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Has anyone ever seen a set of stock OEM LS7 titanium rods in this good of condition? These have 17,000 miles on them and all 8 of them are in absolute mint condition!
I had two sets that looked that good. After sending them in to be inspected/honed all of them were out of round on the large end, and had to be sold as scrap.
I would definitely have them inspected if your going to reuse them.
I had two sets that looked that good. After sending them in to be inspected/honed all of them were out of round on the large end, and had to be sold as scrap.
I would definitely have them inspected if your going to reuse them.
What application were those in? Power level, rpm?
They were so out of round they couldn't be over-bored?
One was stock and the other had a tune. The one with a tune broke a piston ring landing.
You can probably confirm with Jason but he told me that they were honed to the end of production tolerance and still out of round, and my only option was to get another set.
Originally Posted by Michael_D
What application were those in? Power level, rpm?
They were so out of round they couldn't be over-bored?
Has anyone ever seen a set of stock OEM LS7 titanium rods in this good of condition? These have 17,000 miles on them and all 8 of them are in absolute mint condition!
gmkillr, do you have pics of all the rods? This is just one out of the set.
Originally Posted by erick_e
One was stock and the other had a tune. The one with a tune broke a piston ring landing.
You can probably confirm with Jason but he told me that they were honed to the end of production tolerance and still out of round, and my only option was to get another set.
erick_e, did you end up getting a third set of LS7 rods or go with something else?
I'm pretty sure the top and middle photo are the exact same rod, and if I were a betting man I would bet the bottom image is that same rod turned 180 degrees.
Shouldn't the newer version of the LS7 rods have a chamfer at the parting line?
I've never found any information on the implementation date of the Ti rods with chamfered parting lines, and it's rare to see them come up for sale. Hib Halverson's article "Ruthless Pursuit of Power" on LS7 development, talks about the Ti rods and adding the chamfer. However, the information in the article seems to conflict. The article quotes John Rydzewski, GM V8 engineer as follows indicating the chamfers were added sometime during production.
Also, we had issues with 'Ti dust wear' during our first round of builds. And then we started seeing some signs later on, once we got into parts that came off manufacturing equipment. The two rods (on the same crankshaft journal) rub against each other. Titanium on titanium does not wear well. If you have sharp corners, particles can break off. They get between the rods and start wearing away the coating and get you into trouble.
The article continues,
Ti dust forced implementation of special manufacturing procedures at Mahle. At the part line between the rod and cap, there can be slight misalignment resulting in a sharp edge which can abrade the adjacent rod. The ti dust problem was traced to that area. For engines built for the second phase of development, a small groove was added on the sides of the rod's big end right at the parting line which eliminated the possibility of any sharp edges. Besides Ti dust control, during the LS7 development, other procedures were introduced to avoid impact damage to the rod which causes stress risers and damages the coating.
This would seem to indicate the chamfers were added during the development phase, not after production was underway, but most of the rods taken out of LS7s do not have chamfers. Maybe Hib can add some clarification in this?
03-26-2015, 10:20 PM
LS7 Titanium Rods
