RED LT4

Ok I installed new springs and Im wondering what the steps are to torque the rockers down and all that good stuff? I know that they are 22lbs but other than that....?

lucky131969

You know you have to rotate the engine accordingly so the valves are closed when you torque the rockers down....right?

Do you have a service manual?

RED LT4

No I dont have one.....so all you have to do is make sure the valve is closed when it is torqued down?

lucky131969

Yes, but you need to start from TDC(compression stroke #1). Did you set the engine to TDC #1 compression while the heads were off?

RED LT4

No I didnt. I had one head off. But replaced all the springs. Its all back together now so I just have to do this step and Im done

vettenuts

Here you go:

Deleted, uses Lucky's information.

lucky131969

Well, the proper way to do it is to start from TDC #1, and torque down the install the appropriate rockers, rotate 360 degrees, and repeat:

VGLNTE1

that is the proper way, but a over precaution. tq them all to 22, then rotate the motor 180 degrees then TQ again

lucky131969

Over-precaution? So you just torque them down at an position in the firing cycle, rotate 180 degrees, and retorque? Sorry, that makes no sense at all.......

~Josh

Simple....

Use red Loc-Tite. The rockers can easily come loose from vibration.

Torque them down.... rotate the engine a few revolutions. Repeat. Rotate again.. last pass.

Done.

I've done quite a few cams... even a couple where I didn't have a torque wrench... tightened until "very snug" without stripping the bolt threads, and with each revolution and repass, just take up the small difference (if any) until you know good and well they are tight.

Many years and counting (friends and I) .....

RED LT4

Yes because there is no adjustment right? So what you did is tighten them at 22...rotate the engine and do it again?

~Josh

Yes.... stock rockers have no adjustment. 22lbs is the (supposed) ticket.

But I noticed that sometimes they would be really tight before 22 (couldn't go that high without fear of stripping threads)

So helping a friend long distance (forgot my Torque Wrench home) I tightened them to "very snug" and rotated the motor. Did it again. A few bolts turned another 1/8th inch... but that's it.

After that experiance, on future swaps I didn't bother with the wrench, just used Loc-Tite and snugged 'em down tight.

Call me a shade tree mechanic, or a good friend/engine whiz..... I'm a little of both.

RED LT4

Well thank you

~Josh

You're welcome.

leadfoot4

Just my $0.02 worth.....

~Josh

Always had good results... No aluminum issues with the FOUR times I had to remove rockers on my Twin Turbo LS1.... used red lock tite always. Not to mention changing springs on heavy cammed motors for friends. Red is what "I" use.... find a lesser one if it makes "you" feel better.


The base circle? Yeah so it wasn't bottomed out against a base circle when you initially tighted it.... who cares? -That's what rotating the engine is for. It gets tight (fully) after a couple passes.

leadfoot4

YOU'LL care, if you pull the threads out of the aluminum heads, by tightening a rocker against a partially opened valve/spring. But, since you think I'm completely wrong, HAVE FUN!!

vettenuts

Not exactly. The stock rockers are set so they have an acceptable travel width on the valve stem for a stock lift cam. As you increase cam lift, you push the rocker tip closer to the edge of the valve stem at full cam open, accelerating valve guide wear. You need to reset the rocker height with any cam change to account for this additional rocker tip motion. Once that is done, then you re-measure for pushrod length. Admittedly, most skip both of these steps and they will likely find out down the road as oil use increases and other issues develop long term.

vettenuts

Any bolted joint is dependent on the elastic loading of the parts in the assembly. The elastic loading is developed from the bolt preload, which when a torque value is specified, is dependent on the thread friction. If you tighten bolts that are not on the base circle of the cam, you are also compressing the valve spring which increases thread friction and hence an improper preload is attained even though the torque wrench clicked. Friction is both static and dynamic. I can tighten a bolt to less then 22 lb-ft and then re-check with the torque wrench and it will show 22 lb-ft. The difference is that during the tightening sequence you are measuring the running or dynamic friction based torque. Once tight, it is static and can be considerably higher. Bottom line, checking after rotation doesn't mean anything and certainly is not an indicator that the preload is correct. It is a completely inaccurate measurement. That's why when you re-tighten a head gasket you back the bolt off then re-tighten, you need to measure the running value. Same with rocker bolts. The use of red loctite is not necessary, unless of course they are backing out due to inadequate preload.

Tech

Wow... I would never dream of not torquing the rockers. I also would never use red loctite on aluminum threads if I thought the bolts would ever need to come out again.

I have always torqued them all to 22 lb-ft without any rotation. The trunnion area bottoming out against the pedestal is what causes the torque wrench to beep/click. I don't understand how the location of the lifter on the cam could cause enough variance to cause problems. I'm no physics or metallurgy guru, but torque wrench accuracy can vary. It is my understanding that in many cases, it's more important to have even force applied across all of the bolts than for them to be precisely XX lb-ft.