Uh Oh, Bore Picture and Question

[husker boxster]

Originally Posted by elgyqc

For me the question is... is it going to get worse and destroy the engine? .

"You can't stop him, you can only hope to contain him!" - Dan Patrick from his ESPN days.

Bore scoring starts because the coatings on the cyl and piston skirt have been worn off and you're left with alum on alum, and that doesn't go well. Once it starts, you can't stop it but if caught early you may be able to slow it down (see Jake's video series). But chances are you'll be unaware of the coatings wearing off until it's too late. It doesn't take long for it to get so bad it's drinking oil like a drunken sailor and finally the knocking noise arrives. By then it's too late.

[nuvolari]

Oh, JFP, one question I have is if it is possible to tell anything by how much the pistons rock in the cylinders? How much is normal and can you even tell how much is not? They don't rock excessively but they do move when pushing on them. Is there a method to test them? Should they be at TDC or BDC or can nothing even be determined by any of this?

Thanks as always for your help....

[JFP in PA]

Originally Posted by nuvolari

Oh, JFP, one question I have is if it is possible to tell anything by how much the pistons rock in the cylinders? How much is normal and can you even tell how much is not? They don't rock excessively but they do move when pushing on them. Is there a method to test them? Should they be at TDC or BDC or can nothing even be determined by any of this?

Thanks as always for your help....

No, because there is no spec for how much they should move, plus these cylinder liners tend to go oval with wear. The proper way to measure piston to bore clearance is to use a bore gauge to measure the bore at the thrust sides and use a micrometer to measure the piston skirt diameter, subtract one from the other.

[Homeoboxter]

Can you remind me, was this engine actually running with these deep scores? I'd be surprised.. FYI, there's a Boxster S engine with an alleged IMS failure for $200 in L.A. I'd take a look at it if I were you, the bores can be easily checked with a borescope, they might still be great even though the timing got messed up.

[nuvolari]

Originally Posted by Homeoboxter

Can you remind me, was this engine actually running with these deep scores? I'd be surprised.. FYI, there's a Boxster S engine with an alleged IMS failure for $200 in L.A. I'd take a look at it if I were you, the bores can be easily checked with a borescope, they might still be great even though the timing got messed up.

Yup, it was running great. I bought the car in LA and drove it for a couple weeks around LA and then drove it cross country to Nashville where it now sits disemboweled.

Where is this $200 engine? I checked craigslist but didn't see it there. It's far from me now but worth a look maybe....

Thanks.

[Homeoboxter]

Originally Posted by nuvolari

Yup, it was running great. I bought the car in LA and drove it for a couple weeks around LA and then drove it cross country to Nashville where it now sits disemboweled.

Where is this $200 engine? I checked craigslist but didn't see it there. It's far from me now but worth a look maybe....

Thanks.

Strange. I would think those grooves get rounded after the engine running like this.
The ad is on facebook marketplace. 2004 Porsche Boxster S Motor for $200, was $500; in Marina del Rey, CA, near Venice.

[nuvolari]

Originally Posted by Homeoboxter

Strange. I would think those grooves get rounded after the engine running like this.
The ad is on facebook marketplace. 2004 Porsche Boxster S Motor for $200, was $500; in Marina del Rey, CA, near Venice.

Thanks, found it and asked how bad it is but no response. Pretty difficult to deal with on the other side of the country but for $200, it's worth considering.


I got a couple borescopes but, geez, these things are not easy to use! And that's with the engine out, on an engine stand and turned upside down! And I'm trying to see into cylinder #2 which is the easiest of all to get into! Then when I was able to get the camera into the cylinder, the fact that what you're trying to see is basically a half circle of shiny aluminum makes the view extremely difficult to make out due to reflections and focusing. Also, I am using a scope with the tiny 45 degree mirror on it which completely destroys the quality and adds all sorts of reflections and focusing difficulty. I think a 90 degree camera tip is needed but that adds much expense to the scope and makes it impossible to find one to borrow from an auto parts store.

So, does anyone have any tips? Of course, I'm talking about trying to use the borescope to see the bottom ends of the cylinders, going in from the sump. I don't think it's really possible to use the mirror attachment for this purpose; has anyone used this attachment successfully? The scope I bought was an Amazon $30 part and without the mirror, the quality is very good, much better than you would expect for such a low price. And you really must have a 90 degree view once inside the cylinder or all you will see is the underside of the piston.

It's a very frustrating process and I can't imagine being able to see into all the cylinders. As I've said, the middle #2 has the easiest access but the others....Well, I didn't even try as once inside #2, I really couldn't see anything. I thought saw scoring but it was too tough to tell if it was scoring, reflection or some other anomaly.

Ok, time top research more borescopes/endoscopes....

[The Radium King]

ask yourself what caused the foreign object damage. i'd be suspicious that it was a little piece of piston ring. which means pistons have to come out regardless of what you do about the cyls.

[nuvolari]

Originally Posted by JFP in PA

No, because there is no spec for how much they should move, plus these cylinder liners tend to go oval with wear. The proper way to measure piston to bore clearance is to use a bore gauge to measure the bore at the thrust sides and use a micrometer to measure the piston skirt diameter, subtract one from the other.

Ah, ok, thanks, never heard it to be but worth a check.

Originally Posted by The Radium King

ask yourself what caused the foreign object damage. i'd be suspicious that it was a little piece of piston ring. which means pistons have to come out regardless of what you do about the cyls.

After some close up pics, it looks like the damage was caused with the engine apart since the indentation starts from outside the edge of the cylinder as would happen without the head and gasket installed. So that would point to mechanic error on a previous repair. I don't think the gouge itself poses too much of a problem but there is also a indentation/scratch parallel to the rings which must cause the rings to move slightly on every engine rotation.

Also, the last pic shows a detail of the silicon in the Lokasil coating. Pretty cool!

Oh, and I've been reading up on bore scoring and I never realized there is life with beginning bore scoring. Many videos with Charles Navarro and Lake Speed talk about using moly in the oil to slow the scoring plus oil analysis to show the progression of scoring so you know when to finally abandon all hope! That's a huge plus at this point and gives me hope about seeing this car run again.

For now, I'm going to borrow a borescope from Autozone and check the bottom of the cylinders to see if there is any scoring still not seen. My situation is unique as my damage appears to have been caused by a hack mechanic and not from traditional M96 methods so hopefully the bottom end(s) are all undamaged.

(Crossing fingers...!)

[elgyqc]

Nice pictures or should I say good pictures. To me your analysis is sound. Good luck.