Author Topic: Conrod bolt  (Read 243 times)

Offline hywayman

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Conrod bolt
« on: 14.07. 2019 02:46 »
g'day all,
after searching for new rod bolts to suit a 1950 Long Stroke engine, i found the post where early Ford 289 bolts can be used.
my question is do i torque the bolts to 22 ft/lb as specified or go with ARP's spec of 35 ft/lb?
i'm thinking 35 ft/lb may distort the big end of the rod but 22 ft/lb may not be tight enough for these bolts?
thanks in advance

Online ironhead

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Re: Conrod bolt
« Reply #1 on: 14.07. 2019 04:27 »
22 ft lbs if it were me, others may have a different opinion.
SA

Online muskrat

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Re: Conrod bolt
« Reply #2 on: 14.07. 2019 05:07 »
G'day hywayman,  *welcome*
You are correct in your thinking. 35 will distort them, go 22 with red loctite.
Cheers

Now wander over to Introductions and give us your sales pitch.
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Offline Tomcat

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Re: Conrod bolt
« Reply #3 on: 14.07. 2019 07:15 »
G'day HWM, quite a few years ago I bought NOS Long Stroke con rod bolts and nuts from Modak. Might be worth a try again?
Cheers TC
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Offline Swarfcut

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Re: Conrod bolt
« Reply #4 on: 14.07. 2019 08:36 »
G'day HWM.
     BSA Service Sheet 208 from October1948 (reprinted June1966) recommends 10ft/lbs for early 22TPI BSF Bolts. By early, we reckon this refers to the Longstroke Bolt, together with Steel Conrods.

 A later 26TPI Cycle Thread (CEI) bolt is specified to 8.5 ft/lbs, and this bolt with its nut can supposedly be substituted for the earlier BSF bolt and nut. The torque setting was raised to 22ft/lbs in 1956, but this may be because of the use of  self locking rather than castle nuts and split pins. These are the bolts used with the more familiar alloy rods.

 So if anything, the scenario is confusing, as the service sheet only mentions early and later parts, rather than specific part numbers.

 Maybe worth researching comparable figures for similar engines using steel conrods.  I would have considered there is a fair degree of leeway as the steel rod is a much tougher component than the softie alloy rod. The Ford Engine would have steel rods, so I do not think the higher figure would distort the steel Longstroke Rod. Anyone else with experience of these rarer motors?

 Sorry if this adds to the dilemma, but maybe a useful bit of background for your research.

 I've got this to come, as I have an incomplete basket case Longstoke motor, and sourcing some of the missing bits is taking a fair time.

 Swarfy

Offline Tomcat

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Re: Conrod bolt
« Reply #5 on: 14.07. 2019 09:28 »
IIRC the original bolts and nuts are castellated. Murphy's Law dictates that at the correct tension the split pin hole doesn't line up!
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Online JulianS

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Re: Conrod bolt
« Reply #6 on: 14.07. 2019 10:02 »
Photo is the original 1948 issue of third page of 208. Second paragraph deals with tightening the nuts and just says "REALLY TIGHT".

No doubt torque wrenches were not part of the usual kit in the numerous small motorbike dealers workshops back then.

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Re: Conrod bolt
« Reply #7 on: 14.07. 2019 10:05 »
My apologies, I had forgotten the LS had steel rods.
Cheers
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
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Online duTch

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Re: Conrod bolt
« Reply #8 on: 14.07. 2019 10:14 »

 Hyman hywayman- First thought was 'is this J.C, Willie, Waylon , or KK....'...I know nought of this stuff but as it's your first foray I suggest you sneak to the intro place and do the stuff before anyone notices (just between you'n me and the inter and outernets's)  *shh*....  *welcome*
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 hywayman

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Re: Conrod bolt
« Reply #9 on: 21.07. 2019 10:11 »
g'day all, i have been busy, see attached pic of A7 Long Stroke cases with first coat of sealer.....

can't seem to post pics as my files are too large for 1500KB limit?

Online bsa-bill

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Re: Conrod bolt
« Reply #10 on: 21.07. 2019 10:41 »
Quote
can't seem to post pics as my files are too large for 1500KB limit?

Several ways to reduce the size of pics, my prefered way is to use "Paint.net" free here  https://www.getpaint.net/
load your pic in (open) do any adjustments you require (crop) then "save as" select where you want it saved, it will then give you a screen where you  can alter the size of the pic
All the best - Bill
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Re: Conrod bolt
« Reply #11 on: 21.07. 2019 10:52 »

 I take photos on an Andyroid phone with a thingy doodad called 'Photo Resizer' (dunno where it came from) and works just fine - no dramas, then just do the ' add attachment' process....
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

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Re: Conrod bolt
« Reply #12 on: 21.07. 2019 21:17 »
'51 A7 plunger, '57 A7SS now A10CR, '76 XT500, '77 AG175 '83 CB1100F, '81 CB900F project.
Australia
Muskys Plunger A7