Author Topic: Large Journal Conrod Big-end EYE size please  (Read 8171 times)

Offline duTch

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Re: Large Journal Conrod Big-end EYE size please
« Reply #30 on: 31.07. 2012 15:46 »
Hey Thanks John, I dug up another thread that'll probably show up too.
 My new Thunder/Lightning Rods arrived today, (almost too fancy to hide inside the engine)and should have scales coming soon, so can start to play seriously.
 The Torque settings are 40-43, a bit higher than I expected, .....? the rods fit the cutaways, which are a bit skew-whiff, and I figure if I just square them up should be ok, figuring if there's any more movement than that, there's a problem anyways! 
  Am making a jig to play the balance game, so will see what happens.
 Cheers fer now duTch
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline trevinoz

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Re: Large Journal Conrod Big-end EYE size please
« Reply #31 on: 31.07. 2012 22:03 »
Dutch,
                This may be a silly question, but why don't you get it dynamically balanced?
The metal will be removed from the exact position that way.

  Trev.

Offline duTch

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Re: Large Journal Conrod Big-end EYE size please
« Reply #32 on: 01.08. 2012 09:24 »
G'day Trev,
                 It's not a silly question,and you're no doubt very correct re get someone to do it, and maybe that was the original likely outcome, which prompted the query, not to ask how, but to alert anybody doing same of the possibilities.
   I appreciate all the ideas and am still processing them,
      I haven't discounted the (dynamic) idea but still want to at least have a go at figuring out what's where, and if/when I get stuck will go see my clued-up mate up the coast.
 Maybe though I am in fact sillier than I look??

cheers for now and thanks for the input,duTch
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline duTch

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Re: Large Journal Conrod Big-end EYE size please
« Reply #33 on: 04.08. 2012 10:50 »
Ive done some 'homework',
       First - Road rocket,  bottom of page 1, you were concerned about heavy rods/pistons? Can't you do holes on the crankpin side, instead of the counter weight side, to get it right?

 Kiwi, I think those figures you had were ok, just mis-interpreted, it's the actual % of reciprocating weight. Using Muskrats formula and RR's rod weights, and 60%(for the sake of a #%), I came up with 1046 grm (Std rod), and 1200 grm for Thunder rods.
   My interpretation of Muskrats is; that is the weight required to simulate the rod/ piston(60% factor) on the crankpin? Ie; wrap 500 g around each journal?
   Then do as he says, and add further weights on the flywheel, till you find the 'balance' (where when spun it doesn't stop at the same spot and/or 'pendulate'-like a pendulum?). The added weights is what you weigh and drill opposite to achieve the same effect?
 How'm I doing??

   Trev-....yeah I know....?...!!!
   cheers fer now duTch

 oh yeah, fair difference betwenn 1046 & 1200 grms?? but still hypothetical- waiting on scales.
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline Rocket Racer

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Re: Large Journal Conrod Big-end EYE size please
« Reply #34 on: 05.08. 2012 06:25 »
Ive done some 'homework',
       First - Road rocket,  bottom of page 1, you were concerned about heavy rods/pistons? Can't you do holes on the crankpin side, instead of the counter weight side, to get it right?


Given any rod change is going to need a rebalance, I've changed my plans and now intending to  fit A65 rods as per the attached article and shorten the barrel.

My engineer is shifting premises and I'm between work, so hoping the old rods have a few more races left in them...

A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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Offline duTch

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Re: Large Journal Conrod Big-end EYE size please
« Reply #35 on: 05.08. 2012 09:02 »
Haven't read it yet, but my first thought is that you need to take material out of the bottom-side of skirts to clear flywheel @ BDC? That in turn will lighten pistons a bit?
  Second thought is- good luck with it, I'm not even going to think about it for me(maybe the thoughts came the other way round!!).
  Do you reckon that calculating I did was anywhere in the ball park, or should I just go back to school..???

    Cheers
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Online chaterlea25

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Re: Large Journal Conrod Big-end EYE size please
« Reply #36 on: 05.08. 2012 19:25 »
Hi All,
Quote from Dutch
""My new Thunder/Lightning Rods arrived today, (almost too fancy to hide inside the engine)and should have scales coming soon, so can start to play seriously.
 The Torque settings are 40-43, a bit higher than I expected, .....? the rods fit the cutaways, which are a bit skew-whiff, and I figure if I just square them up should be ok, figuring if there's any more movement than that, there's a problem anyways!"" 

Following on from my last reply attached is a pic of the modified cylinder cutaways for the MAP cycle conrods
Dutch's Lightning rods will be almost identical I believe ???
The modded cutaways are 25.4mm wide and 17+mm deep (1" x 11/16").
Dutch,
The added balancing holes on my crank are at the crankpin side (see previous pic)

Re torque settings, From some research here on the forum
The 40-43 ft/lb seem to be too high,and causes problems
28ft lbs was the figure recommended
It is also recommended to tighten and retorque several times to prestretch the bolts????
I was wondering if I drilled an alloy block and tapped to suit the bolts would this be a better bet than tightening the bolts into the rods to pre strench?????

In "Tuning for Speed" Irving says to consider the top half of the conrod as reciprocating weight (to be added to the piston weight,
If the crank and rod assembly are arranged with the big end of the crank at the 3 0clock position its easy enough to weigh the small end of the conrod

If/when Rocket Racer fits shorter rods will the cutaways need to be deeper?? unless pistons with a different pin position is used?? (must read the article??)
Back when I was considering options on building my SR engine I enquired about using Carrillo rods??
I was informed that this would require removal of the flywheel to mill away enough material from it on the crank pin side  *eek*

Regards
John



1961 Super Rocket
1963 RGS (ongoing)

Online KiwiGF

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Re: Large Journal Conrod Big-end EYE size please
« Reply #37 on: 05.08. 2012 21:35 »
Some things I learnt ref rods, might be useful to someone. The 040 under shells I'm using require the full 43 ft lbs if not more to get them round (being so much thicker than standard). This does not bode well given the comments that 43 is too much.....

