LS3 valve spring test
Thread Starter
Joined: Apr 2006
Posts: 5,604
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From: Pittsburgh
I thought it was interesting that PAC doesn't recommend the titanium retainers on a street car due to the potential to get small bits of titanium throughout the engine.
Last edited by wannafbody; Dec 28, 2025 at 03:03 PM.
That is VERY interesting! Because, being in Michigan, I live less than 50 miles from PAC. I drove down to their manufacturing plant, and bought my 1905 springs AND titanium retainers directly from @TurboBuick6 , a Tech forum member here. He never said anything about them not being correct together......
TECH Senior Member
Joined: Jun 2016
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From: Central Cal.
That is VERY interesting! Because, being in Michigan, I live less than 50 miles from PAC. I drove down to their manufacturing plant, and bought my 1905 springs AND titanium retainers directly from @TurboBuick6 , a Tech forum member here. He never said anything about them not being correct together......
It's more a "street-and-daily-use" durability vs. "absolute lightest for racing use" longevity issue.
Staging Lane
Joined: Oct 2025
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Or what many don’t want to hear was in the second test, the beehives made the exact same horsepower as the dual springs. Using too much spring may cause other problems. Wear is the biggest one. Given that the LS oil system has flaws. If your system bypass lets dirty oil past. The extra high pressure causes wear faster. Most often seen in cam lobes and lifter rollers or bronze rocker bushings. Low oil pressure can do it too. Sure stock engines fail too. It’s just lately seeing more posts about parts failing more often when dual springs are used. And if proper beehives make just as much power and handle the rpm’s . Why Risk other problems?
Staging Lane
Joined: Oct 2025
Posts: 89
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Yes, most of the bee hive springs have a spring rate of 340 to 375 lb/in. Duals are 400 to 415lb/in. The extra pressure accelerates the wear. Then if the oil pressure is compromised it can lead to failure. IMHO running more spring pressure then you actually need is just going to accelerate wear and failure.
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On a std dual Hyd Roller, Ti retainers are fine for a street car. When a Ti retainer isn't recommended is either on a dampered spring, or a solid roller application with aggressive valve trains and high spring forces. On an LS dual, Ti retainers all day long.
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Anyway, Tony only changed 1 or 2 of them....I think 1, and reused the original 14 or 15. My statement is a sad statement, eh Gary? Imagine PAC saying not to run Ti retainers for long term use, when they are more reliable than OEM LS7 heads. At least MY LS7 heads. I guess bottom line is if you're running OEM LS7 heads, there are a lot more things besides retainers to worry about!!
Last edited by grinder11; Dec 29, 2025 at 01:32 PM.
That may be true for some. Not in my case. My LS7 heads were purchased new, and Thomson Automotive did a precision valve job on them. 20,000 miles later, all the guides were shot, and 7 of 8 Ti intakes had lost some of their CrN coating. I sent them to AHP, and they're the ones who found the scrap valvetrain, except for the springs and retainers. AHP did the second build, and I had the concentricity checked on our shops CMM machine. They did a good job. But I knew my heads must have some other kind of machining error, because when I talked to Kohle, he said whoever did them originally did a pretty good job! So, NO SMOKING GUN. There are a LOT of other machining operations on a cylinder head besides seat to guide concentricity. Anyway, 30,000 miles later, 1 guide had at least .015"-.020" slop, and you could rock the stem tip back and forth at least an 1/8 of an inch!!! Third build went to Tony Mamo, and this time I went with YT roller tip rockers. All seems fine in the first 4,000 miles or so, and the wipe pattern is dead nuts after Tony got done with them. Hard to get a wipe pattern with factory rockers. So,....Crossing my fingers....
That may be true for some. Not in my case. My LS7 heads were purchased new, and Thomson Automotive did a precision valve job on them. 20,000 miles later, all the guides were shot, and 7 of 8 Ti intakes had lost some of their CrN coating. I sent them to AHP, and they're the ones who found the scrap valvetrain, except for the springs and retainers. AHP did the second build, and I had the concentricity checked on our shops CMM machine. They did a good job. But I knew my heads must have some other kind of machining error, because when I talked to Kohle, he said whoever did them originally did a pretty good job! So, NO SMOKING GUN. There are a LOT of other machining operations on a cylinder head besides seat to guide concentricity. Anyway, 30,000 miles later, 1 guide had at least .015"-.020" slop, and you could rock the stem tip back and forth at least an 1/8 of an inch!!! Third build went to Tony Mamo, and this time I went with YT roller tip rockers. All seems fine in the first 4,000 miles or so, and the wipe pattern is dead nuts after Tony got done with them. Hard to get a wipe pattern with factory rockers. So,....Crossing my fingers....
