Quote:
Originally Posted by Dick Boneske
Regarding the failure of the hydraulic roller lifter in Pontiacs. Isn't it true that the aftermarket hydraulic rollers for Pontiacs today are actually GM LS engine lifters--which is why the oil band is too low for Pontiac engines?
If it's true that these are LS lifters, it seems odd that there are actual failures of the lifter body itself. Most LS motors run well beyond 200,000 miles without lifter failures. Why do they fail in Pontiac engines if the problem is not lack of oil flow while the lifter is on the base circle of the cam?
I have heard that hydraulic roller cams for Pontiacs today have a smaller base circle than OEM cams had, by significant amount, worsening the problem of the low oil band.
I'm concerned about this because we're having a Butler 468 stroker built now. The engine shop wants to use Comp Cams solid Extreme Energy flat tappets because of the trouble he's seen with retrofit hydraulic rollers. I just can't see the logic in using a solid flat tappet cam in a street engine. The 20 HP gain means nothing compared to the noise, need for adjustment, and risk of cam failure as so many see with flat tappet lifters, solid or hydraulic.
Help me understand this right way to go.
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I mean honestly, there's no perfect answer right? I lost a solid flat, lost a solid roller, now I have a hydraulic roller with the Comp lifters. So far the hydraulic roller has held up better than the first two, but then again the current engine was built by a different shop than the first two.
It's hard to say what approach is going to be most reliable because you've got so many different variables when you read these threads. If you see a broken lifter from one guy and another guy says he has 50k trouble-free miles with the same lifters, is that dumb luck? Spring pressure? Oiling issues? Cam bore alignment? Lifter bore clearance? Proper valvetrain geometry?