need some help...checking pushrods LS6
Well there are several things that can cause the variance, some mechanical and some having to do with method of measurement. The valves could differ if there was a valve job done in the past where the amount of grinding/lapping done varied. The method is tricky because used lifters don't always have enough internal spring pressure left to work with the adjustable pushrod consistently.
Based on the measurements you have taken, if I had to get pushrods today, I would put in 7.350 pushrods. This will result in a preload of 0.0375" to 0.1125". The actual range may be smaller depending on error in the measurement. Others may have a different opinion.
Based on the measurements you have taken, if I had to get pushrods today, I would put in 7.350 pushrods. This will result in a preload of 0.0375" to 0.1125". The actual range may be smaller depending on error in the measurement. Others may have a different opinion.
Ok using the torque method on intake valve with cyl one at tdc I got right before 2 full turns for 22ft lbs. this was with stock ls6 pushrod from 01 z06. I think they are 7.4
thoughts? my local store closes at 3 and I am still puzzled as I have gotten 3 different measurements on 3 different cylinders, and not sure if i did the EO/IC method properly..but i marked the bolt and counted the turns.
Well there are several things that can cause the variance, some mechanical and some having to do with method of measurement. The valves could differ if there was a valve job done in the past where the amount of grinding/lapping done varied. The method is tricky because used lifters don't always have enough internal spring pressure left to work with the adjustable pushrod consistently.
Based on the measurements you have taken, if I had to get pushrods today, I would put in 7.350 pushrods. This will result in a preload of 0.0375" to 0.1125". The actual range may be smaller depending on error in the measurement. Others may have a different opinion.
Based on the measurements you have taken, if I had to get pushrods today, I would put in 7.350 pushrods. This will result in a preload of 0.0375" to 0.1125". The actual range may be smaller depending on error in the measurement. Others may have a different opinion.
well, i wont be getting the car done this weekend it looks like. I know 7.35 was suggested, I just dont feel comfortable just getting something and throwing it in just to meet my deadline. The store closes in 55 mins and I am puzzled as all get out from my varying measurements. I cant find anything online at all of others having issues with measuring and getting different results for different cylinders.
ok wait...i just found this...so is with the crank and cam gear dots lined up (cam dot at 6pm, crank gear at 12), is this not TDC compression firing stroke?
If not, I may have been measuring wrong. is that the case?
https://ls1tech.com/forums/generatio...dot-1-tdc.html
If not, I may have been measuring wrong. is that the case?
https://ls1tech.com/forums/generatio...dot-1-tdc.html
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Verdad Gallardo ok im having more thoughts now...when I lined up my dots (cam dot to crank dot, I did not think to check if the crank was actually at 1 cylinder of the compression or the exhaust stroke...i bet i need to recheck that.
Edit..nevermind..brain fart...when I lined them up I had no chain on..so intake / exhaust stroke wouldnt have mattered...it would have still been TDC.
Ok yeah im still puzzled on my measurements now.
Edit..nevermind..brain fart...when I lined them up I had no chain on..so intake / exhaust stroke wouldnt have mattered...it would have still been TDC.
Ok yeah im still puzzled on my measurements now.
Last edited by 93civEJ1; Apr 26, 2014 at 01:57 PM.
Ok I think I am maybe on to something. Im not sure if I measured cylinder 1 at TDC compression or exhaust stroke...How can I figure that out? So I would measure cylinder one and six at TDC...but how do I know which is a compression and which is at exhaust stroke or does this matter when measuring the pushrod length?
Ok. I just found this. Using this I will redo my measurements and see what I get as I was measuring each cylinders one being at compression and one being at exhaust stroke...could be the reason for my odd measurements:
Quote:
Originally Posted by Joseph
LSX Firing Order 1, 8, 7, 2, 6, 5, 4, 3
TDC Cyl. #1) Camshaft dot at 12:00 / Crankshaft dot at 12:00
TDC Cyl. #8) Camshaft dot at 1:30 / Crankshaft dot at 3:00
TDC Cyl. #7) Camshaft dot at 3:00 / Crankshaft dot at 6:00
TDC Cyl. #2) Camshaft dot at 4:30 / Crankshaft dot at 9:00
TDC Cyl. #6) Camshaft dot at 6:00 / Crankshaft dot at 12:00
TDC Cyl. #5) Camshaft dot at 7:30 / Crankshaft dot at 3:00
TDC Cyl. #4) Camshaft dot at 9:00 / Crankshaft dot at 6:00
TDC Cyl. #3) Camshaft dot at 10:30 / Crankshaft dot at 9:00
Quote:
Originally Posted by Joseph
LSX Firing Order 1, 8, 7, 2, 6, 5, 4, 3
TDC Cyl. #1) Camshaft dot at 12:00 / Crankshaft dot at 12:00
TDC Cyl. #8) Camshaft dot at 1:30 / Crankshaft dot at 3:00
TDC Cyl. #7) Camshaft dot at 3:00 / Crankshaft dot at 6:00
TDC Cyl. #2) Camshaft dot at 4:30 / Crankshaft dot at 9:00
TDC Cyl. #6) Camshaft dot at 6:00 / Crankshaft dot at 12:00
TDC Cyl. #5) Camshaft dot at 7:30 / Crankshaft dot at 3:00
TDC Cyl. #4) Camshaft dot at 9:00 / Crankshaft dot at 6:00
TDC Cyl. #3) Camshaft dot at 10:30 / Crankshaft dot at 9:00
Ok followed the above and made sure I was tdc compression stroke. Checked cyl 1 and 2. 10 1/4 turns worked well for exhaust. 10 1/2 on the intakes.
