Top end oiling issue after hydraulic roller change.

[Hotrodhawk]

This was the first fire up about 4 weeks ago. So any lifter noise you may hear in this clip adjusted out after I ran the valves a 2nd time.

[Hotrodhawk]

https://youtu.be/8phjupe5Tic

[In-Tech]

Why did you decide to change ?

Did you change anything else ? Looks like the LS7 lifters might require a slightly longer pushrod ?

How much preload did you use when you adjusted the valves ?

I changed because I had two different sets of 875's loose plunger retainers back in the day. The car had set in storage for 12 years after the second failure (lost interest).
Now this last year I decided to do something and get this car back running and read that these new Ls7 lifters are drop ins and spin at higher rpm.

Set them zero lash then preload of 1/4 turn on 7/16 studs. So around .075 -.078

Just fyi,
7/16 studs are usually 7/16-14 bottom and 7/16-20 on the top where you are adjusting. 1 full turn is ~.050" It's been a long time since I physically checked, from memory it seems like the value doubles in stud/nut. I might have to dig some old parts up
https://www.atlanticfasteners.com/tech- ... full-turn/

[skinny z]

Having a similar discussion a while back and was informed that the rocker ratio comes into play here as well.
What you push down on the fulcrum is multiplied at the pushrod end. Made sense to me at the time.
EDIT:
It's not the ratio itself but a formula used with includes the ratio. I'd have to look it up.
POST EDIT:
The formula follows as lifted from another forum conversation:
However, the push rod end of the rocker moves
((1 + ratio) ÷ ratio)
times that, since the rocker acts as a lever. 1601 rocker arm is a 1.52 ratio, so that means that 1 turn on the nut = (2.52 ÷ 1.52) × 1/24 (which is .041" for a 3/8-24 stud), or, about .069". ½ turn is about .035".

So, use your current rocker ratio and stud pitch accordingly.

[skinny z]

.

Set them zero lash then preload of 1/4 turn on 7/16 studs. So around .075 -.078

Using the above formula with a 7/16th-20 stud and 1.6 ratio rockers, one full turn would equal:
((1 + 1.6) ÷ 1.6) x 1/20
=~.081"

[Hotrodhawk]

Thanks for the thread pitch info

[Hotrodhawk]

Thanks for the thread pitch info guys. Right now I'm not going to have time until next week to get the covers off after I get another pushrod checker in my hands. Can't find it after my move from Michigan to Utah.
The Salt Flats/ speedweek are calling my name and start Saturday. Gonna head out and watch some really fast stuff.
I'll be sure to update my findings and progress, thanks everyone!

[HDBD]

Problems with the lifter feed happens when the oil fill band does not match the feed passage. I have grooved some lifter bands to aid / add to the feed time the passage is exposed to pressure.

[Hotrodhawk]

Problems with the lifter feed happens when the oil fill band does not match the feed passage. I have grooved some lifter bands to aid / add to the feed time the passage is exposed to pressure.

I wish I had one of my old 875's laying around but they hit the trash can over 10 years ago. Looking at pictures of the 875's, I have to say the LS7 lifters have no where near section area that's exposed to a LT1 block feed passage as a 875. I've got some figuring out to do on my hands. I've been running a AFR rev kit in this combination since 1998 and not looking forward to removing those springs to get down to the lifters.

[dfarr67]

roller rockers don't need much oil.

[skinny z]

Thanks for the thread pitch info guys.

How many turns of the rocker nut did you apply for how much preload? And what's the rocker ratio?

[Hotrodhawk]

How many turns of the rocker nut did you apply for how much preload? And what's the rocker ratio?

Set them to zero lash then preload of 1/4 turn on 7/16 studs. 1.6 ratio

[skinny z]

How many turns of the rocker nut did you apply for how much preload? And what's the rocker ratio?

Set them to zero lash then preload of 1/4 turn on 7/16 studs. 1.6 ratio

For what it's worth the math says that's about .020".

One full turn would equal:
((1 + 1.6) ÷ 1.6) x 1/20
=~.081

I'm not certain what the target is or if too little or too much would restrict the top end oiling.
EDIT:
I see you were going .070"(+/-).

Set them zero lash then preload of 1/4 turn on 7/16 studs. So around .075 -.078

That's more like 3/4-1 full turn.

Even taking the rocker ratio math out of it, a 7/16-20 stud has a thread pitch of .050". So one turn on the nut moves it .050".

I wonder if insufficient preload might lead to some component seperation at RPM. THAT would certainly kill the top end oiling.

[Tom68]

Slowmo oiling.

https://www.instagram.com/reel/Cg4XUyrD ... _copy_link