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I did somewhat of a mixture of everyone's posts on the last 5 times that I did this. I always tried to get mine centered, but as narrow as possible.
I agree, doing this on a bench is easiest, dial indicator to get to your exact lift, and definitely get yourself a larger caliper, trying to get the exact length just by turning pushrod checker and counting turns is not accurate.
I have the Yellas, but did not like their shims since they could not get a good pattern, I ordered a few strips of precision ground flat stock after I figured out the proper thickness, and made it so it was one piece for a rocker pair instead of possibly dropping washer in your motor. I can post pics of this. I also did not like the amount of thread engagement into the heads, so I machined up longer bolts (same strength and brand) to get all the engagement as possible.
I purchased 2 checkers to save time and turned them so that they had some looseness between the rocker cup and lifter. Torqued the rockers fully with the shim in place and then squeezed my fingers in there and turned it till it just touched, making sure to add 0 preload. I probably checked them at least 5 times each for every rocker and like you did, made a chart.
Then I made another chart with the preload added to find an average pushrod length that would work with all rocker / lifter. When I ordered them and received them, I took the caliper and measured every pushrod and laid them out with their length written on them and then consulted my first chart and matched up each pushrod to the correct lifter / rocker combo that made the preload as close to being equal with each other and being in the preload range that the manufacturer recommends.
Then I just made a chart that showed where each pushrod is, and what preload is on each lifter, and whenever anything is torn apart, everything goes back in the same exact place.
Nice to see detailed posts like this to help everyone out
Yes I wrote "pusrods". You know what I mean...
Last edited by BlackDuk98; 12-23-2015 at 06:53 PM.
Curious how you came up with 0.075" per bolt rotation. I get 0.0625" but that is using pure math.
I got .048" on the bolt threads. Being very clear, I'm talking about the rocket bolt. The valve tip end is fixed, and the length ratio is 1.7:1. So, the distance traveled by the pushrod end is 2.7/1.7 or 1.58x further. I rounded down to .075
Nice job on the write up! Glad I could help with some of the pictures!
Wrapping the pushrods threads in Teflon tape was a must for me. My comp adjustable pushrods were very loose. The tape really helped get an accurate reading. I also used 8" calipers-- 12" would have been easier to handle though.
I got .048" on the bolt threads. Being very clear, I'm talking about the rocket bolt. The valve tip end is fixed, and the length ratio is 1.7:1. So, the distance traveled by the pushrod end is 2.7/1.7 or 1.58x further. I rounded down to .075
Found the difference, I used 1 instead of 1.25 for the 8mm threads before correcting for the rocker ratio.
Does anyone have recommendations on which check springs to buy? I am not see any tensions/pressures listed on Summit's page. Also which diameter is needed?
So if I am reading this right, once you have your half turn of preload, approx .038, you should then torque to 22 ft-lbs, and will not affect preload at all? Or should the 1/2 turn be the 22 ft-lb torqued down value? Sorry, just trying to decipher between this and a YouTube video where a guy is measuring pushrod length on a ls3. I will be measuring this Saturday, so I want to make sure I have the process figured out.
So if I am reading this right, once you have your half turn of preload, approx .038, you should then torque to 22 ft-lbs, and will not affect preload at all? Or should the 1/2 turn be the 22 ft-lb torqued down value? Sorry, just trying to decipher between this and a YouTube video where a guy is measuring pushrod length on a ls3. I will be measuring this Saturday, so I want to make sure I have the process figured out.
Yep. When you go from preloading the lifter to torquing the bolt, you're no longer adding preload. You're actually stretching the bolt a very slight amount, and that bolt tension is what helps keep the bolt tight.
Yep. When you go from preloading the lifter to torquing the bolt, you're no longer adding preload. You're actually stretching the bolt a very slight amount, and that bolt tension is what helps keep the bolt tight.
Darth, I just found this thread and wish this was last weekend instead haha. Your answer to this question above...does the 22ft/lb torque come in step 13 at the final install? If you have a chance, check out my pushrod install thread and see my issue from last night. What we had talked about didn't work right with my pushrods, so I think I should just start from scratch.
I found when you check the length of 16 pushrods multiple times you're ending up doing it a 100 times or more in total. It takes fussing to get repeatable measurements if you don't hit it exact on the end and parallel to the tool. It took literally 5 minutes to make a jig by putting a groove in a piece of 2x6 with a couple of small pockets drilled for the adjustment locking nuts. It made it really easy to slap in the checker and get repeatable results in just a second.
I found when you check the length of 16 pushrods multiple times you're ending up doing it a 100 times or more in total. It takes fussing to get repeatable measurements if you don't hit it exact on the end and parallel to the tool. It took literally 5 minutes to make a jig by putting a groove in a piece of 2x6 with a couple of small pockets drilled for the adjustment locking nuts. It made it really easy to slap in the checker and get repeatable results in just a second.
I did something similar and it definitely helped a lot!
Darth I'm glad you and others took the time to post this. This will help me out temendously in the next few weeks and save me some phone calls to that same ( trusty vendor ) lol. Thanks again. Bookmarking this.
Last edited by Firebirdmuscle; 11-30-2016 at 09:52 AM.
I have the Johnson Short travel .058" total lenght. I aim for around .030" preload with it cold. The .048" preload for one turn was right for me as well. I'd measure the total degrees needed to hit 22ft/lbs... say 240/360 = .667 x .048 = .032 as a check against my measurements. I realize a lot of that comes from the precision of the tools being used. But that goes for measuring the length of the pushrod checker too. If you can get in the ballpark using different approaches and tools then you're going to be close either way.
Thank you for your efforts to write this thread. It helped me a lot!
I also have Johnson short travels (0.058). Manton instructed me to aim for 0.038" preload to compensate for the difference in shape of the pushrod end vs. the length checker tool.
This equates to turn of the wrench somewhere between 6 o'clock and 7 o'clock until meeting resistance. Tightening further doesn't add value because it's just stretching the bolt in the head and you want to avoid torquing a bunch of times to preserve the threads in the aluminum.
If you are running a short travel, you can also throw a feeler gauge under the rocker tip and bottom out the lifter. Pull out the feeler and you are at you desired preload. If you are aiming for 0.038 preload, and you have 0.058 of travel, put a 0.020 gauge under the rocker tip. Seemed to make things faster for me.
12-23-2015, 06:27 PM
