BROTHER, I am so glad I found your channel! I am in the process of rebuilding my 6.0 LQ4 on my channel, but unlike you, I have no clue what I am doing. Thank you for the info! MURICA!
man, big help! doing my first LM7 rebuild and i was wondering how to get the correct valve setting so im not burning vales and getting optimal opening... on it! thank you! 🙏
Thank you for making this, i looked at a lot of other videos and so many are missing information or have general assumptions they are confusing. you earned a sub from me good sir.
Since the fulcrum of the rocker is not exactly in the center of the lifter (it is closer to the pushrod), then adding 0.035 to the pushrod length will actually add MORE than 0.035 preload. It may still be within tolerance but there is some geometry needed here. IMO
Exactly! I wish he would have measured the adjustable pushrod bottomed out at the advertised minimum length. That would put things in perspective in terms of the difference between tip to tip length and measurement from the fulcrum (advertised length).
The fulcrum position doesn't come into effect, remember that the rocker bolt is being torqued to spec making it absolutely fixed in position so you aren't adjusting your preload from the fulcrum like the traditional small block. Once zero lash is set then the extra 35 thousandths of pushrod length acts directly on the plunger of the lifter. Don't get confused between valve lift and lifter preload. Valve lift is affected by the rocker arm ratio, lifter preload is not.😢
@@justinroehll You can disagree and use whatever terms you like but the actual mechanics of this don't support your argument. The rocker is, at zero lash, essentially fixed in position. The only way to add preload is through the pushrod length. The pushrod is between the rocker and the lifter plunger. Adding 35 thousandths to the pushrod length depresses the plunger 35 thousandths. Even if the pushrod and lifter are somewhat angled to the rocker that preload is still applied directly to the lifter plunger. The slight angularity change between the pushrod and lifter, which there must be with the top of the pushrod following the arc of the rocker motion while the base of the pushrod follows the straight motion of the lifter plunger, is so small as to be irrelevant, considering the plus or minus 10 thousandths in the lifter's specification.
@@brianbrigg57 I think the point, and the way to clear up the disagreement, would be to screw the adjustable pushrod down to it's shortest length and then measure with the calipers. If that measurement is exactly the advertised length of the adjustable pushrod, then this all is a moot point. However, if the measured length is slightly longer than the advertised length of the pushrod, then the point is valid in terms of taking measurements from the pushrod turn-out/turn-in rather than from calipers, once zero lash is reached. It's obviously going to be a small deviation if one exists but something to be mindful of depending on the lifter travel you have to work with.
if measure a push rod that has a length mark on it with caliber. it's about about average.015 because they have there own measurements.i think some things to do with the oil hole at the tip of push rod.
This is a great video, very well produced and explained. Some folks are adamant that you need to use a special lifter when checking pushrod length so that it won't compress, but you didn't mention that - do you just use a standard lifter?
So in theory, using the pushrod checker, whatever length you come up with at zero lash, you add that length + lifter preload and that's the length pushrod I would need to order?
Got some Johnson lifters and I give up .. did what you said and then ordered two sets of pushrods .. one set just a hair over zero lash and it's still holding the valves open
@@cameronfeltz2875 How did you fix it? Did you have to order a set of pushrods that was a different measurement for reach one? I don't understand sometimes how things can be this difficult when it would involve a situation like you described. Thats something that would happen to me, no doubt.
I ended up buying texas speed roller tip rockers .. doing the math they required shorter pushrods while the lifters required longer pushrods .. i ended up using my factory length pushrods
My texas speed roller tip rockers required pushrods .175 shorter . I forget the lifters exact but its .010 difference... I would say 7.225 +- .010 is about the length i needed
Jacob, Question; did johnson changed their short travel lifters plunger height over the years? Im most certain it was .175 extra longer PR length on an early production Gen IV, LS seen a few engines taking 7.575 PR with a Comp Cam
Is there no need to do the 1½ turn at 22lbs if u use a pushrod checker sorry first motor I'm building and this is the first video I've seen where they don't use the torque down method
If I have a stock head ls1 with stock ls6 cam . The pushrod are 7.4 assuming it’s oem length ls1 . If I replace the pushrod , wouldn’t I could just replace it with aftermarket 7.4 harden steel ?
Thanks for the pushrod length procedure. Liked your explanation about the lifter preload specifications. I have a question regarding the hydraulic lifters. When assembling an engine, do you pre-soak the lifters (either flat tappet or roller) in a bath of oil? Or, do you think pre-lubing the engine oil system is sufficient to fill the lifters?
