L92 stock valves NOT GOOD
I wonder what company he works for 
what does this have to do with anything? 
03-04-2008, 12:01 PM
#43
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Like others have said. Part of the problem is not having enough spring to control that heavy *** valve. If you want to run beehives try installing them a little tighter for some extra seat pressure (keeping enough clearance to coil bind) or just run duals (patriots, 921, etc)
I agree 100%
If you must run heavy valves and or agressive lobes then spring pressure is your friend
. But remember to increase the stiffness of the pushrod at a certain point. I don't sell springs, but have a litte experience testing stock type components on a spin tron.
Also tested on the engine dyno, the chassis dyno and at the track. Then we pull em apart and inspect everything to be sure of our findings.
I said it in another post, I believe that a large number of valve failures are due to loss of control of the valve. The bouncing can hammer a valve to death. I have had it happen with some of the best stainess valves available. And yes it can happen at 5000 RPM.
Have a good day!
Robin
03-04-2008, 12:11 PM
#44
I agree 100%
If you must run heavy valves and or agressive lobes then spring pressure is your friend. But remember to increase the stiffness of the pushrod at a certain point.
I don't sell springs, but have a litte experience testing stock type components on a spin tron.
Also tested on the engine dyno, the chassis dyno and at the track. Then we pull em apart and inspect everything to be sure of our findings.
I said it in another post, I believe that a large number of valve failures are due to loss of control of the valve. The bouncing can hammer a valve to death. I have had it happen with some of the best stainess valves available. And yes it can happen at 5000 RPM.
Have a good day!
Robin
If you must run heavy valves and or agressive lobes then spring pressure is your friend
. But remember to increase the stiffness of the pushrod at a certain point. I don't sell springs, but have a litte experience testing stock type components on a spin tron.
Also tested on the engine dyno, the chassis dyno and at the track. Then we pull em apart and inspect everything to be sure of our findings.
I said it in another post, I believe that a large number of valve failures are due to loss of control of the valve. The bouncing can hammer a valve to death. I have had it happen with some of the best stainess valves available. And yes it can happen at 5000 RPM.
Have a good day!
Robin
I run stock L92 valves (N/A), Comp 921 shimmed to .050 and Trend .110 wall thickness pushrods.
No problems so far.
06-01-2008, 08:04 PM
#45
I just bought a complete very low mileage L92 engine and it had an intake valve broken off at the keeper AND at the head. Just about 2" of stem stuck in the guide (bent). I bought it knowing this, but it ruined a piston and a valve seat (hopefully easily replaced by machine shop). The cylinder walls are good though. All I really cared about...
06-02-2008, 06:59 AM
#46
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*knocks on wood* 2k miles on my setup in sig thus far on a .61X/.62X lift LSL lobe cam. Only reving to 6500rpm to make sure everything is kept in control w/ the Comp. 921's.
06-02-2008, 05:19 PM
#47
I've had no problems with stock l92 valves on my 402ci. I pound the **** out of it to 7,000 rpm's and have hit the 7,300rev a few times. All seems good. I guess if it ever brakes and kills the motor it will give me a reason to build a 454ci w/ls7 or tfs 235cc heads.
06-02-2008, 06:12 PM
#48
Considering how many gen III and gen IV engines that GM produces every year there are very few failures of this type. The hours of durabilty testing far out number those of the aftermarket suppliers invest on their products. Some of the same suppliers you buy your aftermarket springs from are actual OEM suplliers too.
As usual, we hear about the failures but never about the 100,000 mile no issue vehicles. This is the internet, take what you hear with a grain of salt. Mass produced vehicles will have failures, just ask Toyota what it is like to finally produce as many as the General and how hard it is to control the quality. Look what happened to the Comp 918 springs, their reputation was damaged because of a quality spill at their supplier. They are now fixed and people still say they are bad because they are misinformed.
If you are staying under .600 lift than beehives are fine but if you want higher lift or are planning on turning high rev's, get off the dime and buy new springs designed for your cam.
As usual, we hear about the failures but never about the 100,000 mile no issue vehicles. This is the internet, take what you hear with a grain of salt. Mass produced vehicles will have failures, just ask Toyota what it is like to finally produce as many as the General and how hard it is to control the quality. Look what happened to the Comp 918 springs, their reputation was damaged because of a quality spill at their supplier. They are now fixed and people still say they are bad because they are misinformed.
If you are staying under .600 lift than beehives are fine but if you want higher lift or are planning on turning high rev's, get off the dime and buy new springs designed for your cam.
06-02-2008, 10:07 PM
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06-05-2008, 04:10 AM
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06-05-2008, 08:42 AM
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06-07-2008, 10:07 AM
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06-09-2008, 03:14 AM
#56
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ive been running psi beehive springs on my std l92 heads,on my 427, with .630",only turning to 6500rpm,touch wood,have been fine,moly pushrods are definetly required.
cheers dave.
vn commodore,iron 427,dd,still waiting on street warrior.
cheers dave.
vn commodore,iron 427,dd,still waiting on street warrior.
06-09-2008, 07:04 PM
#57
Does anyone know thew REV part number for the intake valve? The Manley which I have are 2.165 and eat up about .030" at the head end taking away from the P/V clearance. Does anyone know if the Rev's are the same deal or are they a better fit?
06-10-2008, 09:50 AM
#58
I would not worry, we had a timing chain break on a customers car and it bent the valve like in the pic above, but did not break it. New valves and a new timing chain, and its back on the road with over 12k miles on the setup.
My personal car had REV intakes, but now has stock hollow stems
My personal car had REV intakes, but now has stock hollow stems
03-18-2009, 12:05 AM
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03-18-2009, 12:50 AM
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I would not worry, we had a timing chain break on a customers car and it bent the valve like in the pic above, but did not break it. New valves and a new timing chain, and its back on the road with over 12k miles on the setup.
My personal car had REV intakes, but now has stock hollow stems
My personal car had REV intakes, but now has stock hollow stems