Advantages/Disadvantages Of A Titanium Crankshaft and Camshaft

[nicholastanguma]

Advanced Materials Technology is a metallurgical development company in Germany; they say they've developed some proprietary titanium alloys that are suitable for engine components such crankshafts and camshafts. Various deep-pocketed racing teams and manufacturers of high spec engines from Porsche to Yamaha have been using ti valvetrains and/or connecting rods for years, but ti's poor modulus of elasticity and propensity for galling and like problems have precluded its use for larger items such as cranks and cams.

Okay, throw out the usual complaints of massive cost and difficulty in machining usually associated with titanium, I'm not interested in rehashing those old issues. Instead, let's assume AMT's ti alloys are indeed suitable for crankshafts and camshafts. What would the advantages/disadvantages be?

Obviously lower parasitic power losses due to the extremely light weight is a big plus, buuuut...doesn't the crankshaft also help dampen an engine's vibrations and "create" torque in tandem with the flywheel? I'm assuming if the engine were equipped with a counterbalancer then perhaps the astoundingly lightweight crank wouldn't need to play such a big role in damping vibration, but am I wrong?

 

[Deleted member 9101]

Well...combine a TI crank with a flat plane design and you'd have one fast reving motor.

As for the rest... Who knows... Modern engines produce far less vibrations than older ones and they do it with lighter weight components.

 

[NatersXJ6]

Disadvantage: Cost and associated fear of failure factor with ultra high tech in the backcountry or 3rd world.

Huge Advantage: Win every argument with the spork people.

Them: “Titanium is the best and sporks are the best and you suck without one you pre Victorian troglodyte caveman still eating with TWO separate pieces of stainless steel! That is why your rig is overweight... spork, spork, sporky, spork...”

You: “Come talk to me when you get a titanium crankshaft you poser!”

 

[javajoe79]

Considering the cost of TI parts that already exist, I can't imagine any benefit that they offer being worthwhile for what we do.

 

[rayra]

lower the rotating mass, increase the HP.
But I doubt it's a good idea for a high HP internal combustion motor. The galling thing would be a real bummer, since all those moving parts have bearing surfaces involved.

 

[nitro_rat]

Titanium has a finite number for cycles that it can handle before it cracks. You could measure crank life by tracking RPM's over time. Yep, an new $10,000 crank every 10 hours sounds great...

 

[Hoooogan]

For anything other than a racing vehicle, it's unnecessary and would hinder performance in a daily driver or expedition vehicle. The closest comparison would be swapping to an aluminum flywheel. It'll rev up quick for spirited runs, but you want weight to help maintain momentum (torque) while cruising. I had an aluminum flywheel on my old 99 Tacoma that I turboed and the swap was night and day difference. She was quick, but starting required more feathering and throttle input. She also could not spin on the 3rd gear shift like it could with the stock flywheel. I eventually went back to the stock flywheel because it was more fun and practical.

 

[85_Ranger4x4]

I'm assuming if the engine were equipped with a counterbalancer then perhaps the astoundingly lightweight crank wouldn't need to play such a big role in damping vibration, but am I wrong?

Most remotely modern car engines already have harmonic balancers. And yes, cast iron is good at eating vibration too.

 

[CampStewart]

On the fence if titanium should go in the engine of an overland vehicle or if it should be designed to construct a pulpal, traction mats, or rotoplax style fuel tanks. So many applications for titanium and so few people filling the void.

 

[nicholastanguma]

For anything other than a racing vehicle, it's unnecessary and would hinder performance in a daily driver or expedition vehicle. The closest comparison would be swapping to an aluminum flywheel. It'll rev up quick for spirited runs, but you want weight to help maintain momentum (torque) while cruising. I had an aluminum flywheel on my old 99 Tacoma that I turboed and the swap was night and day difference. She was quick, but starting required more feathering and throttle input. She also could not spin on the 3rd gear shift like it could with the stock flywheel. I eventually went back to the stock flywheel because it was more fun and practical.

Genuinely helpful, thanks. ?

 

[obchristo]

Disadvantage: Cost and associated fear of failure factor with ultra high tech in the backcountry or 3rd world.

Huge Advantage: Win every argument with the spork people.

Them: “Titanium is the best and sporks are the best and you suck without one you pre Victorian troglodyte caveman still eating with TWO separate pieces of stainless steel! That is why your rig is overweight... spork, spork, sporky, spork...”

You: “Come talk to me when you get a titanium crankshaft you poser!”

 

[b dkw1]

lower the rotating mass, increase the HP.
But I doubt it's a good idea for a high HP internal combustion motor. The galling thing would be a real bummer, since all those moving parts have bearing surfaces involved.

The galling isn't an issue unless you loose oil pressure. At that point your bearings are going also so it really isn't a big deal if the crank bearing surfaces gall too. Nitriding the crank would stop this, but would make it just that much more expensive.

 

[broncobowsher]

GM has a production engine (LS7?) that has factory titanium connecting rods.
I have heard rumors of a competition motorcycle that had a crankshaft made of Tungsten at one time. Lighter isn't always the direction you want to go.
There was once a company making aftermarket magnesium pistons for a small block chevy, that is one engine you don't want to run lean.
As for galling a titanium crank, not really an issue. Just have the journals hard chromed. If it is good enough for rebuilding turbine engines it better be good enough for a crankshaft. Puts a hard non-galling layer down.
bout 5 years ago I got to hold the cutist short stroke crankshaft. For a 20,000 RPM F1 engine. The crank isn't balanced by drilling holes in it, they bolt different counterweights on. The only crank that I ever saw with bolt on counterweights.

 

[nicholastanguma]

GM has a production engine (LS7?) that has factory titanium connecting rods.

LS7, yes.

 

[MatttheHatt]

Titanium has a finite number for cycles that it can handle before it cracks. You could measure crank life by tracking RPM's over time. Yep, an new $10,000 crank every 10 hours sounds great...

Only when push past its elasticity limits, stay under and like steel the number of cycles is nearly infinite.

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