First look....new LSX lifters
#81
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I don't disagree with you, and in my install I included the assumption that I would lose approx .010" to thermal expansion. If you do the install and everything is at 70* F and you assume 220* F temps fully warmed up, there's a 150* F differential. I'm no mettalurgist, but near as I can tell, aluminum expands about 13 micro inches per *F and steel expands about 8 micro inches per *F. 150 X 13 = 1950 micro inches of expansion for the aluminum, and 150 x 8 = 1200 micro inches. one micro inch = .000001". The aluminum would expand approx .000001 x 1950 = .00195" and the steel would be approx .000001 X 1200 = .0012". .00195" - .0012" = .0075", so, there may be a loss of about 7.5 thousandths of an inch. I set my cold pre load at .012" so that should have me in the .004 range fully warmed. I've been running the comp "r" that way for 3 or 4 years now w/o issue. That's the way I did it. Works for me. That's all I can say about it.
#82
I don't disagree with you, and in my install I included the assumption that I would lose approx .010" to thermal expansion. If you do the install and everything is at 70* F and you assume 220* F temps fully warmed up, there's a 150* F differential. I'm no mettalurgist, but near as I can tell, aluminum expands about 13 micro inches per *F and steel expands about 8 micro inches per *F. 150 X 13 = 1950 micro inches of expansion for the aluminum, and 150 x 8 = 1200 micro inches. one micro inch = .000001". The aluminum would expand approx .000001 x 1950 = .00195" and the steel would be approx .000001 X 1200 = .0012". .00195" - .0012" = .0075", so, there may be a loss of about 7.5 thousandths of an inch. I set my cold pre load at .012" so that should have me in the .004 range fully warmed. I've been running the comp "r" that way for 3 or 4 years now w/o issue. That's the way I did it. Works for me. That's all I can say about it.
Salemetro, thanks for taking the time to isolate the cam/springs change and the lifter swap. This thread should have some good information come from it!
ETA: kenp, I didn't see the 1st part about you agreeing with me, I read right over it I'll still leave my response anyway
Last edited by Havoc40; 03-07-2012 at 01:43 PM.
#83
TECH Apprentice
Here is what my engine sounds like with morel linkbar lifters
http://www.youtube.com/watch?v=noG0b9wL7_8
http://www.youtube.com/watch?v=noG0b9wL7_8
#84
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[QUOTE=CHADsterss;16055302]Here is what my engine sounds like with morel linkbar lifters
I F'n hate you, Man! lol Seriously though, mine will be there soon enough.
I F'n hate you, Man! lol Seriously though, mine will be there soon enough.
#86
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[QUOTE=salemetro;16054385] If the heads have been milled then you can subtract that amount from the 7.450"
There has been alot of debate about the different height of LS7 lifters. Shane from Thunder Racing had a post comparing them to a stock LS1 lifter and found the distance from the wheel tip to where the pushrod sits to be identical. The body of the LS7 lifter was slightly taller. Even if some are measurably taller from cup to wheel GM used them in thousands of truck engines without changing the pushrod length. I think that the taller ones you speak of have more travel and are happy using what we would measure and think to be excessive preload.
I had a set of the early LS7 lifters and came up with a 7.350" pushrod length after measuring. The engine sounded almost as bad as yours so I swapped to a 7.4" pushrod and the engine was much quieter. For reference this engine had heads milled 0.030" and an 0.040" gasket. From my personal experience the LS7 lifters do not require a shorter pushrod.
The comp trunnion kit will not change the fulcrum point of the rocker.
The LS6 is the only engine that had the special lightweight and longer stem valves in the 243 head casting. If the heads weren't factory installed on a Z06 or CTS-V then they have the same valves as any other LS1.
There is some other talk in here about the thermal expansion of the block and heads. This is absolutely true. I have learned this from working on LS motors with solid roller cams. If the lash is set with the engine cold and the the engine is warmed up to full operating temperature and the lash checked it will be .015-.020" more than the cold lash. When I measure pushrod length I always add .010-.015" to compensate for this expansion.
