Blue smoke... head scratcher

clutchdust

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I have an issue with the 454 in my work truck. I know I'm limping at least one or two cylinders. Thing is, it blows blue smoke. Not out of the tail pipe though, out of the valve cover breather. And it's bad too. Especially when warm and under load. I'm killing bugs in three states. Planning on pulling it down in the next week and re-ringing and putting valve stem seals on (this thing still uses umbrella seals in 93!). I figure that will take care of it but I would like to have a better idea of what's going on before I pull it down.
 
Ide run a compression test, sounds more like to me you wiped out the cam. Ive drive small blocks with bad valve seals and yes the smoke but it has never felt like dead cylinders. I know if the valve dont open you will have blowby the air has to go somewhere if say the exhaust valve ain't opening. The only place it can go is past the rings and that could explain the blowby you have.

Of course I could be wrong and generally I am.
 
Planning on a leakdown test as soon as I get a chance. But at 230k on the clock, I figure I'm pretty much due for a re-ring anyway. I'm just hoping the cylinders aren't so bad they won't clean up with a hone.
 
Aaaaww Hell

Not even done yet but I'm not entirely sure I have all eight pistons. Started my leak down/valve seal replacement on D/S bank. Cylinders 1,3,5 worked pretty good. I could hear leak by in the crank case, but what would anybody expect from an engine with 230k miles on it? Moved to #7. More of a blow down test than a leak down test. Compressor had a hard time keeping up. I think the air was going out as fast as it could go through the hose. Couldn't even hold the valves closed. Just started on P/S and #2 is about the same as the other side, but just stopped for a lunch break and to whine.
$h!t. I just really hope the block isn't wrecked. I don't need a lot of machine work and cash out right now. That would be bad. A piston, I can do. Full set, bore and hone? Not so much.
 
Not even done yet but I'm not entirely sure I have all eight pistons. Started my leak down/valve seal replacement on D/S bank. Cylinders 1,3,5 worked pretty good. I could hear leak by in the crank case, but what would anybody expect from an engine with 230k miles on it? Moved to #7. More of a blow down test than a leak down test. Compressor had a hard time keeping up. I think the air was going out as fast as it could go through the hose. Couldn't even hold the valves closed. Just started on P/S and #2 is about the same as the other side, but just stopped for a lunch break and to whine.
!t. I just really hope the block isn't wrecked. I don't need a lot of machine work and cash out right now. That would be bad. A piston, I can do. Full set, bore and hone? Not so much.


If you do have to bore it its a good Idea to have it plate honed for the best ring seal. I find that GM blocks are pretty frail and I see alot cylinder distortion on a torque plate it put on. Check piston weight to and make a decision on balancing.

Here is a link on plate honing.

http://www.camaros.net/forums/showthread.php?t=58964
 
Meh, you misunderstand the purpose of this engine. It will not see a machine shop unless there is a hole somewhere. Just needs to go down the road. And I'm on a pretty strict time and money budget. If it's that bad, I'm going to look for another short block to build. This all needs to happen between tomorrow night and Monday morning. I'm taking Friday off and working through the weekend so I can have it back up Monday.

I checked out the link you posted but don't know if I understand what I'm looking at. I assume the darker line just down inside the bore is bad, but don't know what it means. I also don't know the difference between what you're saying and regular torque plate honing. Please explain.
 
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Meh, you misunderstand the purpose of this engine. It will not see a machine shop unless there is a hole somewhere. Just needs to go down the road. And I'm on a pretty strict time and money budget. If it's that bad, I'm going to look for another short block to build. This all needs to happen between tomorrow night and Monday morning. I'm taking Friday off and working through the weekend so I can have it back up Monday.

I checked out the link you posted but don't know if I understand what I'm looking at. I assume the darker line just down inside the bore is bad, but don't know what it means. I also don't know the difference between what you're saying and regular torque plate honing. Please explain.


I think this was the engine that was build with about 2000 miles on it and you can see the rings had no seal as as it had blowby all the down to the oil rings

I blued the cylinder put the plate on which shows the cylinder distortion and why thre was a problem with ring seal.

