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I stripped 2 rocker adjusting nuts sad smiley

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HiPowerShooter Avatar
HiPowerShooter Gold Member James Booker
Lake Winneconne, WI, USA   USA
1973 MG MGB
I can see 16# being reasonable.

55 on the head, 25 on the rockers and 15 on the adjusters would be easy to remember...the first being the only one I'd actually measure.

If you've never done so, you should "calibrate" your elbow. Tighten and average sized nut by and and apply varying amounts of force then check that torque to better see what you feel. Not entirely accurate but if you're shredding fittings then you REALLY need to know your own strength!lol!



"One test is worth a thousand expert opinions"--Alvin "Tex" Johnston...Boeing test pilot.

73 MGB. Tires: Round, black, hold air. Oil: Sometimes old, sometimes new...always slippery. Oil filter: Yellow, usually full of oil. Carbs: 2 SU HIF. Distributor: Yes. Headlights: Not that bright but bright enough. A bunch of other stuff most cars have but not really important enough to itemize. Oh, wait...it has a cool sounding exhaust with stickers on the chrome tips. Really slays the ladies...

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Steve S. Stephen Strange
Harrisonburg, Virginia, USA   USA
1972 MG MGB MkII "The Mouse Trap"
Phil-
The OE jam nuts are Grade 5 machine jam nuts. I wouldn't trust any ungraded nuts that came in a plastic envelope from a home improvement store. Beware!

If you managed to strip a jam nut, then you probably also damaged the threads on the ball-ended adjusters. If I were you, I'd take Basil up on his offer.



Edited 1 time(s). Last edit at 2017-08-12 10:11 PM by Steve S..

benhutcherson Avatar
benhutcherson Gold Member Ben Hutcherson
Louisville/Frankfort, Kentucky, USA   USA
1970 MG MGB
I just posted this in another thread about someone having the opposite problem(jam nuts too loose).

I generally turn the jam nuts finger tight and then give them another 3/8 to 1/2 turn with the wrench.

In my experience, that's plenty to keep them in place but not anywhere near where you'll start putting undo stress on the adjusters or nuts.

I can't imagine using a torque wrench on them. The final tightening is when you really have to worry about changing the adjustment(and why you need a big, correctly fitting screwdriver to keep it from happening) and obviously at least with a conventional socket torque wrench you can't do that.

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Fairtax4me Scott Mahanes
The Big City, Virginia, USA   USA
Yeah you have to be careful tightening the jam nuts on rocker adjusters.
Had a customer bring me a golf cart engine once. He broke the adjuster end off the rocker arm tightening the nut.
Most Torque specs are to keep you from over tightening the fastener. In the case that overtightening either damages the fastener or the component (such as a bearing).

benhutcherson Avatar
benhutcherson Gold Member Ben Hutcherson
Louisville/Frankfort, Kentucky, USA   USA
1970 MG MGB
In reply to # 3571954 by Fairtax4me Most Torque specs are to keep you from over tightening the fastener. In the case that overtightening either damages the fastener or the component (such as a bearing).

There are places on MGs where IMO even using a torque wrench is inappropriate. The side cover gaskets are the ones I'm thinking of, a place where over tightening(esp. the front one) will likely cause both deformation of the covers and leaks.

A recent thread tossed around 5 ft.-lbs but I doubt that I'd even feel that on my 3/8" drive wrench. A 1/4" might be better. In any case, I just snug them down until there's no "slop" between the covers and the block, and mine don't leak.

HiPowerShooter Avatar
HiPowerShooter Gold Member James Booker
Lake Winneconne, WI, USA   USA
1973 MG MGB
The more I started hanging around(and eventually now working part time after retirement)an engine building(mostly high HP strip/marine engines...but now the occasional MGB) and machine shop...the more I was surprised how LITTLE he uses a torque wrench, how much he uses an impact and how few manuals he needs to consult. Warning: Do not attempt this at home!lol!



