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When exactly did the lead free bearings start being installed in the LS7?
C6 Corvette ZR1 & Z06General info about GM’s Corvette Supercar, LS9 Corvette Technical Info, Performance Upgrades, Suspension Setup for Street or Track
As I understand it, (in large part per Hib's great article on the LS7, page 6) the LS7 was the first production engine to use "increased-eccentricity" main and connecting rod bearings. This also included polymer coated bi-metal main and connecting rod bearings.
The GenV LT1 carried forward on this and uses a similar polymer coated, bi-metal eccentric design. Why the 2013's LS7's in so many 427 Verts had so much trouble, only GM could ever tell us. They only built 478 Z06's in 2012 and I'm still at just over 7,500 on mine, (time will tell.) However, we never heard (from all that I ever read in the Camaro forums) about these issues on all the LS7 Z/28's GM put out in 2014 and 2015. What is interesting and very important to note, is that these new type of bearings do not appear to be an issue in the LT1/L86 (which presume are also used in the LT4/LT5 and on that point, I would presume all of the GenV truck V8's, too. That's a lot of Tahoes, Suburbans, Escalades, and Yukons.)
What gets lubricated by that oil has also evolved a good deal, as (taking cues from the high-performance community) both main and rod bearings are a polymer coated bi-metal eccentric, delivering reduced friction and enhanced durability.
11-14-2018, 11:33 PM
When exactly did the lead free bearings start being installed in the LS7?
