Engine pics: 30k of oil burning

[BeaterShark]

Well, after burning 1 qt every 600 miles, I decided to pull the engine. This is 3 years and 30k miles after I put it in. Over that time, I've gone through great pains to find the reason for the oil burning, but could not.

This is not for the faint at heart.

Anyway, here are the pics:

Driver's side

Passenger's side
http://users4.ev1.net/~theamys/vette/rebuild/PassPistons.jpg

I really don't understand the #3 buildup. Also the exhaust valve was paper-white. I'm pretty sure it was still sealing, though, and overall the engine still ran good. I wonder how much pre-ignition I was getting with those glow plugs sitting on the pistons.

The plan is to go over everything with a fine tooth comb, put in some new rings and bring it to life again. I havn't opened up the bottem end yet, but will turn the crank and put in new bearings if needed. The cylinders do not appear to have any wear.

 

[Fishman]

I keep getting 'the page cannot be displayed' messages on the links.


Did you remove them for us 'faint of heart' folks?

 

[Yoda]

4 & 6 look a bit crisp too
With all that build up.... did the engine knock any???

Bud

 

[BeaterShark]

I think the links will work for everyone now. My "~" didn't get taken correctly.

I really don't know if it knocked (did you see my mufflers?), but I did have the timing set very conservative. Many times I tried to hear it, but could not determine if it wasn't there or everything else was just too loud.

 

[rtpilot]

Burning oil

Have a 69 L46. Originalmowner since new. 3K oil changes and no hard driving. Complete rebuild of engine @ 100K :cry . Was burning a couple quarts every 1000 miles. After rebuild continued to do same. Now have another 85K. Guess I have to live with it. ad My be problem with casting of block.

 

[Jacko]

Well, after burning 1 qt every 600 miles, I decided to pull the engine. This is 3 years and 30k miles after I put it in. Over that time, I've gone through great pains to find the reason for the oil burning, but could not.

IT'S HARD TO DIAGNOSE FROM A PICTURE BUT i'LL GIVE IT A WHIRL by looking at the picture, I see it's a roller cam engine, maybe valve guides are bad ? There is a lot of deposit on that number 3 piston. If I had to guess, I would think possibly a pvc valve sucking oil out of the valve cover , look for baffels between the pvc valve and the rocker arms. If you can look at the rocker arm through the valve cover pvc hole then I think that may be your culprit. It appears that the pistons are washed with oil as they do not have the normal carbon buildup. Last thought I would say broken rings or broken ring lands.
One other thing, check the intake manifold for a crack or big leak. Those pistons really have no carbon on them at all, I don't mean that black buildup, I mean carbon, light gray or tan, I don't see any of that at all. Now if you are running synthetic oil, it probably does not smoke much as that type of oil will burn like fuel to some extent.
Jack Demco

 

[wishuwerehere82]

Those are some dirty pictures.

I think you are doing the right thing by doing a complete rebuild. I have never seen the inside of an engine painted before. Get the heads checked for valve guides and seals, as Jacko suggested. It looks like the valves are spraying oil on the 3,4,5 pistons, or possibly intake manifold gaskets are sucking oil from the valley. The cylinders look nice and shiny, and don't look like they are scored at all.
Good luck, and take your time. It is worth it!

Pete.

 

[brusso]

Were you losing coolant also? Some of those pistons look polished. Thats what a coolant leak, into the cylinders, will do. Did you ever use a soldering iron? After the iron heats up, how do you clean it? You use a wet spounge and wipe the iron accross. Comes out nice and shiney. Just like your pistons.

 

[keech57]

hey guys,

found this forum yesterday and saw this post. those pistons look like the silvolite keith blacks. i'd check the bores for size and make sure they are straight. those hypereutectic pistons are picky and the bores must be on the money. if its a .030 over motor make sure the bores are between 4.030/4.031
max! 4.032 and it Will rattle when its cold !! make sure that the finish hone is correct and the ring gaps on those HB's are critical too! especially if you are running it hard or have Nitrous,supercharger or turbo. also make sure to swap the #6 and 8 pistons as they are in the wrong holes. look at the valve reliefs in the pistons on those holes. they should be E,I,I,E,E,I,I,E . just my 2 cents worth. steve

 

[SG4206]

keech57 ; great observation! I missed the 6 & 8 piston swap.
I agree with Jacko ; check valve guides first. Geometry on a roller valve train is more critical because of higher spring pressures. Guides will go fast when the geometry is off.
If that isn't the reason , I think broken rings are next.
I know this isn't good news, but your attacking this correctly.

 

[BeaterShark]

hey guys,

found this forum yesterday and saw this post. those pistons look like the silvolite keith blacks. i'd check the bores for size and make sure they are straight. those hypereutectic pistons are picky and the bores must be on the money. if its a .030 over motor make sure the bores are between 4.030/4.031
max! 4.032 and it Will rattle when its cold !! make sure that the finish hone is correct and the ring gaps on those HB's are critical too! especially if you are running it hard or have Nitrous,supercharger or turbo. also make sure to swap the #6 and 8 pistons as they are in the wrong holes. look at the valve reliefs in the pistons on those holes. they should be E,I,I,E,E,I,I,E . just my 2 cents worth. steve

Good eye, on both the piston type and mix-up on #6 and #8, although at this point, I don't think it's worth mentioning who did that

I checked the bores and the are good. Also, I'm not running any power adders.

Jacko, I did not intend to really get into why I'm burning oil, but just to post some pics what an engine looks like that goes through a quart every 600 miles. I've read many times where this is acceptable to some. Trust me when I say I've lost my mind trying to find the root cause. At this point it's either a bad intake to head seal or the rings.

I am curious as to why you say the black is not carbon? Isn't carbon a petroleum byproduct of either fuel or oil? If it's not oil, then what do you believe it to be?

 

[keech57]

yes guys, i agree !
it could very well be valve guides,seals or no baffles in the valve covers. I've seen it all. i could go on and on but i think everyone in here has helped.
hope everything works out ok for you! see ya ! steve

 

[grapeknutz]

Looking at the passenger side the pan gasket is pushed out! that indicates blow by, so I would say the rings never seated.

 

[BeaterShark]

Looking at the passenger side the pan gasket is pushed out! that indicates blow by, so I would say the rings never seated.

It's a universal 1 piece oil pan gasket. It has dipstick provisioning for both driver and passenger side. My dipstick is on the driver's side and that's why the gasket stick out on the pass side.