Build Thread - 85 IROC 402 LS3 6 speed
#251
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Car: 91 firebird formula, black
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Re: Build Thread - 85 IROC 402 LS3 6 speed
hi jim, i stumbled onto your build thread recently... read it through... awesome pics!!! that thing is gonna rock! cant wait to hear it! hint, hint...
#253
Re: Build Thread - 85 IROC 402 LS3 6 speed
Note to self: Don't bother measuring pushrod lengths if you're going to write their length in Sharpy until you're ready to clean them with brake cleaner first, otherwise you get a bag full of blue pushrods with no legible writing on them.
So last night I re-measured them after cleaning them with brake cleaner, and lined them up in order of length. I matched these to the 16 corresponding valves based on the measurements I made with the pushrod length checker. This allowed me to line up the longest pushrods with the valves that needed the longest, and the shortest with the shortest. As a result, I wound up with a lifter preload variation of about +/- .005", with a maximum preload of .050 and a minimum of .042. This preload value may give me a little valvetrain noise, but at least I'll know that my valves are opening fully. These LS7 lifters seem to have a pretty generous compression range. After I tightened my pushrods down, I could lift them about .2" or .25" off the top of the valve stem by compressing the lifter.
So last night I re-measured them after cleaning them with brake cleaner, and lined them up in order of length. I matched these to the 16 corresponding valves based on the measurements I made with the pushrod length checker. This allowed me to line up the longest pushrods with the valves that needed the longest, and the shortest with the shortest. As a result, I wound up with a lifter preload variation of about +/- .005", with a maximum preload of .050 and a minimum of .042. This preload value may give me a little valvetrain noise, but at least I'll know that my valves are opening fully. These LS7 lifters seem to have a pretty generous compression range. After I tightened my pushrods down, I could lift them about .2" or .25" off the top of the valve stem by compressing the lifter.
#255
Re: Build Thread - 85 IROC 402 LS3 6 speed
Looks like I forgot to update this last week. Although my progress was minor, it kind of marked a milestone. I got my pushrods installed, which officially makes the motor "Done". I've ordered the rest of the parts I need to complete my f-body accessory drive, and those should be here soon. In the meantime, I've been working on the 350 that I pulled out of the car, in preparation of swapping it into my GTA after a head swap. For anybody that's interested in following that build, I started a thread here:
https://www.thirdgen.org/forums/engi...ml#post5210561
In any case, I'll leave this post with a pic of some pushrod candy. These are my 3/8" Manton pushrods after I labelled their lengths again. After I re-measured and marked their lengths, I compared them to the measured heights of all 16 locations, and matched them up so that the longest & shortest corresponded with the longest & shortest measured values. By doing that, I was able to minimize the stack-up of tolerances that I would have had if I just randomly installed them.
https://www.thirdgen.org/forums/engi...ml#post5210561
In any case, I'll leave this post with a pic of some pushrod candy. These are my 3/8" Manton pushrods after I labelled their lengths again. After I re-measured and marked their lengths, I compared them to the measured heights of all 16 locations, and matched them up so that the longest & shortest corresponded with the longest & shortest measured values. By doing that, I was able to minimize the stack-up of tolerances that I would have had if I just randomly installed them.
#256
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Car: 1984 Camaro Sport Coupe
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Re: Build Thread - 85 IROC 402 LS3 6 speed
You have some serious attention to detail!
#257
Re: Build Thread - 85 IROC 402 LS3 6 speed
Thanks dude. Part of my attention to detail is to compensate for my lack of experience. A professional builder knows what things are issues and what aren't. For me, it's a learning experience every time I do something, so I take my time, measure it, and understand it. Though still slow, my 350 upgrade and my 302 upgrade are going much faster.
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