What's wrong with the GM engine UOA...

[crainholio]

Last week, I put my LS1-equipped '82 Camaro back into service after finishing the engine swap. Full crankcase of GC, new Katech ported oil pump, no piston slap whatsoever at this time. Even with the 0.563" lift cam it's no noisier under the hood than my old smallblock 350/TPI engine.

Thus far I'm happy w/ GC. Still thinking I'll use Delvac-1 on the road courses this season for the extra high-temp thickness.

 

[T-Keith]

The Series II 3800 has almost no skirt on the piston and I've never heard this "piston slap" from any 3800 engine.

I can tell you of plenty of 3.8s at more than 200k. Mines getting close.

-T

 

[T-Keith]

A series II piston:

http://www.thrashercharged.com/images/engine/engine19.gif

-T

 

[tpi]

Engines are open systems, with intake and exhaust. Wear particles can leave via the exhaust, and not all wear material winds up in the oil. I have not seen studies indicating the proportion of wear material ending up in the oil is constant in engines of different design. Each engine is going to have it's signature oil analysis.

Piston slap, I have had so many recent vehicles with cold piston slap, I pretty much ignore it now. IMO it is caused by short skirt pistons and ring location. Coupled with mfg. tolerances, you get a knock in a cylinder or two until things heat up.

Recent vehicles with slap:
1990 Mazda B2200 Cold slap, little change over 120 K miles.

1997 Nissan Quest 3.0 Slap when cold, no change over 70K miles.

1997 Ford F150 w/ 4.6 modular engine. Slapped cold for a minute, no change over 100K miles.

1999 Corolla 1.8 Slapped cold for a minute, no change over 100K miles.

None of the above used oil.

Engines without slap:

1995 Jeep 2.5 100K miles, no sign of slap
1992 Chev C1500 pickup 350, no sign of slap over 180K miles.

 

['03 EB/B Corvette Z06]

quote:

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You gotta be kidding! I dont know anybody that drives a Corvette daily. Most are garage queens. 317000 miles is unreal, especially for the LS1 series engine.

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Hey, Hey I drive my '03 Z06 everyday no matter what! Corvette's are made to be driven and that's where the enjoyment of owning one comes from.

 

[Patman]

quote:

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Originally posted by '03 EB/B Corvette Z06:

quote:

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You gotta be kidding! I dont know anybody that drives a Corvette daily. Most are garage queens. 317000 miles is unreal, especially for the LS1 series engine.

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Hey, Hey I drive my '03 Z06 everyday no matter what! Corvette's are made to be driven and that's where the enjoyment of owning one comes from.

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Now that's what I like to hear!

When I get myself a C5 in a few years, it'll be my daily driver too.

That guy with the 99 is now up to 330,000 miles!

 

['03 EB/B Corvette Z06]

quote:

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Originally posted by '03 EB/B Corvette Z06:

quote:

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Originally posted by Patman:

quote:

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Originally posted by '03 EB/B Corvette Z06:

quote:

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You gotta be kidding! I dont know anybody that drives a Corvette daily. Most are garage queens. 317000 miles is unreal, especially for the LS1 series engine.

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Hey, Hey I drive my '03 Z06 everyday no matter what! Corvette's are made to be driven and that's where the enjoyment of owning one comes from.

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Now that's what I like to hear!

When I get myself a C5 in a few years, it'll be my daily driver too.

That guy with the 99 is now up to 330,000 miles!

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It's no fun to just polish it in the garage! Get out and throw it around the track a few times.

 

[OdinsRageSS]

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Originally posted by Patman:

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Originally posted by JohnBrowning:
Patman just be real picky. Try to get an LS1 that does not knock on start up.

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Believe me, when I go looking for a Corvette, I'll be listening very closely to the engine on startup to see if it has piston slap. Even if the engine can still last long, it's a noise that I could not live with day in and day out, especially since the Corvette I do buy will be my daily driver. I went insane when I owned the 94 Grand Am GT which had a piston slapping 3.1 engine.

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dont worry, it seems all dealers put in some additive to hide the slap

When I bought my 01 SS, the piston slap was VERY minimal, and non exsistant warm, now after 4 oil changes+ and auto rx before, it slaps awfully, SO BAD.

And, at ls1.com you can read tons of people who have experienced this. And it was a ford dealer also!

 

[Patman]

I put GC in my Corvette the same day I bought it, and the next morning I opened the hood and listened to the engine after starting it cold, and it sounds perfect. Not a hint of piston slap. It was cool that morning too, only 55 degrees.

It only has 32,000 miles on it, so I expect the first UOA will show about 50ppm of copper though (in a 5000 mile run)

 

[White 03]

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Originally posted by Patman:

It only has 32,000 miles on it, so I expect the first UOA will show about 50ppm of copper though (in a 5000 mile run)

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Patman you bring up a point that I have been looking at also but on another car. My question is why high copper on a sample from a engine with 32,000 miles? What causes the copper in an engine otherwise broken in?

I hope I am not dragging this off topic.

Thanks

 

[Patman]

It's not off topic at all, in fact that's basically what the topic is about here!

In the LS1 engine it tends to show high copper for a long time as it comes from the cam bearings and just simply takes a very long time to stabilize. It's not a problem area, nor does it cause other wear metals to be high.

PS-it's funny how at the beginning of this thread I mentioned how I was not getting a C5 for about three years, but here I am finally owning one! Life is good!

 

[Patman]

quote:

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Originally posted by JohnBrowning:
Patman just be real picky. Try to get an LS1 that does not knock on start up. To date the ones that do not knock have had the best UOA.

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By the way, I got a good one, as it's got zero piston slap on a cold startup, even when it was 55F the other morning. I even opened the hood and listened real close to see if I could hear it, but my LS1 is smooth as butter.

 

[White 03]

quote:

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Originally posted by Patman:
It's not off topic at all, in fact that's basically what the topic is about here!

In the LS1 engine it tends to show high copper for a long time as it comes from the cam bearings and just simply takes a very long time to stabilize. It's not a problem area, nor does it cause other wear metals to be high.

PS-it's funny how at the beginning of this thread I mentioned how I was not getting a C5 for about three years, but here I am finally owning one! Life is good!

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Patman,

Thanks. My engine in question is a Honda V6 but I assume the answer is the same for both.

Thanks again.