Engine rebuild - do I need a decent torque wrench?

[The Disapproving Brit]

Pretty much as title. I've done an engine swap, now its time to strip and rebuild the old engine, pretty much from scratch. I have no idea what I'm doing, but isn't that half the fun of a project bike?

I have a £15 silverline torque wrench, but its not really something I'd want to rely on to give me an accurate figure. "Just tight" or "tight as fuck" has always done me right so far, but I'm guessing the innards of an engine are likely to be more fussy? Is it worth investing £100 or so on a halfords one?
____________________
Current Bikes: 1983 Honda VF400FD / 2003 Honda VT750 Shadow
Bike Test Passed 18/03/09, Car Test Passed 14/05/13

[Clutchy]

I have always gone down the line of guessing the correct torque but IMO with engine work I'd always said to myself just do it properly and buy some good equipment.
____________________
Malaguti F12 Phantom-Dead, Suzuki AY50- Dead, NRG power DD LQ, CBR125.
*33 BHP restriction up on 10/12/14* Current bikes/car: SV 650 S/ MKIV GOLF
Guide to pass your test with no lessons!

[yampug]

i've got a machine mart clarke one can't have cost that much and has worked fine for me doing engine rebuilds. only thing i've really used it for is torquing up head bolts and engine mount stretch bolts.

[Old Git Racing]

Most of the bolts in an engine rebuild where torque really matters are at the low end of scale, bolts going into ally etc. Get a decent quarter drive torque wrench from Halfords or somewhere and use your current one for the big bolts that need a lot

OGR
____________________
2022 Tiger Sport 660 2019 Street Twin 2003 K3 gixxer 1000 1998 Srad 600 track hack

[Ichy]

You're not that far from me. PM if you want and you can use mine for a bit rather than wasting money on something you'll not use again.
____________________
https://www.metacafe.com/watch/1972097/how_to_behave_on_a_forum/

[Blue_SV650S]

If your knuckles go white, then it is tight!

I have used torque wrenches before and actually snapped bolts, so mostly do by feel.

The only place I still tend to use a torque wrench is on bolts that have to be very similar in torque i.e. the cylinder head.
____________________
The purpose of life is to fight maturity.

[Copycat73]

a torque wrench takes away the guess work,
particularly when you are cold as your hands, tired and pissed off.
wouldn`t be without them.
you don`t have to spend £100 on one though.
____________________
Whatever I post I have no citation and no intention of providing one..
caveat emptor

[The other Paul Rudd]

[MarJay]

[The other Paul Rudd]

[The other Paul Rudd]

Quick bit of hunting on the net revealed a page on the Halfords site where a customer service adviser states they're made by Norbar. Personally I'd give them a miss and go for something more expensive.

[Teflon-Mike]

Short answer.. probably not.

Slightly longer answer, snipped from reply I made in another thread:-

First up; for the amateur DIY mechanic, you don't need to be TOO worried about buying a 'great' Torque Wrench. They are not the most used toy in the box, but frequently one of the most expensive; yet dont often HAVE to be. Like so many things, its not how good the tool is, but the person using it!

For most automotive mechanics, torque wrench is not needed to set torque to a hugely critical degree of accuracy on any one fastener, but to ensure a 'fairly' accurate clamping pressure on ALL studs across a flange, or pattern of fasteners holding two bits together.

Technique is more important.

1/ You dont use your torque wrench as a fancy ratchet or a breaker bar with a ratchet! Its a MEASURING instrument; you do your nuts and bolts up with spanners or wrench, and use Torque Wrench for FINAL 'setting' of the tightness.

2/ Using common 'click-head' or 'Snap at Torque' cartridge wrench, like one you linked to; you wind the torque setting scale right off the scale, to take the pressure off the balence spring so it wont 'relax' when not in use... do this and even a really cheapo torque wrench can last decades and stay reasonably accurate.

3/ When you need it to make that final tightness setting; you ook at the work-shop manual; you find the torque value for your fastening, and you TRIPPLE check.
a) the numbers, in book and on wrench
b) the units, in book and on wrench!

Many books and wrenches give both Imperial ft-Lb or torque as well as metric values, which can be Nm or Newton-Meters, or Kg-m Kilogram Meters
Theres 10Nm per Kg-m, and I think about 7ft-lb per Kg-m.
Muddle the units and numbers and VERY easy to get it all to cock, and either not tighten them up, or start stripping and shearing stuff.

4/ after tripple checking book, wrench and units... you double-tripple check to make sure you have the RIGHT WRENCH

Most automotive torque wrenches, as one you linked are 'high range' torque wrenches, sized and calibrated for the sort of torque values commonly used on CAR cylinder head bolts or brake caliper bolts. One you linked in machine mart has range from 28 to 210 Nm

Back to the book and make sure that the torque value you need to set on your cylinder head IS in that range!

A lot of MOTORCYCLE fasteners are 'low torque' fastenings, threads tapped into soft aluminium, where torque values are given NOT so much so you make sure stuff is tight enough to hold pressure, BUT not SO tight that you risk stripping threads!

Cylinder head studs on the Honda CB125 Twins I like playing with, are actually very low torque, I think 18Nm, and possible, if not likely that the CB125S/J Single you have is similarly low-torque.

