Setting lifter preload on an Hydraulic LS motor with a Thompson Motorsports LS7 style lifter
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- Опубликовано: 25 мар 2020
- At Thompson Motorsports we will show you how we recommend setting lifter preload on a Thompson Motorsports LS7 style RPM series lifter. This will be done with common tools to allow you to do this on install in your garage without the use of any specialty tools.
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I've watched more than 15 videos about this and this is by far the best one I've seen. Thank you.
Finally a very well explained lash and rod length video for LS. Keep em coming!
This is going to be a lifesaver!! My 6.0 block has been decked slightly, Trick Flow heads, aftermarket cam, 7 layer LS9 head gaskets. Thanks a million for this detailed video
This is very useful to make sure you have the right length pushrod. Thanks
These guys do great work. I'm extremely happy with my LS383.
Elegantly simple. Great vid. Congrats.
Really helpful I just ordered Johnson 2110 for my lt engine
all my respect for building an engine inside the house!
Helpful information thanks and greetings from down under..
Good videos! Keep them coming!
Simply explained. Thank you.
Great informational video!
GOLDEN ADVICE THANK YOU
Inspection is key to knowing what to do for the engine.
Always think engine basics to achieve a good result. Good engine operation is key for success.
Great Video Guys! keep up the good content
Great info, thanks!
Great video right on point
Good job well explained
GR8 VIDEO THANKZZ FOR SHARING!!!!
Super cool video
Great content
Awesome info
Great video, best explanation of this procedure I have found, The best instructor, sounds like ex military. Loved it.
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@Adrian Cash instablaster =)
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@Adrian Cash you are welcome :)
@@gavindecker5915 I Love it when Brother gearheads can help each other. I can see us in a garage all gathering around a buddy's ride telling him how it's done.
This is an interesting way about checking pushrod length.
Thanks for the video guys. I changed to a pedestal mount set of rockers with gide plates. Im thinking it will still be the same process. If not plz stop me. hahahaha. I got the china pro comp ls3 offset solid aluminum roller rockers, for my G8 GT.
Much Obliged Sir,,,
How about a PSA on windage trays? I found different opinions on what to use and required clearances. Great product and info. Thanks
Great video. Maybe add another video of using a push rod length check tool. Took me forever to try and understand the turns method for preload but about one time with a checker tool. Either way, great tech!
I agree seems like checker tool works faster and easier
I used comp cams tool, then measured using a digital caliper...however you have to measure a known length pushrod length and subtract the difference to get back to the correct length. Example 7.4 read 7.410 so subtract -.010 to get to 7.4. It works.
Thompson Motorsports. I’m just learning this. 51 years old later and I’m gonna do a valve train on my 5.3. One turn is 0.050. Now I got it. Never did get that until you generously gave it. Thanks. Other vids they don’t get to much information like we already no why this don’t work. Lol. Thanks.
Yeah, just as long as you require the valve rocker not to be noisy and no extra tension to keep valve open at the wrong time and rotation. Good valve seal is good for the proper valve overlap for performance or emissions standards if applicable.
Thanks for the video, very informative. One question regarding the preload on hydraulic lifters. Should they be soaked in oil before we check the preload? Or done dry?
25 ft ? i have an aftermarket cam is torqued at 22 ft should I torque to 25 ft? Thanks
What about changing to a lifter like Johnson 2110 that is +.045 taller CUP valve than LS7/LS3 . Does that +.045 only impact pre-load.
Will this method work with adjustable roller rockers? Adjust to zero lash, turn it 1-1/8 and lock it down...or would it be a different process?
I like the way you explain for the people that watch you, I don’t using silicone in the inner engine components, I prefer using the aviation glue same thing is Indian head, like Rod and main torquing I use it on main cap bolts ,head bolts cause it doesn’t let the coolant affect the threads, and torque is never a dry torque It should have a slick thread so there’s less friction and more accurate for the torque.. putting any silicone in where there’s oil eventually it will end up in the oil pump system and that’s not healthy for an engine, it turns into a Jello..
