The BSA A7-A10 Forum

Technical => A7 & A10 Engine => Topic started by: duTch on 12.07. 2012 01:33

Title: Large Journal Conrod Big-end EYE size please
Post by: duTch on 12.07. 2012 01:33
 Hi all,
         As the title suggests I need the measurement for-Large Journal Conrod Big-end EYE diameter without bearing shells  size please.
 Am sure I've seen the info somewhere but now can't find(found centre-centre= 6.469"), Haynes have the Small journal spec, but no mention otherwise that I can see!
  Thanks in advance, duTch
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: KiwiGF on 12.07. 2012 02:19
Service Sheet 207 has this. I'll tried to post this but pdf are not allowed. Let me know if you need it and I will make a jpg file of it.

As well as the size you may need to know the clearance with shells, as an engineering firm will grind the crank to suit anyway. I asked for 001 clearance when it came to my crank regrind. LJ BE diameters are shown as:

1.687 std (not actually on the service sheet but I've calculated this from the first regrind dia)
1.677 first regrind (-010)
1.667 second regrind (-020)
1.657 third regrind (-030)
1.647 4th regrind (-040, BSA do not show this size on the sheet, but -040 BE shells are available)

More inf. The BSA technical litarature states the correct big end clearance as "effectively nil" and 002 is the wear/replacement limit, but the Haynes manual gives the dimensions for the standard size journal (1.460 nominal) and rod eyes as:

Rod Eye ID                    Journal OD
min        max                 min       max
1.4610   1.4615             1.4595   1.4600       

         
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 12.07. 2012 05:05
Thanks Kiwi,
                 I have all that info,odd that there's data for the S/J rod-eye but not L/J,  and have just been reading the thread that you started last december(?), with your saga and all the discussion re; bearing materials.
  I dropped my crank and rods into an engineering place yesterday, now waiting for a call. I measured the journal with a digital vernier,smooth and seems round, @1.675~ a bit rough-0.0015~, but see what they reckon.
  I replaced the shells as a matter-of-course(-0.010), as the crank has only done a couple thou miles since ground, it may have been done wrong,or;-
  I think I may need new rods, be easier as the little end bushes are out of whack as I suspected as per post a few weeks ago, and am not too sure the integrity of the B/E eyes as.
  I've seen your rods post re Thunderlightning, and also looking at MAP rods, and Ridgecrest.
    Cheers for now duTch

BTW, SRM have the journal sizes-
http://www.srmclassicbikes.com/technical/bsa-a7-a10-big-end-journal-sizes (http://www.srmclassicbikes.com/technical/bsa-a7-a10-big-end-journal-sizes),
 But not the rod size, as per 'size rods to fit shells/crank'
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: KiwiGF on 12.07. 2012 05:38
Hi, Dutch, oops, you asked for con rod eye dia! On that topic, and using old rods, you probably know, but in case not the eng. shop can "resize" the rods to suit the shells, they shave a bit of the mating face then make them round again. It's the end caps that distort over time (the main part of the rod is stronger and doesn't - generally!) and this causes the shells to not get clamped correctly. The eng. shop will probably be able to work out what the size should be from the thickness of the shells and target journal size.

I'd measure my rods for you but they are SJ.

I was quoted about $200 to resize and shot peen my old rods, I spent the extra $300 odd to get new ones from Thunder instead.
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 12.07. 2012 06:13
 this is what I was looking at-found as a goole search, not a bad read from all concerned(it's a rainy day).
Title: Big end clearance and indium coating
Post by: KiwiGF on 08.12. 2011 08:47 (http://Title: Big end clearance and indium coating
Post by: KiwiGF on 08.12. 2011 08:47)

 Thanks again, but I'm fairly sure I had them re-sized first time 'round(I know I had some done), but now that it's possible to get new rods-yay-, like you, could be best, don't want to stuff around any more, just want to ride it.
 Without the shells in each eye measures within a thou, but with the shells in about 3 or 4 thou ovality, and the new shells(again with verniers) measure almost 2 thou thinner(~0.079) than the old ones(~0.081)??

