Author Topic: Science! (fitting ARP conrod bolts)  (Read 973 times)

Offline Zander

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Science! (fitting ARP conrod bolts)
« on: 09.07. 2017 11:52 »
Talk about blind yourself with science!  I bit the bullet and bought a set of ARP conrod bolts which cost an arm and both legs, and the piggin nuts were EXTRA!!
Come to fit them this morning, so went on the ARP web site to get the relevant info., as there were no fitting instructions re lubrication etc., in the kit.  Obviously, I don't want to screw up on this but I found the ARP site to be pretty useless regarding the fitting of motorcycle bolts, apart from a catalogue of wondrous features of said bolts and the promotion of their super special lube.
They do give the three options i.e. Stretch, torque and angular measurement and mention progressive tightening.  Draganfly state these bolts should be tightened to 28 lbs.ft.  I can probably get close to this with my uncalibrated and very old torque wrench and as a double check, I can measure the stretch after applying torque, which would be great if I could find out what the stretch should be!  Alternatively, I could just do what I've been doing for years on a fair number and variety of engines, and just tighten the bloody things up.  I won't, of course, I will torque them up progressively and equally, and hope for the best!

adm edit: title edited to reflect post content
'59 GF

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Re: Science! (fitting ARP conrod bolts)
« Reply #1 on: 09.07. 2017 17:42 »
...Alternatively, I could just do what I've been doing for years on a fair number and variety of engines, and just tighten the bloody things up.  I won't, of course, I will torque them up progressively and equally, and hope for the best!
The science is all very well but these bikes have survived for many years without having carnal knowledge of a torque wrench.  *shh*

Offline RichardL

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Re: Science! (fitting ARP conrod bolts)
« Reply #2 on: 09.07. 2017 18:11 »
GB,

If I recall correctly, the film available on YouTube showing A10 engine assembly at Small Heath shows them using s torque wrench for heads and rods, only.

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Online JulianS

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Re: Science! (fitting ARP conrod bolts)
« Reply #3 on: 09.07. 2017 18:57 »
Interestingly, the SRM website selling ARP bolts also supply fitting instructions with a purchase.

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Re: Science! (fitting ARP conrod bolts)
« Reply #4 on: 09.07. 2017 19:46 »
GB,

If I recall correctly, the film available on YouTube showing A10 engine assembly at Small Heath shows them using s torque wrench for heads and rods, only.

Richard L.
Well done, young man you spotted my deliberate mistake *good3* come on up for your Kewpie Doll!

Offline Zander

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Re: Science! (fitting ARP conrod bolts)
« Reply #5 on: 09.07. 2017 19:55 »
Interestingly, the SRM website selling ARP bolts also supply fitting instructions with a purchase.

Ain't not got none in stock!!!
'59 GF

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Re: Science! (fitting ARP conrod bolts)
« Reply #6 on: 09.07. 2017 21:36 »
Talk about blind yourself with science!  I bit the bullet and bought a set of ARP conrod bolts which cost an arm and both legs, and the piggin nuts were EXTRA!!
Come to fit them this morning, so went on the ARP web site to get the relevant info., as there were no fitting instructions re lubrication etc., in the kit.  Obviously, I don't want to screw up on this but I found the ARP site to be pretty useless regarding the fitting of motorcycle bolts, apart from a catalogue of wondrous features of said bolts and the promotion of their super special lube.
They do give the three options i.e. Stretch, torque and angular measurement and mention progressive tightening.  Draganfly state these bolts should be tightened to 28 lbs.ft.  I can probably get close to this with my uncalibrated and very old torque wrench and as a double check, I can measure the stretch after applying torque, which would be great if I could find out what the stretch should be!  Alternatively, I could just do what I've been doing for years on a fair number and variety of engines, and just tighten the bloody things up.  I won't, of course, I will torque them up progressively and equally, and hope for the best!

adm edit: title edited to reflect post content

Don't trust your old torque wrench! I trusted my almost brand new power built wrench and after a blown headgasket found it read around 50% high, this also meant a strip down of the newly built engine to re tighten the con rods  *problem* . I used a kitchen scale and bottles of water to establish what it would read at the correct torque for con rods and head.....from memory it read something like 60 ft lbs when the true torque (as measured with the bottles) was 40 ft lbs.
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1956 A10 Golden Flash EA7-168x, CA10 913x, left BSA together for Liverpool, 5th Dec 1955.

1949 B31 rigid “400cc hot rod” (favourite bike)

1949 C11 rigid, but why!!! (cos it was cheap)

1937 B21, missing parts so mission impossible?

1952 Armstrong Siddeley Whitley for rainy days (with wife).

GL1800 Goldwing not sure why, maybe cos it always starts

Offline RichardL

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Re: Science! (fitting ARP conrod bolts)
« Reply #7 on: 10.07. 2017 00:32 »
Kiwi

Did you calculate the needed weight on the bar based on the actual length from the center of the socket mount to the center of the handle (on my torsion-bar type, this is a pivot point to apply the force at a uniform length)? For example, when I needed 65 ft-lb for the cush drive, I divided 65 by 16.5" and hiung that resulting weight on the handle to see what I should be reading under the pointer.  Before using my new clicker I checked it against the torsion bar calibrated in this fashion.

