setting valve lash with new lifters jeep 4.0

98zjstroker

98zjstroker

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Oct 14, 2009
Location
concord nc
Ok so just installed the head on my 4.7 jeep stroker and trying to adjust the lifters to the correct spec. There are several videos I have found that talk about setting it to zero lash before torqueing it down to spec ( I have seen anywhere between 19-21 ft/lbs).

Other stuff I have read...including the instructions sent by howard performance cams which is what im using, after setting to zero lash if I have 7/16x20 adjuster nut (can someone please verify this is the right thread pitch), for every quarter turn the nut moves .0125". The specific lifters I am using require me to be set at .020-.025.

this means it needs a half turn to set to the proper preload. After I did this it was obviously not at the correct torqueing specs I have seen. to test it I ended up having to give it 1 and 1/2 more turns if I remember correctly to be at the correct torque.

everything I have found either says torque to spec or turn a half turn...….but neither mention the other one.
Is this because some are using the stock old lifters and others are doing a new install and need to set preload?

Do I need to first set preload (half turn) and then torque after that? would that not mess with the preload? I am so lost so please help and speak slowly cause my brain is fried.
 
or do I make the half turn after setting zero lash, then run it (break in) then after its been broken in torque to spec? Howard cams specifically mention to not pump up the lifters with oil due to it toping out and not setting correctly during break in
 
If it's adjustable rockers where you adjust them by the nut in the center of the rocker, a la old small block Chevy, there is no torquing. You set the lash by wiggling the pushrod up and down while turning the nut til there is no play then give it the 1/2 to 3/4 turn to set preload on the lifter. The nut is a lock nut so it shouldn't move.

Non adjustable rockers usually get torqued down, like older small block Ford's, the preload on them is set by carefully setting the valve installed height and a pushrod of a certain length.

Aftermarket roller rockers adjust like the factory ones in the first paragraph, except you adjust the nut then tighten a jam screw (usually a hex socket head) to lock it down and those jam screws get torqued while holding the adjuster nut with a wrench so it doesn't turn.

Post a pic if that's not clear and I can help you get it figured out.
 
4.0 jeep engines do not have adjustable rockers. (Unless you purchased adjustable roller rockers) You will need a push rod length checking tool. if you're using a .043 crush gasket and stock lifters you may get away with the 4.2 push rods at 9.625 length. (IIRC) However you need to verify the actual length you need.

I am running crower cam saver lifters and the .043 crush gasket and ended up with 9.6 length push rods. And I can still hear the lifters pump up for a second on start up. Especially with 10w30. 5w30 and she is silent in the winter.. If your pushrods are to long, you will melt the cam bearings and you will be pulling that engine right back out.
 
Jeff B said:
4.0 jeep engines do not have adjustable rockers. (Unless you purchased adjustable roller rockers) You will need a push rod length checking tool. if you're using a .043 crush gasket and stock lifters you may get away with the 4.2 push rods at 9.625 length. (IIRC) However you need to verify the actual length you need.

I am running crower cam saver lifters and the .043 crush gasket and ended up with 9.6 length push rods. And I can still hear the lifters pump up for a second on start up. Especially with 10w30. 5w30 and she is silent in the winter.. If your pushrods are to long, you will melt the cam bearings and you will be pulling that engine right back out.
Click to expand...

Ok but how will I set the lifters...........
 
84jimmy said:
Ok but how will I set the lifters...........
Click to expand...

I use a magnet to stick them down in the hole with some pre lube on them. There is nothing else you do to them. Did you install the head before the lifters? if you did, go buy another head gasket, you have to install the lifters before the head.
 
Jeff B said:
I use a magnet to stick them down in the hole with some pre lube on them. There is nothing else you do to them. Did you install the head before the lifters? if you did, go buy another head gasket, you have to install the lifters before the head.
Click to expand...


Everything is done........I dont need a new head gasket.....I just need to know if I tightened the adjustment bolt to torque spec or the 1/2 turn installed about in the first post
 
84jimmy said:
Why a picture? The adjustment bolt is the bolt on the rocker arm.......it is the same on all the motors.
Click to expand...
Jeep 4.0s dont use a rocker arm adjustment bolt unless Ive been doing it wrong.
 
Per comp cam and Howards performance cam that's an adjustment nut/bolt. I am looking at the paperwork now. Just cant take a pic.....then upload it to photo bucket and post right now
 
84jimmy said:
Per comp cam and Howards performance cam that's an adjustment nut/bolt. I am looking at the paperwork now. Just cant take a pic.....then upload it to photo bucket and post right now
Click to expand...

FYI no need for photobucket...nc4 hosts your phots for free just paste them directly into your message text
 
as said, no adjuster on the jeep 4.0. you can rotate (to base circle) so your not compressing the spring as you torque to 19ftlb. or you can just tighten them down evenly. both ways are fine, however you cannot tighten one all the way without running the one on the same bridge with it or your bent that bridge and the rocker wont ride correctly on the valve stem top.

your lifters need to be preloaded .020 to .060 max. Hence the pushrod checking tool.
 
Jeff B said:
as said, no adjuster on the jeep 4.0. you can rotate (to base circle) so your not compressing the spring as you torque to 19ftlb. or you can just tighten them down evenly. both ways are fine, however you cannot tighten one all the way without running the one on the same bridge with it or your bent that bridge and the rocker wont ride correctly on the valve stem top.

your lifters need to be preloaded .020 to .060 max. Hence the pushrod checking tool.
Click to expand...

Just easier to do each set if you put then at tdc compression.
 
Ron said:
FYI no need for photobucket...nc4 hosts your phots for free just paste them directly into your message text
Click to expand...

I had tried that a while back and never got it to work. This was of coarse years ago so I will try again once I get back on the project. Sadly the flu has prevented me from going any further.
 

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