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CVO Technical => Twin Cam => Topic started by: Dan_Lockwood on February 23, 2019, 11:23:05 AM

Title: Advantage Of Higher Pre-load On Lifters?
Post by: Dan_Lockwood on February 23, 2019, 11:23:05 AM

Some time ago, maybe several years, some recommended that when using adjustable push rods that once you hit the correct pre-load on the hydraulic lifter that you give a couple more turns down on the pre-load.

This I believe was in an effort to quiet down the lifter noise.

Obviously this is NOT possible with reusing stock push rods, but is there any merit to a slightly higher pre-load on the lifters?

Now that the Rocker Lockers have come out, these may be doing the same thing that people originally thought was helped by the extra pre-load.

Can someone enlighten my inquiring mind?

Thanks and have a great weekend.

Title: Re: Advantage Of Higher Pre-load On Lifters?
Post by: HD Street Performance on February 23, 2019, 11:46:22 AM

Look at the root cause of the noise for your answer. In some cases running the lifters right off the bottom will cut the noise a little but in that case the lifters are bleeding too easily which could be caused by either or both poor quality or worn lifters or excessive spring pressure. There are a host of other issues that will cause noise and some not even lash in the valve lift. Short answer is the lifter is not a jack just a take up device. it works equally well in its full range of plunger stroke which for most lifters is .200 nominal.

Title: Re: Advantage Of Higher Pre-load On Lifters?
Post by: MCE on February 24, 2019, 09:43:25 PM

I have to say, I agree with your analogy. Lifter quality/condition have allot to do with it, as does the spring pressure. If you have to run the lifter at the bottom of their travel, something else is going on. You should be able to run the lifters anywhere in between top and bottom of their travel if everything else is correct.

Quality lifters (in good condition) along with correct spring pressures should negate the need to fiddle f--k around
with the preload to reduce noise. fwtw.

But what do I know?

Title: Re: Advantage Of Higher Pre-load On Lifters?
Post by: Dan_Lockwood on February 25, 2019, 03:01:18 PM

Thanks guys, just what I was looking for.

Title: Re: Advantage Of Higher Pre-load On Lifters?
Post by: Mountainman streetbob on October 01, 2019, 09:23:23 AM

FWIW

Here in the South, extreme noise from the valvetrain is PREVELENT more in August than other months...

I kept having friends bike  making a clatter when we got stuck in traffic Jul/Aug/Sept

We started experimenting....

#1 rocker lockers work. at lowering valvetrain noise... PERIOD

#2 Full synthetic 50w, full synthetic 60w AND 20w-60 oils are all QUIETER when your motor is heat soaked in Atlanta, Memphis, Birmingham traffic during our sweltering months.

#3 I have not seen ill effects from running straight 50w or 20w-60 HERE! Of course I don't ride below 29* either! AND it is rarely below 40* here in the dirty south anyway...

#4 if you are running a fast rising, fast falling high lift cam IE Woods TW9, 408 etc YOU BETTER LIKE VALVETRAIN NOISE! It will happen.... Nature of the beast

 :apple: