where to buy isky red zones or crower severe duty
12-24-2007, 06:52 AM
#21
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12-24-2007, 09:11 AM
#22
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Dick, more lift less duration = more aggresive profile, will not help. Have you checked the springs on disassembly? Have they lost significant pressure? That's a good indicator of float. Are the spring shims beat up? Also - look at the valve tips. Is there 1 or just a couple of distinct wear lines from the roller tip (a good thing)? If not floating the valve does not really rotate. If the tip looks frosted you can bet it is floating.
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Marc
www.mercruiserparts.com
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www.bammarine.com
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12-24-2007, 09:15 AM
#23
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Dick,
Why Isky Ez-roll lifters? Does anybody really know if they are more reliable? If you hunt around on the internet, you will see that the Schubeck lifters are not fail-safe. Is it the bearings that are causing the failures? The industry doesn't think so as most use needle bearings. All (most) the NASCAR Bush and Truck teams use the Jessel .937 lifter w/the 850 wheel (mostly keyed lifters). Why...they don't fail. They are also pricey at $2500 set for the keyed, dogbone or tiebar style...probably cheap compared to a failure at 6000 RPM. These teams have also done a lot of SpinTron testing to make sure the lifter is tracking the cam with no lifter bounce on back side of the cam...soft landing. In my opinion, this stability outweighs the parts.
SpinTron is like dyno testing for the valve train. My limited SpinTron experience would say that your cam profile is suspect for an endurance application because of your cam damage (assuming the Rockwell is within spec). To get control of the lifter, the main varibles you adjust are the springs and pushrods....if this doesn't get you stablized, you are probably looking at the cam profile. You have not hurt yourself with the bigger stiffer pushrods....like sex, it is hard to have too much! We have our valve train stable and close to perfect up to 7000 RPM with 1.55 springs @ 230 lbs. seat pressure.
If you are interested, it would be easier for me to talk than type.
Why Isky Ez-roll lifters? Does anybody really know if they are more reliable? If you hunt around on the internet, you will see that the Schubeck lifters are not fail-safe. Is it the bearings that are causing the failures? The industry doesn't think so as most use needle bearings. All (most) the NASCAR Bush and Truck teams use the Jessel .937 lifter w/the 850 wheel (mostly keyed lifters). Why...they don't fail. They are also pricey at $2500 set for the keyed, dogbone or tiebar style...probably cheap compared to a failure at 6000 RPM. These teams have also done a lot of SpinTron testing to make sure the lifter is tracking the cam with no lifter bounce on back side of the cam...soft landing. In my opinion, this stability outweighs the parts.
SpinTron is like dyno testing for the valve train. My limited SpinTron experience would say that your cam profile is suspect for an endurance application because of your cam damage (assuming the Rockwell is within spec). To get control of the lifter, the main varibles you adjust are the springs and pushrods....if this doesn't get you stablized, you are probably looking at the cam profile. You have not hurt yourself with the bigger stiffer pushrods....like sex, it is hard to have too much! We have our valve train stable and close to perfect up to 7000 RPM with 1.55 springs @ 230 lbs. seat pressure.
If you are interested, it would be easier for me to talk than type.
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12-24-2007, 10:10 AM
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i have found a lot of lifter failure is due to loose adjustment and weak spring pressure i am running the redzone with good results for now. I am runnig a spring pressure of 230 on the seat but i do not adjust the valves as the manf. says i set them tighter.
12-24-2007, 12:54 PM
#28
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Very interesting, You are not the first to suggest this to me BTW.
How do you determine aggressiveness? Lift divided by duration?
Either way. Thats is .020 tighter than where I am at. I need to be cognizant of coil bind too. I generally stay at .070" from bind, and you?
How do you determine aggressiveness? Lift divided by duration?
Either way. Thats is .020 tighter than where I am at. I need to be cognizant of coil bind too. I generally stay at .070" from bind, and you?
12-24-2007, 01:13 PM
#30
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Marc,
I have not yet pulled the motor down to check spring presures. I checked them when I installed the new lifters, 20hrs ago, they all checked good with little variation, 280 seat, 675 at .700 lift. I will look at the valve tips, in the past it was one or two lines where the roller made contact. I will look for the frosted tips... good tip (sorry about the pun )..
)
I discussed the issue of less duration more lift = more aggressive profile with the cam manufacture. I was told that the difference between advertised duration (.020") and duration at .050" determines the aggressiveness of the profile. The larger the diff the more aggressive the profile.
The old cam came out with a diff of 35.2* In. 40.9* Ex.
The new cam comes out to 31.6* In. 34.3* Ex.
So what they are telling me is that the new cam is less aggressive. They are the experts I guess, so I have to put some faith into what they say. But logic tells me what you are saying may be true also. I would like to map each lobe and see how it falls into play. Buddy of mine pointed out that my flat tappet cam had over .700 lift but the ramp wasnt as steep.??
Ben,
I am running a .903 lifter in a bushed bore that was cut on a 5 axis CNC, suppose to be right?? The Schubeck lifter had a .775" wheel I believe. The Isky has an .850 wheel. Isky's says they see wheel deflection on the spintron with the needle bearings and not with the solid bushings. The Schubecks used a similar theory with the ceramic wheel riding on oil psi. They worked good, but the outer case cracked on two of them. I would be still running them if Joe hadnt gone under. I had 90hrs total on the Schubeck lifters before failure.
The damage to the lifter wheels was like imbedded metal in the surface of the wheel. I will post a pic ...
I would love to chat with you Ben, if you want to pm me your number I will give you a call. Tell me when a good time is for you.
Mike, my cam is not a close lash cam. I dont think you can tighten up my lash from .025" to much below .020" without doing damage, from what I have been told.
Keep these ideas coming.. all very good info..
Thanks
Dick
I have not yet pulled the motor down to check spring presures. I checked them when I installed the new lifters, 20hrs ago, they all checked good with little variation, 280 seat, 675 at .700 lift. I will look at the valve tips, in the past it was one or two lines where the roller made contact. I will look for the frosted tips... good tip (sorry about the pun )..
)I discussed the issue of less duration more lift = more aggressive profile with the cam manufacture. I was told that the difference between advertised duration (.020") and duration at .050" determines the aggressiveness of the profile. The larger the diff the more aggressive the profile.
The old cam came out with a diff of 35.2* In. 40.9* Ex.
The new cam comes out to 31.6* In. 34.3* Ex.
So what they are telling me is that the new cam is less aggressive. They are the experts I guess, so I have to put some faith into what they say. But logic tells me what you are saying may be true also. I would like to map each lobe and see how it falls into play. Buddy of mine pointed out that my flat tappet cam had over .700 lift but the ramp wasnt as steep.??
Ben,
I am running a .903 lifter in a bushed bore that was cut on a 5 axis CNC, suppose to be right?? The Schubeck lifter had a .775" wheel I believe. The Isky has an .850 wheel. Isky's says they see wheel deflection on the spintron with the needle bearings and not with the solid bushings. The Schubecks used a similar theory with the ceramic wheel riding on oil psi. They worked good, but the outer case cracked on two of them. I would be still running them if Joe hadnt gone under. I had 90hrs total on the Schubeck lifters before failure.
The damage to the lifter wheels was like imbedded metal in the surface of the wheel. I will post a pic ...
I would love to chat with you Ben, if you want to pm me your number I will give you a call. Tell me when a good time is for you.
Mike, my cam is not a close lash cam. I dont think you can tighten up my lash from .025" to much below .020" without doing damage, from what I have been told.
Keep these ideas coming.. all very good info..
Thanks
Dick
