If I over-torque by....

5 lbs. on my head bolts can you see any problems, immediate or later?
All new studs, nuts and bolts.

I would take the 8 smaller size bolts to 25 ft. lbs instead of 20 and the 2 larger to 30, or 35? Maintain the 10 pound difference?

My torque wrench is an old timer and starts at 25 ft. lbs.

I don't like guesstimating torque settings even though I have had to do so on this bike because the torque wrench head and socket won't fit in some of those itty bitty VFH to get at places on the head

New composite head gasket on a 74 850.

I don's see it as a problem but know someone/maybe many in here have encountered a similar issue...and I don't want to buy another torque wrench when mine works, but, is 5 lbs. short on the scale.

Thanks.

You purchased a torque wrench, at some point in the past, for good reason; if it starts at 25 ft/lb, is an old timer then the readings it gives you are almost as accurate as reading tea leaves; your gut must have told you this already. if you are under age 65, or think you'll live another 10, buy a good quality (not from Harbor Freight, please) new one; think of the guesstimating (stress?) it will save you. You'll be re-torquing the head at least 2 more times, maybe 3 with the composite head gasket.

Best.

I over torqued a Moto Guzzi rear main seal bearing bolt, and then spent two days drilling, tapping and helicoiling. I think the most important part of an engine build is confidence in the assembly, so I second RoadScholar.

here is a youtube out there showing how to perform calibration of most torque wrenches.

Sorry , never used a torque wrench with Nortons , just by learning and feel of what's right. Re-torquing or in my case re-tightening is very important. I know all you engineer types will shoot me down on this but I'm on my 5 th and final one (Commando) before expiring from this world. Never had a head gasket go or any exhaust or other gaskets for that matter. Always replace with new and tighten by feel and re-tighten accordingly after a run in. Have a nice day.

I'm guilty. Most of my torqueing concerns have always been with alloys, but if I could locate my wrench I would for sure use it on the top end bolts because I wouldn't desire to do them twice... The Guzzi is all alloy so I'd buy or borrow one for that. Auto Zone has loaners I'm pretty sure.

I have one, I was just too stupid to use it. That and my Haynes manual for Tonti Guzzis conspicuously omits torque values for pretty much everything. Rod bolts are a no brainer though.

Lineslinger said:

5 lbs. on my head bolts can you see any problems, immediate or later?
All new studs, nuts and bolts.

I would take the 8 smaller size bolts to 25 ft. lbs instead of 20 and the 2 larger to 30, or 35? Maintain the 10 pound difference?

My torque wrench is an old timer and starts at 25 ft. lbs.

I don't like guesstimating torque settings even though I have had to do so on this bike because the torque wrench head and socket won't fit in some of those itty bitty VFH to get at places on the head

New composite head gasket on a 74 850.

I don's see it as a problem but know someone/maybe many in here have encountered a similar issue...and I don't want to buy another torque wrench when mine works, but, is 5 lbs. short on the scale.

Thanks.

Click to expand...

Within 5lbs I woud'nt fuss too much about it, more important that they're all torqued equally at that range

If you are serious about torque settings, you have to have wrenches that operate for most of what you do in the middle of their torque ranges - where they are most accurate. IOW, you probably should have 3 of them, a 1/4, a 3/8, and a 1/2" drive. As noted, they need to be quality torque wrenches. ALSO, and vitally important, you have to know if the fitting you are tightening is supposed to be dry or lubricated. If lubricated, you should know WHAT lubricant.

If you lubricate a fitting that the torque setting is for dry, you are applying 30% more stretch to the bolt than spec. It's a good way to strip threads in alloy and possibly break a bolt. Conversely, the fitting will be 'under torqued" by that amount if it's supposed to be lubed and you tighten it dry. FWIW, antisieze, thread lockers, etc are 'lubricants' as far as the fitting is concerned when you apply it and tighten the fitting. But they each have different frictional characteristics as do various oils/greases.

In factory auto service manuals back in the day, they commonly stated whether the torque settings were dry or lubricated and, if lubricated, with what lubricant - often 30 wt motor oil. In some cases different fittings in the same engine were specified to use different lubricants.

If you don't have good quality, calibrated torque wrenches and/or you don't know whether the torque settings are for dry or lubricated fittings, you can't ensure the bolt is properly tensioned/stretched for the application. OTOH, "This seems tight enough" has worked for experienced mechanics for as many years as there have been threaded fittings!

Gotta wonder if there were any torque wrenches at the Norton factory.

Lineslinger said:

5 lbs. on my head bolts can you see any problems, immediate or later?
All new studs, nuts and bolts.

