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Possible collapsed Caddy Race Lifter, please lend a helping hand
I've attached some pictures below that seem to show a collapsed caddy race lifter on the #3 cyl intake lobe. The valve train was all replaced 3k miles ago when I did a cam swap. I used caddy race lifters, the FMS F13 cam, BTR .660 Platinum spring kit with titanium locks and retainers, BTR 7.425 hardened pushrods, and 1.7 YT roller rockers. The engine developed a pretty distinct tapping at idle that only got louder and worse as time went on. I pulled the valve covers and the #3 intake rocker arm was "loose", not on the pedestal (checked the torque spec and it was properly torqued to 22ft lbs) but there was movement between the roller tip and the on top of the valve, about .020" worth. Pulled the intake and exhaust roller rockers off and what I found is pictured below. There is some irregular wear that to me looks like a collapsed lifter plunger, and the pushrod seems to be rubbing on the inside of the lifter body. If this is the issue what do you guys recommend I use when replacing the caddy race lifters? I have read about replacing with either the LS7 lifters or Morel 5290 link bar lifters. Also, any help with diagnosing this issue would be helpful.
Pushrod on the left is the #3 intake.
More zoomed in picture of premature wear on the #3 intake pushrod.
Approximately .020"-.024" or 180 degrees of turn after zero lash was achieved with the shims that were provided in the yella terra kit. Utilizing the following method....
The washers included with YellaTerra rockers are used to obtain proper rocker arm geometry - not to adjust for zero lash. Once you have the wipe pattern set correctly using the washers as shims, you generally use an adjustable pushrod to set zero lash and measure for rocker arm length. It doesn't sound like you did this correctly.
The method used in the LS1HowTo article might work with stock heads, cam and lifters but isn't suitable for custom parts. The link below is a far better tutorial and will lead to better results.
Why do people use that worthless "turn method"? If they turn until toque they are "measuring" mostly the bolt stretch not preload. Increasing or decreasing torque does not increase or decrease preload by smushing or expanding the pedestal. If you want to do it that way you need to get zero lash where the lifter, pushrod, rocker and valve tip just meet and then count turns until the pedestal just makes contact from the stand to the rocker, not easy to do. Then you'd have to factor the lever multiplication from the fulcrum to the tip. Isn't it a lot easier and more accurate to just measure the da*n push rod?
Why do people use that worthless "turn method"? If they turn until toque they are "measuring" mostly the bolt stretch not preload. Increasing or decreasing torque does not increase or decrease preload by smushing or expanding the pedestal. If you want to do it that way you need to get zero lash where the lifter, pushrod, rocker and valve tip just meet and then count turns until the pedestal just makes contact from the stand to the rocker, not easy to do. Then you'd have to factor the lever multiplication from the fulcrum to the tip. Isn't it a lot easier and more accurate to just measure the da*n push rod?
The turn method works really well, that's why. Preload on a typical hydraulic lifter isn't super precise so the turn method doesn't need to be super precise either. I always use it but I stop when the rocker bottoms out on the pedestal, which is easy to do because it's pretty obvious when it does. I don't know who said you stop when it reaches full torque. Like you said, that's just wasted motion going I to stretching the bolt, not adding preload.
Obviously a short travel or solid lifter needs more precise measurements, but they're not really intended to be used with the non-adjustable rockers anyways.
The turn method works really well, that's why. Preload on a typical hydraulic lifter isn't super precise so the turn method doesn't need to be super precise either. I always use it but I stop when the rocker bottoms out on the pedestal, which is easy to do because it's pretty obvious when it does. I don't know who said you stop when it reaches full torque. Like you said, that's just wasted motion going I to stretching the bolt, not adding preload.
Obviously a short travel or solid lifter needs more precise measurements, but they're not really intended to be used with the non-adjustable rockers anyways.
I'm sure it gets within hand grenade range if done "right" but most posts you'll see they count until 22# is achieved which is wrong. If it kinda works it's as much happenstance rather than the math I've seen from thread pitch. You're tightening the bolt in the middle not the push rod end and whatever the count/distance is is multiplied by the lever advantage. I guess an adjustable rod and a cheap HF 8" caliper is too much to do.
First, ls1howto.com is wrong. As previously mentioned, the shims are for setting wipe. Wipe needs to be verified first. Once wipe is set, then measure for pushrod length.
Also, you have 1/2 turn per your post (Approximately .020"-.024" or 180 degrees of turn after zero lash was achieved with the shims that were provided in the yella terra kit.) This is not correct. Most of that 180 degrees is stretching the bolt (it's really preloading the bolted joint). I found that this takes about 1/3 turn to reach 22 lb-ft when I did my comparison of the various preload measurement methods. For your case, you end up with approximately 1/6 turn of preload. Therefore, your preload is likely much less than you think. I come up with approximately 0.013" of preload.
Before pulling it all apart, I would go back through and take proper measurements to see what your setup truly was and if that is the problem. You may have ended up with clearance in the lash once the engine reached temperature due to expansion and the very low preload you were running.
If you find this to be the case and new longer pushrods are required, I would also upgrade to a larger outside diameter to increase the pushrod stiffness and reduce flex in the valve train.
07-17-2016, 09:30 AM
Possible collapsed Caddy Race Lifter, please lend a helping hand 