@@cameronfeltz2875 This was 3yrs ago. I recall placing each lifter on the base circle, used a Comp Cams adjustable pushrod checker to find 0 lash with the oem rockers torqued to 22ftlbs. I think the preload on the lifters was .035+/- .005? I collected all the lengths and narrowed the number of lengths to about 10. Still had two that were causing a valve to hang open and needed to custom order a few more.
I see no mention of a solid lifter. All over the internet it is seen as required. What are your thoughts? I'm doing cam and heads on my 6l and your videos are so helpful and informative. Thanks.
So I have only the new gaskets and no longer have the old head gaskets. My guess is I need to install the heads and torque to specs. Then go back and do PTV clearance. Any way to do this without having to buy another set of head gaskets? Or maybe my ordering is off and some how I can to the PTV first then pushrod?
I know your post is old but in the future just snug (not torque) the head down bare and get your measurement. Then add the compressed gasket measurement to that pushrod length measurement if you don’t have a used one on hand.
so what pre load will you run some Chevrolet performance ls7 12499225 they recommended preload is .050-.100 I'm finally throwing a cam on my gen 3 5.3 stock heads they recommended to run a 7.400 push rod
New lifters have approximately .220" of plunger travel. Going with more the half of that say .120 will quite down your valve train and will help with hp at high rpm because less oil in the lifter chamber will result in less bleed down
Question for you. My lifter is moving in about 10mm while trying to get my length. Turning the bolt with a nut driver keeps pushing the pushrod down. I was warned that if I soak them in oil this may happen. I cannot press the pushrod in with my finger only the nut driver. So if I bottom out the pushrod using the nut driver after several turns is this my starting point?
Hey man I know this has nothing to do with this particular video. I just built a new 6.0 and installed it. I got some crappy oil psi. Have 45psi at cold start up and at operating temp I have 30ish at idle. I’m kinda concerned I might have messed something up.
What should you do if you measure each intake and exhaust and end up with numbers that don't quite match up for each pushrod? Would you order a custom set based off the numbers you found, even if they varied? Thanks!
It is normal for intake & exhaust to be different by ten-thirty thousandths. If every intake or exhaust valve is ten-thirty thousandths different I would just shoot for the average.
Just subbed after watching your other video. Great content and very informative. Im just doing a basic ls1 rebuild using ls7 lifters. I've read general rule is about .07 to .1 in your experience does this seem pretty accurate?
Hey! I used this technique and my new factory 7.400" length pushrods gave me exactly 0.035" of preload. No advertised recommended preload for my cam but if it's the same it's gotta be good, right?
Did you measure anymore after that? I’m running the same lifters, and I can’t really get a general consensus on if I should measure a few, ALL, or just one. Thanks in advance!
That depends on the installed height of the valves being equal. The valve seats are sometimes cut differently on intake and exhaust which can make a small difference between the valve's installed heights. I generally check across the valves with a straight edge and if there is enough difference between them I will measure intake and exhaust separately. Pushrods are generally available in 25 thousandths increments so there needs to be a fairly big difference in installed heights before you needed to order different sizes but it can happen, especially if the valves are from different manufacturers. If there's a significant difference between intake valves then I would consider getting that fixed, likely by cutting new seats to the same height, rather than trying to order a mish-mash of pushrod lengths.
All this work building a great motor but your using the OEM rockers??? Could you explain why please? I would think after market roller rockers would have been a much better choice here. Sorry, I'm a little confused about this choice because I'm building my first LS engine and nothing is the same as old school GM motors on this rebuild at all.
Yes, OEM stock rockers are the best rocker for 95% of every possible application. With a trunnion upgrade this is the best option for a mild street engine running 400# open spring pressure and .620” valve lift.
I have a question 🙋♂️. I have new LS3 crate 6.0. I bought a new cam/springs set. 624/.624 lift pretty much Max lift for valve piston clearance. I have a set of comp cam pro mag roller rockers 1.8. Knowing the 1.8 will give me more lift. How do I compensate the pushrod to give me the same lift as a 1.7. Roller rocker.
Why wouldn't you say what the torque spec was. "Torque it to spec" which in this case is?? Great video otherwise, just a pet peeve of mine when people don't say torque spec or size of the socket. That's what makes the difference of good and great.
For me, you are wasting HP and you are not even checking how much preload you have. I will say that it might be ok for a street engine, but is not ok for high performance. But that's my personal opinion.