 Thanks for your time, cheers duTch
   
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: KiwiGF on 12.07. 2012 07:51
The new shells being thinner is a showstopper if you were not intending to regrind the crank, any chance of finding some thicker ones? But I guess you had thought of that. If the journals are round it would be a shame to regrind them.

Maybe someone can provide some specs on the shells available? There are glacier and vandervell brands maybe others. The specs will probably include the rod I.D. Which I think are accurate to much less than a thou, when resizing I think they in "10ths"  Eg 0.0001
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 12.07. 2012 10:29
AH yea,
         hooboy, yes it's curious and a bit rough measuring, but using same method. I think I'll go buy some proper micrometer tomorrow(replace what went walkabout), that way I can compare to the workshop measuring, and see. I been trying to find bearing info on the net, but only got square eyes.
      Also had a yarn with Steve at ThunderEng. was about to finish of a batch of rods an hour ago.
Cheers mate kick back 'n relax, duTch
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: muskrat on 12.07. 2012 11:19
 G'day Dutch.
                  There should be a crush on the shells of about 5 thou. So if you put the shells in the rod and do the nuts up finger tight. With one side of the rod and cap meeting there will be a gap of about 5 thou between rod and cap on the other side.
Just came up from shed so will try to dig one out tomorrow to measure.
Cheers
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 12.07. 2012 11:51
Thanks Musky,
                     I guess that's with the shells butting together at both joints (diametrically)? I think I had a bit of that when I put them together the other.um month(?) I remember looking at against the setting sun, because my young fella turned up and was looking at me kind of funny-till I explained-he nodded. Will have a better look when I get them back tomorrow.
 Also anyone know about MCA slippers??
                   cheers duTch

ps Just reread the "Big end clearance and indium coating' thread yet again, seems the consensus on MCA is they're ok for general road use?? Just cos I can get those locally . cheers again
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 14.07. 2012 11:34
Little update here,
          The engineering shop, measured up and crank is 1.6752( close to what I got with my verniers),about 0.001-0.0015 under spec.
Measurement on 'rod-eyes'-1.8920/1.8930 (+/-0.0004/)..?
 I got 1.841~, about 0.050" difference...? is that ~1.25mm or not??

When I dropped it off he said 'so you want us to supply bearings and grind to size..? '......no,grind nothing, just measure please'.
Also I found variation in the new shells, they're ~ 0.081 thick, and the old ones are ~0.0825  (+0.0015)!!
 I'm buying replacement micrometer.

Point is, be very careful what you're told by those who 'know', and double check.
 Please anybody tell me if my maths is wrong!!
 cheers duTch
   
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: kommando on 14.07. 2012 12:12
Quote
I got 1.841~, about 0.050" difference...? is that ~1.25mm or not??

Yep 1.27mm, Internal diameters are notoriously more difficult to measure than OD's but 1.27mm is a lot.

Where did you measure the thickness of the bearing, it needs to be measured in the central area using a micrometer with ball points, on the edges there is a relief so that when the crush is squeesed by the con-rod the deformation of the bearing in this area does not cause this are to contact the journal, any measurement here is not representative of the bearing thickness.
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 14.07. 2012 14:12
Thanks Kommando,
                   
Yes I agree that I should use 'ball-points', but don't have them. It's a very arbitrary measurement with sliding verniers, but using the same method on different shell sets produces different results, measured with the 'pointy ends' of calipers at various points round, and across the semi-shell, enough for me to question why should I not just use the older thicker ones(under duress)??
  Just tried to take some pics but too much flash, will try again in the morning in daylight.
Also,1.27mm(difference) just isn't in the ballpark. Kind of hard to be that far out and not notice! The shells'd have to be 0.108" thick, not much less than 1/8".
 I'll take the rods back and get them to do it again,if for no other reason than to point out they're wrong, and why trust them with an item that's getting close to irreplaceable. Fairly confident I'll just get new rods and shells,and get on with it.
 cheers, duTch
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: Rocket Racer on 19.07. 2012 22:28
Thought I would hi jack this thread as rods always interest me and had just got an interesting email.