I think thread locker will be better
I have a fresh build lq4 6.0L and haven't primed engine oil yet. Doing turn method i get 1/4 to 3/8 turn to 22ft lbs on rockers which seems to requirelonger p.rods. Will that change after engine is primed and lifters are full of oil?
when installing new ls7 style hydraulic lifters do you guys soak them in oil first or just assembly lube them prior to install? will doing one vs. the other affect the rocker install process you show on this video?
what happens if you torque rockers with piston at tdc?
While this is a good video for its intended application of stock rockers; many of its points cannot be used when upgrading to roller tip rocker arms, where MID-LIFT geometry must be used. There are a lot of videos out on roller tip rocker geometry that is completely misleading on the priorities of what should be checked, how to set, and what their effects are. For those who fall into this more high end application of rocker geometry for any of the LS series engines, please find the following comments helpful.
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You NEVER want to worry about where the wear pattern is at on the valve to set rocker geometry. The wear pattern has NOTHING to do with "geometry." Because none of the manufacturers have any "accurate" standards for stud and stand mount dimensions from the valve, and because the stud leans into the valve, and because engine builders use varying length valves, and lastly, because every custom engine has a different NET valve lift, no rocker arm is going to be able to have the exact length required (on a mass produced basis) to accommodate all these variables. That is why you shouldn't worry about where the witness mark on the valve tip is at. Just worry about the angles. The BEST way to assure you are measuring ANGLES correctly with HARD measurements, is to use the VALVE SPRING RETAINER, because it is perfectly mounted at a 90 degree angle to the valve, and that is the principle of MID-LIFT precision.
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You NEVER want to use "checking springs" to set rocker geometry. You need to check for NET valve lift with ACTUAL springs. Once you know what your NET valve lift is, then EVERYTHING after that is done with a CLOSED valve, no tension on the valve train; not even necessary to have an adjuster in place. Just an adjustable push-rod; dial calipers and KNOWLEDGE.
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With all the tools I've made; and all the engines I've built; and all the tricks I've learned (many from other creative engine builders), to this day when I still occasionally help an old friend out on setting up his rocker geometry, I do it in less than 5 minutes with the following technique. It's all done in the CLOSED VALVE position, because you don't need to worry about hydraulic lifter valve compression or flex. You don't even need to have the adjuster on the rocker arm; it is all laying loose. And obviously, unlike this video, you are not rotating the whole thing over under valve spring pressure. Once you know what your NET valve lift is, everything after that is math, and setup; and this can all be done with the rocker laying loose on the stud, and an adjustable push-rod lifting or lower it as needed.
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It's not complicated:
A. Know your NET valve lift; divide in two; that is your MID-LIFT "motion" (MLM).
B. Measure the height of your valve tip above the retainer.
C. Measure the diameter of the roller; divide in half (this precisely gets you from the bottom of the roller to the AXIS).
D. ADD "B" and "C" together, to get the STACK HEIGHT. An illustration can be found at: www.mid-lift.com/TECH/TECH-Installed-G1.htm
E. Now, use a straight edge like the little machinist square shown in this video, and lay it across the valve spring retainer and alongside the trunnion.
F. SUBTRACT or ADD (as needed) the STACK HEIGHT to or from your MID-LIFT MOTION, by raising or lowering the rocker arm on the stud.
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EXAMPLE:
* NET VALVE LIFT IS .700", so MID-LIFT MOTION is .350". That's cut in stone, now forget it for the moment (you've written it down).
* Valve tip is .050" above the top of the retainer; and the .500" rocker arm roller diameter tells you its radius is .250", so the STACK HEIGHT is .300".
SOLUTION:
If the STACK HEIGHT is .300" and the MLM is .350", then you need to place the trunnion .050" BELOW the valve spring retainer. If your math has the inversion of this, then your trunnion centerline would be above the straight edge coming off the retainer.
