L92 Valves @ 6500 rpm
Thread Starter
TECH Resident
Joined: Aug 2004
Posts: 875
Likes: 2
From: Portland Oregon
L92 Valves @ 6500 rpm Will the stock L92 valves work for road racing at 6500 rpm? What's the popular theory, go for it, or buy aftermarket valves from Manley.
I'm reading that the LS3 valves are hollow stem and may not be quite as strong. How about the L92's are they bullet proof?
I'm reading that the LS3 valves are hollow stem and may not be quite as strong. How about the L92's are they bullet proof?
Stock L92 valves are strong although intakes are a bit heavy. With aftermarket springs (PSI) only, the engine shows no head problems on dyno to 7200rpm. We tracked a LS7 for hours with stock valves and PSIs it was flawless shifting @ 7k. I ran them on 402 with 0 problems.
Running the LS3 head, ported in a week or so and with PSIs again, expect no problems.
Running the LS3 head, ported in a week or so and with PSIs again, expect no problems.
Thread Starter
TECH Resident
Joined: Aug 2004
Posts: 875
Likes: 2
From: Portland Oregon
Wow, Good input. If you are running them to 7200, that proves that they will take the rpm without falling apart. How much spring pressure are using to get to 7200? That must be dual springs and solid cam?
As with any GM intake power starts dropping @~6100 so there is no real good reason to over rev unless you are in a no time to shift situation.
We have run L92s with LS7 lifters, Patriot golds and the PSIs.
PSI LS1511
Endurance Spring: Single- Beehive LS1 & LS6 (O.D.: 1.290") (I.D. Outer: .630") (I.D. Middle: N/A) (I.D. Inner: N/A) (Seat Pressure: 120lbs.@1.800") (Open Pressure: 360lbs.@1.175") (Rate Lb./In.: 384) (Retainer Step: .000") (Max Lift: .625") (Coil Bind: 1.100").
The Nascar Spec motors run these >8k with ti valves.
We have run L92s with LS7 lifters, Patriot golds and the PSIs.
PSI LS1511
Endurance Spring: Single- Beehive LS1 & LS6 (O.D.: 1.290") (I.D. Outer: .630") (I.D. Middle: N/A) (I.D. Inner: N/A) (Seat Pressure: 120lbs.@1.800") (Open Pressure: 360lbs.@1.175") (Rate Lb./In.: 384) (Retainer Step: .000") (Max Lift: .625") (Coil Bind: 1.100").
The Nascar Spec motors run these >8k with ti valves.
Last edited by See5; Sep 9, 2007 at 01:26 PM.
TECH Addict
Joined: Jul 2002
Posts: 2,261
Likes: 0
Originally Posted by See5
As with any GM intake power starts dropping @~6100 so there is no real good reason to over rev unless you are in a no time to shift situation.
We have run L92s with LS7 lifters, Patriot golds and the PSIs.
PSI LS1511
Endurance Spring: Single- Beehive LS1 & LS6 (O.D.: 1.290") (I.D. Outer: .630") (I.D. Middle: N/A) (I.D. Inner: N/A) (Seat Pressure: 120lbs.@1.800") (Open Pressure: 360lbs.@1.175") (Rate Lb./In.: 384) (Retainer Step: .000") (Max Lift: .625") (Coil Bind: 1.100").
The Nascar Spec motors run these >8k with ti valves.
We have run L92s with LS7 lifters, Patriot golds and the PSIs.
PSI LS1511
Endurance Spring: Single- Beehive LS1 & LS6 (O.D.: 1.290") (I.D. Outer: .630") (I.D. Middle: N/A) (I.D. Inner: N/A) (Seat Pressure: 120lbs.@1.800") (Open Pressure: 360lbs.@1.175") (Rate Lb./In.: 384) (Retainer Step: .000") (Max Lift: .625") (Coil Bind: 1.100").
The Nascar Spec motors run these >8k with ti valves.
THANKS!! Trending Topics
That spring is proven with the heavy valves. If you have not bought the heads yet you could use the LS3 intakes and save a few grams. I am putting the first set together that way now, but don't expect much difference in performance.
Going to dyno both ways but it will be a few weeks.
Going to dyno both ways but it will be a few weeks.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Gas Monkey Built a 6-Wheel Ferrari Testarossa With a Corvette LT4 Engine
Verdad Gallardo
7 Most Reliable High-Performance Engines GM Has Ever Built
Verdad Gallardo
Amazing '71 Camaro Restomod Is Modern Muscle Car Under the Skin
Verdad Gallardo
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
since I am planning to shift at 6500. 
I put another vote for the 1511 springs. I have them in my LS7 application with big lift (650int/670exh) and run them to 6.5K rpms, and not a hint of valve problems. They're really a great spring.
Originally Posted by Louis
Stock L92 valves and 921s @ .050 of coil bind will control to 7400. I have not dynoed that setup past that 
There is nothing wrong with the stock L92 valves. They are back cut nicely and the weight is comparable to aftermarket valves. Just because there are aftermarket valves doesn't mean they are any lighter.
BTW: I hit my 6800 rev limiter somtimes/often with 921's no problem. They are setup correctly though.
I read somewhere that the stock valves are 2-piece and the stock LS3 intake was lighter because it's hollow and it's a 3-piece valve. If this is true, what kind of durability are we talking here?
