ARP bolts

[new to this]

Hi any one know where i can get ARP Rod bolts and also main end bolts ?

Thanks Dave

[bullstarz]

These are the main importers in the UK for ARP. May not have the example on the shelf you can always order them and cross reference to find out what other vehicles there may be fitted to,

https://shop.arrowprecision.com/catalogsearch/result/?q=ARP

[jbuckl]

Afaiaa the rod bolts are not bolts… they are studs & nuts.
New ones were available.
Although ARP are respected, not certain that stags should be fitted with bolts instead of studs & nuts… due to cap alignment.
…. Could be wrong / stand corrected.

[Motorsport Micky]

I've built a number of TR engines with ARP studs and nuts and they are great fastenings...and expensive.
Also Triumph fastenings torques are ...dry, no oil, no high viscosity paste, nada, nothing,...as confirmed to me by Dave Gleed, ex Triumph Competition mechanic... "lubed ? nope, fitted dry as a Vicars toast" (apparently they only drink tea !).
The ARP and also most modern fastenings are fitted lubed, and torqued and stretched (so they don't come undone) by measured bolt increase of length (you need to measure them in situ torqued up) into the elastic range of the studs (critical, stretching by maybe 5 thou (differs by size) to the correct parameter within a thou...any more and you undo the bolt and nut out and throw them...and start again.
The initial torque suggested by ARP just gets you into the range of bolt stretch and requires multiple tightening's to that torque (one after the other) to "burnish" (smooth and remove any micro snagging on the thread) the thread for full stretching. The bolts will recover (to a degree) having been stretched but retain a small degree of stretch to stand another rebuild.
But that's not all, applying force one way also has an equal force applied the other. The lubing with sliiiippppyyy oil INCREASES the actual torque clamp applied to the fastening (it removes stiction, (sticking friction) and also the block or conrod studs are screwed into. As an example the cylinder head stud torque on a 4 cylinder TR2-TR4a engine is 105 lb ft. But lubricating with the very slippy oil supplied increases the actual torque applied to the engine block by 20% (from tables available on the internet) when the torque wrench clicks off, That makes actual equivalent torque applied through the threads as being 126 lb ft to the block, that's a very high increase to apply to 50 year old materials. So when I use ARP studs and nuts on cylinder head studs with lube I only apply 90 lb ft, the lubing increasing the applied torque by 20% making an increase to 108 lb ft. I know that's in the block material strength range by experience having regularly used 110 lb ft dry when torqueing race engines and some exotic interior changes. Next time I have a scrap block come by I've determined to torque a cylinder stud up lubed to whatever it reaches and achieve some parameters for ARP v Block loadings.

So the advantage these very nice ARP fastenings give you is...? Unless you are running something a lot more exotic the standard Triumph fastenings do a great job, cost effective and adequately achieving the build required for a Stag engine.

Oh...and my cylinder head on the Stag was torqued up at 65 lb ft for the long studs (2 threads...one in the block and another for the head nut, plus a longer fastening length) means the fastening only torqued to 55 lb ft stretches more and actually reducing the head clamp, hence the increased torque is applied to counter that. The long set bolts with only the 1 thread are torqued to 55 lb ft as per the book, and the shorter set bolts with one thread are torqued to 35 lb ft, because they are shorter than the long set bolts which means less material length to stretch (hence greater applied torque) and I consider the 55 lb torque too much "tilting" the head because the head material under these shorter bolts is minimal and doesn't compress as much as the heads full depth fastenings do. So that's my attempt to achieve an even cylinder head clamp and after 15,000 miles with a retorque annually (the nuts have not moved (after releasing 1 flat and retorquing to the above numbers after the first 4 years).
Now this is what I run at, and it suits me, I know there are engines out there which are torqued exactly as the manual says and have probably achieved greater mileages than mine since rebuild, and that's fine too. Your cars, your choices.

Micky