Anyone using titanium engine parts??

[Jim Nielsen]

I have used for retainers and connecting rods. Had a 1452cc Suzuki GSXR motor. With the Cosworth superlight pistons and ti rods the reciprocating mass was like that of a 600cc bike. Tremendous throttle response. Had to be careful closing the throttle also as it would lock the rear wheel.
I would think that an aluminum flywheel and aluminum harmonic balancer would be a much cheaper way of cutting rotating mass. Another big way to reduce rotation weight is go to a multidisk clutch. The clutch diameter is usually very small and you can swiss cheeze the flywheel our to the starter ring gear as all it does is hold ring gear for starting. I did this to my Off Road racer and throttle responce was excellent.

Jim

 

[Doug S.]

More info, please, Cliff

Interestingly, titanium is pretty malleable and quite resistent to shattering unlike some of the really hard steel out there.

Cliff, would you mind expanding on this part of your answer? My concern regarding Ti relates to it's tendency to flex and rebound. The Ti used in bicycle frames, my only exposure to Ti, is pretty thin, and obviously, the type of automotive parts we are discussing here are going to be of much thicker material. I am just wondering if, for example, a con rod would flex at the instant of combusion, and even if it did would it matter due to it's tendency to rebound to it's original shape. I notice I do not see Ti used for push rods or rocker arms, applications in which I would suspect it's light weight would be very welcome. I've seen Ti valve springs mentioned and that surprises me b/c I speculated that Ti isn't used in applications where it might be under constant pressure (i.e.--pushrods and rocker arms), but then again it is used for valve springs. Perhaps the very tendency to return to it's intended shape would make it an ideal valve spring material--I know Ti bycycle frames tend to "oscillate" when landed from a sick air move, and they don't damp very quickly. It can be very unnerving!

What is your feeling about this issue? Imagine the harmonics 8 Ti con rods, all flexing and oscillating at the impulse created by the combustion event, could induce in the rotating assembly IF that were a real problem, or the problems in valve timing created by the push rod flexing--IF it were a problem.

Do you think it's a problem?

So many contradictions, so many Q's..........

Thanks for sharing your knowledge!

Doug

 

[Sandy]

Found this link about springs -

http://www.coilspring.com/performance/why_titanium/ti_vs_steel.html

Interesting, but looks a little sales-e.

Still looking to learn a bit more as well.

[EDIT]

This is the thread that I found and had read a long while ago, lots of good info, but quotes like -

"You need to keep in mind that the strong Ti alloys are ~75% of the strength as high strength steel, but only half the weight."

Other info like galling, and the high degree of notch sensitivity.

http://www.eng-tips.com/viewthread.cfm?qid=90426

Sandy

 

[CliffBeer]

Cliff, would you mind expanding on this part of your answer? My concern regarding Ti relates to it's tendency to flex and rebound. The Ti used in bicycle frames, my only exposure to Ti, is pretty thin, and obviously, the type of automotive parts we are discussing here are going to be of much thicker material. I am just wondering if, for example, a con rod would flex at the instant of combusion, and even if it did would it matter due to it's tendency to rebound to it's original shape. I notice I do not see Ti used for push rods or rocker arms, applications in which I would suspect it's light weight would be very welcome. I've seen Ti valve springs mentioned and that surprises me b/c I speculated that Ti isn't used in applications where it might be under constant pressure (i.e.--pushrods and rocker arms), but then again it is used for valve springs. Perhaps the very tendency to return to it's intended shape would make it an ideal valve spring material--I know Ti bycycle frames tend to "oscillate" when landed from a sick air move, and they don't damp very quickly. It can be very unnerving!

What is your feeling about this issue? Imagine the harmonics 8 Ti con rods, all flexing and oscillating at the impulse created by the combustion event, could induce in the rotating assembly IF that were a real problem, or the problems in valve timing created by the push rod flexing--IF it were a problem.

Do you think it's a problem?

So many contradictions, so many Q's..........

Thanks for sharing your knowledge!

Doug

Doug, while Ti is quite malleable and resistent to shatter, it definitely is not so much so that it would flex or compress incompatibly on a firing stroke. In other words, it's plenty tough to resist constant beating without deforming. This would be in contrast to say aluminum which weighs even less by volume but can't take a constant beating without deforming (hence, no aluminum con rods and the like). You can't go wrong with high quality Ti con rods properly sized and fitted for the application.

I would think that Ti is pretty good for push rods. As for rocker arms, it seems that aluminum in the proper grade, dimension and shape works OK and at much less cost than Ti so hence not a lot of Ti rocker arms out there. In other words, an aluminum rocker arm can be made to be stiff enough and strong enough to effectively resist deformation just because of the dimensional freedom provided by the room under the valve covers.

Hope the above is helpful.

 

[Doug S.]

Thanks!

I appreciate your comments, Cliff. One of the things that sold me on the Ti bicycle frames was a display, not suprisingly right next to the Ti frames, that held 2 small rectangles of metal--one Chromoly and the other Ti. The suggestion was to bend each piece and see what happened. The Chromoly bent and stayed bent, whereas the Ti was like spring steel--it always returned to it's original straight form. Deformation doesn't seem to be an issue with Ti!