Lastly: if you are using a dial caliper to measure the end to end length of a checking pushrod then you will always get a shorter than desired pushrod length. The length of a pushrod is not measured from the flat spot of the oil passages. It is measured to the hypothetical arc that would be there if the oil passage did not exist.
salemetro: I think you are running a pushrod that is way too short. QUOTE]
Something to consider, is that the heads have been milled, and I'm using aftermarket head gaskets (I didn't check compressed thickness)...also, there are 2 different height LS7 lifters that have been produced over the years...varying from each other by .050. I'm not sure which "batch" mine are from, but I would assume they are the taller ones. Additionally, I'm not sure if the comp trunion kit would change rocker installed height at all (can't imagine that it would). From looking at it, the swipe pattern looks normal. Also...it's an L33...so should have the same lenghth valves as the LS6...correct?
I get what you're saying, but I have verified the measurements 3 different times, as well as checking (for the hell of it) installed spring height. 7.295 has been the repeated zero-lash MULTIPLE times. Don't know what else to say here....except that I've been over it a few times, with the same result.
I'll be tearing into the car tonight after work, and finishing over the next few days as time allows. I'll be using OEM head gaskets this time, and won't be changing the cam out yet.
Something to consider, is that the heads have been milled, and I'm using aftermarket head gaskets (I didn't check compressed thickness)...also, there are 2 different height LS7 lifters that have been produced over the years...varying from each other by .050. I'm not sure which "batch" mine are from, but I would assume they are the taller ones. Additionally, I'm not sure if the comp trunion kit would change rocker installed height at all (can't imagine that it would). From looking at it, the swipe pattern looks normal. Also...it's an L33...so should have the same lenghth valves as the LS6...correct?
I get what you're saying, but I have verified the measurements 3 different times, as well as checking (for the hell of it) installed spring height. 7.295 has been the repeated zero-lash MULTIPLE times. Don't know what else to say here....except that I've been over it a few times, with the same result.
I'll be tearing into the car tonight after work, and finishing over the next few days as time allows. I'll be using OEM head gaskets this time, and won't be changing the cam out yet.
There has been alot of debate about the different height of LS7 lifters. Shane from Thunder Racing had a post comparing them to a stock LS1 lifter and found the distance from the wheel tip to where the pushrod sits to be identical. The body of the LS7 lifter was slightly taller. Even if some are measurably taller from cup to wheel GM used them in thousands of truck engines without changing the pushrod length. I think that the taller ones you speak of have more travel and are happy using what we would measure and think to be excessive preload.
I had a set of the early LS7 lifters and came up with a 7.350" pushrod length after measuring. The engine sounded almost as bad as yours so I swapped to a 7.4" pushrod and the engine was much quieter. For reference this engine had heads milled 0.030" and an 0.040" gasket. From my personal experience the LS7 lifters do not require a shorter pushrod.
The comp trunnion kit will not change the fulcrum point of the rocker.
The LS6 is the only engine that had the special lightweight and longer stem valves in the 243 head casting. If the heads weren't factory installed on a Z06 or CTS-V then they have the same valves as any other LS1.
There is some other talk in here about the thermal expansion of the block and heads. This is absolutely true. I have learned this from working on LS motors with solid roller cams. If the lash is set with the engine cold and the the engine is warmed up to full operating temperature and the lash checked it will be .015-.020" more than the cold lash. When I measure pushrod length I always add .010-.015" to compensate for this expansion.
Lastly: if you are using a dial caliper to measure the end to end length of a checking pushrod then you will always get a shorter than desired pushrod length. The length of a pushrod is not measured from the flat spot of the oil passages. It is measured to the hypothetical arc that would be there if the oil passage did not exist.
#88
11 Second Club
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[QUOTE=5.3LJimmy;16057690]
Lastly: if you are using a dial caliper to measure the end to end length of a checking pushrod then you will always get a shorter than desired pushrod length. The length of a pushrod is not measured from the flat spot of the oil passages. It is measured to the hypothetical arc that would be there if the oil passage did not exist. I'm guessing this is why if I measure my 7.4" pushrods they appear to be closer to 7.375"?