I have been considering options for some new rods for my race bike and had never seriously considered steel rods as I had assumed they would cause vibration due to their greater weight. However a mixture of seeing a utube clip of some heavy duty modern alloy rods and also seeing a reference to Carillo's being lighter than many OEM rods set me thinking.

My existing std BSA rods weigh (according to my scale) 370 grams being 150g reciprocating weight (stops-and changes direction each stroke so implicates inertia) and 220g rotating weight (affects balance but primarily just spins).
I sent out inquiries to several supplier and both Thunder Engineering and BritCycle kindly got back to me with corresponding weights for their Alloy and Steel rods.
The weights make interesting reading:
Std Rod         370g, 150/220 split
Thunder Eng   440g  125/312 split
Carillo            479g  130/349 split
So there is little difference in reciprocating weight between a replacement alloy or steel rod *eek*.
I havent done any maths on the implication of the additional rotating weight of both rods but am assuming it will simply move the vibration up or down the rev range slightly *dunno* or the crank could be rebalanced if necessary.
My current thinking is that with no effective weight disadvantage, a steel rod will retain oil pressure better due to lower expansion rates, so be superior in a performance engine.
Now just need to save up enough money...
Tim
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: KiwiGF on 20.07. 2012 09:16
Thanks for that rocket racer, thats good info. I assume the weights include nuts bolts etc?
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 20.07. 2012 09:19
Hiya Tim,
          Hi-Jack away. better than being 'you-jacked', figures Steve at Thunder'nLightning gave me was 126/314(440g overall)- close enough, as I was wondering also how different weight rods will affect the show, even though mine's just a 'run around'(currently a 'carry bits around'!), don't really want more vibes than necessary, and so thought maybe I may need to look at balance adjustment.
 Like you I'm not sure how to analyse it, as if there's a difference in either of reciprocating or rotating, creates different dynamics, and in my case if it's not much different won't matter too much. I guess it's another case of suck and see??
 Cheers for now, duTch
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: muskrat on 20.07. 2012 10:58
 G'day fellas, it's the reciprocating weight that you use your balance factor on. So a bal fac of 60% is 60% of recip weight (this includes piston,rings,pin & clips) + rotating weight. Make lead strip weights and wrap around b e journals, balance crank on knife edges as you would a wheel.
129g difference between the std and carillo is quite a bit when x 2 so would make a big difference to vibes.
Cheers
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: Rocket Racer on 21.07. 2012 04:32
Thanks for that rocket racer, thats good info. I assume the weights include nuts bolts etc?

Yes, but I have not verified either of the weights provided to me.

Muskrat makes a good point the increases of either the new alloy or steel rods adds 140-218 grams to the crank and most modern pistons are also typically heavier than the original beesa ones so balance factor the next question, so I need to do some maths *eek*
Eddy Dow recommended increasing from 54% to 65% (for racing) in his "Twin Tips" and Paul Dunstall recommended a balance factor of 70% for the norton 650ss (for racing) , so quite a variation.
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 21.07. 2012 10:39
The money's come out of my bank, so I assume I have some Lightning-Thunder-rods, in transit or close to, so in about a week or so, I should be able to take them to my local health food shop and weigh them accordingly.
 Now,balancing is stuff I've had JS to do with?
       So my guess that to calculate the....'reciprocating weight'..
 
Quote
So a bal fac of 60% is 60% of recip weight (this includes piston,rings,pin & clips) + rotating weight. Make lead strip weights and wrap around b e journals
,
   ......is to maybe assemble all the aforementioned Muskie bits, and park the rig so the piston/rod L-e assembly bit is supported horizontally, and see what weight holds the crank/pin+big-end of rod horizontal, in same plane???(comprende ??) Tell me if that's wrong please?? or a better way.

