I found out why LS1s show high copper

Patman

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I sent my cousin an email asking about LS1s and high copper in the UOAs, I figured he would know since he's the engine test engineer at the LS1/LS6 assembly plant! I don't know why I didn't think to ask him this before! Anyhow, here is his response:
quote:
Cam bearings have copper in them. You can see copper at the joint in the bearing. The copper levels you're referring to are not serious. It is not like the bearings are wearing out. If that were the case, the copper levels would increase over time. What you are seeing is probably just the residual copper at the bearing joint.
 
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Thanks Patman! This is nice to know! Do you think he REALLY knows this to be fact? Also can you ask him what these LS1's knock and if is a durability problem? Also why do they burn oil so much? Thanks a lot!!! [Cheers!]
 

Patman

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quote:
Originally posted by Chris B.: Thanks Patman! This is nice to know! Do you think he REALLY knows this to be fact? Also can you ask him what these LS1's knock and if is a durability problem? Also why do they burn oil so much? Thanks a lot!!! [Cheers!]
I've asked him that in the past and he's pointed the finger at the short skirt design of the pistons, which he feels is cutting it too close and GM is sacrificing a few things in order to make more power. He does not feel the piston slap will shorten the engine life significantly though. He's done a LOT of durability testing with these engines, many many hours on the dyno.
 
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This is good stuff Patman. Now I wonder if running a higher visc. (i.e. 40 weight) would provide better protection to these cam bearings or is the bigger concern getting quick flow to this area on cold startup ?
 
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Cressida, I'd think you'd want to stick with 0w-30 or 5w-30 with this engine design, particularly in colder weather. It is the rate at which you pump oil up to the valvetrain that really matters here and not how thick it is .... Tooslick
 
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Patman, ask your cousin what oil and filter he recommends for use in a LS1. What oil would he use to break in a new LS1/LS6. How long a break in period? Any suggestions for adding long life and perf to an LS1?
 
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It is a sad sad day when an engineer decides that piston slap is not a durability issue!! I guess we should have been makeing all engines slap happy all along! They do not think that main or rod knock is a durability issue either as evidenced by the long term knock associated with the 3.1 and 3.4V6. It makes me wounder what the durability target is if the piston slapp is not an issue? It must we a really low number like 70% of the engines makeing it to 150,000 miles with out the need for an overhaul! THeir is no way a slap happy LS1 would ever make it to 300,000 miles! P.S. Not all LS1 are have piston slap issues some of these engines actualy leave the factory properly fitted! [ November 08, 2003, 02:13 PM: Message edited by: JohnBrowning ]
 

Patman

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quote:
Originally posted by medic:
quote:
Originally posted by Jim Spahr: Patman, ask your cousin what oil and filter he recommends for use in a LS1. What oil would he use to break in a new LS1/LS6. How long a break in period? Any suggestions for adding long life and perf to an LS1?
As a rule, these engineers know nothing about lubrication beyond what viscosity is needed for adequate lubrication. Other than that, the only oil they know of is the factory fill.

It's true, he doesn't keep up much with oil and lubrication type of stuff, that's our job here! [Smile]
 

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quote:
Originally posted by JohnBrowning: It is a sad sad day when an engineer decides that piston slap is not a durability issue!!
It really isn't a durability issue though, it's just annoying to hear. I know lots of guys with piston slap in their LS1, but not a single one of them has had their engines fail as a result of it. I saw an oil analysis recently on an LS1 where the owner claims to have some pretty nasty piston slap, and his wear numbers looked the same or even slightly better than other LS1 UOAs I've seen. I believe it's posted here too (I usually copy and paste all UOAs I find in other forums)
 
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The slap issue is bigger now than in the past because of design considerations for power and fuel efficientcy. First the piston is almost skirtless, second the ring grooves have been moved as close to the piston crown as is feasible. Since the wrist pin cannot be moved closer to the crown the piston is much more prone to slap, the rings, positioning the piston in the cylinder now have to deal with a larger side-to-side force from the reciprocating rod, draw a vector diagram. And since the piston skirt is so reduced the piston to cylinder tolerance must be very close, the distance between rings and bottom of skirt is short so when the piston cocks the angular position where interference occurs is greater than with a long skirt piston. Since the angle is greater the acceleration and impact force is higher resulting in what sounds like a slapping sound. All this until the pistons heat up! You need oil between the skirt and cylinder as soon as possible to reduce this annoyance.
 
quote:
Originally posted by Jim Spahr: Patman, ask your cousin what oil and filter he recommends for use in a LS1. What oil would he use to break in a new LS1/LS6. How long a break in period? Any suggestions for adding long life and perf to an LS1?
As a rule, these engineers know nothing about lubrication beyond what viscosity is needed for adequate lubrication. Other than that, the only oil they know of is the factory fill.
 
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