Do lifters matter?

Rallim

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So I'm putting together a GT40P top end, ported, F303 cam, upgraded valve springs. With that cam it should make peak power at about 6k, so I plan to have it able to rev out a bit higher then that to maybe 6500. Would it be worth the money to go with better lifters, or would OEM ones be fine? I havn't been able to find the difference on the Ford Racing high performance ones or anything, so I'm just curious if it'd even be worth it. A couple other forums say the OEM ones are fine up to about 7k anyways, anyone have input?
 

mcglsr2

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Interested in seeing a definitive answer as well. In my research, I found the opposite: the Ford ones tend to start having pumping up issues at the higher RPMs. I am also looking to turn around 6500 RPM. The only thing I found that seemed consistent was the lighter weight the lifter, the better able it is to withstand higher RPMs (as in the less stress it puts on the rest of the valvetrain, springs in particular).
 

Addermk2

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stock lifters will be fine. There is no need to upgrade on your combo.
 

Michael Plummer

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Not going to go into a lot of detail (because this post would be to long) but there is tons of information online about everything I'm going to mention.

Less weight on your valvetrain is an easy way to pickup more rpm and more HP. Most stock valvetrain pieces are only reliable up to 5500 rpms, after that upgrades may be needed to handle higher loads.

* Valve springs: Most crucial part in terms of rpm potential and durability. Titanium springs are always an option but due to their cost, I'm not going to talk about them. A beehive spring is a more affordable option for a street/strip car. Less mass in the area where it matters most (upper half) and its unique design allows it to handle higher rpms without valve bouncing or floating. If you decide a dual or triple valve spring is the way to go then titanium retainers are a must to reduce weight.

* Spring retainers: Options are steel, tool steel and titanium. If you can't afford titanium retainers then tool steel is a low cost alternative and an easy way to save some weight. Example: A beehive spring with a steel retainer will be lighter than a conventional dual spring with a titanium retainer. Please note most beehive springs are only rated for a max. lift of .650".

* Pushrods: Weight on the valve side of the rocker has more to do with valvetrain loading and engine rpm than weight on the pushrod side. So with that in mind its okay to want the opposite, where you want a larger diameter and thicker wall tubing pushrod which will help prevent pushrod flex at high rpms. See Manton, Smith Brothers or Comp cams for more information on pushrods.

Rockers: Aluminum rockers will weigh less than stock stamped steel rocker arms which will add increased durability, reduce friction because of the needle bearing fulcrums and roller tips. Most manufacturers today are using CNC machines to design rockers with more weight removed without hurting strength or durability.

Lifters: Reducing weight will be beneficial for increased rpm. One tip is to reduce the the distance the plunger travels inside the lifter. This reducing plunger travel reduces lifter pumps up at higher rpms. First up: Hydraulic lifters easily maintain zero lash, so no need for re-adjusting. Are quieter than solid or mechanical lifters, higher leakdown rates will improve idle vacuum, idle quality and in some cases low-end torque. Please note high leak down hydraulics lifters are noisy. For an all out racer, a solid or mechanical flat tappet lifters is generally recommended. Stk. Ford Racing/Motorcraft lifters are fine for almost all street/strip applications. Mike Freedman used stk. Ford Racing lifters in his 1994 Ford Cobra when he won the 2002 NMRA Renegade Championship.

Valves: Titanium valves=$$$ enough said. Usually recommended for an all-out race car or bad-ass street cars. Valves with smaller stems and thinner heads can help reduce weight but the trick setup is to use titanium.

Every gram of weight reduction in your valvetrain will add approx. 35 rpm potential to the engine. So if you saved 10 grams of weight, you will gain 350 rpm to your engine with no other changes. A typical titanium retainer will save 7 grams vs a steel retainer. So the next time your heads are off your car maybe its time to THINK about your valvetrain.

I hope this helps
Michael Plummer
 

Addermk2

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At what point would you upgrade? Mine are still stock and I have been wondering with all the changes when it would be time.
I was advised by a certain "valvetrain guy" not to bother with anything above stock, even in my 347 stroker that was shifted at 6800rpm.

My turbo 351 uses a standard lifter
 

Rallim

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That's a lot of good info, thank you for that. Sounds like what I've got now should work well and I can swap out rockers and stuff later and make it a bit happier. Not going with a very aggressive setup, but the weight part I can focus on later.
 

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