Con Rod Bolt Torque settings

[chaterlea25]

Hi Richard and All,
I have a similar small rod Ariel Huntmaster engine to reassemble  once this Bl***y knee will let me stand for any length of time,
The conrods have the small nuts with built in washer, they are 26tpi
While convalescing I have been thinking on what torque to use on those bolts / nuts,
My thoughts are that the "8" is a misprint for 18  which would be similar stretch on a BSF bolt (I think it was the long stroke engines had BSF bolts ????)
I think I am going to aim for 0.004in bolt stretch rather than any notional torque value 
That is what I did with the last A10 engine using new ARP bolts after completing their stretch cycling

There was a very interesting group of posts some years ago about the torque value to use when fitting new alloy rods with ARP bolts, If torqued to ARP's values the alloy rods would distort and jam the big ends
I cannot remember the final outcome of that discussion 

John

[RichardL]

John,

Maybe it was this discussion: https://www.a7a10.net/forum/index.php?topic=8093.msg56905#msg56905  (Apologies that it's me.)

In that thread, I was talking about 49 ft-lb called for with the M.A.P (really, Thunder Eng.) billet rods in my A10.

I like the idea of going to a uniform stretch length, but I think I'm going to test to see about what torque equates to 0.004, or thereabouts. I'm thinking a little less stretch might be right because the bolts are plain rather than having a couple of reduced-diameter zones.

Another touch of confusion is whether I would do it using my leftover ARP lubricant, or dry, except for Loctite. I had planned a drop of Loctite as belt-and-suspenders to the nut's thread-locking feature.   

Richard L.

[Brian]

It was me who had the thread about ARP bolts, some years ago now. Anyway I bought a set and they came with some ridiculous torque figure so I contacted ARP's technical department and we ended up with a figure of 28 ft/lb for alloy rods as fitted to our A10's.

Incidently I purchased the bolts from SRM and they wouldnt reply to my e-mails about them which was why I contacted ARP. Seems SRM is happy to sell stuff but not so keen on any sort of after sales service.

[RichardL]

We your rods stock alloy or billet?

 Maybe they didn't respond well to emails, but I've never failed to get throught to Gary or John when using the phone.

Richard L.

[Brian]

Stock alloy rods.

If you were using any sort of aftermarket rod then some research would be needed, the manufacturer should be able to supply that information.

[RichardL]

Mine are stock. I asked about yours because 28 ft-lb would be low for, say, Thunder rods. I guess you got ARP  bolts from SRM based on SRM having them made custom. I didn't see bolts for stock rods on the ARP site. Anyway, I've finished mounting the rods using a hair more than 15 ft-lb.

Richard L.

[JulianS]

An interesting paragraph from Chapter 30 of Roland Pikes autobiography concerning conrods;

http://beezagent.blogspot.com/2009/02/roland-pike-autobiography-chapter-30.html

[Seabee]

Thanks Julian! That was a great read. Can you imagine adjusting the valves at 7K RPM!

[Swarfcut]

Again, Thanks Julian. One of the names in that linked chapter was Gordon Smith. There was an engine reconditioner in Halesowen, West Midlands in the 1970's by that name, "Gordon Smith Engineering".  He enjoyed a fair wedge of my hard earned, but always gave value for money and knew the answer to many a conundrum. Bet it was the same fella.

 Swarfy.

[RichardL]

I read that several years ago but had forgotten about it. An interesting takeaway from that is the direction for clean and dry when getting to a torque-wrench setting (back then, dial indication, I suppose), but ARP provides lubricant so you can easily get to the bolt stretch length without regard to torque value.

Richard L. 

[chaterlea25]

Hi All,
That's the thread I was thinking of 
Then I read one of my replies , Fkn  'ell  that was seven years ago 
and here I am in 2021 recovering from another operation 
Sad to report little or no progress since then on the RGS build either 

Now that I have closed shop for customer work, once back on my feet I can concentrate on my own projects

John

[RichardL]

Now that I have closed shop for customer work, once back on my feet I can concentrate on my own projects

John,

Hoping for another chance to meet you on a Cannonball Run.

Richard L.

[chaterlea25]

Hi Richard
I believe the two guys I did back up on the Cannonball for in 2018 are not going to enter again ??

John