Which rod bolt?

[Ark1]

I have a set of Berg H beams I'm using on an engine I'm putting together right now. I acquired them second hand from a respectable local builder. The heads are 12 pt. 3/8 and are arp8740 's. The engine will be a pretty mild 1641 (cheater cam, dual dcnfs, and a header.) Was considering upgrading to arp 2000 bolts, but would it be worth it on my 1641 (these rod bolts are used, I was just going to torque them to spec). ?

[Ark1]

If replacing for ARP 2000, which bolts would I need exactly?

[Ol'fogasaurus]

This is a case where, to be safe, I would contact ARP directly. Is the old bolt reusable or is it a single use fastener. Is the ARP2000 a correct replacement for the ARP8740. This could be a big deal or no big thing but it is going to be cheaper if you have an engine failure because you didn't check.

Discussion: If I was positive that the use/installation of the old bolts was correct and there wasn't a major catastrophe with them ARP should be able to tell you if they thought it was safe to reuse. They would also be able to tell you if it was a single use fastener or, if installed correctly, there were more uses for the fastener available.

ARP, from what I understand cold rolls their threads after heat treat (http://www.astm.org/DIGITAL_LIBRARY/JOU ... I13069.htm) I don't know if this is a new thing or older thing we are just now hearing about (http://www.enginelabs.com/features/shop ... to-finish/).

One of the things that ARP was saying in the bit on TV I saw was that since they cold roll threads they are stronger than equivalent fasteners that do not do not roll their threads after[b/] heat treating (single use/torque to yield [https://en.wikipedia.org/wiki/Torque-to-yield_fastener] so their fasteners are reusable (usually). Rolled threads are much stronger than cut threads as with cut threads you cut the grain flow. Rolled threads to disturbe the grain flow but by squashing the grain during forming.

Again, to be safe I would talk to the experts as their rep is under fire and they are going to give you the best information they can. A phone call is going to be much cheaper than a failed engine.

Lee

My opinion is worth much less than you paid for it.

[sideshow]

You are no where near the point of needing to upgrade a quality rod or bolt.

FYI if it is a "Berg" rod, they can do an excellent job refurbing it.

[Ol'fogasaurus]

You are no where near the point of needing to upgrade a quality rod or bolt.

FYI if it is a "Berg" rod, they can do an excellent job refurbing it.

This is a case where, to be safe, I would contact ARP directly. Is the old bolt reusable or is it a single use fastener. Is the ARP2000 a correct replacement for the ARP8740. This could be a big deal or no big thing but it is going to be cheaper if you have an engine failure because you didn't check.]/quote]

Again, my point was to be sure of what you have and to be safe using it. I was not doubting ARP fasteners at all just to make sure that what he had was not a single use design fastener.

There was a engine design change a while back where the head bolts or head studs were "single use" do to some design requirements and the head and block expanding or shrinking at different speeds or levels. This is probably more common on water pumpers but I seem to remember seeing some custom rod bolts going that direction too; e.g., there are rod bolts that are designed for single use application and to make sure of the "unknown" he has.

Lee

[Ark1]

Checked stretch, and the old 8740's were looking pretty tired, so I went ahead and ordered new 2000's to replace them.