Valve adjustment question

[Jamieboy]

Last weekend I went to check my valves for the first time (!).

Probably a typical newbie frustration/question but was faced by the issue that after adjusting the valves and tightening the locknuts a bit by hand I then went to fully tighten them to the 8nm in the manual with a torque wrench - which of course kept then throwing off the adjustment as I wasnt able to hold the hex key for this last tightening.

Presumably people tighten the locknuts by a 10mm spanner whilst holding the hex key (?) - anyone got a good tip to get around the right torque and avoid over-torquing the locknuts? E.g. finger tight then 1/8th turn (or more, or less) I'm just really paranoid about stripping them.

Thanks

 

[Hay Ewe]

I check mine and did in-adverntantly adjust them once.....
If you are paranoid, then you could get a crows foot that will fit on the end of your torque wrench so that you can use the hex key to hold the 'stud / bolt' and torque up the nut.

This is a crows foot (not to be confused with a flare nut)
https://store.snapon.com/Open-End-m...-Open-End-Metric-Crowfoot-Wrench-P631861.aspx

HOWEVER, you then need to make a calculation to adjust the torque you set on your torque wrench because the lever / moment is longer
To do that, here is a diagram and calculation
http://www.engineersedge.com/manufacturing_spec/torque_wrench_1.htm
Some will say that if you have the crows foot ad 90degrees then there is no length adjustment and so no calculation needed

If you are going to that level , then you need to use an appropriate torque wrench.
The torque is 8Nm you quote below, so you need a torque wrench where 8Nm is in the middle of the range. if you had a torque wrench that went from 2Nm to 12Nm that would be fine.
You can also get single drives that are preset at a specific torque.

I shall leave it to you to work out what you want to, I am sure that others will chime in with what they do and I bet I do similar to them.

 

[MarkShelley]

I have never used a torque wrench on mine. I have always done it to that light hearted maintenance guide you can download which, from memory, says to use a small 10mm spanner with your fingers right close to the nut (so the lever is small) and give it a `snerk`

 

[Nin]

Find a 10mm nut and bolt of same pitch as the adjusters. Stick them in your vice and tighten to 8Nm then undo with a ring spanner. Get the feel for how tight that is and then use feel to tighten the lock nuts. Don't think I've ever used a torque wrench on adjusters in 30 odd years working on bikes, landrovers, outboards, and never had a problem just using feel at those low torques.

 

[The Grey One]

I don't use a torque wrench either but then I have 35 years experience of such work on professional basis. Never had one come loose or sheer off although it does take time to develop a feel for it. If you have some mechanical sympathy but just lack experience then the advice to practice getting the feel of what the torque setting feels like is a good one. If you are the spannering equivalent of having two left feet either give the job to someone else or continue to use a torque wrench

John

 

[King Rat]

Smack it with a shifter.....Finger tight on a spanner will be plenty.

How long is the spanner? I hear you ask - how big and strong are your fingers is also a pertinent question. SENSIBLY tight is all you need. Think spark plug, plus a bit.

 

[The Grey One]

Smack it with a shifter.....Finger tight on a spanner will be plenty.

How long is the spanner? I hear you ask - how big and strong are your fingers is also a pertinent question. SENSIBLY tight is all you need. Think spark plug, plus a bit.

Does depend on experience/mechanical sympathy to get it right. I lost count of the number of stripped spark plug threads I dealt with,mostly to the if tight is good extra tight must be better brigade.

John

 

[Smug]

Note the position of the ring spanner before undoing the lock nut and then do it up to the same position after adjusting the clearance. After adjusting a couple of valve clearances you should have a feel for it. This does assume that the nuts were tightened up correctly the last time.

 

[Timolgra]

Note the position of the ring spanner before undoing the lock nut and then do it up to the same position after adjusting the clearance.

You might want to think that one through

 

[dubster]

Think spark plug, plus a bit.

Surely 8nm is less tight than a spark plug

 

[Comfy Old Boots]

@drfarkov

This thread makes me look good!

 

[Smug]

You might want to think that one through

Okay what don't you understand?

 

[tadhgocuilleain]

Okay what don't you understand?

If he adjusts the valve, the locknut will have to be in a different position to get the same torque!

 

[Timolgra]

Okay what don't you understand?

If he adjusts the valve, the locknut will have to be in a different position to get the same torque!

Like I said, think it through

 

[Deleted account 211025001]

............which of course kept then throwing off the adjustment as I wasnt able to hold the hex key for this last tightening.

...................Thanks

Adjust the gap so it's a bit bigger than it should be then nip up the lock nut and measure the gap. Once you've done this a few times you get a feel for how much bigger to set the gap ( 1/8 of a turn for example). It's a bit of trial and error but works for me on engines where you can't hold the threaded adjuster easily.

Andred

 

[Slipperyeel]

Okay what don't you understand?

No, Tim has a point .

How can the spanner be in the same position after you've adjusted the valve? You won't have adjusted much if it is!

 

[Nick591]

No, Tim has a point .

How can the spanner be in the same position after you've adjusted the valve? You won't have adjusted much if it is!

Come on chaps, think about it. It's the inner threaded adjuster that is changing position. The pitch of the thread on the pin doesn't change when it is adjusted so, given even wear etc. you still have to turn the locknut the same amount down onto the rocker to get the locking force required so the rotational position of the locknut when tight should not change on any given rocker whatever the adjustment of the gap.

 

[Jamieboy]

Thanks chaps.

The 'snerk' explanation within that (incredibly long) American tutorial that Mark Shelley referred me to was very helpful. Just got in there again and tightened by hand which (I hope) has allowed me to get a more even clearance all round.

 

[Smug]

Come on chaps, think about it. It's the inner threaded adjuster that is changing position. The pitch of the thread on the pin doesn't change when it is adjusted so, given even wear etc. you still have to turn the locknut the same amount down onto the rocker to get the locking force required so the rotational position of the locknut when tight should not change on any given rocker whatever the adjustment of the gap.

Well said there Nick. Obviously the ones that didn't understand don't get to adjust valve clearances too often.

 

[tadhgocuilleain]

Come on chaps, think about it. It's the inner threaded adjuster that is changing position. The pitch of the thread on the pin doesn't change when it is adjusted so, given even wear etc. you still have to turn the locknut the same amount down onto the rocker to get the locking force required so the rotational position of the locknut when tight should not change on any given rocker whatever the adjustment of the gap.

This assumes that you hold the locknut still while adjusting the clearance - that wasn't specified. It also assumes that they were torqued properly the last time. Too much assumption for my liking.