HP and changing lifters and rockers
lol 
01-04-2007, 07:06 PM
#3
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Phil,
I think that the factory hydraulic roller lifters are excellent pieces. I have run the stock ones in my highly modded '87 IROCZ for 18 years. And in my '99, I have documented 400 RWHp and trap speeds of 117mph and shift at 6500 rpm, they have held up very well also. However, I think that the stock LS1 rockers will suffer a needle bearing failure. Some I have read on here at about 80,000 miles, but then again, these are highly modded engines.
Does this help ?
I think that the factory hydraulic roller lifters are excellent pieces. I have run the stock ones in my highly modded '87 IROCZ for 18 years. And in my '99, I have documented 400 RWHp and trap speeds of 117mph and shift at 6500 rpm, they have held up very well also. However, I think that the stock LS1 rockers will suffer a needle bearing failure. Some I have read on here at about 80,000 miles, but then again, these are highly modded engines.
Does this help ?
01-05-2007, 07:05 AM
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I upgraded to the LS7 factory lifters in my car. They should be good for about anything most people will throw at them and they are cheap, less than $100 for a set. If you are really worried about the rockers, just send them to Harland Sharp and have them rebuild them for you. Again, thats about all most of us would ever need.
01-05-2007, 11:34 AM
#6
I have a completely different philosophy on all of this, one that many won't agree with. When you install an aftermarket cam, you lower the base circle and thereby lower the lifter in the bore. The stock lifters have shown on occasion oil starvation issues as a result. I went with Morels to ensure that this didn't occur since in their development work they ran into this same problem and corrected it.
As for the rockers, I couldn't get a decent wipe pattern out of the stockers and have gone to roller rockers as a result. The bearings were less of a concern then was the potential for accelerated guide wear with a rocker that wasn't placed correctly on the valve stem and much higher spring loads. Again, stock rockers are good pieces, but they were designed for lower spring loads and therefore the tolerance on the wipe pattern was not as critical. Start upping the over the nose spring loads and wipe pattern gets more critical in a hurry.
None of this is related to hp but rather the installed setup of the valve train you are running. Z06 valve springs will provide good hp with the right cam but don't provide nearly the valve train loads as something like Comp 921's.
As for the rockers, I couldn't get a decent wipe pattern out of the stockers and have gone to roller rockers as a result. The bearings were less of a concern then was the potential for accelerated guide wear with a rocker that wasn't placed correctly on the valve stem and much higher spring loads. Again, stock rockers are good pieces, but they were designed for lower spring loads and therefore the tolerance on the wipe pattern was not as critical. Start upping the over the nose spring loads and wipe pattern gets more critical in a hurry.
None of this is related to hp but rather the installed setup of the valve train you are running. Z06 valve springs will provide good hp with the right cam but don't provide nearly the valve train loads as something like Comp 921's.
01-05-2007, 03:33 PM
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I dont think too many people would disagree with you per say. Some might think that is a bit overkill, but to each their own.
The issue with the lifters being lowered .050" is probably not a serious concern unless you are talking about a max effort engine. The rocker issue is about the same. That said, the details are what makes the difference...
The issue with the lifters being lowered .050" is probably not a serious concern unless you are talking about a max effort engine. The rocker issue is about the same. That said, the details are what makes the difference...
