Katech How-To: Check lifter preload
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Joined: Oct 2005
Posts: 13,975
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From: Clinton Township MI
C7 of Year Finalist (track prepared) 2019
Katech How-To: Check lifter preload
I get asked this a lot so I thought it would be helpful to post:
1) The only way to properly check (and know where you are in the travel) is
to use a special checking lifter or completely compress a stock lifter.
a) Checking lifter consists of a lifter that has been disassembled
to install shims that lock the plunger at the top of travel in the lifter body.
If using this method you would add length to the checking pushrod to put the
final pushrods into the middle of travel of the plunger.
b) Using a stock lifter, you must make certain that you have pumped
all the oil out of the lifter. To do this leave it at valve full open (highest
spring load) for a while with an indicator on the pushrod side of the
rocker. Watch to see when the indicator stops moving (when the plunger is
fully compressed in the lifter body). Once you have compressed the lifter
rotate the engine to close the valve, extend your checking pushrod to full
length. Using this method you will subtract length from your checking
pushrod to put the final pushrods into the middle of travel of the plunger.
2) Typical plunger travel on Gen 3/4 lifters is 0.150 - 0.200 depending on
the manufacturer, year, etc. We recommend 0.075-0.100" from the bottom of
travel (using method 'b' described above) or 0.075 from the top of travel
(using method 'a' described above). That will generally put you close to
the middle of travel. While there are many different strategies for where
to put the plunger, for street use we strongly suggest that near the middle
of travel is the safest for durability.
3) The more precise method of checking is 'a' because you are not guessing
that you got all the oil out.
With this though, I do have to make the disclaimer that since we are not doing the assembly ourselves, we cannot be responsible for any misunderstandings. We recommend assembly by experienced professionals to avoid possible issues.
1) The only way to properly check (and know where you are in the travel) is
to use a special checking lifter or completely compress a stock lifter.
a) Checking lifter consists of a lifter that has been disassembled
to install shims that lock the plunger at the top of travel in the lifter body.
If using this method you would add length to the checking pushrod to put the
final pushrods into the middle of travel of the plunger.
b) Using a stock lifter, you must make certain that you have pumped
all the oil out of the lifter. To do this leave it at valve full open (highest
spring load) for a while with an indicator on the pushrod side of the
rocker. Watch to see when the indicator stops moving (when the plunger is
fully compressed in the lifter body). Once you have compressed the lifter
rotate the engine to close the valve, extend your checking pushrod to full
length. Using this method you will subtract length from your checking
pushrod to put the final pushrods into the middle of travel of the plunger.
2) Typical plunger travel on Gen 3/4 lifters is 0.150 - 0.200 depending on
the manufacturer, year, etc. We recommend 0.075-0.100" from the bottom of
travel (using method 'b' described above) or 0.075 from the top of travel
(using method 'a' described above). That will generally put you close to
the middle of travel. While there are many different strategies for where
to put the plunger, for street use we strongly suggest that near the middle
of travel is the safest for durability.
3) The more precise method of checking is 'a' because you are not guessing
that you got all the oil out.
With this though, I do have to make the disclaimer that since we are not doing the assembly ourselves, we cannot be responsible for any misunderstandings. We recommend assembly by experienced professionals to avoid possible issues.
Thread Starter
Premium Supporting Vendor
Joined: Oct 2005
Posts: 13,975
Likes: 980
From: Clinton Township MI
C7 of Year Finalist (track prepared) 2019