I would take the 8 smaller size bolts to 25 ft. lbs instead of 20 and the 2 larger to 30, or 35? Maintain the 10 pound difference?

My torque wrench is an old timer and starts at 25 ft. lbs.

I don't like guesstimating torque settings even though I have had to do so on this bike because the torque wrench head and socket won't fit in some of those itty bitty VFH to get at places on the head

New composite head gasket on a 74 850.

I don's see it as a problem but know someone/maybe many in here have encountered a similar issue...and I don't want to buy another torque wrench when mine works, but, is 5 lbs. short on the scale.

Thanks.

Click to expand...

I assume you are only talking about the Initial tightening during the initial assembly of the engine?

That’s exactly what I was advised to to by an old time ex Norton racer. Over torque by 5lbs on the initial build and then use standard settings after that.

I tried it. It definitely reduced the crush of the gasket and subsequent loosening of the head fasteners, with no ill effect.

I wouldn't be concerned with an overtorque of only 5lb from my experience I'd be more concerned with old torque wrenches that have been in people's tool chest for years, not wound off, used as breaker bars and generally not maintained or calibrated

Don't worry.
A torque wrench is only an indirect way to measure what really matters: the stretch in the bolts. If and how you lube the threads will make a far greater diff. than 5 lbs.
And: your bolts and studs have different length, so uneven tension is guaranteed..

The design of the Norton head fastening makes torquing properly, with a torque wrench, pretty tricky.

It’s very easy to learn to get a ‘feel’ for torque. Just tighten some fasteners with a torque wrench then tweak them a degree more with a spanner.
And tighten with a spanner to a target torque setting and check your results with a torque wrench.

After a bit of practice you won’t be far off, and you’ll probably be far closer than with a cheap old torque wrench squeezed into a tight space at an angle etc !

What did NVT repair centres/shops do at the time when it came to the correct tightening procedure, torque wrenches & figures
I believe the only time the head bolts saw a torque wrench was at initial build or when the motor was out of the frame??
And as Eddie says even with special shaped tools & extensions torqueing the head bolts in frame is "challenging"....to say the least

The design or the Norton head fastening makes torquing properly difficult.

I believe it is a good thing to learn the ‘feel’ of torque. It’s easy to do, just tightening some faster

olympus said:

What did NVT repair centres/shops do at the time when it came to the correct tightening procedure, torque wrenches & figures
I believe the only time the head bolts saw a torque wrench was at initial build or when the motor was out of the frame??
And as Eddie says even with special shaped tools & extensions torqueing the head bolts in frame is "challenging"....to say the least

Click to expand...

As the guy who advised me to over torque by 5lbs on the initial build was there back in the day, and had a lot to do with Thruxton Motorcycles, my hypothesis is that it is exactly what such shops did back then.

Tightening fastenings by feeling them up is pretty much second nature for me and was indeed part of my apprenticeship....many moons ago
You want to try having a DTI mounted on each bolt head or stud and tightening by bolt/stud stretch.
As you say its a really good idea for people not familiar with this practice to get a drilled plate in a vice with a decent size nut & bolt installed. and using a torque wrench on the bolt to tighten it to various figures & then do the same by feeling them up

Not Norton, but on topic...

"The Rover Company was a British bicycle and motorcycle manufacturer before it began the manufacture of motor cars. “
"In June 1896 John Starley formed the Rover Cycle Co. Ltd. at the New Meteor Works in Coventry. "

https://tinyurl.com/roverMotor

No torque wrenches were injured in the making of this movie...

maylar said:

Not Norton, but on topic...

"The Rover Company was a British bicycle and motorcycle manufacturer before it began the manufacture of motor cars. “
"In June 1896 John Starley formed the Rover Cycle Co. Ltd. at the New Meteor Works in Coventry. "

https://tinyurl.com/roverMotor

No torque wrenches were injured in the making of this movie...

Click to expand...

Awesome movie! Thanks for digging it out.. The past certainly is a strange land where they do things differently. Both testers pipe smoking And was that mallet Whitworth or AF ? Priceless.....

IIRC, there is a Norton service bulletin mentioning +5 lb. torquing...
Maybe a smart person knows how to find it.

Torontonian said:

Sorry , never used a torque wrench with Nortons , just by learning and feel of what's right. Re-torquing or in my case re-tightening is very important. I know all you engineer types will shoot me down on this but I'm on my 5 th and final one (Commando) before expiring from this world. Never had a head gasket go or any exhaust or other gaskets for that matter. Always replace with new and tighten by feel and re-tighten accordingly after a run in. Have a nice day.

Click to expand...

Yep same here, if its critical I would, but I've gone on "feel" also depends on the tool your using to tighten.