Richard L.


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Offline coater87

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Re: Science! (fitting ARP conrod bolts)
« Reply #8 on: 10.07. 2017 02:19 »
 Zander,

 If you have a 2 inch micrometer, they fit pretty well. We just need to find a stretch figure.

 But before you go that far, lightly assemble the crank into the cases with the rods and make sure your bolts clear. Mine rubbed on the cases *ex*

 Lee
Central Wisconsin in the U.S.

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Re: Science! (fitting ARP conrod bolts)
« Reply #9 on: 10.07. 2017 06:14 »
Kiwi,

Did you calculate the needed weight on the bar based on the actual length from the center of the socket mount to the center of the handle (on my torsion-bar type, this is a pivot point to apply the force at a uniform length)? For example, when I needed 65 ft-lb for the cush drive, I divided 65 by 16.5" and hung that resulting weight on the handle to see what I should be reading under the pointer.  Before using my new clicker I checked it against the torsion bar calibrated in this fashion.

Richard L.

Hi Richard, I used a 5kg kitchen scale to get 5 water bottles weighing 6.67lbs (3.02kg) each, I marked on the bar where 1.5 feet from the centre of the socket would be and put the wrench horizontally in a vice, then hung one bottle on the mark, that equates to 10 ft lbs (1.5x6.67). I then adjusted the wrench to be just on the verge of clicking, and made a note of the actual reading on the wrench (which should have been 10 ft lbs, but wasn't) I then added a bottle and repeated this until I had 5 bottles hanging on the wrench (50 ft lbs).

So, as my wrench was so inaccurate, to get 40 ft lbs I would set the wrench to nearer 60 ft lbs and then do the nut up being pretty confident I would be getting 40 ft lbs.

Whilst my wrench had a very inaccurate scale I found it at least would "repeat torque" accurately multiple times.
New Zealand

1956 A10 Golden Flash EA7-168x, CA10 913x, left BSA together for Liverpool, 5th Dec 1955.

1949 B31 rigid “400cc hot rod” (favourite bike)

1949 C11 rigid, but why!!! (cos it was cheap)

1937 B21, missing parts so mission impossible?

1952 Armstrong Siddeley Whitley for rainy days (with wife).

GL1800 Goldwing not sure why, maybe cos it always starts

Offline Zander

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Re: Science! (fitting ARP conrod bolts)
« Reply #10 on: 10.07. 2017 07:06 »
I have a range of micrometers and have measured the bolts, noting the dimensions so I can easily check the stretch if I can find out what it should be.  I'll also have a go at checking my torque wrench for accuracy or otherwise.  My plan today is to set the end float and I'll be taking Lee's advice to check the bolt clearance in the crank case.  On a previous mock up re end float, I even applied Wellseal to two flat ground parallels, to check the difference between dry and "wet" conditions, as obviously this would affect the shimming.  Happily, the difference was negligible.  Appliance of science again!  Who'd have thunk it on a 60 year old engine?
'59 GF

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Re: Science! (fitting ARP conrod bolts)
« Reply #11 on: 10.07. 2017 09:42 »

 Hey guys, am I missing something here ?? Are you talking foot pounds or pounds feet ?

 I had the notion that 10 pounds at one foot radius, is 10 pound foot. 10 foot pounds would be one pound at ten feet?

 For example, according to the Haynes manual for my Hilux, (from memory)  the method for adjusting the front wheel bearings (Fourby) is to attach a spring scale to a point somewhere on the wheel and pull it to 7lbs at which point the wheel should just move

 It can be confusing to people like me who know enough to be dangerous...so I've added a pic from my Hilux Haynes manual of torque conversion figures.

  *dunno* *dunno*

 I did it by the usual feel...but another way of saying the above ^^ would be to attach 7Lbs at 1 Foot radius, and loosen the adjuster nut until it starts to turn...would it not ??


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Offline Zander

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Re: Science! (fitting ARP conrod bolts)
« Reply #12 on: 10.07. 2017 11:23 »
Lbs. Ft .  Force x distance if I remember correctly, however, I stand to be corrected!  I WAS wrong once before !!  Anyway, that's what's stamped on my torque wrench.
After going through the procedure of calibration, to achieve 28 lb ft, I had to set it to 43!!
As per Lee's timely advice, a dry run check assembly showed one of the con rod nuts scraping the crank case, so I've chamfered it, and may take the edge off the others in the relevant area.  Next job is end float.  Wish me luck - I'm going in *work*
'59 GF

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Re: Science! (fitting ARP conrod bolts)
« Reply #13 on: 10.07. 2017 12:44 »
Found this

Offline RichardL

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Re: Science! (fitting ARP conrod bolts)
« Reply #14 on: 10.07. 2017 12:47 »
Quote
I divided 65 by 16.5" and hiung that resulting weight on the handle to see what I should be reading under the pointer. 



Of course, I mistated this. Actually:  12"/16.5" x 65lb.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.