In which case you would ACTUALLY want a low range torque wrench, like this one, with a 5 - 25Nm range:https://www.machinemart.co.uk/shop/product/details/040210674 This is low-range Torque Wrench I have co-incidentally, so can reccomend it

Side Note: That 25-250 torque wrench, like most high-range has 1/2" socket drive; Ie BIG. that one comes with a socket dropper from 1/2" to 3/8 which is the more common general purpose socket size drive; but you DO need to check drive sizes and possibly buy adaptors to suit the sockets you have, or even buy new sockets.

That low-range torque-wrench has small 1/4" drive; so to use 3/8" drive sockets you'd need a step up adaptor, or new sockets. And TBH, I bought a couple of 'rails' of 1/4 drive sockets specifically to use on my low-range torque wrench. They aren't that expensive, and keeps them 'clean' for use with the setting tool. Having got the wrench, you will find you over-use it a lot at first, which is no bad thing; particularly after my comment about low-range being to avoid stripping threads, and you'll find yourself using it on primary drive cover screws, or lever bolts and stuff, and anything the Haynes gives a torque value for! The smaller 1/4 drive sockets then will earn thier keep where you have tighter access around fasteners, like on primary drive covers and 'stuff' thicker 3/8 drive sockets cant so easily get on 'flat'.

5/ Having double & tripple checked numbers, and units AND made sure you have the correct range Torque Wrench.... You 'stage set' up to specified torque.

Numbers in the book, for the CB125Twin head bolts, spec is 16-20Nm. I have tripple checked that, and consequently gone and got the low-range wrench to set it on... BUT I dont wind the scale in straight to 16 or 18 or 20... I set 5Nm... the LOWEST setting on the scale.

Then I go round all eight (in my case) studs, following the tightening plan in the manual, so that they all pull down square and even, if not, I start at the middle, and work out doing diagonals and back, to get same effect.

Having done all eight studs, without touching the setting scale, THEN, depending on how far up the scale the tolerance is, I will either set something half way between lowest setting and lowest value of my tolerence, or if its a long way up, 1/3 or even 1/5th, make new wrench setting ONCE and again, go round and do ALL studs at that one setting. Then repeat, upping the torque setting in 'stages' until I get to the LOWEST value in the specified torque tolerence.

That way, I know that all studs HAVE been torqued down 'evenly' and each done each time to the exact same setting as every other.

Remember, being 'even' accross the flange is more important than how accurate you are; so even if its a not very accurate torque wrench, it will be close enough; but important thing, making sure clamping pressure accross the whole part is even is assured much more closely.

What you DONT do, and many people do; is change settings on the torque wrench between fasteners on a flange. EVEN if its a good wrench, highly accurate, chances you will get the 'same' setting made twice, between fasteners is not great; so just dont do it; and doing all on one set, you get the job done, and done well.

And yup; may sound like a ball-ache, going round each fastener umpety times, doing each up a tiny bit at a time; especially on early stages when the wrench is likely to click straight away, having put more torque on with the spanner before hand, that you aren't actually doing anything; BUT... makes sure you pull the thing down flat and true, and squash gasket evenly, and get a good seal... its that Murphey Fellow and giving him his cut 'up-front' Laughing

OK. So thats Torque Wrenches. Got all that? In short; that Machine Mart one, probably as good as anything IF its the right range, if not, try the low range one I suggested.

More important is TECHNIQUE, using the thing well, being pedantic checking numbers and units before making settings on the tool; making sure you have the right range tool; and when you come to do a flange, do it up finger tight with spanner first, use torque wrench to 'set' final tightness, and do it in stages, following tightening pattern each time; AND never changing wrench setting between fasteners in a pattern on a stage. AND you zero the scale on the wrench for storage, to preserve accuracy.

Follow that advice, get good technique in using the tool, and how 'good' a tool it is to begin with, is no where near that important.
____________________
My Webby'Tef's-tQ, loads of stuff about my bikes, my Land-Rovers, and the stuff I do with them!
Current Bikes:'Honda VF1000F' ;'CB750F2N' ;'CB125TD ( 6 3 of em!)'; 'Montesa Cota 248'. Learner FAQ's:= 'U want to Ride a Motorbike! Where Do U start?'

[Musketeer]

I wouldn't touch any engine without a decent torque wrench. I would probably have a tendency to overtighten all my bolts which is not good and later can lead to them snapping. So it's that plus your mind is happy that everything is torqued to manufacturer's spec.

But saying that many things can affect torque wrench readings.. water/oil/grease/threadlock paste etc. on bolt threads.
____________________
Current Bike: Yamaha XSR900 Previous bikes: Honda CBR1000RR Fireblade, Kawasaki ZX-6R Ninja, Aprilia RS125 2-stroke

[clancy]

A decent one is very expensive for something you'll barely ever use, a cheap one is worse than anything else

Best answer... Go hire a decent one from machine mart etc for the day you need it, save you wasting money and gets the job done. You don't need to buy one, if you needed one often you'd already own one

/thread
____________________
KLX 300r

[The Disapproving Brit]

Thanks all. I'm not in a desperate hurry for one (plenty of other bits to get done first) but it's something that often seems like it would be useful to have. My Silverline one is really only trustworthy as a bigger socket wrench, I wouldn't want to rely on it for delicate engine work.

The talk of cylinder heads needing the accuracy has pretty much convinced me that it's worth the effort of picking one up. I'm going to wait until after Christmas though, on the off chance that they come down in the sales. I'm thinking the Halfords Professional ones purely because their socket sets have always been pretty good.

[Ichy]

[The other Paul Rudd]