lifter preload

[8driann]

Hello, I am going to be installing some new rocker arms and pushrods (all stock engine) but I keep hearing things like preload or some sort of sequence. I am a little mechanically inclined and I took my engine part but this is my first LS and I was wondering if anyone could give me details on how to install them or explain what preload is and how do I go about it? Or maybe someone has a helpful video link they could share with me?

[Clarkstar]

Why would you change either of those parts on your engine?

[InFiD3ViL]

Watch this if using stock style LS7 lifters. Aftermarket lifters may require a different preload than stock.
Edit: If you are installing an other than stock ratio rocker arm (1.70:1) then there are other steps that should be taken which aren't explained in that video, ie. checking valve tip sweep pattern.

[christianchevell]

You would be looking for the " golden Zone" for stock lifters on a stock ls engine its .045 to .060 max . LS7 are .070 with different rocker ratio and rev limit. The more preload the more typewriter noise but also better for accidental over revs if a manual as it better controls the top end... Just some thoughts form a old timer... Good Luck, that and some bushings on the rockers is golden...

[FasNuf]

Completely stock engine? Why are you replacing the pushrods and rockers? Unless something is broke, there shouldnt be a need. As far as preload, using stock pushrods wlll set your preload provided you have the stock cam, stock lifters and stock rockers. Rockers are torqued to 22ft lbs. Preload is set with pushrod length. If you change the cam, you will need to measure for new pushrods and calculate preload. Comp has a tool to measure this.

Base circle
https://youtu.be/RxGTmlQvzrU

Comp tool
https://youtu.be/hvBEjeKqktM

This should help give a basic understanding even though it's for the LSA engine

[wasthatacop?]

Originally Posted by 8driann

Hello, I am going to be installing some new rocker arms and pushrods (all stock engine) but I keep hearing things like preload or some sort of sequence. I am a little mechanically inclined and I took my engine part but this is my first LS and I was wondering if anyone could give me details on how to install them or explain what preload is and how do I go about it? Or maybe someone has a helpful video link they could share with me?

This is a rare upgrade. Was there a problem? If not, typically these items are replaced for a camshaft change. Lifters require removing the heads, which is digging pretty deep into the engine.

[8driann]

Originally Posted by Clarkstar

Why would you change either of those parts on your engine?

I had ticking in my engine even after lifters and stock cam (they were very worn and had pits in them as well as flat spots). So I inspected the pushrods and they were bent so I picked up some new ones and the rocker arms had uneven wearing on some so I picked up some new ones too.

[8driann]

Originally Posted by FasNuf

Completely stock engine? Why are you replacing the pushrods and rockers? Unless something is broke, there shouldnt be a need. As far as preload, using stock pushrods wlll set your preload provided you have the stock cam, stock lifters and stock rockers. Rockers are torqued to 22ft lbs. Preload is set with pushrod length. If you change the cam, you will need to measure for new pushrods and calculate preload. Comp has a tool to measure this.

Base circle
https://youtu.be/RxGTmlQvzrU

Comp tool
https://youtu.be/hvBEjeKqktM

This should help give a basic understanding even though it's for the LSA engine

oh ok, I understand. I was switching them out because I had ticking going on, and even after cam and lifter replacement (they were both very worn down with pits and flatspots on some lobes and lifters), I still had the noise. So I inspected my pushrods on about two were a little bent, and some rocker arms had uneven wearing, so I decided to replace them.

[8driann]

Originally Posted by wasthatacop?

This is a rare upgrade. Was there a problem? If not, typically these items are replaced for a camshaft change. Lifters require removing the heads, which is digging pretty deep into the engine.

Im tired of typing lol, you can see the replies to others on why I was doing this upgrade.

[FasNuf]

Sounds like your on top of it maintenance wise. Sounds like you dodged a bullet with thd pitting being on the parts. What mileage on the engine?

[Greenhornet2]

There is a push rod length tool pretty cheap for checking what length you need. If you are replacing the rockers with factory rockers you should consider upgrading them with a CHE bushing trunnion upgrade, or BTR V2 trunnion kit. If staying with stock parts you won't need to check the length just torque the rockers down as mentioned above.

[8driann]

Originally Posted by FasNuf

Sounds like your on top of it maintenance wise. Sounds like you dodged a bullet with thd pitting being on the parts. What mileage on the engine?

about to hit 127,000

[8driann]

Originally Posted by Greenhornet2

There is a push rod length tool pretty cheap for checking what length you need. If you are replacing the rockers with factory rockers you should consider upgrading them with a CHE bushing trunnion upgrade, or BTR V2 trunnion kit. If staying with stock parts you won't need to check the length just torque the rockers down as mentioned above.

did that. Will take it to a tuner soon and I guess I can only hope that it is a header leak or just the "normal" header noise.

[8driann]

Originally Posted by Greenhornet2

There is a push rod length tool pretty cheap for checking what length you need. If you are replacing the rockers with factory rockers you should consider upgrading them with a CHE bushing trunnion upgrade, or BTR V2 trunnion kit. If staying with stock parts you won't need to check the length just torque the rockers down as mentioned above.

So I would always hear "trunnion upgrade" but i never knew what that was. After further research, I noticed that the new rocker arms come with an upgraded trunnion kit. I got them from autozone and the brand is melling.