Rocker Arm Eccentric Bolt Question

[72MetallicMalaga]

There's a great torque tightening reference page for the M10 motor on this forum.

 

Im looking at it right now, I just want to verify, the tightening torque for the rocker arm eccentric bolt is only 6.5 - 8lb ft, according to the chart linked below. Seems low, just double checking before valve adjustment.

 

 

[tzei]

I think i go harder. Specially steel rockers seems to need more.

[kbmb02]

45 minutes ago, tzei said:

I think i go harder. Specially steel rockers seems to need more.

 

^agree^

 

I've had some KM steel rockers which required torque of 'just-about-stripping' to hold the eccentrics.

 

The torque required for Lester Owens steel rocker arms is more reasonable/comfortable (Lester's being a better piece, in my opinion).

 

And, IE's heavy duty rocker arms usually require more torque than OEM-spec (especially if you use IE's eccentrics, which I've found are sometimes a couple-thousandths thinner than OEM eccentrics). -KB

[Mike Self]

My primitive--but effective--method (never had one loosen) is to use a 1/4" drive ratchet and tighten the 10mm nut until the edge of my index finger (pressed against the ratchet handle) hurts a little bit.   That's for the OEM aluminum rocker arms...

 

mike

[TobyB]

Yeah, agreed- tighter than it really ought to have to be is about tight enough!

 

I've always got a spare nut or 2 kicking around (shut up, Esty)

because the first thing to go is the thread on the nut.

And it's an odd (fine) thread.

 

t

 

[72MetallicMalaga]

Alright! Just finished this up, motor is a bit quieter. Occasional chatter. Video sound OK to you guys?

 

I realized I wouldn't have been able to torque all the eccentric bolts anyways because my sockets are too thick with the torque wrench. Made them pretty snug, I guess we'll find out if they are OK or not lol. 

 

 

Edited January 17, 2023 by 72MetallicMalaga

[cda951]

On 1/16/2023 at 8:03 PM, 72MetallicMalaga said:

Alright! Just finished this up, motor is a bit quieter. Occasional chatter. Video sound OK to you guys?

 

I realized I wouldn't have been able to torque all the eccentric bolts anyways because my sockets are too thick with the torque wrench. Made them pretty snug, I guess we'll find out if they are OK or not lol. 

 

Kinda hard to hear valvetrain noise, I think I could more hear the dancing intake screens  Maybe try a video from the exhaust side, closer to the valve cover.

 

As for torque specs, unless you have a really good and well-calibrated inch-lb torque wrench (Snap-On or the like), one shouldn't become too reliant on that with such low torque specs. Practice and feel go a long way. I have seen plenty of amateurs and "professionals" either greatly under- or over-torque fasteners while using a torque wrench. 

 

It is impossible to get a torque wrench on the valve adjuster locknuts of most of the cars I work on (air-cooled Porsches and old BMWs) so learning by feel is a must. Don't get me wrong, I am all about using a good torque wrench any time it is practical and possible!

 

A great exercise is to use scrap pieces of metal and/or old parts that already have tapped holes, set up some bolts and nuts with washers, and look up average torque specs for the grade/size/pitch of the fasteners you have. First tighten and torque the bolts/nuts by hand, then go back and use a well-calibrated torque wrench and see how far off you were. Rinse and repeat until you have a good feel for what it takes to tighten and loosen the bolts.

 

This all goes out the window a bit when one gets to torque-to-yield or "stretch" bolts used in modern cars which have a torque-angle spec and are designed to only be used once. Anyone here who has experience with the myriad aluminum stretch bolts used on BMW's mag-case N51/N52 series engines knows the sickening feeling of the bolt stretching as you apply the final 90 degrees of torque---instinct tells you to stop, but it is normal for that application!