What chews up lifter rollers?
Never ran it low on oil, 40+ hot idle oil pressure all its life.
> too much preload
Stock non-adjustable rocker were used.
> lifter twisting in it's bore
nope, they were all correctly oriented.
> bore damage
Nope, the bores were all clean and showed virtually no wear on the bore or the lifter sides.
> high miles
90K, but only 10K with the cam. Mostly babied and easy highway miles. Still on the stock clutch.
> bad lifter holding cups
These seemed to be fine. Pulled them and cleaned them out before reassembling.
> miss shift
Nope, not any time recently anyway. Besides the dual springs and hardened pushrods should be able to keep the valvetrain under control, no?
> wrong geometry
I have the standard 1.450 base circle, unmilled heads with 7.4 pushrods, when i really need 7.425 PRs or to mill the heads .025. I wouldnt think hydraulic lifters would have a problem with the .025" discrepency.
> etc.......
This is also a strong possibility.
Never ran it low on oil, 40+ hot idle oil pressure all its life.
Nope, not any time recently anyway. Besides the dual springs and hardened pushrods should be able to keep the valvetrain under control, no?
This is also a strong possibility.
1. Positive oiling via an EDM (Electron Discharge Machining) passage right to the rollers.
2. Meticulous sorting of roller diameters, as one as little as 20 microns larger than most will be overloaded and may fail prematurely.
3. New tool steel pins, to better reduce deflection under high load.
I expect other brands are following suit.
I'd say you're playing Russian Roulette by not changing out all the lifters now, and doing some pretty careful checking re where all the fragments wound up...
Last edited by MadBill; Nov 9, 2005 at 04:03 PM.
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As for playing russian roulette not swapping all the lifters, Im going to be doing a head swap in another month or two. Ive already ordered a full set of lifters for then. I only replaced the four because I needed to repace them right then and there cause my car is a daily driver and I needed to get it back on the road.
1. Positive oiling via an EDM (Electron Discharge Milling) passage right to the rollers.
2. Meticulous sorting of roller diameters, as one as little as 20 microns larger than most will be overloaded and may fail prematurely.
3. New tool steel pins, to better reduce deflection under high load.
I expect other brands are following suit.
I'd say you're playing Russian Roulette by not changing out all the lifters now, and doing some pretty careful checking re where all the fragments wound up...
I use Comp 850-16. Their ability to handle ~.600 lift cams is much better than stockers.
I use Comp 850-16. Their ability to handle ~.600 lift cams is much better than stockers.
#1 More and more people are running dual springs with higher pressure. Maybe the added pressure is killing em.
#2 The clatter that some cams make can't be good for the valve train. Perhaps the growing amount of time it's been clattering is finally taking it's toll.
#3 Maybe it is just high mileage. More and more people are getting up there with mileage as our LS1's age.
I sure would like to have an answer before I pull the trigger for a new F13.
i would bet $0.25 that the majority of valve train component failures are due to improper geometry. do your homework, get the geometry right, and your valve train should last a good long while

