Hydraulic Lifters

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Hydraulic Lifters

Postby Ray Espinoza » Fri Jul 10, 2015 10:04

Just for those interested in replacing loud lifters. I have a 1992 Cappa a japanese import and 1 of my intake lifters kept leaking back and rattled badly and the new ones I found on the internet were to expensive since I live in Australia so I improvised and found that a V6 3.5 G.M ecotech engine had the same lifters in it with stronger springs and alot cheaper. They work great and needless to say quite as a mouse.

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Re: Hydraulic Lifters

Postby Ian Linden » Sat Jul 11, 2015 20:25

Is it true that stronger springs will make the engine harder to turn over and reduce power output or reduce economy?
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Re: Hydraulic Lifters

Postby Murray Betts » Fri Jul 17, 2015 16:31

I guess you mean the extender springs in the lifter itself, in which case it won't affect the friction significantly.

The lifters get full oil pressure fed to them, although this isn't what makes them "fill", the extension springs do that as it makes the oil get drawn into the pressure chamber through a check valve. They will actually work with absolutely minimal oil pressure, they just need a supply of oil, all the rest is done by the lifter internally.

I've done validation testing of engines fitted with this type of lifter (or "HLA", hydraulic lash adjuster), and to demonstrate acceptable valve operation we regulate the oil supply to them from essentially zero up to well above the max pressure the engine will see, and they must fill at very low pressures but not jack the valves open at the high pressures. High oil pressure does get transferred into the pressure chamber which does load the valve stems (reducing seating loads), but due to the areas and leverage involved it will always maintain sufficient seating loads.

HLAs do rely on a slow leakdown to purge the pressure chamber and lubricate the plunger, and they do work best with low viscosity oils, the pressure chamber filling is the most important aspect. If the extender springs get weak or the plungers get sticky they can be reluctant to fill after leakdown.

Useful to know of another suitable source.
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