"One test is worth a thousand expert opinions"--Alvin "Tex" Johnston...Boeing test pilot.

73 MGB. Tires: Round, black, hold air. Oil: Sometimes old, sometimes new...always slippery. Oil filter: Yellow, usually full of oil. Carbs: 2 SU HIF. Distributor: Yes. Headlights: Not that bright but bright enough. A bunch of other stuff most cars have but not really important enough to itemize. Oh, wait...it has a cool sounding exhaust with stickers on the chrome tips. Really slays the ladies...



Edited 1 time(s). Last edit at 2017-08-13 12:05 AM by HiPowerShooter.

Ex-Calif Avatar
Ex-Calif Gold Member Dan D
Cincinnati, Ohio, USA   USA
1968 MG MGB GT "Bart - Yellow And Naughty"
1977 MG MGB "Red Betty"
2012 Jeep Liberty "Tank"
2014 Hyundai Accent "Skate"
Part of calibrating your "elbow" is understanding torque and wrenching in a repeatable manner. This means positinoing you arm the same way each time and gripping the wrench at the same spot each time.

6 inch pounds is 1 pound of force applied at 6 inches from the centerline of the bolt/nut. It is also 1/2 a foot pound. The biggest error is putting 6 foot pounds on when 6 inch pounds is pecified.

Most small nuts don't really need a torque wrench. Your hand is usually 5-6 inches out the wrench. If you need 15 ft/lbs that's 30 pounds of pressure at 6 inches.

Interestingly, wrenches get longer as they get bigger. This give you mechanical advantage which means a 1/2 inch wrench and a 9/16 wrench when gripped naturally at their ends require similar arm force to get different torques. It matters most below 9/16 wrenching becuase these are nuts and bolts you can easily break and strip with arm force. Once you get to 9/16-3/4 wrenches you'd have to be Hulk Hoganish to break something. (Caveat on something like a tranny plug - Steel into aluminum, you gotta be careful.

So to practice calibrating yourself use a torque wrench (rocker nuts) then put the 1/2 inch on and slowly apply pressure until the nut starts to tighten more - learn to feel that pressure and you'll get pretty close after a while without the torque wrench.



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Donthuis Avatar
Donthuis Don van Riet
Rijswijk, ZH, Netherlands   NLD
Or only use ring/open combination spanners of a limited size to restrict the torque by hand. Another trick is grabbing your spanner not at the end, but in the middle. I do this always when torqueing the three thermostat housing nuts by hand. My garage mech once did not and broke the stud off. Of course getting the broken part out is easier in a garage full of tools, but prevention is better. thumbs up

BTW I also use these shorter ring spanners on the locking nuts you're having problems with....eye rolling smiley

Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
I put a lot of rocker arm assemblies together, I use grade 8 5/16"-24 jam nuts. I get them either from my local source, or McMaster Carr. The new adjuster bolts are total crap, and they all come form one source, XRN, so everyone's has the same POS. I tried to find NOS adjust bolts that come from old rocker assemblies, on the race cars I will not use the drilled variety, I've seen them break on more than one occasion.

There several layer of crap when it comes to the new rocker arm adjustment bolts, first off they are very sloppy black oxide coated, all that crap needs to be wire brushed off, and a thread chaser is not a bad idea either. Then there is the bigger problem, the bust out/break at the screwdriver slot, seen this more times than I can count. If you need to buy a new good quality adjuster bolt, just happen Triumphs use the same adjustment bolt, .Richard Goode Part has some new custom one made, only visible difference is they have a allen slot on top side, rather than a screwdriver slot, they are quality made here in the US.

