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Sizing pushrods in built LS

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Old Feb 16, 2013 | 05:24 PM
  #1  
five7kid's Avatar
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Sizing pushrods in built LS

For the stroked LQ4 I'm building, reminder this is the cam:

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And 823 L92 heads. The LS book I have says to put the valve at half lift and check if the rocker is on the middle of the stem, but that seems a bit weird. I checked for zero lash with an adjustable pushrod, and came up with 7.355".

I remember seeing someone post to go for .050" to .100" preload. If that's correct, then I should get pushrods that are 7.405" to 7.455" long. Stock are 7.400", I believe.

Tried searching, didn't find anything meaningful.
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Old Feb 18, 2013 | 12:00 AM
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five7kid's Avatar
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Well, my son's 5.7 came with TSP .080 wall 7.425" push rods and an unknown lumpity cam. He's put an LS6 cam in it after a refresh, and those push rods seem too long. So, he's going to put a set of LS6 push rods I had laying around, and I'm going to use his TSP push rods. Win/win, I think.
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Old Feb 19, 2013 | 03:04 PM
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cam-'s Avatar
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From: In the Garage
Car: Camaro
Engine: 6.2L
Transmission: T56
Re: Sizing pushrods in built LS

50-80 is where you want to be. 100 is too much for safety sake imo. IIRC 1 turn of the rocker arm bolt is 45 thou

Adjustable pr length checker is what you need
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Old Feb 19, 2013 | 07:46 PM
  #4  
five7kid's Avatar
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Re: Sizing pushrods in built LS

I used an adjustable push rod to establish zero plunger preload.

The 7.425" pushrods will put me at .070" plunger preload. Close enough, eh?
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Old Feb 21, 2013 | 09:58 AM
  #5  
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Car: seeking '90.5-'92 'bird hardtop
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Re: Sizing pushrods in built LS

Looks like win / win to me.
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Old Feb 25, 2013 | 05:47 PM
  #6  
five7kid's Avatar
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Joined: Mar 2000
Posts: 43,187
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Probably is. He isn't squawking about giving up his fancy aftermarket pushrods for factory pieces: but then he knows I'm using them in my LS6-clone in the Camaro and they're doing fine, plus he probably realizes I haven't said anything yet about reimbursement for his rings that I included with an order for my own stuff from Summit...
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Old Feb 25, 2013 | 05:54 PM
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Engine: 6.2L
Transmission: T56
Re: Sizing pushrods in built LS

Ya 70 is a go imo
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