It's terrible what has happened to some guys. Buy GMs flagship car at the time, get a few thousand miles out of warranty, BOOM-Youre suddenly out $20,000 for a new engine! What pisses me is GM is still giving Linamar (the company that did the awesome job machining the guide to seat concentricity, or lack thereof!
) contracts to build parts for them. They farmed out differential fluid fills to them a few years back for a different vehicle, and diffs started failing-Often. Turns out they put the wrong amount of gear lube in the diffs!! Where is GM's logic here?? Where is the quality control?? If I were calling the shots at GM, Linamar would be off my list of vendors, and on a very different list!!
) contracts to build parts for them. They farmed out differential fluid fills to them a few years back for a different vehicle, and diffs started failing-Often. Turns out they put the wrong amount of gear lube in the diffs!! Where is GM's logic here?? Where is the quality control?? If I were calling the shots at GM, Linamar would be off my list of vendors, and on a very different list!!Last edited by grinder11; Dec 30, 2025 at 08:47 AM.
Thread Starter
Joined: Apr 2006
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From: Pittsburgh
Gotta wonder if part of the problem is that there aren't a lot of true machinists left. For the most parts it's guys who chuck some numbers into a machine and let it go hog wild.
back in 1981, the skilled tradesmen apprenticeships have virtually disappeared. Until recently, when someone in the federal government actually used logic and common sense to figure out that if they didn't teach younger guys before the old guys retired, we'd be in a Helluva position if we had another big war. Because nobody would know how to manufacture parts! If we're at war with China, I doubt they'd call and ask if we need another 5,000 machine guns to use against them. Some things can't be learned online and in a classroom. I had to take college level classes for 4 years, plus learn the machines hands on for 10 hours a day. Nowadays, somebody drills a hole using a Bridgeport type mill, and theyre suddenly a Toolmaker or machinist. Our company stopped all our apprenticeships in 1984, and just let us existing Tool & Diemakers get old and retire...... You are exactly right. Since Reagan neutered unions by allowing airlines to use replacement workers for air traffic control back in 1981, the skilled tradesmen apprenticeships have virtually disappeared. Until recently, when someone in the federal government actually used logic and common sense to figure out that if they didn't teach younger guys before the old guys retired, we'd be in a Helluva position if we had another big war. Because nobody would know how to manufacture parts! If we're at war with China, I doubt they'd call and ask if we need another 5,000 machine guns to use against them. Some things can't be learned online and in a classroom. I had to take college level classes for 4 years, plus learn the machines hands on for 10 hours a day. Nowadays, somebody drills a hole using a Bridgeport type mill, and theyre suddenly a Toolmaker or machinist. Our company stopped all our apprenticeships in 1984, and just let us existing Tool & Diemakers get old and retire......
back in 1981, the skilled tradesmen apprenticeships have virtually disappeared. Until recently, when someone in the federal government actually used logic and common sense to figure out that if they didn't teach younger guys before the old guys retired, we'd be in a Helluva position if we had another big war. Because nobody would know how to manufacture parts! If we're at war with China, I doubt they'd call and ask if we need another 5,000 machine guns to use against them. Some things can't be learned online and in a classroom. I had to take college level classes for 4 years, plus learn the machines hands on for 10 hours a day. Nowadays, somebody drills a hole using a Bridgeport type mill, and theyre suddenly a Toolmaker or machinist. Our company stopped all our apprenticeships in 1984, and just let us existing Tool & Diemakers get old and retire...... Absolutely!! I'll gladly have a Toolmaker with high mechanical skills, which you must have to be a Toolmaker in the first place, machine a part on a good machine over an inexperienced one on a brand new machine, 24/7...
Yup. It shouldn't have taken an Einstein to figure that when you're at the top of the worlds economic scene, the only way you can go is down. We've taught the Chinese how to manufacture things 1/10 the cost of what our own manufacturing base can make the product for. It was ALL junk at first, but we kept buying it anyway, and the complaints and reviews only helped them improve things. Its finally gotten to the point that some of their stuff is actually not bad. We've opened the floodgates, then we wonder why there's no water....
