Backside method valve adjustment question

[kach22i]

Originally Posted by lindy 911

You won't get accurate torque if you use a swivel in the combination.

Lindy

Good point.

[911pcars]

Originally Posted by mtndawg

Keep the updates coming. I'm going to adjust my valves for the first time in the coming days (just ordered the pelican feeler gauge and head cover gaskets). Now I know to check my head bolt torque.

If adjusting valves via the "backside" method (between camshaft and rocker arm), be aware that the equivalent feeler gauge may not be the same as the usual adjustment location (between valve and rocker arm).

Sherwood

[Gunter]

Originally Posted by bsimonson

Just got back from the garage where I have checked all the cylinder head studs. None of them were in need of tightening and more importantly, none of them were broke.

Since it was only a $7 part I decided to try the socket extension I posted above (or rather its bigger brother) which turned out to be almost perfect. With a swiwel, a long extension, about 4", and a 3/8 to 1/2 adapter to fit it to my torque wrench it was a 30 min job.

Many thanks to all of you, now on to the valve adjustment!

Unless you have a calibrated 3/8"drive torque wrench with an approximate range of 10-75 ft-lbs and straight connections (no swivel) into the hex of the head stud, no true torque can be expected.

23-24 ft-lbs is pretty low and only a quality, sensitive and calibrated torque wrench ensures correct reading.

I find it hard to believe that at least some of the studs didn't need a little tightening?

[SP2]

I know both methods done with the engine on a stand. The backside method is accurate and easier, especially when the engine is in the car.

[911pcars]

Originally Posted by Gunter

Unless you have a calibrated 3/8"drive torque wrench with an approximate range of 10-75 ft-lbs and straight connections (no swivel) into the hex of the head stud, no true torque can be expected.

23-24 ft-lbs is pretty low and only a quality, sensitive and calibrated torque wrench ensures correct reading.

I find it hard to believe that at least some of the studs didn't need a little tightening?

Gunter,
See my response in #15. Accurate torque can only by determined as the fastener rotates in the threads. Static friction, as in a fastener already tightened, will be higher in order to either tighten or loosen it.

Thus, if the spec is 23 ft.lbs. and is already to spec., the fastener will require a higher application of torque to break it free. The correct method of "retorquing" is to loosen the fastener (at least below final spec.), then retighten to spec.

I think the objective in this thread is to confirm the cyl. head nuts aren't loose or a stud isn't broken, in which case if a preset-type torque wrench signals "OK" at the specified torque, I would call it a day.

Sherwood

[kach22i]

Originally Posted by Gunter

I find it hard to believe that at least some of the studs didn't need a little tightening?

Me too, but I'd leave well enough alone at this point and get on with the valve adjustment.

Originally Posted by 911pcars

I think the objective in this thread is to confirm the cyl. head nuts aren't loose or a stud isn't broken, in which case if a preset-type torque wrench signals "OK" at the specified torque, I would call it a day.

Sherwood

Yea, why push one's luck when it comes to head studs?

I read a press release on some new product a few years ago. It claimed that many structural failures on heavy equipment (ship boiliers etc..) could be traced back to checking and rechecking the torque on retaining bolts. The stress caused from inspection torquing eventually caused the failure they were trying to prevent. The product was some sort of washer which changed color based on existing nut/bolt pressure present (applied torque).

[JJ 911SC]

Originally Posted by kach22i

... I read a press release on some new product a few years ago. It claimed that many structural failures on heavy equipment (ship boiliers etc..) could be traced back to checking and rechecking the torque on retaining bolts. The stress caused from inspection torquing eventually caused the failure they were trying to prevent...

When I was in the Navy we had a few golden rules;

Never do major PM or any CM on Monday...

If the stuff work, don't F$%# around with it.

I remember a 6 months Nato deployment that my total CM time was 1 hours... due to the brake band on the Revox recorder (recording the Commies at the time) broke... Fixed it by using the plastic band from the 40Lb chicken box. Probably still there.

[bsimonson]

Yes, I probably should have thought of the inaccuracy brought by a swivel and I'll have it in mind for the future. I do have a nice calibrated 10-60 Nm wrench so I should be able to get accurate torques if not using a swivel.

Like some of you mentioned it is probably best to leave the studs as is for now and that is what I will do, although it is nice to know that at least no one is broken or much too lose.

I'll see if I can get on with the valve adjustment tomorrow, today is hung over day.

/b