Wrong rods, bolts or have they been machined ?

[v8ivor]

C&D sent me a new bolt set (Updated version of the BSA ones with split pins ) Forgedthread rolledEN 16 Boren type 2 hardened & tempered to condition X (85 tons ) ( BS3111 ) and they measure .312" at the widest part of the stem. But the existing bolts measure .335", meaning that the caps are "floating about". I noticed that the photos that Guy showed in the last post showed the casting marks on the rod and cap sides and my caps have are recessed for a washer to fit below the nuts.

[chaterlea25]

Hi V8
 
It sounds and looks as if some PO drilled out the bolt holes
0.335 = 8.509mm
I dont think a "cure" is possible   

John

[a101960]

C&D sent me a new bolt set (Updated version of the BSA ones with split pins ) Forgedthread rolledEN 16 Boren type 2 hardened & tempered to condition X (85 tons ) ( BS3111 ) and they measure .312" at the widest part of the stem. But the existing bolts measure .335", meaning that the caps are "floating about". I noticed that the photos that Guy showed in the last post showed the casting marks on the rod and cap sides and my caps have are recessed for a washer to fit below the nuts.

Maybe I can offer a partial explanation to your problem. Unfortunately, the problem is that over the years due to prevailing circumstances various modifications have been necessary as a matter of expediency. As an example, a few years back when my large journal crank was rebuilt no BSA big end bolts were available that met the correct specification (forged bolts with rolled threads). The solution was to use Triumph big end bolts. I cannot remember what the exact model was now, but at that time the Triumph bolts were the only ones that I could obtain. The trouble was however, that the over all length of the Triumph bolts was slightly shorter than the correct BSA bolts. What this meant was that the end caps had to be machined to suit the Triumph bolts. Obviously this was not an ideal solution because the end cap was irrevocably changed, but it got the bike back on the road. This is of course not a problem for me because I know what has been done and why, but one day in the future it might cause someone to wonder why the bolts and big end caps are dimensionally different. I don’t expect that when these bikes were designed that BSA expected them to last as long as they have. We are all familiar with the comments about the design faults of old British bikes, but they are a product of their time. Technology has moved on, and materials have evolved and improved. Old bikes are always going to be high maintenance, and at times ingenuity, resourcefulness, and imagination is required to keep them on the road. I suppose that in an ideal world we would all keep a log book that recorded any modifications that we have done to achieve that aim. Sadly we do not live in ideal world.
John

[v8ivor]

Thanks for your help John,
I think you have "Hit the nail on the head" And I think that is exactly what has been done (And you are one of a few that could of given me that information ) This motor has been laid up for at least 35 years, and I think that the work carried out was ok and only looked down on by Today's exacting standards. I have an idea that your average garage mechanic would rebuild engines without considering new rods or even bolts back in the day. As I see it, my low risk option would be new rods and bolts, but would be expensive. Next option would be to see if I can get longer Triumph bolts or machine and fit two sleeves around the new BSA bolts between the cap and rod. Or if I remove the washers from the existing set up, the bolts would just protrude past the bolts, but some people say using old bolts is a No No.

[kiwipom]

hi guys, got some bolts that I bought some time ago but did not use them because I purchased billet rods from SRM which came with bolts which were torqued to 45lbs/in as per instructions,cheers

[kiwipom]

hi guys, more pics with measurements, cheers

[v8ivor]

Thanks KP, I just checked and the diameter of your bolts is to small for my rods that have been drilled out.

[kiwipom]

hi guys, v8ivor you will need some more rods then? cheers

[chaterlea25]

Hi V8,
Remind me?? are these small or large journal rods?
If cash is very tight?
I think I have a set of small journal rods?? no guarantees with them tho
There are a few sets on fleabay too

HTH
John