Question on LS7 lifter preload and Pushrod length.
#11
TECH Veteran
iTrader: (5)
Sorry, I don't know what I was thinking. My morning pill must have not kicked in yet when I posted.
No, I never understood that you already have the tool. I hope you accept my apology.
Originally Posted by 07NBSChevy
and I do have a pushrod length tool. You do not seem to be to keen on this do you?
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#12
TECH Apprentice
iTrader: (2)
Another question on a somewhat different topic. For torquing down the rocker arms it is recommend to do 22 ft. lbs. which should be 1 to 1-3/4 revolutions. I am using ARP Rocker Arm Studs instead of the OEM bolts. ARP recommends a torque of 25 ft. lbs. Now which torque should I use when using the pushrod length checker to determine to correct length?
#13
Launching!
Thread Starter
I was just giving you a hard time.. no wories man. Heck, I wish I new more about getting the desired pushrod length, and I was an engine tech for GM back in the day. Tho it was something I never did because I never did cam swaps at the dealership.
#14
Launching!
Thread Starter
It doesn't really matter what torque spec you use when using the pushrod length checker, rockers will be tight. You are using the known minimum length of pushrod checker + desired preload amount + thread pitch of length checker X number of turns to get to zero lash. Thread pitch is .05"
#15
Launching!
Thread Starter
Also, I forgot to ask. Is it necessary to measure all 16 pushrods for each cylinder or do I just need to do one cylinder? I am currently going to use cylinder #1 and measure intake and exhaust.
#16
Launching!
Thread Starter
So messed around with it today and started with 7.350"
-On intake I got 22 ft lbs at 1-1/2 turns which is 0.0705 Preload.
-On exhaust I got 22 ft lbs at a tad over 1-1/2 turns which is roughly 0.075 preload
I tried 7.375" and got 22 ft lbs at 1-7/8 turns which is 0.135 preload and way to much. Also tried 7.325" and it was to short.
So looks like 7.350" pushrods and 0.070-.0075 preload is going to be it. I will check again tomorrow since I am a bit tired and do not want to do this twice.
-On intake I got 22 ft lbs at 1-1/2 turns which is 0.0705 Preload.
-On exhaust I got 22 ft lbs at a tad over 1-1/2 turns which is roughly 0.075 preload
I tried 7.375" and got 22 ft lbs at 1-7/8 turns which is 0.135 preload and way to much. Also tried 7.325" and it was to short.
So looks like 7.350" pushrods and 0.070-.0075 preload is going to be it. I will check again tomorrow since I am a bit tired and do not want to do this twice.
Last edited by 07NBSChevy; 01-09-2017 at 02:17 AM.
#19
Launching!
Thread Starter
I did figure it out. Thanks for all the help guys. The ARP Head Studs, #234-7207, The nut is a 24 threads per inch. I did try today with torquing them down to 25 ft lbs and noticed I got another 1/32 or less, more of a turn, which is not really going to effect much. Either way both Intake and Exhaust valves I got 25 ft lbs between 1-5/8 and 1-7/8 turns, at least on cylinder 1, so 0.076375 on exhaust and 0.088125 on intake. Even if I go over .083 preload shouldn't hurt, I read that .070 thru .090 preload from center travel of 0.08307085 is ideal for up to 6200 rpm. I will triple check everything once the pushrods come in. I am going with Comp Cams 5/16 7.350" .105 wall. I really wanted Manton 5/16 Series 3 .118 wall pushrods but they said there is some wait time since they were not stocked, and the Mantons were $30 more.
Can someone explain to me the purpose of using tapered pushrods over straight ones?
All you had me wondering about the arp difference on the ARP so I did a test. I am hoping it works out in my favor and maybe this is why ARP recommends 25 ft lbs instead of 22.
So I used the 7.350" pushrod checker and used the ARP stud and started with the exhaust vale. I got 25 ft lbs at 1-5/8 turns. I found my stock rocker bolt and did the same thing at 22 ft lbs. I got 22 ft lbs at 1-5/8 turns. I moved on to the intake valve now. With the ARP Stud I got 25 ft lbs at 1-7/8 turns. Used the stock rocker bolt and got 22 ft lbs at 1-7/8 turns. So I am wondering if the added torque equals out with the ARP over the stock bolt.
Can someone explain to me the purpose of using tapered pushrods over straight ones?
All you had me wondering about the arp difference on the ARP so I did a test. I am hoping it works out in my favor and maybe this is why ARP recommends 25 ft lbs instead of 22.
So I used the 7.350" pushrod checker and used the ARP stud and started with the exhaust vale. I got 25 ft lbs at 1-5/8 turns. I found my stock rocker bolt and did the same thing at 22 ft lbs. I got 22 ft lbs at 1-5/8 turns. I moved on to the intake valve now. With the ARP Stud I got 25 ft lbs at 1-7/8 turns. Used the stock rocker bolt and got 22 ft lbs at 1-7/8 turns. So I am wondering if the added torque equals out with the ARP over the stock bolt.
Last edited by 07NBSChevy; 01-11-2017 at 01:43 AM.