Retorque?

Flame ring headgasket replaced. Retorqued at 50 and 150. Coming up on 500, retorque again or don't disturb? Everything seems fine, no leaks.

Do it at 500 miles to be sure and after that I would leave it alone, if not leaking, when I did my engine rebuild over 5 years ago I did just over 500 miles before retorquing and haven't touched it since and I have just over 25,000 miles up on it now, but mine you I am running a copper gasket, but I did the same when I was running a flame ring gasket many years ago, I think some just go over board when it comes to retorquing the head and the manual only say to do it at 500 miles, well mine does anyway.

Ashley

If it still NEEDS retorqueing when you keep checking it, you still need to be checking it.

Don't be stripping stuff though, thats not so good.....

My issues with steel bolts and clamping alloy. Once the bolt's have had a torquing ,the engine heats up the Alloy head and more pressure is applied due to expansion . this causes the bolts to stretch a bit more, once cooled the bolts looses some torque , so a bit more is added , this keeps on, untill the alloy around the bolt/and gasket is compressed enough to resist further compression . There comes a point when the head/gasket and bolts become married.
Les emery recons , Torque the head, start and half warm up, cool and re-torque, then full heat, cool and re-torque , then a 5 mile run, cool and re-torque.

Well, I'll give it a go at 500, that would be the third time. From what I've gathered from other posts the correct way to retorque is to back each bolt off about a quarter of a turn then torque it down again before going to the next one. I assume start with the front center bolt, number one on the torque diagram?

Go by the manual when retorquing even when undoing the head bolts, very important you do it in seqence.

Ashley

As said earlier torque-torque and keep on torqueing; the less Emery comment is perfect.

Check after every 5 - 10 heat cycles and keep torqueing until you don't see the fasteners taking any rotation. The go worry about something else...

Bill.

Rohan said:

If it still NEEDS retorqueing when you keep checking it, you still need to be checking it.

Don't be stripping stuff though, thats not so good.....

Click to expand...

Unless it's "noticeably" loose, how you gonna know if it "needs" retorquing?

I was undoubtedly overcompulsive about mine but stopped after a half dozen retorquings in the first 1000 or so miles and no issues since.

After a few tedious toque wrenching rebuilds I quit the habit and just crank on everything, less and less often over 1000's but still even after that. if it moves it needed it - if it didn't move then I don't want to break its settledness so just let it be. If it still leaks then what ya do? One let down I learned on re-torque threads here is each time a nut is used its threads distort and requires even more torque to get decent clamp force, sometimes to point ya can't get clamp force to hold w/o renewing the nut or maybe even a bolt. Don't know how to tell till they just don't torque or seal well.

You can over torque the head bolts, the manual says to retorque at 500 miles and if its sealed then leave it alone and I have always worked on that princable and has worked well for me, if your head is flat and not warpped then leave it alone if its sealed up tight, i am still running all my orginal head bolts and nuts and after 40 years it still seals well, I have had my head shaved when I first rebuilt the head it had a 10thu warp, not much but it did leak before the shave, shaved mine at 15 thu on a milling machine at work, but that was over 25 years ago and is still sealing to this day.

Ashley

I was amazed at how loose mine head bolts kept getting each time I checked them. I have th ecomposite gasket and was starting to think my head bolts were stretching or something! I think I did them after the initial start, after the first brief ride, 50 miles, 200 miles and 500 miles. They then seemed settled.

Tony Smith told me that he overtorques them by 5lbs on initial assembly and then never touches them again! Maybe this is what the factory did? There is no way that customers would have followed the routine I did when buying new back in the day...

Fast Eddie said:

I was amazed at how loose mine head bolts kept getting each time I checked them. I have th ecomposite gasket and was starting to think my head bolts were stretching or something! I think I did them after the initial start, after the first brief ride, 50 miles, 200 miles and 500 miles. They then seemed settled.

Tony Smith told me that he overtorques them by 5lbs on initial assembly and then never touches them again! Maybe this is what the factory did? There is no way that customers would have followed the routine I did when buying new back in the day...

Click to expand...

Most automotive head bolts are now Torque To Yield which is pretty much an over-torque to stretch the bolt and provide the clamping force. They are never re-torqued and the bolts are generally considered a throw away item - one use only. The procedure is to torque to a set reading then an additional number of degrees of turn for the stretch. Some manufacturers, I've read but not encountered, allow the bolt re-use as long as the dimensions indicate that is hasn't been over stretched.

I suspect the over torque you've described may have essentially accomplished the same thing.

Factory crew only used T-wrench on rod caps and a number of famous builders have settled on a hand ful of lbft over listed values. What sucks the most to me is once it starts weeping its not always possible to just re-nip to seal again so labor saving to check your's often till stays dry and tight. If fiddling with a T-wrench puts you off just one time ya should of been more disciplined then T-wrench is a bad thing in that case too.

