Burning oil

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dodgedifferent2

dodgedifferent2

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So my 340 stroker has been burning a lot of oil so I have tore into the engine to change the piston rings.

Heads have about 1000 miles on them. They had new seals and the valves seemed to be good when I put them together.
Heads are w2
Now I took the heads off and I found one piston to be spotless and the rest with black crap on them.
Do I blame the heads, piston rings? Or a dead cylinder all together.
Engine ran smooth with gobs of power.

Trying to be sure I fix the issue so I don't have to go back into the engine.
20170729_184956.jpg
 
How much oil was it burning? Was it smoking hard under heavy throttle? Never seen one with 1 New looking piston, with the rest that black.
 
any signs of a head gasket leaking coolant into that cylinder ?

does this engine have gapless rings ?
 
Engine has Keith black molly rings (not gapless)
100 miles I would burn at least 2-3 quarts.
At idle it barely noticeable. If I jump on it i get a cloud of smoke. Then takes awhile to burn the oil off.
No sign of a leaking head gasket
When I took the header off today I had oil drain out of the collector.
 
Oil drain out of colector on same side as shiny piston ?
Pull that one for sure,was re assembling a sb chevy and found one piston had all the oil control rings lined up. So far rest were fine.
 
Did you run a compression test before you pulled it down?
is the oil in all the primary tubes or just one?

blowing smoke out of both sides or just one side?
 
Looks like the head gasket was leaking. The deck surface looks like crap. Was it machined during the rebuild?
 
looks like a blown head gasket on that cylinder- cylinder then got fuel washed..
I would put the heads back on- to pressure test
(leakage test).
before pulling the pistons.

also what does the intake ports in the head look like > intake sealing >sucking oil
 
Pressure check

#1 =170
#2= 180
#3 = 165
#4 = 170
#5 = 160
#6 = 175
#7 = 160
#8 = 180

Check with oil
#1 = 190
#2 = 230
#3 = 185
#4 = 240
#5 = 190
#6 = 240
#7 = 180
#8 = 210

Deck was surfaced before rebuild.
Intake did have oil in it on that piston. That cylinder was the worst one.
 
Looks like you've got some rings that never sealed
 
Did you have a shop assemble the engine or just do the machining?
 
dodgedifferent2 said:
Engine has Keith black molly rings (not gapless)
100 miles I would burn at least 2-3 quarts.
At idle it barely noticeable. If I jump on it i get a cloud of smoke. Then takes awhile to burn the oil off.
No sign of a leaking head gasket
When I took the header off today I had oil drain out of the collector.
Click to expand...

What little I know.........

Jumping on the throttle and getting a cloud of smoke tells me eather bad valve guide seals on the intake valves, and/or sucking oil from valley side of intake ports from bad/misaligned intake gasket. The one shiny piston says to me water in the chamber, that will steam clean the top of a piston like nobodies business; that could be alot of your smoke, you did not say what color it, the smoke, was. Blue oil, white water/coolant. Fuel wash does not make sense to me as why would one piston be clean and the others not? They share a common plenum. If you haven't drained the oil, does it smell like gas?


What machine work was done for the build? Block deck, head shave, intake face?

AJ's got a point about what the witness mark on the deck surface from the fire ring, it looks like it is being pushed hard towards the valley. A little water in the chamber can accomplish that. I have a pair of head gaskets that are garage art that bear witness to that fact.

Go slow and look at every thing, do not discount any thing, the pieces will tell the story.

Good luck!!
 
AJ/FormS said:
What's the fire-ring look like for that hole. The witness mark looks like it was moving up.
Click to expand...
Wow. I agree with posters. Gasket print does not look good at all. Did you remove other head, too? Pic of that may be informative. Did you assemble engine? It kinda looks like either one of the sufaces(head or block, or both) is not flat, or the bolts were not torqued properly.
 
I had exactly that type of oil burning when I accidentally overlapped the ends of the expander on an oil ring set, instead of butting the ends against each other. When you do that, it will break off one end of the expander and there will be no tension on the oil rings. So that is a possibility to investigate in that one shiney hole in particular. I caught it right away (in the first mile!) and replaced the expander in <100 miles from startup, so did not have any oil build up to look at. But I agree on the 'steam cleaning' for that shiney piston as a good possibility.

Another possibility: Bad oil ring set up on that shiney piston; oil gets into cylinder and causes detonation. That would make that fire ring move so radically and perhaps scour the piston top. The oil in the other holes could be from another source like the intake, or blowing back up the intake from this one cylinder on overlap. Check that shiney piston top for signs of detonation.

Those compression numbers with the oil make no sense to me. The dry numbers look reasonable for a high dynamic compression engine.
 
Another thought comes to mind........any port work done to the heads? Possible to have a pin hole in the intake runner/valve bowl of the shiny piston.
 
In my experience when a piston is that clean its burning water..steam cleaned as said above. The fire ring is a major clue. What does the bore look like on that cylinder...all cylinders for that matter. My guess is coolant washed the cylinder and removed the oil causing ring failure. Probably now a combo of steam and smoke out the back from a bad gasket and washed cylinder/warn rings. A snap gauge and hand mike to measure taper from top of cylinder to top of piston at bdc may reveal another clue.
 
That clean it would go through water like my wife goes through money....
 
Not to mention it would have hydrolocked.
 
I beg to differ,that sparkly clean tells me a considerable amount of something washed that piston. And most head gasket leaks result in overheating and a dead cylinder. Compression test tells us something different. Intake doesent have a coolant passage near that cylinder so i would rule that out. Until piston comes out and we get a look at what is in pan we will have to keep speculating.
 
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