Looking to find the preload for Comp Cams 850-1 lifters.
Replacing a bad set of Fuelings.

Bike is a 2013 Sg with SE adjustable pushrods.

Searched and found a few different answers.

Looking for the right preload.

Thanks in advance.

Tom

 

I set my SE push rods at 2 3/4 turns which is about .120".

 

What's the total travel? Most are .200" or thereabouts. Lifter manufacturers will tell you the center of the travel, .100", is correct. I've set them as deep as .150" with no problems.

I think the correct answer is less than .200" and more than .100".

 

^^^^^This^^^^^
There is really no wrong or right answer as long as there's some common sense used. You definitely don't wanna be less than .100 and I don't think you'd wanna go deeper than .150. I have set at .130 on my S&S premiums.

2010 Limited with some stuff

 

I have the same lifters and pushrods on my 2012 Limited with Woods 222 cams. Running mine at 3 1/2 turns at a tuner's advice. No problems in 12k miles....

 

I just installed 850-01s and also have SE adjustable push rods and went 3 turns plus 1 flat. I started at 2 turns plus 5 flats and the 2 extra flats quieted it down and I have Woods cams. Others are running at 3.5 turns with no problems so somewhere between 3-3.5 should be your sweet spot for noise.

 

Thanks guys.
Looks like .120-.125 is the magic number.

Tom

 

Screaming Eagle adjustables are 24 TPI (Threads per Inch ) 1" divided by 24 = .41
1 complete turn = .041 A Hex = 6 flats ,there is always 6 flats to a turn.
1 turn = 6 flats = .041
2 turns = 12 flats = .082
2 1/2 turns = 15 flats = .102
3 turns = 18 flats = .123

 

In theory you only need enough pre-load to compensate for growth when things heat up. The lifters will run fine thru their entire range of plunger travel and only need the plungers deep enough to compensate for any additional clearance added from cold to hot engine.


I have found in recent years, especially with current production OEM lifters that they have inconsistencies in leak down rates so tend to make less noise the deeper that you run the plungers into the lifter bodies.


For standard travel lifters, not limited travel, they are going to be happier when you have the plungers at least .100" into the lifter bodies. So 3 turns is a good place to be, and where I set most of them here.


These engines are not a high rpm design, but do have considerably heavy parts above the lifters to keep in check. For the most part the stock lifters do fine, as these engines seldom see much past 5000rpm's or so in most builds. If you are running high rpm's, aggressive camshafts, etc, it may help to use limited travel lifters, or set the standard lifters with less travel under the plungers, or deeper into the lifter bodies.......Cliff