Lastly: if you are using a dial caliper to measure the end to end length of a checking pushrod then you will always get a shorter than desired pushrod length. The length of a pushrod is not measured from the flat spot of the oil passages. It is measured to the hypothetical arc that would be there if the oil passage did not exist.
#89
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There is some other talk in here about the thermal expansion of the block and heads. This is absolutely true. I have learned this from working on LS motors with solid roller cams. If the lash is set with the engine cold and the the engine is warmed up to full operating temperature and the lash checked it will be .015-.020" more than the cold lash. When I measure pushrod length I always add .010-.015" to compensate for this expansion.
At any rate....let's be conservative and say that I was OFF by .020 when I had them set to ".080".....which is a stretch of the imagination. They were STILL noisy as hell at a theoretical .060.
#93
Figured I'd post some pictures of the total travel of an LS7 lifter. I'll try to track down some older parts for comparison later on today, when I have some time.
I zero'd the indicator with a 2.500" stack of gage blocks, then took measurements over a Dia. .3125 ball. Which this particular ball is actually smaller by .0005", this measurement isn't that critical.
Zero
Extended
Collapsed
measurements: 2.6511" extended length over a .3125 ball; 2.4478" collapsed over a .3125 ball. Total travel of .2033"
I zero'd the indicator with a 2.500" stack of gage blocks, then took measurements over a Dia. .3125 ball. Which this particular ball is actually smaller by .0005", this measurement isn't that critical.
Zero
Extended
Collapsed
measurements: 2.6511" extended length over a .3125 ball; 2.4478" collapsed over a .3125 ball. Total travel of .2033"
#94
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So you had to go .030 beyond GM recommended spec? And still other people in other threads claim .030 LESS than GM spec solved their problems. According to Havoc40, this is just putting a band-aid on a bigger problem......and IMHO, this appears to speak volumes of the factory tolerance issues.
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Seems logical to me. When I used the adjustable pushrod, I just set it to zero lash, then measured end-to-end on the final adjustment....then added desired amount of preload to the measurement...then ordered new pushrods. Doesn't seem difficult to me, and I got exactly what I ordered.
#98
I measured a few more lifters from various manufacturers and dates. All with the same zero and .3125 ball. For this post I'm not going to include all the measurement pictures, but I will if somebody requests (I did take them).
Here's a picture of the group. I had 2 more parts to measure, but the pistons were locked in the bodies from sitting around for god knows how long. I'm using part number 17122490 to describe an "LS7" lifter.
From left to right on the picture...
Sample part #1 (part 1): 2.6588 extended length; 2.4565 collapsed length. Total travel of .2024"
LS7 sample #2 (part 4): 2.6562" extended length; 2.4486 collapsed length. Total travel of .2076"
Sample part #2 (part 5): 2.6491 extended length; 2.4565 collapsed length. Total travel of .1926"
Here's a picture of the group. I had 2 more parts to measure, but the pistons were locked in the bodies from sitting around for god knows how long. I'm using part number 17122490 to describe an "LS7" lifter.
From left to right on the picture...
Sample part #1 (part 1): 2.6588 extended length; 2.4565 collapsed length. Total travel of .2024"
LS7 sample #2 (part 4): 2.6562" extended length; 2.4486 collapsed length. Total travel of .2076"
Sample part #2 (part 5): 2.6491 extended length; 2.4565 collapsed length. Total travel of .1926"
#99
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Gauge length and actual length are defined differently, see attached pic (from another ls1tech pushrod length thread).
#100
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Yep. They are. But when you order an "LSX" pushrod from any of the manufacturers that have them listed as such....after having used an adjustable pushrod that was designed for an "LSX" engine....using OEM rockers, you should have no issue. The cup dimensions should have been taken into consideration by the manufacturer. The only other consideration might be to double check the cups of (in my case) the aftermarket lifters that I'm going to install. Unless I'm missing something?
Last edited by salemetro; 03-08-2012 at 04:19 PM.