1/4 second or so after I let off the throttle?

Greazzer rebuilt the injectors not once but twice. Could I have done something to screw them up again?

Didn't mean to hijack your thread buddy sorry. But it's good to know info for diagnosing.

As far as springs, you have to get down to atomic properties of metal. If you know how magnets work, that helps. Sitting will start to break the bonds. Maybe once you relieve pressure they will return to shape, but heat is a catalyst. What remaining bonds holding the tension will break down with time. How much time, I'm not a chemist nor have looked at your springs under a very expensive microscope.

IMO, I would suspect three separate problems (hey your down from 4)!

Noise from valve springs being loose. A simple method would be to pull one and mic it uncompressed. Mine were at 48.5 and FSM states 50.1. I did this for fun, I'm replacing no matter what.

Acceleration smoke may be your valve stem seals. But I would suspect guides if it's significant. If the clearances were tight as they were supposed to be less oil could drop through. My previous motor has some play, yet to be measured, and wasn't smoking. Maybe my seals were good. Idk.

The black smoke at hard acceleration may be your pump turned up to much. You just switched injectors so don't assume it was fine before. Someone may have cranked it up to deal with faulty injectors.

Personally, I would order valve springs and valve stem seals. I would do a wet and dry compression test to determine where my rings were at. I got the harbor freight compression tester, works good. I got the leak down tester too, I don't think it lets enough pressure through. I ended up hooking my compressor direct to the cylinder and setting my regulator at 20lbs. I unbolted my intake and exhaust and listened out the manifolds. I had air coming out my exhaust manifold, so I have a really bad seat or burnt valve. The leak down test would tell you if you have a valve leaking and influence your decision on getting the head rebuilt or not.

When the springs and seals came in, I would put #1 cylinder at tdc, hold onto the exhaust valve for dear life, remove the spring, put the cap and a nut back on, and lower it to confirm that it hits the piston. If so, remove the cap and nut, and wiggle it around both fully seated and slightly dropped. Your checking for valve guide wear the redneck way. A perfect guide and valve shouldn't wiggle, but a little play might not be a huge problem. Yet.

If I didn't feel any play, I would throw a new seal and spring on and call if done.

If I felt play, I would go back to my compression readings, and maybe leak down test. If I got high compression and low difference between wet and dry I would throw the new seal and spring on. Despite having play your rings are good and your head is sealing. If you have the finances, get it rebuilt. Otherwise check up on your compression regularly. With play comes valve seat issues.

If I got medium or low compression and low difference between wet and dry I would pull the head and have it rebuilt. Your rings are good but your head isn't sealing. Seals will stop the smoke and springs will stop the noise, but you are going to burn a valve eventually.

Walk into the machine shop with it completely disassembled (but labeled in separate bags) and dirty greasy clothes on, unshaven. Tell them a shop referred you.

If I got medium or low compression, and a HIGH difference between wet and dry, I would throw seals and springs and run the SOB. Your rings are worn and your head might not be sealing. You would have time to look for a motor and then sell me your old one dirt cheap 😏

Except for the last scenario, I would then have an expert adjust the pump. I don't do that, but some do. In the case of the last scenario, it's a perfect time to play with the fuel screw yourself and learn, as you will be replacing the motor. You probably won't get it as good as a pro, but if you really wanted to know ask one after you try it.

As far as your injectors, did you put the heat shields in? I just found one without them. I used my injectors from my original motor, and am sending a set to the same man for new nozzles. I have good rings and am having a head fully rebuilt, so I'm going long term.

Your username has toyota in it, what do you have that motor in? Show us some pics. Personally I'm researching dropping something into a 84 yota I have located in hawaii. It has a long travel suspension kit and lockers, and I shipped it there from California so it's rust free.

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OM617YOTA · #57 11-14-2014, 09:35 AM

My Official OM617 Toyota Pickup Repower Thread

Here's my swap thread.

My compression was fine, better than when I first started. I did use new heat shields when I installed the injectors.

I'm really starting to wonder if I have a rod coming loose. When under power and accelerating, no knocking. When coasting down, odd tapping noise. When just applying enough throttle to maintain speed, terrible racket.

I'm at the end of my patience for this motor, and going to hold off on spending any more money on it until after seeing the MBZ guru. Don't throw good money after bad and all that, if this motor is not long for this world I'd really rather dump that money into sourcing another motor.

funola · #58 11-14-2014, 10:31 AM

Quote:

Originally Posted by OM617YOTA

My Official OM617 Toyota Pickup Repower Thread
.........................

I'm really starting to wonder if I have a rod coming loose. When under power and accelerating, no knocking. When coasting down, odd tapping noise. When just applying enough throttle to maintain speed, terrible racket.

I'm at the end of my patience for this motor, and going to hold off on spending any more money on it until after seeing the MBZ guru. Don't throw good money after bad and all that, if this motor is not long for this world I'd really rather dump that money into sourcing another motor.

A technique I've used successfully to localize and identify source of noise is to rig up a contact mic/ amplifier/ listen via ear phones while driving. By moving the mic around and noting the changes in amplitude and sound you can generally narrow down the source of the noise. Look on Ebay for contact mics- they're cheap. A voice recorder with an external mic input works nicely for the amp. (I used an old cassette/radio recorder). To attach the mic, use your imagination (duct tape, bicycle inner tubes, hot glue etc).

Lucas · #59 11-14-2014, 11:38 AM

+1 on having a listen. I like that mic idea. For the time being you can get a stethoscope from any auto parts store for cheap. Rev it up from under the hood and listen through the lower part of the block and the valve cover. Old timers just use a piece of pipe.

I would suspect if it was a rod it would have exploded already. And the noise would be more consistent.

How is it at full load? To me, it sounds like valves are floating. There's a lot of pressure in there and floating valves on a diesel can make quiet the racket.

While you wait, it's not too difficult to remove one valve spring and play. The valve springs should be tested for compression, but it's like under $100 for a set. If there's a problem they will most likely be too short uncompressed. Mine didn't have a noticeable problem and were 1.5mm too short.

Cool project. Idk how many of those 3.0 yotas I have blown, lol. A lot. You have the perfect truck IMO. Just needs trail master 6" long travel and straight axle conversion and ARB's. 38"'s should fit with some cutting. Ok ok Iknow it's a daily driver, but that would be a heck of a lot of fun.

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Maxbumpo · #60 11-14-2014, 03:07 PM

In an OM617.9xx, the turbo-charger ensures that if there is play in the valve stems, air flows UP the stem, and oil does NOT flow down into the intake side. Both the intake manifold and the exhaust manifold are constantly pressurized, so forget about oil flowing down the valve stems.

I think you have four possible problems. Bad IP timing, Bad rings, bad turbo, bad delivery valve seals (copper washers).

If you don't know the history of the engine / injection pump, I'd recommend that you rebuild the delivery valves (i.e. new copper washers, new springs, new o-rings). Pay close attention to the torque procedure (ask if you don't know it / can't find it).

I'd suspect the turbo would go bad before you'd have a ring problem, and a bad turbo would account for the larger smoke issue on start up. Check for play in the turbine and ease of rotation.

Grey / white smoke is generally considered to be coolant. If the engine is not using / losing coolant, the head gasket is probably fine. If you have doubts, smell the smoke, and if you detect any sweetness to the odor, you've probably got a bad head gasket or a cracked head. You can also send an engine oil sample for analysis.