LS1 1.8 roller rockers
11-27-2007, 03:55 PM
#22
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wow, I did not think a quick question would lead to this much discussion. I had the aluminums ones, the 1.6's that I bolted onto my LT1. From what I gather, are the Harland Sharps the only ones that bolt directly on for the LS1?
The LS1 valvesprings sure can accomodate .1 more of compression...? There has to be a direct bolt on roller rocker for 1.8 LS1.
The LS1 valvesprings sure can accomodate .1 more of compression...? There has to be a direct bolt on roller rocker for 1.8 LS1.
11-27-2007, 05:01 PM
#23
wow, I did not think a quick question would lead to this much discussion. I had the aluminums ones, the 1.6's that I bolted onto my LT1. From what I gather, are the Harland Sharps the only ones that bolt directly on for the LS1?
The LS1 valvesprings sure can accomodate .1 more of compression...? There has to be a direct bolt on roller rocker for 1.8 LS1.
The LS1 valvesprings sure can accomodate .1 more of compression...? There has to be a direct bolt on roller rocker for 1.8 LS1.
11-27-2007, 05:04 PM
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I have YT 1.7's on both of my cars. They work great, but may be a little to noisey for some. I could care less how loud/quiet they are. No issues with clearance during or after installation. They saved my *** on my '99 in October. I broke a rocker stud on the exhaust side on #6. The intake stud held together, and the shaft mounted design saved me from having a rocker arm floating around in the head. Would have sucked if I would have lost a valve spring
YT's aren't cheap, but are top quality.
YT's aren't cheap, but are top quality.
11-27-2007, 06:33 PM
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wow, I did not think a quick question would lead to this much discussion. I had the aluminums ones, the 1.6's that I bolted onto my LT1. From what I gather, are the Harland Sharps the only ones that bolt directly on for the LS1?
The LS1 valvesprings sure can accomodate .1 more of compression...? There has to be a direct bolt on roller rocker for 1.8 LS1.
The LS1 valvesprings sure can accomodate .1 more of compression...? There has to be a direct bolt on roller rocker for 1.8 LS1.
11-27-2007, 09:10 PM
#26
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Hey Vettenuts,
How does acceleration speed up? you lost me. due to increased lift, the valve technically is just open longer.
what do you all mean by "wipe"?
How does acceleration speed up? you lost me. due to increased lift, the valve technically is just open longer.
what do you all mean by "wipe"?
11-28-2007, 07:14 PM
#27
The cam remains the same so the angular movement from closed to open happens in the same amount of rotation. Since in that time the valve opens further, the accelerations must be higher. Put another way, if the cam is spinning at a constant RPM and has to lift .5 or .6, the acceleration on the .6 has to be higher because it has farther to travel. This is assuming a constant rocker ratio for the full movement, which is not the case. The stock rocker starts out at 1.54 and then increases as it rotates to 1.7 when fully open. Compare that to a Crane 1.7 rocker that starts movement off the seat at 1.79 and then decreases to 1.72 at fully open. So comparing 1.7 rockers to 1.7 rockers can result in different valve motions too.
The wipe is the area that the rocker sweeps across the valve stem during the open-close sequence. The stock rockers and many aftermarket rockers sweep from the intake side out until maximum lift is achieved and then back across the valve to the intake side again during closing. When the valve is all the way open, you spring forces are maximized as well. So if the rocker is way out towards the edge of the valve stem, you have side loads into the valve guides and this will accelerate valve guide wear. With a fixed fulcrum rocker like the stock or Yella Terra, the contact position on the valve stem when closed and open can be adjusted by moving the rocker fulcrum up and down relative to the valve. For example, I recently installed a set of Yella Terra's on a friends stock heads. When we checked the wipe pattern, it was not centered on the valve but rather closer to the intake side. We then raised the rocker fulcrum with the supplied shims by 0.050" and the wipe pattern was less than 0.060" wide and centered on the valve stem.
Comp cams and a few other web sites have some nice diagrams that will make more sense if you can find them.
The wipe is the area that the rocker sweeps across the valve stem during the open-close sequence. The stock rockers and many aftermarket rockers sweep from the intake side out until maximum lift is achieved and then back across the valve to the intake side again during closing. When the valve is all the way open, you spring forces are maximized as well. So if the rocker is way out towards the edge of the valve stem, you have side loads into the valve guides and this will accelerate valve guide wear. With a fixed fulcrum rocker like the stock or Yella Terra, the contact position on the valve stem when closed and open can be adjusted by moving the rocker fulcrum up and down relative to the valve. For example, I recently installed a set of Yella Terra's on a friends stock heads. When we checked the wipe pattern, it was not centered on the valve but rather closer to the intake side. We then raised the rocker fulcrum with the supplied shims by 0.050" and the wipe pattern was less than 0.060" wide and centered on the valve stem.
Comp cams and a few other web sites have some nice diagrams that will make more sense if you can find them.
12-13-2007, 03:42 PM
#28
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crane cams LS1 1.8 quick lift rocker arm kit= #144759-16
this is a complete kit, which includes everything that you need besides valve springs. I recommend dual springs, either there #144832 or #144833-16 springs. They will also require there spring locators #144460-16 and new gm seals for there direct bolt in replacement.
this is a complete kit, which includes everything that you need besides valve springs. I recommend dual springs, either there #144832 or #144833-16 springs. They will also require there spring locators #144460-16 and new gm seals for there direct bolt in replacement.
