Pushrod length - Camaro5 Chevy Camaro Forum / Camaro ZL1, SS and V6 Forums

Rem0v3r · 07-20-2020, 07:14 PM

Trying to figure out the correct length.
Head and deck milled flat, swapped from l99 cam to a tsp turbo stage 2 ls3 cam..

With the pushrod length checker I cam up with a length of 7.33.. now they're sold at either 7.3 or 7.35.. at zero lash.

I think I misunderstood when I read I had to add preload to the pushrod and took that as needing a longer rod.. with .70 thou it sets the rod at 7.4..and 7.4 rods wont let the rocker sit down on the metal bar at zero lash..

The tsp service rep says that's fine.. I'm having a hard time buying that ideology... can anyone chime in plz?

larry_g · 07-20-2020, 07:55 PM

If you measure at zero lash and then add for lifter preload, the rocker won't sit all the way down at zero lash. Tightening it from that point is how you preload the lifter.

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Rem0v3r · 07-20-2020, 08:30 PM

Quote:

Originally Posted by larry_g

If you measure at zero lash and then add for lifter preload, the rocker won't sit all the way down at zero lash. Tightening it from that point is how you preload the lifter.

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So then is it normal that at zero lash I can twist the rocker off the spring sideways?

sdynak · 07-20-2020, 08:46 PM

Yes if you are pushing in the lifter plunger by doing so.

larry_g · 07-20-2020, 08:57 PM

Quote:

Originally Posted by Rem0v3r

So then is it normal that at zero lash I can twist the rocker off the spring sideways?

If you are on the base circle of the cam, it should only take a couple of turns of the rocker bolt to get tight. In theory, there should only be another 70 thousandths (preload) until it seats. If it's really far off, you are either not on the base circle or something wasn't measured right.

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Greenhornet2 · 07-21-2020, 08:11 AM

From my understanding. When you measure and get 7.33 that is with 0 preload on the base circle. Now you must add to the length of the pushrod to get your preload for the lifter. If you wanted 0.070" preload you add 7.330+0.070 and you get 7.4" exactly. If you wanted 0.040" preload you would get 7.37 pushrod length and so on. I don't know what the factory preload spec is. I know some aftermarkets only want 0.030 and have small windows but I am pretty sure the factory ones like more preload and have a larger window.

acammer · 07-21-2020, 08:36 AM

What lifters are in there car?

07-20-2020, 07:14 PM	#1
Rem0v3r Drives: 2013 ss2 vert l99 Join Date: Apr 2017 Location: South florida Posts: 151	Pushrod length Trying to figure out the correct length. Head and deck milled flat, swapped from l99 cam to a tsp turbo stage 2 ls3 cam.. With the pushrod length checker I cam up with a length of 7.33.. now they're sold at either 7.3 or 7.35.. at zero lash. I think I misunderstood when I read I had to add preload to the pushrod and took that as needing a longer rod.. with .70 thou it sets the rod at 7.4..and 7.4 rods wont let the rocker sit down on the metal bar at zero lash.. The tsp service rep says that's fine.. I'm having a hard time buying that ideology... can anyone chime in plz?

07-20-2020, 07:55 PM	#2
larry_g Drives: 2014 1SS/1LE Join Date: Nov 2015 Location: Louisville, KY Posts: 886	If you measure at zero lash and then add for lifter preload, the rocker won't sit all the way down at zero lash. Tightening it from that point is how you preload the lifter. Sent from my Pixel XL using Tapatalk __________________ 830 WHP 700 WTQ, Whipple 2.9 @ 13lbs Boost, Flex Fuel Tune by Blevins Tuning, LSA SBE, 3.5 GripTec, ATI LS3 Damper, AFR 260cc Mongoose, ARP Studs, Yella Terra Ultralites, Johnson 2110R, BTR PDS Stage 3, Melling 10355, Improved Racing Baffle, ID1050X, DSX Triple Fuel Pump, RotoFab CAI, NW 103mm TB, Stainless Works 1-7/8" LTH to 3" Speed Eng w/ X-pipe to NPP, Powermaster 9509 XS, Detroit Speed Motor Mounts, MGW, Monster LT1-S, ZL1 Calipers, DBA Rotors & Pads, Bilstein B6 Struts & Shocks, BMR 1.25" Drop Springs & Adj Rear Bar, Pegasus Solid Bushings, Z/28 Wheels, other misc parts.

07-20-2020, 08:46 PM	#4
sdynak Drives: 2014 ZL1 Join Date: Aug 2015 Location: Bayville, NJ Posts: 948	Yes if you are pushing in the lifter plunger by doing so. __________________ 2014 ZL1 Black All OEM, Manual SOLD: 2010 1SS LS3, Black, 235/250, .621/.615, 114 + 4, Kooks Stepped Headers, 3.91's, Bo White PTB, Flowmaster Mufflers, Cold Air Industries CAI, Apex Scoop & Windshield Washer Relocate, SLP Wheels, Skip Shift Eliminate, Barton Flat Stick, OEM HID/Halos, Dyno Tuned by ECS

07-21-2020, 08:11 AM	#6
Greenhornet2 Drives: 2011 Camaro 2SS LS3 Whipple Join Date: May 2019 Location: Connecticut Posts: 1,925	From my understanding. When you measure and get 7.33 that is with 0 preload on the base circle. Now you must add to the length of the pushrod to get your preload for the lifter. If you wanted 0.070" preload you add 7.330+0.070 and you get 7.4" exactly. If you wanted 0.040" preload you would get 7.37 pushrod length and so on. I don't know what the factory preload spec is. I know some aftermarkets only want 0.030 and have small windows but I am pretty sure the factory ones like more preload and have a larger window. __________________ Whipple 2.9 CAI ID1050x injectors ZL1 Pump JRE FPCM JMS Voltage booster JRE Rough Idle blower cam BTR .660 springs CHE trunnion kit 1 7/8 Speed Engineering Borla Atak JRE scoop 1.5" lowering springs BMR trailing arms and toe links Cradle inserts 704WHP 603WTQ 93 octane

07-21-2020, 08:36 AM	#7
acammer GPI Sales Consultant Drives: 2011 Camaro 2SS SGM Join Date: Jul 2016 Location: Weedsport, NY Posts: 3,016 View My Garage	What lifters are in there car? __________________ GPI Max Package 2.0: Brodix BR7 heads/GPI porting, MAX3 cam, ST2116LSR, BSR Max Lift rockers, LS7 LSXR with 103mm TB, Vararam OTR, Mcleod RXT, G-Force/Strange 9" IRS setup with 4.63 gear. 551whp, 11.1@124mph. *Got a question about a GPI product? Feel free to shoot me a message!*