The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: Zander on 09.07. 2017 11:52

Title: Science! (fitting ARP conrod bolts)
Post by: Zander 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
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Greybeard 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*
Title: Re: Science! (fitting ARP conrod bolts)
Post by: RichardL 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.
Title: Re: Science! (fitting ARP conrod bolts)
Post by: JulianS on 09.07. 2017 18:57
Interestingly, the SRM website selling ARP bolts also supply fitting instructions with a purchase.
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Greybeard 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!
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Zander 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!!!
Title: Re: Science! (fitting ARP conrod bolts)
Post by: KiwiGF 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.
Title: Re: Science! (fitting ARP conrod bolts)
Post by: RichardL 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.


Title: Re: Science! (fitting ARP conrod bolts)
Post by: coater87 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
Title: Re: Science! (fitting ARP conrod bolts)
Post by: KiwiGF 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.
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Zander 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?
Title: Re: Science! (fitting ARP conrod bolts)
Post by: duTch 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 ??


Title: Re: Science! (fitting ARP conrod bolts)
Post by: Zander 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*
Title: Re: Science! (fitting ARP conrod bolts)
Post by: JulianS on 10.07. 2017 12:44
Found this
Title: Re: Science! (fitting ARP conrod bolts)
Post by: RichardL 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.
Title: Re: Science! (fitting ARP conrod bolts)
Post by: chaterlea25 on 10.07. 2017 15:03
Hi,
I measured the bolt stretch on the last A10 engine I built with ARP bolts (original rods)
You need to tighten and release 3 times and make sure the bolts return to the original length each time
It is essential to use the ARP lube when doing this
Stretch at an indicated 28ft/lbs was 0.13mm, From memory that falls with in the ARP recommendations
I will try to remember to dig out the instructions ????

John
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Zander on 10.07. 2017 17:03
Bugger!  I lubed them, (oil, not ARP lube), then torqued them up to 28 and have now set the end float, fitted the oil pump and am getting on with it.  So, it's ANOTHER strip down and wait while I get the ARP stuff.  Pity Draganfly didn't enclose the instructions which appear to be issued with the ARP bolt set, or advise re the lube,  as obviously it's important to follow the procedure defined by the manufacturer.  Begs the question, are they ARP?  I'm sure they are, but there's nothing anywhere to tell me that. I'm taking it on trust, but at £100 a set, positive identification would be good.   If Draganfly read this, a response would be appreciated.  I'm royally peed off AGAIN! *pull hair out* *problem*
ps I'm going to email Draganfly and ask the question.  So there.... *bash*
Title: Re: Science! (fitting ARP conrod bolts)
Post by: coater87 on 10.07. 2017 17:19
 Zander,

 I personally am not entirely sold on the ARP lube. I think you would be fine as long as you did the torque up 3 times with oil as a lube. I have seen their charts and graphs.

 I am thinking that lube is great stuff, but its just another way for ARP to make a buck. Now if you had a 3500 HP top fuel dragster, I would say you need every chance to keep that motor together for the 3 seconds it runs hard.

 If you have 28 Ft. Lbs. of torques, and everything is free and moves nice, I would run with it myself.

 Plus the ARP lube is like copper slip, once you open it everything in a 50 foot radius has a little ARP ultra lube on it. *eek*

 Lee
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Zander on 10.07. 2017 17:24
Quick update.  I've checked the DF website, and there are two types of con rod bolts available; one is the ARP brand at £20 each, which is what I thought I ordered, and the other is an un- named brand, also at £20 each.  This choice wasn't mentioned when I discussed the order last Thursday, so, as well as having to wait 7 days for delivery, I've not got what I thought I was getting.  According to the invoice,  I think I've got the un-named brand, so I need to clarify this.  If they're standard bolts, I may have overtightened them (28 v 22lbs ft.)  Thanks for comments, Lee - our posts crossed.  Not sure if I need to strip it now, as don't think they're ARP.
Piggin nightmare *problem*
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Black Sheep on 12.07. 2017 22:50
I used to just buy conrod nuts and bolts and fit them with a spot of loctite. Not even a torque wrench in sight. Oddly enough, have never had one let go in coming up for 50 years of hard riding, including a spot of racing.
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Sluggo on 13.07. 2017 09:04
A number of people are selling these rod bolt sets at various prices. 
See: http://www.ebay.com/itm/BSA-500-650-Twins-ARP-Connecting-Rod-Bolt-Set-67-1536-1962-72-A10-A50-A65-/121332396810

$79 and free shipping?

" New USA Made ARP Forged BSA Unit 500 & 650 Twins Connecting Rod Bolt Set. Looking for replacement rod bolts set but not exactly sure about the quality of new production rod bolts? We understand your concern! Which is exactly why ARP has made these new forged BSA rod bolts and nuts. ARP rod bolts use the stretch method, if you do not have a stretch gauge, you can torque them to 37 ft-lbs, see the installing slip for more details. (ARP lube not included) Fits all BSA A50 & A65 Twins (Royal Star, A50, Lightning, Lightning Rocket, Firebird, etc) from 1962-1972. Will also fit late 650 A10 Pre-Unit Twins (Road Rocket, Spitfire, Super Rocket, Etc) from 1958-1963 with the "large crankshaft journals" only. Please refer to your parts catalog for proper fitment.  "
----------------------------------
My good Friends at Rabers parts mart (Ask for Richard) has them for $66.00
See: https://www.rabers.com/parts.asp?sp=&mcat=&pcat=E&subcat=E2&pg=6   (PM me for a discount promo code)
---------------------------------
I can supply them as well,, $60 plus shipping.
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Zander on 19.07. 2017 09:39
Update:  last Thursday DF agreed to exchange the bolts for the ARP items, so I stripped it down again and had the bolts in the post before 4:30pm, and on Monday I received notification the replacements had been sent by first class post. Not here yet😟
The invoice states tighten to 28ft.lb ft. but I'm hoping there'll be instructions re the "torque three times " rule.  One of these days I'll actually get this engine done and back in the bike!
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Greybeard on 19.07. 2017 09:56

One of these days I'll actually get this engine done and back in the bike!
Delayed gratification! I had to wait 40 years to get mine back on the road!
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Zander on 19.07. 2017 11:23
40 years?  I hope it wasn't cos you had to wait for con rod bolts!   *eek*
Title: Re: Science! (fitting ARP conrod bolts)
Post by: Greybeard on 19.07. 2017 12:35
40 years?  I hope it wasn't cos you had to wait for con rod bolts!   *eek*


No, not the bolts. It was the nuts!