2000PewterT/A

I'm helping a friend of mine do a 5.3 build and he has a set of Comp hydraulic lifters sitting around, does anyone know the max rpm these are rated for. They are not the "R" series lifters, just the replacement ones.

mark21742

I spin my ls7's to 8,000 rpms with no problems, and the comps are basically the same lifter

Summitracing

The lifters reliability can be affected by the rest of your valve train components, but the following are some guidelines. Comp High Energy Roller Lifters 850-16 are good to 6800 RPM on most set ups. If your friend has the Comp Pro Magnum Roller lifters 875-16 the RPM limit is 7000-7200. Anything over 7500 RPM Comp suggests the 15850 Comp Short Travel Race lifter

soundengineer

iTrader: (16)

Very Wrong.... they are NOT "Basically the same lifter"
LS7 lifters start to have issues around 6800~7000 rpm....big drop off in power after that...
if you get some that are holding the power out further, they wont do it for long....Its just not the right guts to repeatedly go to higher rpm's


usually you can get more rpm with a rev kit (of which there arent very many for an ls1)
a rocker girdle
and lightweight parts on the top end(valves, springs, retainers, locks, rockers)

Link bar lifters like the Morel's are needed to go to higher RPM's reliably...

and the short travel lifters usually need a cam that is a solid roller design lobe as the lifters are usually a .010~.015 travel plunger which acts like a solid roller at higher rpm's

therabidweasel

iTrader: (5)

Both my Comp Rs and my Johnsons have 0.060" travel and were set with 0.03x" of preload. I have a decent relationship with the engineers at Johnson and we're using LSL lobed roller cams, don't know if those are considered a solid roller design.

J Glen

I 110% agree. People complain about morel's high prices, but then their lifters fail and have to buy them anyway. I can't figure out why people think LS-7 lifters will take anything. Glad to know I am not alone.

mkvamso

iTrader: (2)

The stock ls7 lifters have problems around 6800?
Why do stock z06's redline at 7k, with the limiter not stepping in for another cpl hundred rpm, if they can't take that many rpm. Gm just wanted 60k dollar cars to eat lifters under warranty?

Tony Mamo @ AFR

iTrader: (13)

They can get away with it when the valves are barely 70 grams (Ti intake and very light hollow stem exh valve) so there is alot less valvetrain related drama.

Most folks not running LS7 heads have valvetrain components that are significantly heavier.....hell a steel valve that weighs 100 grams is pretty light (AFR 2.020 valve is like 107 grams....the 2.080 valve closer to 120 grams but its slightly over built with a pretty thick margin).

Anyway....an LS7 lifter is nothing special.....it just works better in an LS7 engine due to the rest of the components its mated up with.

Not true....only some of the "cheater" lifters have that light a number for plunger travel. That is for the class racers that have to run a "hydraulic" lifter in their respective class. As Bidweaseal mentioned, both the Comp and the Johnson lifters run .060 travel and are more of a true hydraulic roller lifter that just happen to feature a limited travel option for better valve control (ultimately depending on the rest of the set-up of course). They don't need or require a solid lobe to be effective.

-Tony

Cstraub

iTrader: (1)

I've got customers with the 5206 and 5274 Morels and properly set up valve trains that are turning these things past 8000 rpm. In boosted applications we have run as much as 225# seat pressure on these lifter.

The 5294 HI rpm stuff is not limited travel and it will take 8500 rpm. The new .903 Hyd rollers will be available in Jan of 2013. Testing them now. They will feature pressure fed oiling to the needles.

Tainted

iTrader: (9)

So Tony, what would you reccomend as an alternative to the ls7 lifter for people running moderate setups, less than .630 lift and running ls3 heads/valves? Theres so many to chose from

S10xGN

iTrader: (11)

Interesting. On aluminum LS block lifter bores, can they just be "bored" or do they need a bushing too? What's the max diameter these can be bored to?

J Glen

You would have to use a bushing if you bored you lifter bore that much.

mark21742

Not exactly sure how it works better than stock, but I've seen/heard proletarian having the lifter bores bored out and getting bronze sleeves put in....just don't know if it helps wear, oiling, or stability.

mark21742

[QUOTE=soundengineer;16820128]Very Wrong.... they are NOT "Basically the same lifter"
LS7 lifters start to have issues around 6800~7000 rpm....big drop off in power after that...
if you get some that are holding the power out further, they wont do it for long....Its just not the right guts to repeatedly go to higher rpm's/QUOTE]

Sorry, think I was misunderstood here....the ls7 lifters are "stock replacement" lifter and the basic standard comp lifters are about the same.

I have my valvetrain set up good, do, and have no problems spinning the ls7's to 8,000.

I personally have never had an ls7 fail, but have had two comp lifters come appart one time on me.

2000PewterT/A

Thanks for all the info, We don't plan on spinning it past 7k so I think we should be fine.