Any reason to not use split pins? They were all there after 53 years. The (highly reputable) machine shop saw no reason to change the method…and they’ve built a lot of XK engines
I had heard somewhere that they were a disaster. Perhaps that was only in competition or something.
I think the idea nowadays is to only open the split pin far enough that it dosen’t back out?
Which, read in a glass half-full manner, is the same as saying they used lock tabs for almost the entire four decades of XK production. Jus’ sayin’ 
I’d definitely query the torque spec for non-standard critical fasteners though, and apply that number for align honing
Pete (occasional Loctite AND lock tab AND ‘extra tweak’ rebel, who hasn’t lost a home-built four stroke yet)
Other than there is ZERO reason to do so, I’ll assume you were kidding…
A common practice is to bin the earlier drilled rods and use the stronger S3 XJ rods with the associated bolts and 12 point nuts.
I do actually know someone who drilled rods for lightness (alloy rods at that!) but you meant rod bolts I’m sure.
No, I meant rods… as in the earlier variant with the drilled oil passage from the big to small end.
The later S3 rod provides better oil pressure to the mains and the big ends as well as being stronger.
I am guilty though of thread drift.
Anyway,where would one purchase new castellated nuts assuming they weren’t re using old nuts and bolts? I can’t imagine any reputable shop up on the latest and best practices using castellated nuts, split pins and cross drilled rod bolts.
If it aint broke…why fix it?
I’m with you on that on many things… but on this one, I think you’re flirting with failure
My uncle, who owned an independent Jag shop for decades, claimed that he had never seen a failed connecting rod split-pin on an engine that was untouched from the factory…only on ones where someone else had obviously been in there previously.
My ‘67 had numerous failed split-pins lying in the sump, but they were cheap, soft, junk parts that someone had used as replacements. A lot of people don’t give these old Brit cars enough credit sometimes…the factory fasteners were typically superb quality.
You can still get high quality split-pins, but they don’t come in a little plastic tray from Harbor Freight 
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I agree. Sticking in a set of aftermarket main bolts, and running them up to factory spec is not ‘engine building’, it’s engine assembling…blindfolded.
The bolts should be torqued to what their manufacturer recommends, with a clear understanding of whether that’s a dry, oiled, or moly-lube spec, and the main journals checked for roundness. If the machine shop already did that, then cool, I would use the same torque and lubrication they used.
If the manufacturer of the bolts can’t be determined, or that manufacturer can’t supply a torque spec, I wouldn’t use them (personally).
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The only sentence structure, where the words, “quality” and “Harbor Freight” can be properly mentioned…
That said, the remark about British fasteners being of high quality is indeed correct. As for the need to use split pins/castellated nuts on con rods is faaaaaar in our rearview mirrors.
I never replaced the split pins, in any Jag rebuild: I replaced the nuts with Chevy nuts, properly torqued, with perfect results.
I knew a machinist who was a real, dyed-in-the-wool Cheby guy, who used to work on my Brit stuff almost begrudgingly. When he complimented the quality of the OE fasteners, I knew they had to be good!
Agree…clean sheet, I’d never put them back in. Buuuuuuut, if I pulled my sump off, and found some failed HF split pins, and the rod bolts threads were anything less than perfect, I would re-use the castellated nuts and high-quality split pins before pulling the engine down to do a rod bolt replacement. I’m talking stop-gap, get in back on the road stuff here.
XJ6 era I believe, they switched to using 12 pt modern nuts on the conrods that required no cotter pin, I suspect because so many of them failed and ended up in the sump. The first time mine got rebuilt 20 years back I was warned against going back in with cotter pins and it got the 12pt nuts. It made it 23k miles before a chain guide failed but the rod nuts were still tight as could be.
To that point–and where this subject tends to go into warp-drive overthink-- is NONE, zero, zip, nada engine I took apart, ever had a rod nut or main bolt loose.
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Norman,
Thanks for the reply and professional guidance. What are your thoughts on re using con rod nuts and bolts and do you verify the torque values by measuring bolt stretch?
TIA
I would never reuse the OE Jaguar bolts, have had them fail, and was the reason Jaguar lowered the RPM red line on the 4.2 engine due to Rod Bolt failurrs due to the heavier pistons.
Unfortunately Jaguar bolts are not ARP quality, definitely throw away item.
For my 6 cyl. Race Engines I use S3 XJ rods, lighter and stronger, together with ARP bolts. (ARP make a Jaguar suitable Rod Bolt but they don’t know it).
Engines regularly ran to 7500rpm. (maximum HP) without any failures.
Did have one customer engine failure, but that was due to inadequate engine warmup (cold winters day), causing seized Rod Bearing the bent rod, pulled Rod Bolt through the Rod.
Nothing broke apart from piston due to the Rod side loading.
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Got a part number for that ARP bolt Norman? Presumably it’s suitably profiled under the head not to bite into the rod shoulder radius?
Doug, thanks. If I’d remembered the drilled small end feed I would have asked which type of drilling, instead of assuming you meant bolts. My apology.
Yes, the Jag installed split pins are fine and last indefinitely if untouched
Peter, you’ve got to get out of the “Stone Age”, NO ONE, I repeat NO ONE uses split pins on Rod Bolts or any other high Torque nut applications these days.
Also, no one makes Rods with oil feed holes, totally unnecessary due to adequate oil mist in the crankcase, Just like 2 strokes don’t need oil pumps.
ARP bolt is #AR310 (400 Cleveland). These come with a standard hex nut which I normally replace with a 12 point one, Standard on all Jaguars from 1968.