If I do 7.4 that will leave me with .075 and .087 preload. Think that will be ok?
If I do 7.4 that will leave me with .075 and .087 preload. Think that will be ok?
so, is this below the sequence to use when i lay the pushrods in and am tightening down the rocker arms??
From Service Manual
Rotate the crankshaft until the number one piston is at top dead center (TDC) of the compression stroke. In this position, cylinder number one rocker arms will be off lobe lift, and the crankshaft sprocket key will be at the 1:30 position. The engine firing order is 1,8,7,2,6,5,4,3. Cylinders 1,3,5, and 7 are left bank. Cylinders 2,4,6, and 8 are right bank.
With the engine in the number one firing position, tighten the following valve rocker arm bolts:
•Tighten the exhaust valve rocker arm bolts 1,2,7, and 8 to 30 Nm (22 ft. lbs.).
•Tighten the intake valve rocker arm bolts 1,3,4, and 5 to 30 Nm (22 ft. lbs.).
Rotate the crankshaft 360 degrees .
Tighten the following valve rocker arm bolts:
•Tighten the exhaust valve rocker arm bolts 3,4,5, and 6 to 30 Nm (22 ft. lbs.).
•Tighten the intake valve rocker arm bolts 2,6,7, and 8 to 30 Nm (22 ft. lbs.).
Install the valve rocker arm covers.
From Service Manual
Rotate the crankshaft until the number one piston is at top dead center (TDC) of the compression stroke. In this position, cylinder number one rocker arms will be off lobe lift, and the crankshaft sprocket key will be at the 1:30 position. The engine firing order is 1,8,7,2,6,5,4,3. Cylinders 1,3,5, and 7 are left bank. Cylinders 2,4,6, and 8 are right bank.
With the engine in the number one firing position, tighten the following valve rocker arm bolts:
•Tighten the exhaust valve rocker arm bolts 1,2,7, and 8 to 30 Nm (22 ft. lbs.).
•Tighten the intake valve rocker arm bolts 1,3,4, and 5 to 30 Nm (22 ft. lbs.).
Rotate the crankshaft 360 degrees .
Tighten the following valve rocker arm bolts:
•Tighten the exhaust valve rocker arm bolts 3,4,5, and 6 to 30 Nm (22 ft. lbs.).
•Tighten the intake valve rocker arm bolts 2,6,7, and 8 to 30 Nm (22 ft. lbs.).
Install the valve rocker arm covers.
I'm having some issues here too and I'm not sure wtf is wrong with me. I have the timing cover back on so no referring back to the timing marks. I'm not sure where I want to be on cylinder one and tdc. Are you at tdc just after the exhaust valve closes? That's what I would think but not too sure
To measure the intake valve length I think I want to use the comp 7702 when the exhaust valve is about to open. Then to measure the exhaust pushrod length i should use the tool just past when the intake valve closed correct?
Not sure why this seems so complicated but I am definitely not getting the same
To measure the intake valve length I think I want to use the comp 7702 when the exhaust valve is about to open. Then to measure the exhaust pushrod length i should use the tool just past when the intake valve closed correct?
Not sure why this seems so complicated but I am definitely not getting the same
I had my cover and stuff on too...i took it off and then followed the TDC mentioned above. cylinder one is TDC on compression when Crank is at 12 and Cam dot is at 12
....use this , it helped me resolve my measuring issues:
TDC Cyl. #1) Camshaft dot at 12:00 / Crankshaft dot at 12:00
TDC Cyl. #8) Camshaft dot at 1:30 / Crankshaft dot at 3:00
TDC Cyl. #7) Camshaft dot at 3:00 / Crankshaft dot at 6:00
TDC Cyl. #2) Camshaft dot at 4:30 / Crankshaft dot at 9:00
TDC Cyl. #6) Camshaft dot at 6:00 / Crankshaft dot at 12:00
TDC Cyl. #5) Camshaft dot at 7:30 / Crankshaft dot at 3:00
TDC Cyl. #4) Camshaft dot at 9:00 / Crankshaft dot at 6:00
TDC Cyl. #3) Camshaft dot at 10:30 / Crankshaft dot at 9:00
....use this , it helped me resolve my measuring issues:
TDC Cyl. #1) Camshaft dot at 12:00 / Crankshaft dot at 12:00
TDC Cyl. #8) Camshaft dot at 1:30 / Crankshaft dot at 3:00
TDC Cyl. #7) Camshaft dot at 3:00 / Crankshaft dot at 6:00
TDC Cyl. #2) Camshaft dot at 4:30 / Crankshaft dot at 9:00
TDC Cyl. #6) Camshaft dot at 6:00 / Crankshaft dot at 12:00
TDC Cyl. #5) Camshaft dot at 7:30 / Crankshaft dot at 3:00
TDC Cyl. #4) Camshaft dot at 9:00 / Crankshaft dot at 6:00
TDC Cyl. #3) Camshaft dot at 10:30 / Crankshaft dot at 9:00