     Also Steve said his Thunder rods have 3/8" bolts instead of 5/16", as said Pete (?) from Ridgecrest, which will explain a certain minimal amount of weight increase there.
      Just for reference, the BSA pistons I have are ~345-355grm and hepolite similar? can confirm that later if need be, how much difference does 10grm(for example) make?
    Hoo boy saturday(I think) night -things to do...
 Cheers for now, duTch
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: muskrat on 21.07. 2012 20:57
 G'day Dutch,
                  I use two identical digital scales (200g x 0.1g cheap on ebay) big end on one little end on other. Don't forget to put the shells with the big end. Measure pistons separate and add to little end.
 Have a beer or ten for me, Working all weekend.
Cheers
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: Rocket Racer on 21.07. 2012 23:30
A mate also pointed out to me that increases in piston/rod weight take the balance factor the wrong way, ie down. So in my case where I would like to increase the balance factor anyway, increasing the rod/piston weights is doing the opposite *sad2*.
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 22.07. 2012 10:50
Thanks Muskr, got the amber sorted, and figured the scale thing, too bad you workin' all w/e and I 'm not- oh well someone has to carry the country..!
 I missed out adding into this bit....,
Quote
,
   ......is to maybe assemble all the aforementioned Muskie bits, and park the rig so the piston/rod L-e assembly bit is supported horizontally, and see what weight holds the crank/pin+big-end of rod horizontal, in same plane???(comprende ??) Tell me if that's wrong please?? or a better way.
.....-is with the rods bolted on the crank. So when weight distribution is determined, then adjusting the balance with the lead weight, but then what, weigh the lead and figure out where to drill/grind/add??
 Keeping in mind though that unless mine is way out of whack it's probably not going to matter much as I'm not racing(...well..um..?), but just be nice to know what exactly is going on down there, and how to rectify if need be.

Also RR, when you say 'piston/rod weight', I take it you mean top end of rod assembly(reciprocating), as compared to the other end(rotating), which means you want less loss of inertia type energy in reciprocation, and more rotational energy(power? torque?), balanced with 'lighter' crank for quicker get upn go?? ..Or something along those lines??
 wphew..heady stuff!!

cheers fer now

Title: Re: Large Journal Conrod Big-end EYE size please
Post by: chaterlea25 on 22.07. 2012 17:27
Hi All,
Dutch,
Remember you will have to have the cutaways in the cylinder barrell widened for the new rods *ex*
Theres also some palaver about pre stretching the conrod bolts and or over tightening problems
There was a discussion on this topic previously????? Does anyone remamber where??
I have a set of MAP rods to fit to the RGS engine build, I think these have the same ARP bolts?

Cheers
John O R
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: Rocket Racer on 23.07. 2012 02:02
Dutch,
 you're on the right track ;) good interpretation, 10 points.
Always worth thinking about what increasing weight to components means. the top end of your rod and the piston change direction every time they get to the bottom and the top so light pistons and minimal reciprocating rod weight reduces load on your engine.
Every time you go up an oversize typically the piston wall gets thicker and the piston is heavier than that the motor was balanced for originally and when you add in heavy duty rods its rebalance time  *sad2*
Cheers
Tim
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: KiwiGF on 23.07. 2012 03:02
Hi Dutch, service sheet 712 has some info on balancing and where to drill holes (albeit the suggested location looks odd to me).

I'm also nearing the point of re-assembling my engine, but thought that as the SJ crank is -040 I was thinking of not getting it balanced, but after reading the other posts I'd also like to hijack the original post as well, as maybe a bit of home drilling is in order to get it closer to 54%.

2 x 18 oz is the figure in the service sheet given for standard % of reciprocating weight on the std A10, it seems to be the same for LJ and SJ cranks, 36 oz is 1020.564 grams. I'm not sure what BSA mean by reciprocating weight. Is it the total of rods/bolts/pistons/rings/pins?

If (and no doubt someone will correct me if this is wrong) the standard balance factor is 54% then the standard reciprocating weight works out to be (1020.564/0.54) = 1889.933 grams?

Does the reciprocating weight increase by 140 grams by using Lightning rods, to 2029.933 grams, if so, does this drop the balance factor to 50.2%?

