pushrods
Team Owner
Joined: Mar 1999
Posts: 22,025
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From: At the beach in little Rhody
Here is the GM procedure if you need it.
Here is the GM procedure for rocker installation. Note that you need to know where the piston is on the firing stroke to use this method.
Last edited by vettenuts; Jul 31, 2017 at 01:33 PM.
Melting Slicks
Joined: Jun 2014
Posts: 2,207
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From: NJ
ok i got the cam dot at 12 o'clock and the crank dot at 12 o'clock.
I put the push rod checker at 7.283 and put it in the exhaust in cylinder # 6. I tightend the rocker bolt with only a socket and my hand. The tick tick went away.
Now, do I take out the push rod checker and put in a stock pushrod?
If yes,
Next do I line up the dial indicator to the oil hole in the rocker and torque to 22 ft-lb?
I understand i need to depress the plunger of the dial indicator some befor zeroing it.
Wheres a good place to mount the magnetic base?
I put the push rod checker at 7.283 and put it in the exhaust in cylinder # 6. I tightend the rocker bolt with only a socket and my hand. The tick tick went away.
Now, do I take out the push rod checker and put in a stock pushrod?
If yes,
Next do I line up the dial indicator to the oil hole in the rocker and torque to 22 ft-lb?
I understand i need to depress the plunger of the dial indicator some befor zeroing it.
Wheres a good place to mount the magnetic base?
Nevermind I see the LS engines, as shown in above post, are diff from the traditional V-8's
Last edited by 1Hotrodz; Jul 31, 2017 at 01:37 PM.
Thread Starter
Burning Brakes
Joined: Jan 2008
Posts: 1,235
Likes: 51
Not sure I understand, was the dial indicator still reading that value once removed? Do you have a "hold" button on it (noticed its digital)? When you did this, you essentially set and measured the lifter preload directly.
Here is what I am seeing. Some guys with LS1's seem to run the 7.425" pushrods with the MS4. However, you have LS6 heads (correct me if I am wrong) that have a 0.050" longer valve than the LS1 heads. So, 0.050"/1.7 = 0.030" shorter pushrod or 7.395" (0.030" shorter than 7.425") The one you measured is in the ballpark but I am concerned that if they run two different lobes on that cam you may have a different result on the other valve. Best to check it prior to ordering the pushrods.
Before I forget, one word of warning. When you start the motor the lifters will be very noisy because the measuring etc. has pushed some oil out of the lifters. They will need to pump back up so don't be surprised that the lifters are extremely noisy on first start. Just let it idle until they all pump up and are quiet.
Here is what I am seeing. Some guys with LS1's seem to run the 7.425" pushrods with the MS4. However, you have LS6 heads (correct me if I am wrong) that have a 0.050" longer valve than the LS1 heads. So, 0.050"/1.7 = 0.030" shorter pushrod or 7.395" (0.030" shorter than 7.425") The one you measured is in the ballpark but I am concerned that if they run two different lobes on that cam you may have a different result on the other valve. Best to check it prior to ordering the pushrods.
Before I forget, one word of warning. When you start the motor the lifters will be very noisy because the measuring etc. has pushed some oil out of the lifters. They will need to pump back up so don't be surprised that the lifters are extremely noisy on first start. Just let it idle until they all pump up and are quiet.
i just recheck the same exhaust valve on cylinder 6 and the dial indicator read 0.1005
I new i did something wrong the first time around. I did not depress the plunger of the dial indicator deep enough. So it maxed out its travel at the reading I got.
Now the 0.1005, im pretty confident with this #
What does this mean now?
I will check the intake on my munch break!
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
Once you measure the other valve, you should have a good handle on the pushrod length. I would definitely go with a larger pushrod to start. I found when I upgraded my pushrods I could see the change on the dyno above 5,800 RPM indicating some pushrod flex and my cam is not as large as the MS4.
Thread Starter
Burning Brakes
Joined: Jan 2008
Posts: 1,235
Likes: 51
I just measure the intake with the push rod checker and got zero lash by hand with a 7.291 lenght. Droped in the same stock rod as the exhaust valve and found zero lash by hand, then set up dial indicator and torqued to 22 ft-lb and the indicator is reading 0.1105
Is this okay?
