Proper lifter preload?
Proper lifter preload, crane 1.8 rr? I am new to the forum and have a question for you all. I have an 02 Trans Am, AFR 205 heads, Crane 220/224 .583 114, Crane gold 1.8 rockers, Kooks headers and all of the associated bolt-ons.
I had the worst time getting the preload right on my rocker arms, At first I had too much (open valves = no compression) then at zero lash they were really loud. I have done some looking around and it seems some people here have installed them at 1.25 turns all the way to the 2 turns recommended by crane. By the way I have 7.35" pushrods, .1" longer than the ones that came with the rockers, as recommended by Vinci. Right now I am at 1.75 turns of preload and everything seems ok, not too noisy, but I was just wondering if this was the optimal setting.
I made 385hp 374tq without a pully, which has been since added. Heres a link to the sheet, it is under "Blacky" http://community.webshots.com/user/blk02ls1a4
What do you all think?
I had the worst time getting the preload right on my rocker arms, At first I had too much (open valves = no compression) then at zero lash they were really loud. I have done some looking around and it seems some people here have installed them at 1.25 turns all the way to the 2 turns recommended by crane. By the way I have 7.35" pushrods, .1" longer than the ones that came with the rockers, as recommended by Vinci. Right now I am at 1.75 turns of preload and everything seems ok, not too noisy, but I was just wondering if this was the optimal setting.
I made 385hp 374tq without a pully, which has been since added. Heres a link to the sheet, it is under "Blacky" http://community.webshots.com/user/blk02ls1a4
What do you all think?
Last edited by Blk02Ls1A4; Oct 6, 2005 at 04:25 PM.
1 3/4 turn, is that where you locked them down at as well? or did you do 1 3/4 turns, then final 1/8 - 1/4 turn is when you locked them? the latter is the correct way. i have zero rocker noise doing it that way.
http://www.vincihighperformance.com/...TRUCTIONS.HTML
http://www.vincihighperformance.com/...TRUCTIONS.HTML
Originally Posted by Vinci's proper rocker adjustment procedure page
in this manner a full 1 and 1/2 to 1 and 3/4 turns, so keep an accurate count of the number of times you make 1/4 turn adjustments. You must wait 10 minutes between each 1/4 turn rotation to prevent the depressed valves from contacting the pistons. When you have finished the adjustment procedure, tighten the jamb nuts by holding the adjusting nut with your wrench and tightening the jamb nut with an Allen tool, and then rotating the tools simultaneously clockwise about 1/4 turn to complete the adjusting procedure.
I think the push rods for the AFR's is due to the height of the guide plates on those particular heads. I did 1-3/4 turns in increments of 1/4 turn at a time. Then I tightened the jam nut. Then I rotated the jam screw and the nut at the same time and got about an 1/8th of a turn more so I am not at 1-7/8th turns from zero lash.
For zero lash, the nut should turn freely in your fingers while you gently lift the rocker tip and hear click click. Keep turning until the click is just gone. The nut will stop turning if you are barely squeezing between your fingers. At this point the rocker will move side to side but if you gently, emphasize gently, lift the tip there will be not clearance to click click.
They will be loud when you first start it, but mine is as quiet as stock now.
For zero lash, the nut should turn freely in your fingers while you gently lift the rocker tip and hear click click. Keep turning until the click is just gone. The nut will stop turning if you are barely squeezing between your fingers. At this point the rocker will move side to side but if you gently, emphasize gently, lift the tip there will be not clearance to click click.
They will be loud when you first start it, but mine is as quiet as stock now.
I did 1 3/4 and then did a little more and locked them down. From yor responses it seems that I did it correctly 
Thanks for the responses, I really appreciate it!
Thanks for the responses, I really appreciate it! Trending Topics
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Originally Posted by mrr23
not guides, deck height is the reason. the deck height on AFRs are .100 thicker than stock heads.
Originally Posted by Adrenaline_Z
1 3/4 turns after zero lash?
How much pre-load does that amount to? Seems like a hell of a lot for a roller
valve train, let alone performance applications.
How much pre-load does that amount to? Seems like a hell of a lot for a roller
valve train, let alone performance applications.
.080-.100"
I too am experimenting with different amounts of preload with my Crane 1.8 and Comp 850 lifters. Each 1/4 turn of the adjusting nut represent .015 of preload on the lifters. I confirmed this with a dial indicator. Also remember, approximately .015 more of preload occurs once everything is heated and expands.
Right now, I'm trying to decrease the amount of valvetrain noise as opposed to the highest dyno number. I've had it has high as 7, 1/4 turns (.105) and as low as 1, 1/4 turn (.015). The 7 was the quietest, but not quiet. The 1 was unacceptable. 3 to 6, 1/4 turns shows no difference in noise. Right now, I'm running at 5, 1/4 turns + 1/16 locking turn for a preload of .080. Once running, that gives me an effective preload of .095.
I'm thinking of going back to 7 turns but, I agree, isn't that a bit high on the preload, especially since Comp recommends .065? Once running, preload would be in the .120 range...
Right now, I'm trying to decrease the amount of valvetrain noise as opposed to the highest dyno number. I've had it has high as 7, 1/4 turns (.105) and as low as 1, 1/4 turn (.015). The 7 was the quietest, but not quiet. The 1 was unacceptable. 3 to 6, 1/4 turns shows no difference in noise. Right now, I'm running at 5, 1/4 turns + 1/16 locking turn for a preload of .080. Once running, that gives me an effective preload of .095.
