Torque for Rocker Arm Assembly Bolts?

JINMA224XR · Dec 13, 2005

Does anybody know, what the correct Torque is supposed to be for the Bolts/Nuts, that hold the Rocker Arm Assembly on a Y380T engine?

Or is there a way to check how much torque is allready on the Bolts?

Have a nice day,
Joe

JINMA224XR · Dec 15, 2005

Well, I noticed that 45 people have read the original post.

With no replies, then I am assuming that about 45 others here in the Chinese Section, are also needing this information as well. /forums/images/graemlins/smile.gif

Don't trip over yourselves trying to answer this Highly technical question.

Have a nice day,
Joe /forums/images/graemlins/cool.gif

n4807g · Dec 15, 2005

in what increments is your wrench adjusted? 2lbs?, 5lbs?

I'd set the wrench at around 35 lbs and start tightening. Adjust the wrench torque higher by increment until you get movement in the bolt. When the bolt moves = tightens the torque was the previous setting. Of course if the bolt moves at 35 lbs. set the torque lower say 15 lbs go to another bolt and repeat the process until the correct torque setting is determined. At that point set all the bolt to that torque. Of course, this assumes that the bolt you use to determine torque was set correctly. It might be worth going to a third bolt and confirm the torque setting by starting at a lower setting and repeating the process.

MarkNHow · Dec 15, 2005

I did a search on the site and here is a good description of the process and the torque.
http://johnstractor.homestead.com/JMretorque.html
Mark H

JINMA224XR · Dec 15, 2005

I did a search on the site and here is a good description of the process and the torque.
http://johnstractor.homestead.com/JMretorque.html
Mark H


Hey Mark,

They gave the values for the Head Bolts, but did not mention the bolt values for the Rocker Arm Assembly Bolts.

I don't know how they got to the head bolts with a torque wrench, without removing the Rocker Arm Assembly.

Have a nice day,
Joe /forums/images/graemlins/cool.gif

JINMA224XR · Dec 15, 2005

I'd set the wrench at around 35 lbs and start tightening. Adjust the wrench torque higher by increment until you get movement in the bolt. When the bolt moves = tightens the torque was the previous setting. Of course, this assumes that the bolt you use to determine torque was set correctly. 

Hey N4807G,

Interesting.

Is this a method that you are comfortable with?

What happens when you encounter a bolt/nut, that is allready at the maximum of it's torque strength and you continue to tighten, using your method? Oops, do we have a Plan B.

Have a nice day,
Joe /forums/images/graemlins/cool.gif

psj12 · Dec 15, 2005

First determine what size bolt and thread pitch you are dealing with then go here . Now look under standard metric fastener torque values.
That's what Google's for.

greg_g · Dec 15, 2005

( Don't trip over yourselves trying to answer this Highly technical question)

Nothing techical about it Joe. Nothing Chinese about it either. Bolts are simply torqued based upon their size; for the most part that means diameter. Those nuts/bolts to which you refer are M8. Torque range of a M8 is 19-28 nm/m (14-21 ft/lbs) whether it's on a bicycle or a bus.

//greg//

n4807g · Dec 15, 2005

I guess I assumed the bolts are already torqued and you just want to determine at what torque they are set. If that is the case this method should work fine. I suggested 35 as a safe low setting to begin. Frankly I'm not sure there is another way if you don't have the mfg's suggested torque value.

If you are concerned about shearing a bolt head (if I read your response correctly don't be). Undoubtedly the bolts aren't tightened to their maximum possible setting.

Obviously make every effort to find the recommended setting 1st. The information is out there somewhere.

JINMA224XR · Dec 15, 2005

Bolts are simply torqued based upon their size; for the most part that means diameter. Those nuts/bolts to which you refer are M8. Torque range of a M8 is 19-28 nm/m (14-21 ft/lbs) 

Hey Greg,

Thanks Greg.

How much below max, do you recommend setting the torque wrench?

