Studs & Rod Bolts Group Buy! - Ferrari Life
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post #1 of 2 Old 02-28-2015, 02:52 AM Thread Starter
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Studs & Rod Bolts Group Buy!

As some of you may recall, last year I had tried to work with ARP to produce some high spec fasteners for our engines, but their prices only became affordable on large quantities, primarily because of their fixed engineering, setup and tooling costs. They're primarily a production shop, not a job shop.

I had much better luck with a company who manufactures fasteners for the motorsport industry in the UK, as well as for Rolls Royce, and the European Space Agency. They made the custom 12 point M11 nuts that I’ll be using to hold the heads on my engine and that order turned out very well:

So over the last few months I’ve been working with them to manufacture more of the critical fasteners for the V12 engines, and I’ve sent them samples of the fasteners we use, which they’ve x-rayed and hardness tested to determine the material and treatment required. They’re now in a position to offer us a group buy for the following:

Rod bolts (Ferrari P/N: 158186)
These will be dimensionally identical with same threads, 12 pt heads, same shanks, etc. as the Grade 12.9 SPS rod bolts used in the Pankl Ti rods for the 355, 512, 550, and F50 engines, but they will be a higher grade aerospace steel (British Spec S99). The SPS bolts were tested and were found to be AISI 4140 steel, with hardness and tensile strength equivalent to British spec EN24. The new rod bolts will will meet or exceed British spec EN26.

These are fairly complex little bolts because they serve not only as fasteners, but as doweling devices for the Ti rods/caps in these cars. This is very critical to prevent shifting/fretting of the rod caps under load, and eventual failure of the rods. The later rod designs incorporated separate dowels in the rods, so the bolts were a simpler shank design, and much cheaper to manufacture. That’s why Ferrari charges over $100 per bolt for the early bolts, but less than $45 for the later design.

Here’s a pic of the early SPS bolt (from my engine) that we’re reproducing:

And a pic from the Ricambi website of the rod bolt for the later rods in the 575M/612, etc.:

Mains Studs (Ferrari P/N: 140553)
Again, these will be dimensionally identical and same threads, etc. to the mains studs used in the 456 & 550 engines, however a higher grade aerospace released material (British Spec S97). The OEM studs were tested and found to be AISI 4340 with hardness & tensile strength equivalent to British spec EN19. The new studs will be tested and certified for aerospace service and will meet or exceed British spec EN25.

Head Studs (Ferrari P/N: 140591)
Again, dimensionally identical, etc. to the OEM head studs used in the 456/550/575/612 engines, but with the same improved material specifications as the mains studs above.

General Points:

Steel is guaranteed to be British aerospace released stock.

Manufacturing will be done in an ISO 9001 certified facility

All threads will be rolled, not cut.

No plating, as these fasteners will be Class 10.9 and 12.9 tensile strength, and it’s better/safer not to plate to avoid any possibility of hydrogen embrittlement and eventual failure of the fastener.

Prices in the table below are for the quantities shown (number of fasteners necessary for an engine), and the table reflects the quantity discounts available for 1 through 4 engines. No further discounts are available for more than 4 engines. Prices do not include transatlantic freight from the supplier, nor onward freight from my place in TX to your destination. Sorry for the tiny size of the image, but if you'll click on it, it should open in a separate window and be more readable:

Delivery will be in 8-10 weeks after I place the order.

As you can see, the prices are VERY attractive on the rod bolts. This supplier makes a similar bolt for Rolls Royce for their gas turbines, and in 20 years they’ve not had a single fastener failure. They’re also a supplier to the European Space Agency, so they’re no strangers to the world of high spec fasteners.

Although the studs are somewhat higher priced than Ferrari’s, they’re also going to be much better quality. Back in 2013 I mentioned how disappointed I was with the quality of the Ferrari head studs, and in fact my thread checking gauge wouldn’t even thread onto the block side of a brand new stud – that’s how poorly made the threads were. The step from the 12mm shank to the 11mm side was poorly done too.

I plan to run this group buy until the end of March, take payments on March 31st, and order whatever quantities we’ve accumulated by then. Initially I'll take payments only for the cost of the hardware, then after I've received the order in bulk, and have split it up for each buyer, I'll send you a PayPal invoice for the additional freight. Sorry, but I have no way of knowing in advance how much that will be. Steel is heavy, and they'll be crossing the Atlantic......

Additionally, my engine will be the acid test for these fasteners, as it will be broken in on an engine dyno here in Houston, hopefully this summer or fall, so we'll be able to see how well these fasteners perform. I fully intend to give it a good thrashing on the dyno, as I want to find/eliminate any issues with it there, rather than after it's back in my car.

Obviously, I have a selfish motive here to gain a greater discount on the fasteners for my own engine build by purchasing in quantity, and in the process, others can benefit as well.

Keep in mind that while Ferrari doesn't specifically state to change these fasteners during a rebuild of the 550 engine, it's good practice to do so, especially the rod bolts. But don't take my word for it, check with any good engine builder.

BTW, you don’t have to order all three types of fasteners. If you only want a set of rod bolts, that’s OK.

I don’t plan on stocking or selling these in the future, so this is a one time opportunity.

Questions? Fire away

'99 550, Rosso Corsa / Nero, S/N:114654, Assy: 31836, Engine: 52084

High mileage, low compression, and missing on a few cylinders.....just like my cars.

Maranello Skunkworks Team Member

Last edited by cribbj; 03-02-2015 at 06:12 AM.
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post #2 of 2 Old 03-06-2015, 05:31 AM Thread Starter
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I'm closing the group buy as there's been no questions or interest shown in it.

'99 550, Rosso Corsa / Nero, S/N:114654, Assy: 31836, Engine: 52084

High mileage, low compression, and missing on a few cylinders.....just like my cars.

Maranello Skunkworks Team Member
cribbj is offline  

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