By my calcs (using a density of a 10mmx5mm deep hole equates to 3.15grams so 140 grams at 54% would require 24 holes of that size, but actually more than 24 as they could not be all be positioned opposite the counter weight?  

24 is a lot of holes! (so I sort of hope its not 24).
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 23.07. 2012 09:18
Hiya Kiwi,
         I'll get back with more later, but for now have a look at Muskies and RR's earlier posts re:- reciprocating/rotating weights.
  36oz is 2,1/4 lbs -as you say 1020+ g that's a kilo....? 1/10th of the whole crank. You'd need a miners license for that- look out Gina! Bit of recalculating in order here??
 Be back after I analyzed the other stuff, and look at S/S 712, think I've looked at it it before
 Ciao fer now
   
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: muskrat on 23.07. 2012 10:35
 G'day all,
             what I do after I have worked out the amount of lead I have to wrap around the crank pins and set up on balance beams. I use bluetak to stick bits of lead on the flywheel till I get a balance. Weigh the bits and drill the flywheel opposite to where they were stuck. A 1/2" hole 1" deep removes 0.80 oz of cast iron or 0.88 oz of steel. A 3/8" hole 1" deep removes 0.45oz ci or 0.50oz steel, a 1/4" hole 1" deep removes 0.21oz of ci or 0.23oz of steel. 1oz = 28.4g.
 I used 70% for the A7SS racer (but first took 2Lb off flywheel  *eek*), 65% for the A10 cafe. Both a lot less vibes than the A65 (factor unknown).
A must do if foreign rods and os pistons are to be used.
Cheers
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch on 23.07. 2012 12:46
Thanks Musky I'll sleep on that one,
    Also John for the heads up re cutaways, and yes I'm fairly sure they have the same 'ARP' bolts.
Not sure about the other queries, re  discussion- stretching/overtightening.
 cheers for now
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: Brian on 23.07. 2012 12:59
I used ARP bolts in my 61' A10.

I bought them from SRM but they recommended some ridiculous torque setting for them and would not reply to my e-mails when I queried it.

I ended up contacting ARP direct and had a few e-mails with their technical staff and in the end they recommended 28 Ft lbs. I went through the procedure of taking them up to the required torque twice before the third and final tightening. I used loctite on mine.

So far so good  *eek*
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: KiwiGF on 24.07. 2012 03:47
Hi Dutch, I think my calcs above for recip weight based on the 36oz in service sheet 712 are incorrect, unless BSA had a different definition for reciprocating weight to what is generally used nowadays.  

Anyway, taking on board the comments on earlier posts I'm going to get some scales, weigh everything I'm using, and find out how to do the correct calculation, as it seems the billet rods in particular can have a big effect on the balance factor.  
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: chaterlea25 on 31.07. 2012 15:28
Hi Dutch and All,
Attached is a photo of the additional balance holes drilled in the crank of my RGS project
to accomodate the MAP conrods.
The crank has been dynamically balanced by SRM
The 2 holes nearest the flywheel bolt are approx 1/2in deep and the others app 1/4 deep
I'll leave you to figure out how much weight has been removed  ????

Theres a good reference to balance factors etc in "Tuning for Speed" 
no home should be without a copy LOL

Regards
John O R
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch 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
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: trevinoz 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.
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch 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
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch 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.
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: Rocket Racer 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...

Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch 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
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: chaterlea25 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



Title: Re: Large Journal Conrod Big-end EYE size please
Post by: KiwiGF 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
>
> P:  949-567-9000                       
>
> F:  949-567-9010                       
>
> www.cp-carrillo.com [1]               
> A member of Pankl Racing Systems
> Facebook:  CP Pistons-Carrillo 
> Find the hyperlink for our electronic disclaimer at:
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch 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
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: Rocket Racer 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.
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch 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
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch 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 (http://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
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: KiwiGF 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
Title: Re: Large Journal Conrod Big-end EYE size please
Post by: duTch 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