SUMMARY:
DO EVERYTHING IN THE CLOSED VALVE POSITION, AFTER YOU KNOW NET LIFT. It's much easier to get an accurate DIAL CALIPER measurement on hard points, to find their true center-lines, than trying to use visuals that only give you approximate values. You can use the outer edges of the trunnion's diameter and divide in two for its center, which is far more accurate than eye-balling. For those who want to know what is important, and how to fix existing systems, you can get the book on this at: www.mid-lift.com/MID-LIFT_ARAT-2016.htm It's this simple: KNOW YOUR MLM; KNOW YOUR STACK HEIGHT; USE THE RETAINER AT CLOSED VALVE; and SET YOUR ROCKER TRUNNION as needed. Good luck to all. --Jim Miller
This only for this specific lifter? Or is this the procedure for standard ls7 lifters as well ?
I just had new cam and lifters installed on my truck. It has a tap at higher rpm. Not at idle. Could it be this making the noise?
Was this done without soaking the lifters? I'm about to do this and was curious about the whole soaking rumors.
Hi i have a promplem with a lm7 engine..is fresh rebuild..new piston cam bearings...rod bearing main bearings.. lifters..all new..i start up the engine start right up ..when i go to put a litle throtle goes to die end dont respond..i check that work with 6 cylinder...5-7 didnt work..a check harness ...all are ok ..end replace coils... please can you help?
Only Thing They Forgot To Mention Was You Can Only Use This Method 1 Time On A Pumped Up Lifter. After You Tighten It Down The Lifter Is Gonna Bleed Down And Get Spongy. I Did This With With Pumped Up Lifters And Even Low Tension Springs Slowly Bleed Them Down.
Can you set valve lash in a similar fashion with an SBC hyd lifter and roller rocker or do you have to use a soft (light) checker spring?
By the way that was a great video on the valve lash on the LS motor
I don’t believe so , sbc is a pain in the ass compared to the sbm and ford and neeeer LS
People I need a high performance 5.3 or 6.0 for my 2000 Chevy Tahoe. I want to desimate all . Cameros ss . Mustang 5.0. If I can beat those two cars in a roll race then I would be happy with that. At least stock ones. Heavy truck my truck. 2000 Chevy Tahoe. Looking for a dependable daily high performance 5.3 or 6.0. built . And maybe a turbo kit install in the future. What do you guys at Thompson Motorsports think?
I jusr wanna say you sound just like Tyler Tube on youtube 😂😂
Newbie here so forgive if a dumb question but does this apply to stock everything
I dont understand how tightening down on the rocker arm 1 and 3 quarter turns before the tourque wrench clicks at 25 ft pounds what ever that means would make the push rod too long while tightening down on the rocker arm 1 and a quarter with the click of the torque wrench at 25 ft lbs of pressure on the lifter or (preload) means the the rod is shorter shouldent it be the other way around?
I just bought a 2008 gmc truck with a 5.3 with 156,000 miles. It sounds like a sewing machine under the hood. The previous owner said that he had the lifters change about two years ago and the engine had about 120,000 on it.
Is there a chance that i need to get in there and re-torque the rockers in order to get the sewing machine sound out of my motor? And can these valves be adjusted like this at anytime in this motors life? Thanks for any help with this.
^valve lash is net built no valve adjustment is required^ it is needed only when you get involved in aftermarket heads/cam/lifters the combination will dictate the pushrod length adjustment
If you go over to Richard holders Channel and watch how he recommends doing it you could have it done in the amount of time it took you to debate something in the comment section. 👍
I thought one full turn=.078 of preload ?
I'm confused how a pushrod that's too long takes more turns than the one that's the right length. It seems backwards.