With a stock build you can get away with alot more once you start adding dynamic compression with cams heads and pistons the weak area show up laot more.

Actullay a leak down test @ TDC will show issues with ring seal.

TORQUEPLATEHONING001.jpg
 
[If you do have to bore it its a good Idea to have it plate honed for the best ring seal. I find that GM blocks are pretty frail and I see alot cylinder distortion on a torque plate it put on. Check piston weight to and make a decision on balancing.

Here is a link on plate honing.

I've always wondered about this.

Did the GM factory do it this way? I was thinking not.
 
At this point, I am actually more concerned that the whole piston is still there. Well, even that doesn't bother me so much. Just so the cylinder is still in semi-decent shape. Picked up a used stock piston/rod from my local machine shop today. Fingers crossed that when I pull the head off it's "just" a big fkn hole in the middle of the piston. Granted, not sure how that would even happen but that would be the best thing I could hope for at this point.

Still interested in learning the difference between plate honing and torque plate honing.
 
At this point, I am actually more concerned that the whole piston is still there. Well, even that doesn't bother me so much. Just so the cylinder is still in semi-decent shape. Picked up a used stock piston/rod from my local machine shop today. Fingers crossed that when I pull the head off it's "just" a big fkn hole in the middle of the piston. Granted, not sure how that would even happen but that would be the best thing I could hope for at this point.

Still interested in learning the difference between plate honing and torque plate honing.
Good luck "Professor". :smash::friends:
 
[If you do have to bore it its a good Idea to have it plate honed for the best ring seal. I find that GM blocks are pretty frail and I see alot cylinder distortion on a torque plate it put on. Check piston weight to and make a decision on balancing.

Here is a link on plate honing.

I've always wondered about this.

Did the GM factory do it this way? I was thinking not.


No but they should be doing this, Stock block blocks with low compression and stock bores done' distort as much as the bigger bore blocks and using better fasteners makes for distrotion as well.

Here is a 502 and I see this alot on marine 502's

glazed.jpg
 
clutch, I guess the easiest way to describe this is: you wnt the bore to be round when the heads are installed and torqued.... it is quiet difficult to hone the bores with the heads in the way - that's why a torque plate is used.... now you can distort the block / bores and then hone....

the factory never did this.... when it comes to factory spec for piston clearance it's more like: "as long as the piston doesn't fit in the bore sideways it's fine "

:crutches::crap::sweat:
 
I thought I understood torque plate honing but just the way I read CNC's posts it sounds like there are two different kinds of honing. Maybe I just misunderstood what he was saying. That's why I was asking for clarification.
 
Got the heads off just a little while ago. No signs of cylinder damage, not even a ridge. Good news there. No idea yet why it had no compression. I suppose it has to be rings. I just find it odd that the other cylinders had good/decent compression and this one has practically none.
Taking a lunch break and then I'll snatch the short block out and pull the pan. Will post pics when I figure out what the hell is going on.
 
Well there's the problem

Found this:
834fee93a7d927b.jpg
Anybody have a working theory (or even a wild ass guess) as to what caused it. Haven't pulled any of the others out but no indications of damage to any other cylinders. Good news is *somehow* there is virtually no damage to this or any of the other cylinders. Hell, there's not even a ridge (engine has 230k on the clock).
Glad I bought a used piston from my machine shop yesterday.
 
Found this:
834fee93a7d927b.jpg
Anybody have a working theory (or even a wild ass guess) as to what caused it. Haven't pulled any of the others out but no indications of damage to any other cylinders. Good news is *somehow* there is virtually no damage to this or any of the other cylinders. Hell, there's not even a ridge (engine has 230k on the clock).
Glad I bought a used piston from my machine shop yesterday.

Detonation maybe???
 
I don't think that they were built to last 230k....if they did, the prices would be a lot higher of the floor and the aftermarket would be a lot smaller and much more expensive....my theory....shit breaks after a while.
 
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