84 300 CD suddenly making HORRIBLE noises and running VERY rough - Page 4 - PeachParts Mercedes-Benz Forum

jt20 · #46 09-28-2008, 01:50 AM

the tool for the PC is not a bike pedal. It is a crank removal tool. The threads of this toola happen to be the right pitch for the PC. It s not a practical implementation of this tool. It requires either some welding, or some other means of impact resistant construction which out-performsa the threads on the tool. Get the right tool to remove the PC. Don't mess around!!

In my useless opinion.. it would be more reasonable to remove the head after having the pump inspected. your knock does not sound mechanical.. it is not the crank

bgkast · #47 09-28-2008, 02:20 AM

How long have you run it on the fresh fuel, enough to clear out the fuel filters and fuel system of the bad batch?

Mark DiSilvestro · #48 09-28-2008, 09:33 AM

Quote:

Originally Posted by jt20

the tool for the PC is not a bike pedal. It is a crank removal tool. The threads of this toola happen to be the right pitch for the PC. It s not a practical implementation of this tool. It requires either some welding, or some other means of impact resistant construction which out-performsa the threads on the tool. Get the right tool to remove the PC. Don't mess around!!

In my useless opinion.. it would be more reasonable to remove the head after having the pump inspected. your knock does not sound mechanical.. it is not the crank

I wasn't able to access your video-clip, but often audio recordings will distort or mute mechanical noises.

Does it sound like it's knocking on all cylinders, or just the (#2) one?
If it's just the one, it might be easiest at this point (Certainly easier than pulling the head) to drop the lower oil-pan and check #2 bearing.

Happy Motoring, Mark

jt20 · #49 09-28-2008, 11:29 AM

I have dismantled a 616 that recently began to 'knock' (a general and often misused term). It was the #2 throw on the crank. Significant amounts of metal will be present in the oil pump strainer and the bottom of the lower pan when there is a 'rod-knock'. The OP has dropped the loer pan already and found some metal, not enough to cause knock in the bottom end unless he has a comprimised rod cap.

even with rod knock, engines do not run that bad.
even with one non-firing cylinder, these engines do not run that bad

...perhaps pulling the head is jumping the gun.

rcounts · #50 09-29-2008, 01:39 AM

OK, here is a better audio file (sorry it has to be downloaded to listen to it). It is audio only because I was cracking injector lines one at a time while recording it and the file would have been too large if it were video AND sound https://publish.comcast.net/modal_windows/file_details/YEfAvULGv8aH81Lu8fdTE5fX1pjiJTsXWme9rk_qdzdfFHrWeoS87RhNfnO-TWXsAQij4HmOXwo01NDwWVGCO4fF_mploSm_yHBT0BtJEag,IMG_0306.WAV,audio,362556,1222666046,Wave%20sound,Ye s,all/

Here is a better video clip with clearer audio (Warning: 20 Mb file)

Still sound "too soft" to be mechanical?

rcounts · #51 09-29-2008, 01:47 AM

Quote:

Originally Posted by jt20

I have dismantled a 616 that recently began to 'knock' (a general and often misused term). It was the #2 throw on the crank. Significant amounts of metal will be present in the oil pump strainer and the bottom of the lower pan when there is a 'rod-knock'. The OP has dropped the loer pan already and found some metal, not enough to cause knock in the bottom end unless he has a comprimised rod cap.

even with rod knock, engines do not run that bad.
even with one non-firing cylinder, these engines do not run that bad

...perhaps pulling the head is jumping the gun.

Actually I haven't dropped the pan yet - just drained it and strained the oil - and all I found were a few small metal flakes. Dropping the pan is one of the next things I'll be doing...

rcounts · #52 09-29-2008, 01:52 AM

Quote:

Originally Posted by bgkast

How long have you run it on the fresh fuel, enough to clear out the fuel filters and fuel system of the bad batch?

Oh yeah, plenty long enough. I emptied the fuel filter and refilled it with fresh fuel, then disconnected the suction hose for the pump and put it into a container of fresh diesel. Pumped over a gallon and a half through it like that while idling...

Then I hooked up a pump to the line from the tank and pumped everything I could out of the tank (6+ gallons) - until the pickup wouldn't suck any more fuel from the tank. Then I added 7-8 gallons of fresh fuel to the tank and reconnected the tank line to the suction side of the fuel pump. Idled it some more like that today to make sure it was pulling fresh fuel from the tank. You can hear what it sounds like above.

DeliveryValve · #53 09-29-2008, 02:36 AM

Quote:

Originally Posted by rcounts

So, I started cracking injector lines. #1,#3,#4,& #5 all made it run worse, but didn't make the hammering any better or worse. #2 was the only one that didn't seem to make it run much worse, but seemed to make the hammering sound decrease a lot.......

From the sound bite and what you stated earlier that the sound disappears when you take the load away from the cylinder, I think you have either a bent rod, bad piston pin or a cracked ring. I don't think the bearings are an issue. I think the bad fuel caused a violent situation in the combustion chamber that bent the rod or caused piston problems. It is time to open it up or have a piston shoot through the block.

Brian Carlton · #54 09-29-2008, 08:45 AM

Quote:

Originally Posted by rcounts

OK, here is a better audio file (sorry it has to be downloaded to listen to it). It is audio only because I was cracking injector lines one at a time while recording it and the file would have been too large if it were video AND sound https://publish.comcast.net/modal_windows/file_details/YEfAvULGv8aH81Lu8fdTE5fX1pjiJTsXWme9rk_qdzdfFHrWeoS87RhNfnO-TWXsAQij4HmOXwo01NDwWVGCO4fF_mploSm_yHBT0BtJEag,IMG_0306.WAV,audio,362556,1222666046,Wave%20sound,Ye s,all/

Here is a better video clip with clearer audio (Warning: 20 Mb file)

Still sound "too soft" to be mechanical?

I was not able to listen to the better audio file.........link didn't take me to the clip..........

The better video clip with clearer audio certainly leaves the door open for a mechanical issue. The sound is harder now.........not the typical soft sound of an injector knock.

I'm sure you're going to have to dig into it...........

jt20 · #55 09-29-2008, 10:44 AM

the new sound bit says alot more. Sounds pretty serious. A stethoscope or even a hose will tell you even more.

sounds like that engine is coming out.

I thought I read you dropped the lower pan. MY apologies to Mark - i agree ,drop the pan and inspect whatever is accessible

rcounts · #56 09-29-2008, 12:11 PM

Yeah, dropping the pan is next - though I'm pretty sure I know what I'm going to find

Anybody got a low-mileage 917 for sale in the NW?

jt20 · #57 09-29-2008, 02:27 PM

contact Aurora auto parts. You are prob gunna want a shortblock.

I know another person in Portland who might sell a shortblock also.

pm me when the time comes

rcounts · #58 09-29-2008, 03:11 PM

Quote:

Originally Posted by jt20

contact Aurora auto parts. You are prob gunna want a shortblock.

I know another person in Portland who might sell a shortblock also.

pm me when the time comes

Any clue on cost? Might I be better off to find a whole, low-mileage engine? With a short block there are gonna' be a lot of other gaskets and parts, and with these things parts costs are outrageous....