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Cat 951c engine, oil in exhaust manifold

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3 years 2 months ago - 3 years 2 months ago #229735 by uisum
Hi guys ,
this and the 951c
As you can see in the last photos, to remove the plate under the oil sump, it is necessary to lift the engine at least 3 centimeters to remove the bolts. Unfortunately .
As soon as I can I check the plugs in the rocker shaft.. However, I believe I have not seen any losses.
Last edit: 3 years 2 months ago by uisum.

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3 years 2 months ago - 3 years 2 months ago #229740 by Rome K/G
Are those front idlers in the raised position?? Looks like the bottom rollers are worn more towards the front. Unless the idler wear strips are shot.
Last edit: 3 years 2 months ago by Rome K/G.

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3 years 2 months ago #229742 by Ray54
That is nice looking machine, I hope edb has found the problem.


Has such good undercarriage that a link has rusted and is not flexing at present. Hopefully a few hour use will loosen it up.

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3 years 2 months ago #229744 by uisum
Hi guys ,
here, I created a private video in HD.
If you look at it all you can see and hear the strange sound of the engine. He seems to be coughing. I also framed the exhaust manifold and a few minutes already a leak. I don't understand if the cough is exploding oil.
As already mentioned, no blow by even at full throttle. This makes me suspect. I have seen engines, and usually bad rings give a very evident blow by. So listen to you experts who surely have much more experience than me.
I'm planning the disassembly. I'm taking some time.
So, if a piece of advice comes up before you take it all apart it would be great.


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3 years 2 months ago #229745 by D4Jim
Thanks for the video. Sure a lot of smoke when there should be none. There are a lot of guys on here that know a lot more about engines than me but I can't help but think there is a problem with some broken or badly worn rings. I keep going back to what OM said that a leak down test is in order prior to dismantling the engine. I don't think you will get that kind of hit or miss from worn valve guides and if they are worn that bad the valves are going to be bouncing around on the edge of the seats and affecting the compression. The minimal blow by would indicate the top ring or two are "OK" but the lower rings could be shot and letting oil get into the cylinder.
The puzzling part as you have described is the lack of blow by, good compression yet horrific oil consumption.

ACMOC Member 25 years
D47U 1950 #10164
Cat 112 1949 #3U1457
Cat 40 Scraper #1W-5494
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3 years 2 months ago - 3 years 2 months ago #229749 by Old Magnet
Not all that uncommon to have decent compression but oil control rings are shot. Often a product of poor oil change maintenance or stuck/broken rings Got one of those in a D4 but not that severe so I live with it for now. No doubt you are burning oil based on that amount of smoke and the huffing engine.
Last edit: 3 years 2 months ago by Old Magnet.
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3 years 2 months ago #229757 by kittyman1
thanks for the video as well, that really helps explain the situation...very odd....never seen that kind of random popping although not a diesel expert..(only have 4)
-it doesn't seem to clean up and get smoother as it runs, warms etc...i agree it's likely oil consumption

-i have seen engines with good rings and poor valve guides burn horrific amounts of oil....its possible...
-also seen/have engines that seem to have blow by from crank vent....but are solid engines...capable of a lot more hours..and low oil consumption(diesel) so that's not really a complete tell all story..

-also wonder if it's a fuel problem...injectors, pump...any recent work in that area?
-have you done a valve lash...that tells a lot....even in a low rpm engine....valve springs(broken)...rocker arms..cam lobes...lifters...push rods...valves...valve seats...on and on..(head gasket) the problems are endless..
-never found a leak down test that effective...prefer a compression test if possible..
-do whatever checks you can before tearing into it...
-and when taking apart, inspect everything closely...every part tells a tale

Greatest Lie told to mankind: just give us 2 weeks to flatten the curve!
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3 years 2 months ago #229758 by trainzkid88
is there much vapour from the crankcase vent. it is definitely burning oil and since the smoke is intermittent its possible only one is bad or worse than the others that can happen with broken/ bad oil rings.

i have seen a engine that developed a nice 1/4 inch hole in one piston just the size of a valve stem yet every part was were it should be, what was real strange is the top edge was smooth as if cut with a drill yet the bottom egde was jagged and broken away just one of life's mysteries.

compression tests can only tell you 1. how much compression you have and if it fluctuates does it improve with a squirt of oil in the cyl and it is going somewhere. and which is the poor cyl.
a leak down test can tell you if you have good hearing where that compression is going is out the valves past the rings or between the head or into a water jacket.
really it still requires disassembly to confirm what the problem is.
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3 years 2 months ago #229759 by trainzkid88
there is a misfire you can here it clearly. try backing off all the injector lines and retighten to factory spec check the manual for correct procedure. some engines are fussy and must be done in stages or they wont seal properly.
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3 years 2 months ago - 3 years 2 months ago #229771 by uisum


Hi guys . In the meantime, thanks to everyone for the support.
I removed the cylinder head.
The gasket is like new.
Before disassembling I eliminated the exhaust.
I could see that the cough was coming out of cylinder # 2. During the strange explosion you could see sparks like fire. I could not tell if the oil was coming from the valve guide. The cylinders are mirrored and the pistons are all in all good.
I attach video of the valves and images of the cylinders and cylinder head.
That blowout ??????

Attachments:
Last edit: 3 years 2 months ago by uisum.

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