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The hole by #2 in your photo would be an oil drain-back. One at each end of each head. I think you'd want to remove the intake and check the Valley. Oil collects there and drains back, again, front and rear, to the sump or oil pan, so there could be debris there too. When you remove the oil pan, you can also remove a few bearing caps and check the bearings. If any are scored, you're probably looking at a complete tear down. Hopefully, none got picked up and circulated with the oil.
Is it possible for a cam bearing to be ground away like this? Is there such bearing near cylinder 5, because diameter wise the big chunk curvature would fit the bill, alas.
Is it possible for a cam bearing to be ground away like this? Is there such bearing near cylinder 5, because diameter wise the big chunk curvature would fit the bill, alas.
I just don't see how such a big chunk could make it's way up from the cam or anywhere else below the heads. The only way oil gets up there is through the push rods.
Seems to me that you have floated a valve along the way and this the result.
It has been mentioned before, but I would definitely pull the pan and have a look and clean out any crap in there.
I also believe that you caught this before it will cost you lots of cash, so I would suggest bringing down your redline by 500 RPM...
regarding that big chunk....I'd pull all the rockers on that side and inspect them closely.....I'm sure that thing came from somewhere on that valvetrain.
I just don't see how such a big chunk could make it's way up from the cam or anywhere else below the heads. The only way oil gets up there is through the push rods.
I see.
Originally Posted by sstocker31
Seems to me that you have floated a valve along the way and this the result.
It has been mentioned before, but I would definitely pull the pan and have a look and clean out any crap in there.
I also believe that you caught this before it will cost you lots of cash, so I would suggest bringing down your redline by 500 RPM...
regarding that big chunk....I'd pull all the rockers on that side and inspect them closely.....I'm sure that thing came from somewhere on that valvetrain.
Originally Posted by RBrid
My first reaction when I saw that big round metal piece was that it's part of a spring retainer lock.
But I'm just a rookie...
#5 exhaust valve stem has strange witness markings. And the stud for #5 intake valve looks stripped somewhat.
I'd look over the rockers for that cylinder especially. Possibly poor upper valvetrain geometry.
Would be nice to see inside the oil pan.
Keep digging...
I just don't see how such a big chunk could make it's way up from the cam or anywhere else below the heads. The only way oil gets up there is through the push rods.
Shine a bright light into the cylinders after removing the oil pan.....are the cylinder walls scored/scratched/scraped?
I have also seen a head that was not cleaned properly from the factory....metal particles/pieces were in places you normally wouldn't check before installing the heads "out of the box".
I can't really tell without removing the springs, the dampers seems to be here but this makes an awfull lot of sense.
The thickness and the curvature of the bug chuck I've found would totally match those of a spring damper. It could be the top of the damper that broke of, started to rub again the valve stem and got chewed by the spring.
I will probably go down to the short block eventually, but the summer window is closing fast. With the little free time I'm getting this autumn it gonna be a case of next summer. And I have this all aluminum 5.3 LS waiting in the garage...
Find which part that larger tapered piece came from and you will be able to determine what happened. My guess is that this piece fractured and pieces of it got hammered into pulp, except for that larger piece. What about something involved with a valve seal?
I think the best course of action would be to remove the affected valve springs, etc [piston at TDC to prevent dropping valve], from that cylinder and inspect it all very carefully. If you find the source of the debris and it caused no damage to the engine other than that one rocker, it is likely that the remainder of your engine has not suffered any damage. As mentioned, the filter screen and oil filter would have prevented circulation of that debris into the rest of the engine.
If you cannot determine the source of the debris, that becomes a problem. At that point, dropping the pan, looking for more debris (probably necessary in any event), and inspecting the lower portion of the engine...possibly removing/inspecting a bearing cap or two...would be in order.
Your focus should be on identifying that broken part and chasing down how it got there.
Look closely "inside" the valve spring on the right of the picture. It looks like there's a sharp edge....maybe the inner damper spring broke. That was my first thought, when I saw the "rounded" piece of metal that you posted.
Look closely "inside" the valve spring on the right of the picture. It looks like there's a sharp edge....maybe the inner damper spring broke. That was my first thought, when I saw the "rounded" piece of metal that you posted.
Might be right. But, could also be more of the [shiny] debris laying on that spring.
You'll just have to dig a bit deeper to determine what happened.
Good luck!
Sure thing I will remove the spring the oil pan and the intake before making any move.
Given I have a better replacement engine sitting in the garage I have to ponder how much time and money I'm willing to pour in an engine that will eventually go.
Another observation.
You said it has a somewhat radical cam in it.
Were the valve springs matched up to the cam?
A broken damper inside what looks like a set of "Z/28" style springs could be a valve floated when over-revved.
And according to the pic of #5 valve (the most likely source of the metal) the rocker arm geometry looks like it does not ride the valve stem face properly. Have you looked at that aspect?
Any other pics of #5 intake and exhaust valve springs available?
Good luck with the detective work.
Hope it is an inexpensive fix considering you have another engine waiting in the wings.
Alas the list doesn't provide information about the valve springs.
Originally Posted by bmans vette
A broken damper inside what looks like a set of "Z/28" style springs could be a valve floated when over-revved.
And according to the pic of #5 valve (the most likely source of the metal) the rocker arm geometry looks like it does not ride the valve stem face properly. Have you looked at that aspect?
Any other pics of #5 intake and exhaust valve springs available?
I will provide some tongith
Originally Posted by bmans vette
Good luck with the detective work.
Hope it is an inexpensive fix considering you have another engine waiting in the wings.
If the duration is at 0.050", I'd say that's a pretty stiff cam, especially with lift at over half an inch. One would hope the builder matched the valve springs to the cam. Makes me wonder why it has dampers instead of a second, inner, spring on each valve. But I'm not an expert, just throwing out some thoughts.
Pete
Originally Posted by Denpo
No idea, the engine is just like when I bought it.
I dug up the bill from the engine assembly, here's what it's supposed to be make of
Correct
Looks like there is
Not each spring, only at the base of one
While checking for those seats, here is was I found stuck again the head bold just of the right of "1" in the previous picture, drowned in a slurry of metal paste.
The more I think the more I see kissing my 350 goodbye. So, after restoring the whole car looks like I will have 100% of the car replaced afterall.
That looks like a piece of the valve spring dampener. Looks like you might have some binding of the valve spring.
Should have read the whole thread before posting. Looks like you found the prob.
08-21-2017, 06:58 PM