Torquing bolts, Not as simple as first thought,
1, is the bolt tread rolled or straight cut, if rolled the "waist" is smaller in diameter and requires less poundage than straight machine cut.
2, what lube is provided , or dry? this can have an over tightening effect if molyslip is used, allow approx 10% less.
3, material ; 10.10 bolts will not stretch as much , lower grades do. be carefull where you get them, some ebay shops retail poor standards.
4, washer type ,dia and thickness, thin washers tend to become dished, with the load not being spread over a greater area.
Food for thought...

I love using TW's and need to during repairs and maintenance at my work place.
I have agonised over the accuracy of TW's so took both of mine to my workplace and calibrated them on an often checked digital calibration unit.
My Toledo 3/8" drive is very close within a FT LB or two, but the 1/2 in drive GS tool is way out, luckily it under registers.
Here is a couple of samples to see the difference. Note the Toledo is in FT LBS, the GS in Nw (newton metres)
Toledo Range 5 FT LBS to 80FT LBS
At 5 indicated it is 6.3 , at 25 indicated it reads 25.3, at 40 indicated it reads 40.0. at 60 indicated it reads58.6 at 80 indicated it reads 75. So happy with the this tool in the midrage as that is where it is used the most.
Now for the 1/2 ' drive GS range is 28 Nm to 210 Nm
28 indicated reads 10.8, 84 indicated reads 58.5, 140 indicated reads 108 and 210 indicated 172 . So a long way out. ( And no I didnt have the wrong units selected !!)

At least I now have an accurate chart to work off for both of them
Regards Mike

Ugh I almost want to comprehend the details of the various calibration skewings to compensate for but I do know that torque is the tangent force to twist a certain distance so the correct terminology is: force multiplied by distance, which in our Norton' is: pounds x feet which is abbreviated as: lb f, not ft lb. Technically should more often be lbs ft. Slang is fine as long as ya know its slang and understood as just slang by others. If ya timed the application of this lb ft + time then could calc the hp or watts to nip up a Norton. The air cooled push rod alu head cast iron jug lawn mower puller guys learned they had to check parts temperature before setting their T-wrenches, do you?


http://www.macsmotorcitygarage.com/2013 ... ifference/

Ambient room temerature for motor and tools after overnight cooling after a heat cycle, so yes!
i then go ride and race both bikes for their respective tasks. dont need to over analyze the whole scenario, it is a means to happy end.
Regards Mike

You are preaching to the choir to me on making too complex - to point I shun T-wrenches on Nortons and have a suspicious view of those knowingly spouting T-wrench benefits to rationalize its necessity while using the wrong terminology. In the end I'm a motorcycler too so no reason to follow my 'common sense' either. I envy your scope of Commando fastener use Brooking.

Hobot, not spouting as you put it, the FT LBS/ LBS FT is a moot point here , just showing how an example of how accurate (or inaccurate)the tools can be, in fact the Toledo tool has it stamped FT/LBs, maybe you could direct your comments to the manufacturer , I am sure they would listen.
I am happy to use TW's for some of the settings on my Nortons as per the manuals. Everyone have their own ways and methods .
Regards Mike

I shouldn't even open re-torque threads Brookling as I think I know too much about torque issues details not to tease=correct those who think a tw-click is the cat's meow on our elastic engines with fasteners only meant to tolerate 500 cc worth of thermal-pressure violence. LIke oil this is a cyclic repeated subject that in years past I've quizzed the most respected and device instrumented Nortoneers to get them to admit there
s exceptions they went by feel alone to re-torque. I know that its The Exception To The Rule That Test-Proves The Rule. What annoys me the most is not that some use T-wrenches but the attitude that anyone who don't is not equiped mentally or mechanically to deal with a Commando.

My sort of sad failure tale to retorque often enough happened few 100 miles after Trixie Combat recovereed from re-used rod bolt let go at low throttle 50 mph sight seeing interval, early October headed out with Wes to Texas Lake of the Pine -comnoz Meca, most a 1000 miles, gas stops only, Trixie was an oily mess on arrival. Didn't have enough tools to re-torque for return trip but was able to get resealed again by 'calibrated' feel - until new carb boots both cracked and eat rings up -which could lead to another thread on how many times can a copper gasket be re-torque on. Btw I measured the rod bolt stetch vs torque wrench setting each .001" to find it takes about 5 lb ft more torque than listed to get between .006-.0065" stretch which is what's listed for that size fasterner and quality - in case ya think I'm ignorant on what matters most seeking proper clamp force.

Trixies used rod bolt with new nut had a unknown fracture that corrosion Not failure to torque right or from mechanical over loads slowly worked its way half way across metal grains of bolt before it let go - so somewhat my fault for not buying all new rod cap bolts but exactly same thing happened to Doug MacRae on Herb Becker re-bulit engine. In the end if ya feel better with T-wrench then I would use t-wrench all the time too.