I'm thinking of going back to 7 turns but, I agree, isn't that a bit high on the preload, especially since Comp recommends .065? Once running, preload would be in the .120 range...
Originally Posted by vettenuts
I think the push rods for the AFR's is due to the height of the guide plates on those particular heads. I did 1-3/4 turns in increments of 1/4 turn at a time. Then I tightened the jam nut. Then I rotated the jam screw and the nut at the same time and got about an 1/8th of a turn more so I am not at 1-7/8th turns from zero lash.
For zero lash, the nut should turn freely in your fingers while you gently lift the rocker tip and hear click click. Keep turning until the click is just gone. The nut will stop turning if you are barely squeezing between your fingers. At this point the rocker will move side to side but if you gently, emphasize gently, lift the tip there will be not clearance to click click.
They will be loud when you first start it, but mine is as quiet as stock now.
For zero lash, the nut should turn freely in your fingers while you gently lift the rocker tip and hear click click. Keep turning until the click is just gone. The nut will stop turning if you are barely squeezing between your fingers. At this point the rocker will move side to side but if you gently, emphasize gently, lift the tip there will be not clearance to click click.
They will be loud when you first start it, but mine is as quiet as stock now.
byter, have you checked rocker wipe. VHP/Crane supplies .100 longer p/rods for AFR heads, at 7.350. original crane rocker kit comes with 7.250 pushrods, so if you subtract for your mill of.024 and associated other differences thrown into the mix, you may need .025 shorter pushrods to 7.325. i am using stock lifters, only 5k miles on the car, but valvetrain is quiet.
Originally Posted by Byter
vettenuts, what lifters are you using? Thanks...
Have you done any dyno runs with the different pre-loads? Interesting discussion as I have something "funny" going on at 5,800 RPM-6,200 RPM and my tuner thinks its valve float. I was investigating shimming the springs. Would lifer pump up be caused by too much or too little lifter pre-load?
Originally Posted by smask04C5
byter, have you checked rocker wipe. VHP/Crane supplies .100 longer p/rods for AFR heads, at 7.350. original crane rocker kit comes with 7.250 pushrods, so if you subtract for your mill of.024 and associated other differences thrown into the mix, you may need .025 shorter pushrods to 7.325. i am using stock lifters, only 5k miles on the car, but valvetrain is quiet.
I have heard the stock lifters don't bleed down as fast as the Comp 850's, but I'm not sure if that matters except when trying to determin 0 lash. However, I'm not in the mood to pull the heads again.
vettenuts, I wish I had a dyno close enough to do that kind of testing! I did read from XTrooper on the Corvette Forum that he experienced a "funny" problem (a dip in HP) and it was a spring issue. He swapped out his dual springs (I forget which brand) for Crane dual springs and his "funny" problem went away. Perhaps you are onto something with the shimming.
I set the crane 832 springs @1.78 installed height, and achieved 122#'s on the seat. your cam is larger, but you won't need any less than 1.77 installed height. FWIW, AFR does a masterful machining job, very little deviation.
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Right now, I'm trying to decrease the amount of valvetrain noise as opposed to the highest dyno number.
friction?
0.015 inch from heat alone? Seems a bit high for parts to be expanding that
much, but I`ve never measured expansion on LS1 engines so this is purely an
observation.
It would be really cool to see before and after dyno with a zero lash setting +
0.001 inch cold pre-load leaving a total of 0.016 inch with thermal expansion.
My biggest question is: What is different with the design of these particular
lifters that requires high amounts of pre-load? I`m used to seeing sub 0.020
inch settings - especially on a roller valve train.
Thanks.
Originally Posted by Adrenaline_Z
Are the Cranes a touch noisier by nature due to loose clearances reducing
friction?
0.015 inch from heat alone? Seems a bit high for parts to be expanding that
much, but I`ve never measured expansion on LS1 engines so this is purely an
observation.
It would be really cool to see before and after dyno with a zero lash setting +
0.001 inch cold pre-load leaving a total of 0.016 inch with thermal expansion.
My biggest question is: What is different with the design of these particular
lifters that requires high amounts of pre-load? I`m used to seeing sub 0.020
inch settings - especially on a roller valve train.
Thanks.
friction?
0.015 inch from heat alone? Seems a bit high for parts to be expanding that
much, but I`ve never measured expansion on LS1 engines so this is purely an
observation.
It would be really cool to see before and after dyno with a zero lash setting +
0.001 inch cold pre-load leaving a total of 0.016 inch with thermal expansion.
My biggest question is: What is different with the design of these particular
lifters that requires high amounts of pre-load? I`m used to seeing sub 0.020
inch settings - especially on a roller valve train.
Thanks.
Your sub 0.020, while I've heard many people use that on the Comp-R's, I haven't seen that on stock lifters and/or Comp 850's. Typically, I've seen (on this forum) 0.060 - 0.090.
By the way, yes I think the Crane RR's are a tad noisier than stock. Also, the LGM LT headers amplify sound like the horn on the Ricola cough drop commercial! Most of the noise I hear comes from beneath the car, through the headers, than from the top. And please, no one go down the, bent pushrod, bad lifter, valve cover clearance, bad rod bearing, piston slap road. I've replaced ever part in the engine except for the valves and springs that came with the AFR heads.