I notice Alex (I think???) posted a photo of his $4k broken oil pump drive. I used one just like it with better luck, but how about twisting? Do you think Ti would tolerate twisting forces as well? I can see it might not be financially advisable to use Ti for this application, until you look at the $$ damage done to Alex's motor, then it might make sense. Nothing is bulletproof, but closer is better in this case, IMHO.

I'll check for Ti push rods, but your explanation of the preference for alum for rocker arms from a financial standpoint makes sense, too. The only alum rocker arm failure I've witnessed was the bearing, not the arm. This issue of reliability and longevity are very important to me--I don't want to have to build this engine more than once, but I want it to wind high and last a long time, so I'm willing to put my $$ where it needs to be.

Doug

 

[CliffBeer]

I appreciate your comments, Cliff. One of the things that sold me on the Ti bicycle frames was a display, not suprisingly right next to the Ti frames, that held 2 small rectangles of metal--one Chromoly and the other Ti. The suggestion was to bend each piece and see what happened. The Chromoly bent and stayed bent, whereas the Ti was like spring steel--it always returned to it's original straight form. Deformation doesn't seem to be an issue with Ti!

I notice Alex (I think???) posted a photo of his $4k broken oil pump drive. I used one just like it with better luck, but how about twisting? Do you think Ti would tolerate twisting forces as well? I can see it might not be financially advisable to use Ti for this application, until you look at the $$ damage done to Alex's motor, then it might make sense. Nothing is bulletproof, but closer is better in this case, IMHO.

I'll check for Ti push rods, but your explanation of the preference for alum for rocker arms from a financial standpoint makes sense, too. The only alum rocker arm failure I've witnessed was the bearing, not the arm. This issue of reliability and longevity are very important to me--I don't want to have to build this engine more than once, but I want it to wind high and last a long time, so I'm willing to put my $$ where it needs to be.

Doug

Doug, I think most grades of Ti would be as resistent to rotational/twisting forces as good steel. Provided the dimensioning and shape/size is sufficient for the application then Ti should be just fine.

If you really want to make this engine capable of high rpm then stiffer springs and a not-too-radical cam is the way to go. Keep in mind, stiffer springs will wear the cam lobes and rocker lobes faster - just the price of a high revving engine.

 

[Sandy]

Doug -

Did some poking around in some of the materials tables and Alumininum looks to be lighter then Ti (for given volume) might be the reason you don't see it being used on the rocker arms (besides the cost). This would be a great question for the likes of Jessel or the folks at T&D who make the bulk of the Nascar valve trains. (I think they use 2024, and I have a set that someone made with 7075 that were in the pic of the broken shaft rocker). Still makes me wonder why not Ti too...

When I bought some pushrods a while ago from Manton (They just make pushrods), the guy told me that the most gain from saving weight is on the valve side of the fulcrum, pushrods, lifters and half the rocker don't make a huge difference acording to him.

Very interesting stuff, and Cliff thanks for the Ti info as well.

Sandy

 

[Doug S.]

Great info, Sandy!!

Found this link about springs -

http://www.coilspring.com/performance/why_titanium/ti_vs_steel.html

[EDIT]

This is the thread that I found and had read a long while ago, lots of good info, but quotes like -

"You need to keep in mind that the strong Ti alloys are ~75% of the strength as high strength steel, but only half the weight."

Other info like galling, and the high degree of notch sensitivity.

http://www.eng-tips.com/viewthread.cfm?qid=90426

Sandy

Thanks, Sandy. I'm not sure how I missed your earlier post, but I did surf into the two websites you provided and I found the information in the eng-tips website extremely enlightening. Those guys are at the heart of the matter regarding the issues brought up by this thread. Thank you very much for forwarding that information on.

As it stands now I think I may consider using Ti for the con rods, but if there is a good forged steel H-beam alternative I'll certainly consider using it. The SBC Ti rod in the eBay link weighed in at under 500 grams, but I suspect Carillo or someone else out there might make a good forged steel H-Beam con rod at probably close to the same weight. One of the issues that came to mind is balancing--if one needs to remove weight from one or more rods in a set to equalize their weights, would one be able to do that on a Ti rod given Ti's problems with machining? If it were possible, I don't think I would mind spending the price differential for Ti, as I want this to be a one time build with longevity in mind. Like I said, so many contradictions and so many Q's.

There will certainly be Ti in the valvetrain--valves, springs, and retainers at least, as you stated that the greatest advantage is obtained on the valve side of the rocker fulcrum. I suspect that weight for weight, given the way rocker arms are constructed, Ti might just flex more than Al. Ti's lack of rigidity might just be the reason Ti doesn't seem to be used for rocker arms (??). I have an Al framed bicycle, a Cannondale, that uses large tube, thin aluminum. It is brutal on a bumpy road--everything the tire runs over is transmitted to the seat and on to the anatomy. The Ti framed bike, however, is very comfortable b/c it is not nearly as rigid as the Cannondale. The Ti frame is marginally lighter--the aluminum used on the Cannondale must be only slightly thicker than that used for a beer or soda can! I also have a Cadex carbon fibre frame and it combines many of the advantages of both materials. I've been waiting to hear about carbon fibre push rods, etc, but haven't heard much--that's another thread altogether, though.