Have a nice day,
Joe

JINMA224XR · Dec 15, 2005

First determine what size bolt and thread pitch you are dealing with then go here . Now look under standard metric fastener torque values. 

Thanks PSJ12,

The conversion chart helped a lot.

Have a nice day,
Joe /forums/images/graemlins/cool.gif

JINMA224XR · Dec 15, 2005

If you are concerned about shearing a bolt head (if I read your response correctly don't be). Undoubtedly the bolts aren't tightened to their maximum possible setting.

Obviously make every effort to find the recommended setting 1st. The information is out there somewhere.


Hey N4807G,

The metric fastener torque value chart helped a lot.

The Rocker Arm Assembly has to be removed in order to Retorque the Heads on my 224. And I wanted to torque the bolts/nuts on the Rocker Arm Assembly when I reattached it to the head. I could have used a non torque wrench, but I want to try and get a tight even attachment, if I can.

Thanks &
Have a nice day,
Joe /forums/images/graemlins/cool.gif

bruce1966us · Dec 15, 2005

Thread pitch has alot to do with the torque the (nut in the case) can tolerate. metric threads usually range from 1.25 to 1.75 The finer thread bolts/nuts can withstand higher torque values.

gunslinger101 · Dec 15, 2005

Bolt diameter, hardness and thread pitch are all important to proper torque.
And to answer how to torque head bolts without removing the rockers is with the use of a crows foot.
Never thighten a bolt to figure what torque it is at now, torque wrenches have a left and right scale or a dial or click type the setting works in either direction.
When Backing off the bolt , watch the scale and when it cracks lose, thats the torque it was set at.

greg_g · Dec 15, 2005

( How much below max, do you recommend setting the torque wrench?)

When considering a torque range, I generally take the middle ground. For those M8s, I'd set my torque wrench for 18 pounds. If yours is type graduated in 5 pound steps, you should still be quite safe at 20.

//greg//

JINMA224XR · Dec 16, 2005

And to answer how to torque head bolts without removing the rockers is with the use of a crows foot.


Hey Jim,

Tell me it's true!

Then I can use a crows foot on the torque wrench to get to those nuts, without removing the Rocker Arm Assembly?

If I can, I will go down to Harbor Freight and get me a set of Crow's Feet to put on my Torque Wrench.

I sure hope so.

Have a nice day,
Joe /forums/images/graemlins/cool.gif

bluechip · Dec 16, 2005

As I understand it, if you use crow foot, you have to make an adjustment to the torque, since it is not measured at the point of rotation.... the longer leverage point will give a lower torque reading than you are actually applying so it may be a good idea to stay to the lower end of the range when using a crow foot "socket".

greg_g · Dec 16, 2005

( And to answer how to torque head bolts without removing the rockers is with the use of a crows foot.


Hey Jim,

Tell me it's true!

Then I can use a crows foot on the torque wrench to get to those nuts, without removing the Rocker Arm Assembly?

If I can, I will go down to Harbor Freight and get me a set of Crow's Feet to put on my Torque Wrench.

I sure hope so. )

No no no no no no. Those cheap U-shaped crows foot extensions are NOT the tool for this job. They only make contact on two sides of the hex head, slippage in a high torque environment is almost guaranteed. At best, you ruin the extension. At worst, you round off the hex head.

They're considerably more expensive, but the RIGHT crows foot for the job looks more like the end of a line wrench; full contact on four sides, with wraparound on sides 5 and 6.

Click HERE.

And then like Chip says, you've got to do the math to compensate for the torque offset

//greg//

Ranch_Hand_Supp · Dec 16, 2005

If you are going to use a crows foot for the job you are describing....I would use a true boxed end crows foot that would not try to spread open.

Ronald
Ranch Hand Supply

greg_g · Dec 16, 2005

( If you are going to use a crows foot for the job you are describing....I would use a true boxed end crows foot that would not try to spread open. )

Minor point Ronald, but if it's boxed - it's technically not a crows foot anymore. I'm curious though, where have you seen such an extension anyway?

//greg//