What push rod should I order?
7.383 and 3/8ths OD?
Is this okay?
What push rod should I order?
7.383 and 3/8ths OD?
Last edited by Georgies; Jul 31, 2017 at 07:42 PM.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I would first contact TSP and ask if the lobes have two different base circles.
Don't believe 3/8" OD pushrods will fit the stock head, the maximum I have seen guys run is 11/32" OD. If one length, then I guess I would go with the 7.380" unless you want to run two different lengths and have one length for intake and one length for exhaust. That should back the one you measured before to a bit under 0.080" and the one you measured last night to around 0.095".
Don't believe 3/8" OD pushrods will fit the stock head, the maximum I have seen guys run is 11/32" OD. If one length, then I guess I would go with the 7.380" unless you want to run two different lengths and have one length for intake and one length for exhaust. That should back the one you measured before to a bit under 0.080" and the one you measured last night to around 0.095".
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Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
The other valve that you just measured came in at 0.1105". If you go with the 7.383" pushrod, that will reduce to 0.1005" (by math) and going with the 7.380" pushrod will reduce it further to 0.0975".
Your other valve will now reduce to 0.075". You could go to 7.375" to reduce them another 0.005" but at that point you are splitting hairs and there will be a tolerance on not only the pushrods but each valve setup in the motor.
Last edited by vettenuts; Aug 1, 2017 at 10:21 AM.
Thread Starter
Burning Brakes
Joined: Jan 2008
Posts: 1,235
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I also just got off the phone with TSP and the tech said that theirs a .02 difference from intake to exhaust.
should I double check that im on base circle? with a push rod and dial indicator...to see if im actually on the lowest point?
He said that its uncommon to need a shorter push rod than stock...
should I double check that im on base circle? with a push rod and dial indicator...to see if im actually on the lowest point?
He said that its uncommon to need a shorter push rod than stock...
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
I would double check both intake and exhaust on that cylinder. The timing marks are still lined up? I think I would also check #1 as well, just to make sure it is #6 that is on the firing stroke.
Sorry, I thought the 0.110 was on the other valve of cylinder #6. Let's get the new measurements.
Not sure why he said anything about shorter than 7.400" pushrods as the Z06 heads have taller valves and you are directly measuring the preload with a dial indicator. The LS6 valves are 0.6mm or 0.024" longer, which going through the nominal rocker ratio of 1.7 requires a 0.014" shorter pushrod.
(Sorry, post above used 0.050" but that was from memory and wrong. I went back and corrected it.)
Sorry, I thought the 0.110 was on the other valve of cylinder #6. Let's get the new measurements.
Not sure why he said anything about shorter than 7.400" pushrods as the Z06 heads have taller valves and you are directly measuring the preload with a dial indicator. The LS6 valves are 0.6mm or 0.024" longer, which going through the nominal rocker ratio of 1.7 requires a 0.014" shorter pushrod.
(Sorry, post above used 0.050" but that was from memory and wrong. I went back and corrected it.)
Last edited by vettenuts; Aug 1, 2017 at 03:11 PM.
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
OK, I'm confused at this point. I know your new dial indicator reading on one valve of cylinder #6 was .1105 as remeasured but I never saw the other valve of that cylinder. If cylinder #1 is currently at TDC of the firing stroke then those two could be measured instead.
Thread Starter
Burning Brakes
Joined: Jan 2008
Posts: 1,235
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Sorry I meant yes. I thought u were talking about cylinder one.
Cylinder #6;
-intake (push rod checker @ 7.283) preload with dial indicator 0.1005
-Exhaust (push rod checker @ 7.291) preload with dial indicator 0.1105
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
As always, check my math.
Thread Starter
Burning Brakes
Joined: Jan 2008
Posts: 1,235
Likes: 51
what would you do?
My options are, install the 7.4 rods from TSP or order 7.370 from Manton 11/32
Im sorry for all these question, tho i am looking up to you as your by far the most knowledgeable person i know of..
My options are, install the 7.4 rods from TSP or order 7.370 from Manton 11/32
Im sorry for all these question, tho i am looking up to you as your by far the most knowledgeable person i know of..