Let's talk short-stroke rods

[Henry Schmidt]

" Titanium bolts "
These are from a 935 rod but I'll bet they are the same as 917 and 962.

[Henry Schmidt]

Originally posted by garibaldi
The titanium rods definetely wont last. You can use them, but you will have to be pulling the motor apart often to check them, and most likely be throwing them out after a short period of time.

Titanium rods have a bad reputation for short life and failure. That said, it's my understanding that the special formula Titanium rods in Honda's V6 NSX have had little or no reliability issues. Not being a Honda tech, I have very little knowledge about this engine, but building a production car with ty rods takes some guts.

[911pcars]

According to my bible, Aird's "Racer's Encyclopedia of Metals, Fibers and Materials", Honda uses ti from scrap aerospace applications for their con rods. Pretty clever. recook it in a plasma furnace and it's still cheaper than new ti. They apply molybdenum or chromium nitrate onto the thrust faces by flame or plasma spray to reduce ti's propensity to gall. The Honda con rod is 3Al-2Fe alloy and weight savings of 30% over steel.

Furthermore:
The most common ti alloy for valves is 6Al-4Fe; same as used in many aerospace fasteners and used by Porsche for their ti con rods until it was replaced by 7Al-4Mo.

Race engine exhaust valves use 6Al-2Sn-4Zr-2Mo-0.08Si and more recently, 6Al-2Sn-4.0ZR-0.4Mo-0.4Si. Kinda rolls off the tongue, eh?

The Blackbird spy plane uses a ti alloy of 13V-11Cr-3Al.

Ti is very expensive, but the strange thing is that this is one of the most abundant raw materials on earth. It just takes expensive processes to manufacture, machine and weld it (currently).

Sherwood

[KobaltBlau]

Originally posted by Henry Schmidt
" Titanium bolts "
These are from a 935 rod but I'll bet they are the same as 917 and 962.

wow, I'm surprised titanium is appropriate for a rod bolt. That nut doesn't look it, but what do I know?

[Henry Schmidt]

Originally posted by KobaltBlau
................... That nut doesn't look it, but what do I know?

The nut doesn't look what?
These bolts are factory 935 titanium rod bolts. They thought this material is appropriate for a rod bolt. The nuts are stock 928 rod nuts.

[KobaltBlau]

The nut doesn't look titanium. But as you stated above (and I forgot) it's a 928 nut, so it would be steel. I'm not trying to argue with the factory, Henry, and I appreciate all the information you are providing. Thank you.

[KobaltBlau]

Henry, My apologies. Grady Clay and I took a bolt out of a 935 rod assembly today because I was curious. The bolt is definitely titanium (As Henry already told me a couple of times), and it was used with a smooth but beveled loose washer and 6pt nut, both in steel. Grady may post some photos if he wants to. Beautiful stuff, everything in the 935 rod assembly. The difference versus a 2.0 steel rod that Grady also had handy is staggering.

Best Regards,

[KobaltBlau]

I meant to say the difference in weight between the two rods. Grady posted a scan of the two rods I compared earlier on this thread.

[Grady Clay]

Guys,

Here is the rod hardware KobaltBlau and
I dissassembled yesterday.




The bolt is Titanium and appears just as Henry's.
The nut and washer are magnetic and I assume a steel alloy.

Jerry Woods assembled this rod for inspection.
It is defective from resonant chafing of the bearing back to the rod big end.
Jerry gave it to me as a souvineer since I drove the 935.

Titanium or steel, I won't reuse rod nuts and bolts
other than test measure or recondition rods.

Best,
Grady

[Henry Schmidt]

Originally posted by Grady Clay
Guys,

Titanium or steel, I won't reuse rod nuts and bolts
other than test measure or recondition rods.

Best,
Grady

I can respect that. I will not reuse stock bolts either. Please send me all your used ARP, Carrillo and 935 Titanium bolts. I will be happy to pay the shipping.
I look forward to receiving these types of bolts from any of you that feel the same way Grady does.