No. You dont want to go to the torque setting. You want to turn until the bolt bottoms out. Going to the torque setting is wrong because youre adding the stretch of the bolt to the turn on the wrench. Use a small wrench so you can feel, and caluclate the thread pitch of the bolt to the number of turns till it bottoms out.
Everybody is a race engine builder, there must be millions of them?
Lash is very confusing to me
1 turn isnt .050 Though.
Isn’t one full turn .078 of preload on a 1.7 rocker? I know gm performance lifers recommend “.050 - .100” preload.
I just watched a video the other day, guys at West Tech and Richard holdener, quite conflicting information from this video. 🤔 someone is rong.
Once you bottom the bolt out, that's your preload, not to what it is torqued to. You got the extra turns on your wrench after the bolt bottomed out, and because your calculated that in, you don't have the correct number. The extra turns after bottoming out, has virtually zero affect on preload. Just thought I'd mention that.
For an 8mm x 1.25 thread bolt I always used 1/2-1 full turn until the bolt seated to check lifter preload. Anything after that, you are not pushing further on the lifter. This method works, it’s just not how I do it lol. You are assuming that every bolt will hit desired torque at the same rotation which hurts your consistency. Also, the zero lash point, you can feel it if you are turning your bolt by hand. It is very slight , but that is the most accurate way, Potatoes, potaaaatoes. Glad to see others have used this method, thanks for sharing.
@@iliketowatchthis no I'm not assuming anything. Once the bolt and the rocker are flat against the mounting surfaces, you cannot get anymore preload into the lifter. The rocker stud mount isn't just going to "squish" and allow this to happen. The rocker bolt can certainly turn some more, and that's all just thread bolt torque. The threads stretch slightly. Counting those turns into your equation does not account for an accurate outcome. But these lifters have a bit of room to play with anyways. Good luck
@@boosted0079 you get zero lash before the rocker bottoms on the stand, if you dont then the pushrods are way to short.
@@robbygray9562 I understand that. That's not at all what I'm talking about though. After zero lash is established, you start counting turns on the bolt like he did here to determine the preload. Once the rocker is seated down onto the rocker mount, and the bolt can no longer turn, then you take how many turns that took and use only that for the preload equation. Any turning of the bolt after that is just bolt torque of the threads, you cannot get anymore preload after that point. That's what I'm trying to explain. You might get 3/4 of a turn more when torqing the bolt down after the preload is established, but your cannot count that turn into the equation for determining preload. That would be inaccurate. That's all I was explaining because in this video he counted the turn of the bolt being torqued after all the preload was into it. I've seen this mistake made ready to many times, and then people wonder why their engine sound like a sowing machine lol. It's because they calculated wrong and got shorter push rods than what they should've gotten.
@@boosted0079 what is your method then? I am trying to measure my push rods on an LS2 with LS7 lifters. BTR cam came with 7.4 pushrods but the valve train is loud.
So much easier then sbc
this method isnt that accurate because the bolt is closer to the rocker centre than the part of the rocker pushing on the pushrod into the lifter, its like a seasaw, the closer to the middle you are the less movement there is. Sure you get 50 thousandths from the 1.25 threads on the bolt but you will see more at the pushrod (I have tested this)
25ftlbs? But Everything online says 22ftlbs.
Also wondering about this.
Once you hit ~ 18 ft/lb the trunion will be seated properly and preload will be set the rest of the torque 22 or 25 is for stretching/securing the bolt
You will see this only if you have a dial indicator setup
3 ftlbs is not going to be a war stopper
Hahaha!! Yeah nobody does it this way.
NO- If the pushrod is too long that would be 3/4 turn, too short would be the 1 1/4. You have it backwards on this video.
I kinda went by what he said and it checked out .. at 7.400 I was at about 3/4 turn . And i went up to 7.500 and got to one full turn . That sweet spot like he said .
He's correct in the video
I’m macanic not a math wiz
😂😂😂who n the hell have time for all those numbers 50 thousand of a inc really
damn sounds confusing as hell