LT1-LT4 Modifications 1993-97 Gen II Small Block V8

What causes a collapsed lifter???

Old 02-17-2009, 02:38 PM
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Originally Posted by Low N Slow
You need to make a solid lifter or put in a weak valve spring to check pushrod length. Without doing it you are collapsing the lifter and can't get an accurate reading.
Good point! I didn't catch that.
Old 02-17-2009, 06:02 PM
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One other basic question....How much preload are you adjusting into the lifters? Also, are you setting them statically, or with the engine running?
Old 02-17-2009, 07:53 PM
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yea, I figured the solid lifter, thanx though. As far as preload goes, I am using the engine running method and 1/4 turn preload. Is it possible to collapse the lifter with too much or too little preload?
Old 02-18-2009, 05:02 AM
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I just bought pro mag 1305's from Lopers speed on ebay. $250 including shipping. Best price I could find new, if your looking to go that route.

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Old 02-18-2009, 08:22 AM
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Originally Posted by ryle
.... As far as preload goes, I am using the engine running method and 1/4 turn preload. Is it possible to collapse the lifter with too much or too little preload?
I would say yes. IIRC, the original question revolved around the LS7 lifters. Since they weren't "OE" for the LT-1 engine, I would think that there might be a queston of what to use for a preload adjustment.

Several years ago, I thought I had a stock lifter getting a little noisy, so I put in a new set. I had the time, while the car was down for the winter. being a "performance oriented" guy, I got a set of the CompCams 875R lifters, 'cause they were supposed to be a "performance upgrade".

The instructions said 1/8 turn of preload, but at that setting, they were a little noisy. So, I set them at 1/4 turn. A while later, I had another question come up, so I called CompCams tech line, and while discussing the original question, I brought up the preload setting for the 875Rs.

Their tech rep was very concerned that I didn't follow their instructions, and he explained why their lifters required only 1/8 turn of preload, and yes, their design is such that they are inherently a little noiser that OE lifters.

But, going back to the LS-7 lifters, they were originally designed for the LS series of engines, which don't really have any adjustment, at least from the factory. Also, there have been a few discussions here, as to whether the LS7's plunger sits a little lower in the lifter body, creating a "shorter" lifter. If so, that might call for longer pushrods, as well as a different preload.
Old 02-18-2009, 12:35 PM
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Yea, i am kinda concerned with getting the right pushrod length. I made a solid lifter last night and in order to get the proper wear pattern on my valvestem i had to go as short as 7.000". I am assuming that the reason for such short PR is because I had to have my heads milled in order to straighten them out (the previous owner took a wire wheel to them to remove the old gasket and put all kinds of divots in the heads). That combined with me using a felpro gasket instead of a stocker. I am concerned because with the particular rocker that I'm using, if the lifter is shorter, I may run into trouble with the rocker hitting on the base of my rocker studs.


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