Carrillo rods, when I enquired, they were not ex stock from Carillo, and I could not find a distributor who had ordered a batch from Carrillo and had some left (ordered by the distributor at a cheap enough cost to make them a margin selling at the retail price I guess).


Here's a quote below from Carrillo, this quote was a lot less than a distributor (like Wassel etc) would quote at the time. I think Carrillo would rather deal with distributors than "individuals"!

On Tue 28/06/11  2:38 AM , "Greatrake, Scott" <scott@cp-carrillo.com> wrote:

> We wound need to make rods for the A10. The current manufacturing time
> is about 5-6 weeks. Your cost as an individual direct is $378.50 per
> rod fitted with CARR bolts.
> Sincerely,
> Scott Greatrake
>
> CUSTOMER SERVICE TECHNICIAN
> Please note; effective May 1, 2011 our phone number will be changed to
> 949-567-9000 and our Fax number will be changed to 949-567-9010
> 1902 McGaw  Irvine, CA 92614 USA
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Offline duTch

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Re: Large Journal Conrod Big-end EYE size please
« Reply #38 on: 05.08. 2012 23:59 »
RR-Tim, That might explain those barrels that were on eBay not long ago,got a bit of discussion, don't know if they sold will chase them up- could save you some work and a (good)set of barrels.
 Just read the article,(bit of a mission- went pixelated), piston profile was covered early.
  Couldn't read the date but looked like late '50's, and explains they use AA7 rods, I guess A65 not much different?

John, Thanks for that info, I expect my rods be same as yours, the cutaways are only just enough, so will need to modify, and noted the balance holes at crankpin.
 
Kiwi, thanks too.

Cheers for now duTch
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
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Offline Rocket Racer

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Re: Large Journal Conrod Big-end EYE size please
« Reply #39 on: 06.08. 2012 08:32 »
I can email a copy of the article if anyones interested (just easier to read, send me a pm), but had to convert it to a jpg to load it to the forum so a bit harder to read as two pictures.
A good rider periodically checks all nuts and bolts with a spanner to see that they are tight - Instruction Manual for BSA B series, p46, para 2.
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Offline duTch

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Re: Large Journal Conrod Big-end EYE size please
« Reply #40 on: 06.08. 2012 10:59 »
Thanks, RR, If I need to read it more I'll holler.
Dunno if it's any help, but a while back I had to email time-sheets for work, and found if I scanned them in a ' .tiff ' format worked ok for b&w (small file size).
 Those Barrels on eBay were "A10? barrels 5hrs to go'- in ebay finds, but sold for £ 200 gbp, but the link still works if you want to look.
n Cheers, duTch

  Bought a single set of scales today, got bored waiting for the ebay ones to arrive- still playing with everything, more later
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Offline duTch

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Re: Large Journal Conrod Big-end EYE size please
« Reply #41 on: 19.08. 2012 10:56 »

 If I didn't say it before it seems the Rod eye size is 1.8435 - 1.8440.
I've fitted two different new sets of minus 10 big end shells, to my new rods, and I still have 'twist' and 'radial' side slop, one set worse than the other, and as I threatened tried the old shells, which had much less slop than either of the new ones.
 The journals measure by me with micrometers, 1.6765"(far as I can gather that's the lower grind figure),in several different positions. The engineering place gave me 1.6752", am not sure what measuring tool they used.
 The only explanation I can find for this variation is this linkhttp://www.mechanicsupport.com/engine__bearing_failure.html.
   There's some interesting video.
 Kind of looks like I have to grind to -.020, or try a lot of different shells till I find some that fit. -Any thoughts on shell quality??
 Cheers duTch
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia

Online KiwiGF

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Re: Large Journal Conrod Big-end EYE size please
« Reply #42 on: 02.09. 2012 09:48 »
Heh Dutch I've got some scales now and have found a few things out including there is stuff all difference in weight between BSA rods and Thunders billet rods, both total weight, small end, and big end weights all similar,  also that JP pistons do not always weigh much more if anything than BSA pistons.

Also, and I'd REALLY like others opinion that a SJ motor as STD has 45% balance factor not the generally accepted 54% if I've calculated that right, I'm thinking a new thread on "Balance factor DIY" might be needed rather than continue on this thread as this info is not really about big end diameter any more, what do you think?

Have you got your scales yet?

Simon
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1956 A10 Golden Flash  (1st finished project)
1949 B31 rigid “400cc”  (2nd finished project)
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Offline duTch

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Re: Large Journal Conrod Big-end EYE size please
« Reply #43 on: 02.09. 2012 11:54 »
Heya Simon-Kiwi,
                       I think you're right- separate topic- Balance Factor DIY is a good idea, so long as all the info is good,I wouldn't want to mislead anyone.
    I've got scales, and enough other armaments and 'intelligence' to rewrite 'war an peace', but where to start??
 My BSA rods weighed in at ~382(103/279) & 388(104/284)
 Thunder Rods ( L.J ) -        439-440grm, (130/310) , which is ~ 50-60 grm difference.

 I'll leave it there for now, and have a go at B/F-DYhI..
 Cheers duTch
Started building in about 1977/8 a on average '52 A10 -built from bits 'n pieces never resto intended -maybe 'personalised'
Have a '74 850T Moto Guzzi since '92-best thing I ever bought doesn't need a kickstart 'cos it bump starts sooooooooo(mostly) easy
Australia