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Pushrod length with 2116LSR ,LS7: did heads, lifters and new pushrods over a year ago. 505hp to the wheels . Stock cam, headers, no cats. I measured my pushrods at the time and ordered/installed. Been running great. It’s a sewing machine like a typical LS. I assumed maybe I had too short pushrods and maybe I could tighten them up a little bit. I had the transmission out, waiting on parts so I decided I would re-measure but this time I used a spring loaded checker with a set screw to get it as accurate as possible. The 2116lsr preload is +.045 on a cold motor. With the new checker I’m getting +.069. Is 2 hundredths of an inch too long really something worth getting new pushrods for? That’s about the thickness of 4 sheets of paper. I can’t see that as a problem but what do I know?
29 thousandths over the upper spec limit is significant. My guess is Johnson made their spec limits tighter than absolutely necessary so a little beyond the spec limits wouldn't hurt anything. I'd try to get closer than 29 thousandths over the USL though.
When I had measurement issues on my 2126 short travels, it was hanging the exhaust valves open. The MS checker is the ****, unfortunately it doesn't fit my tfs heads, so I have never got to use mine on my own car lol
Johnson's preload specs don't say whether they are for hot or cold. Given that the LS doesn't have adjustable preload by turning the rocker stud bolt, I'd hope that they spec a cold pre-load. A hot pre-load is pretty useless since you have to measure pushrod length and pre-load before you have any pushrods. If you were trying to measure a hot pre-load, what then... order a set of best-guess pushrods, run the motor up to temperature, then pull measure for each pushrod length once the motor is hot.
Then again, I think it was common on SBC to specify pre-load specs as hot pre-load by default since there was a way to adjust them to zero lash and add turns to set the right pre-load hot. So it wouldn't be too surprising if that standard carried over to the LS.
Hrmm... I just built an LS3 race motor and I set them up to 0.035 +/-0.05 cold.
Johnson's preload specs don't say whether they are for hot or cold. Given that the LS doesn't have adjustable preload by turning the rocker stud bolt, I'd hope that they spec a cold pre-load. A hot pre-load is pretty useless since you have to measure pushrod length and pre-load before you have any pushrods. If you were trying to measure a hot pre-load, what then... order a set of best-guess pushrods, run the motor up to temperature, then pull measure for each pushrod length once the motor is hot.
Then again, I think it was common on SBC to specify pre-load specs as hot pre-load by default since there was a way to adjust them to zero lash and add turns to set the right pre-load hot. So it wouldn't be too surprising if that standard carried over to the LS.
Hrmm... I just built an LS3 race motor and I set them up to 0.035 +/-0.05 cold.
an aluminum block and aluminum head will grow 0.010-0.012" at temp. So you'd want to be on the tighter side when setting it all up on a cold engine
Preload specs are always to be sought after with a cold engine. I’ve never seen a lifter manufacturer that lists preload specs for a hot engine…or at least I can’t remember ever seeing a lifter manufacturer that lists hot specs. Speaking of hydraulic cams here. Solid camshafts are different of course.
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LS7 Johnson lifter preload too much? 