Here's a link to them
https://www.goodparts.com/shop/index.php?productID=302

As for tightening them, I don't know what to tell you, other than what I tell the guys in the shop, don't lean on it like a gorilla smiling smiley Seriously, the learning curve of turning wrenches is to know what is tight enough, and trusting that, it takes times. Best tip I can give you on smaller low torque fastener, choke up on the wrench to take away some of your leverage, especially important with 1/4" fasteners. You will eventually develop a feel, and then not over tighten things, for sure there is a "feel" to this. If you do use a torque wrench then you need one with a range to do this reliably, the first, and last 10% of range on torque wrench is not trustable, so you either need a small foot pound, or inch pound torque wrench to do this, a 1/2 drive torque wrench with 18" handle is just asking for trouble. A guy who makes his living wrenching never uses such a thing for this, so if you want to master this, you learn the "feel".



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others
riley1489 Avatar
riley1489 Gold Member Bruce H
Great White North, QC, Canada   CAN
1953 Jaguar XK120
1959 Riley 1.5 "King George"
1973 MG MGB
This is only a 'jam nut' such its purpose is to lock the adjuster screw in place and prevent it from backing off.
The other jam nuts visible in your photo show evidence of spanner slip or the like, you may consider replacing them wholesale.

B



Check your ego Amigo!



Edited 1 time(s). Last edit at 2017-08-13 10:05 AM by riley1489.

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Donthuis Avatar
Donthuis Don van Riet
Rijswijk, ZH, Netherlands   NLD
Last week before I wanted to doublecheck on the headbolt torqueing I suddenly distrusted my torquewrench. I compared its value around the 55lbf on a cheaper, non-clicking one I still had around and used a bagage weight puller 40cm outwards from the 1/2" drive. Both approaches showed me my wrench was way out of calibration, so I bought a brandnew one for just €40! Its only disadvantage it's in Nm only, with the recalculation formulas on the box. 55lbf equals 74,5 Nm, say 75. Its max is 210Nm BTW

For smaller nuts and bolts you need a torque wrench with a much lower max value in torque. I preferred to develop some feeling for torqueing in my arms, in secondary school and as a student I still broke smaller bolts on my motorbikes, but that's gone now smiling bouncing smiley

Another advantage I have was my metallurgy course the 1st year of University study. If you understand the way steel follows Hook's law up to a certain point you understand better why above this value stretching leads ultimately to breakage. So any time a nut or bolt starts to act "jerky" I know that I should stop with my torqueing efforts. Beyond this breakage or stripped threads will happen.



Edited 1 time(s). Last edit at 2017-08-13 08:56 AM by Donthuis.

Nicecar Avatar
Nicecar Gary (ex "Harv") G
Victoria, BC, Canada   CAN
1980 MG MGB "Red On Red On Red"
OK I'll anti up.

Bruce #25: "The other jam nuts visible in your photo show evidence of over tightening as well"

How can you tell?

Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
I am not Bruce, but in the pic the corners of the nut look shiny and bit rounded, like little wrench slippage in their lifetime. I see this all the time, I don't always replace adjustment bolts on a rocker arm assembly, but I almost always replace the jam nuts, and I see this sort of torture to the jam nuts too often.



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others
riley1489 Avatar
riley1489 Gold Member Bruce H
Great White North, QC, Canada   CAN
1953 Jaguar XK120
1959 Riley 1.5 "King George"
1973 MG MGB
Fair enough Hap,
Probably a poor choice of spanner, (12 pt vs 6pt) rather than over tightening.

B



Check your ego Amigo!



Edited 1 time(s). Last edit at 2017-08-13 02:28 PM by riley1489.

Speedracer Avatar
Speedracer Platinum Member Hap Waldrop
Greenville, SC, USA   USA
1967 MG MGB Racecar "The Biscuit"
Bruce, I was agreeing with you grinning smiley



Hap Waldrop
Acme Speed Shop
864-370-3000
Website: www.acmespeedshop.com
hapwaldrop@acmespeedshop.com


Member Services:
MG/ Triumph Performance Street/Race Engines - Cylinder Head Porting - Modified SU HS Carbs - DIY Engine Rebuild Kits With Free Tech Advice - Alloy wheels for British Sport Cars,and others
. Hide banner ads & support this website by becoming a > Gold Supporting Member <

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