Cliff has convinced me that Ti might be useful in other applications, but I doubt that the difference in performance for, say an oil pump drive, would justify the cost, particularly since steel works as well as it appears to. I wonder if Alex's catastrophic failure was related to some issue other than just the oil pump drive. My FRPP oil pump drive looked brand new when I pulled the motor down after only about 10K miles, as I would have expected. I notice Ti has been used for CV shafts, so it can be made strong in tubular form and must not need to be "solid" in order for it's benefits to be realized.

Oh, and I really liked jneilsen's suggestion about using a dual disc clutch and swiss cheesing the flywheel. The more I read about dual disc clutches the more impressed I am, and with their smaller diameter I can see that a whole lot of weight could be removed from a flywheel by a competent machinist--this might result in a flywheel with the light weight of aluminum and the strength/wear resistance of steel. I suspect balance issues would arise, but that might be all the more reason to go with a zero balance system rather than a weighted flywheel.

Doug

 

[Sandy]

Doug -

The Eng-tips site is really interesting. Some good conversations on many odd things like the H-Beam vs I-Beam and the X-Beam (pauter) rods.

My first good bike was a Carbon Fiber road bike (Alan Record Carbinio) and it was a good light but flexible frame. I remember many times in the sprints of the end of rides having the bottom bracket flex so bad that it would shift out of gear. I moved to a steel framed after riding my brothers Pinarello and could not believe how much more power I could get the the ground (so to speak). The Carbon was a great cruzier, but the steel was so much more rigid. Another friend had the old Vitus aluminum framed bike and it was way to flexible, never tried the Cannondales, but they would be my first choice for a reasonable lite an stiff frame. I have to get off my fat a$$ and do some biking now. Having it stiff vs. light, I think I'll take a bit of extra weight and keep it stiff (that sounds odd now)

Should we bring beryllium info the mix

Sandy

 

[Doug S.]

The more the merrier?

Doug -Should we bring beryllium info the mix Sandy

Or boron? I had a boron fishing rod once that brought up a huge Jack Crevalle from about 60 feet down. None of the deck hands on board thought that rod had a snowball's chance in h..l of getting that fish up. I suspect Beryllium has many metallurgical properties that might make it valuable in our pursuit, and as a fiber of interest so would Boron. My friend uses a muffler with a carbon fibre shell on his road racing motorcycle to reduce weight so I know they can stand heat as well as stress.

Off topic, but still somewhat germane to the issue--I built one of my ex-wives a bike using an Italian DeBernardi butted steel frame. She was not powerful enough to stress the capabilities of the bike, but even so the frame construction is a gorgeous work of art and even if it never gets ridden again I'm going to keep it. It's too pretty to part with! Those Italians sure know how to combine function with art, don't they?

Doug

 

[Sandy]

Yes, the Italian bikes are fine pieces of art!

The interesting thing I was on a VW site looking for some remote resivors and saw an engine parts listing for Aluminum Pushrods??? Don't know much about VW's but seems like they used them or were for some other part not really a valve push rod.

Sandy

 

[Nathan]

Built a honda engine using titanium retainers. Great for reving up to 10k rpms. Rev limter set at 8500. Motor is still in my daily driver after 30k miles and my daily abuse.


Didn't built my porsche motor but I think some parts are titamiun as well. Can't beleive a 33 year old motor revs to 8000 without complaint.

V8s are new to me but I am trying to learn. Gonna meet with an engine builder in 2 weeks. Hope it goes well. Still I got to admit the idea of a motor redlining at 5500 sounds so odd to me.

 

[Paul Thompson 'Hooligan']

Welcome aboard Nathan...

Talking V8s, not all are limited to 5500rpm many of the forum members run motors regularly to 7000 or even 8000rpm....

Put the right bits in the right places correctly and she'll scream with the best of them

 

[Sammie]

[/QUOTE]

I keep thinking of the Nascar folks running well into the 9k mark with a nice steel rod.

And someone else might be able to answer this, but for the same given size of steel is Titanium as strong? For example if 2 rods were the same exact sizes would the Ti rod be stronger or the Steel? I'm guessing the steel will be stronger but heavier, but don't know for sure.

Sandy[/QUOTE]
I'm not an engineer....but I've thought that the strength of a connecting rod is due to it's *cross-sectional* design(I-beams,H-beams) rather than the material
they're made from.

 

[Sandy]

I'm guessing the strength of the rod has many attributes that contribute to it, one being material 300m, 4130, Ti , Alum, etc, finish, design, and one that is often over looked...rod bolts. (Not in any order for that matter). Look at the link in on of the posts above, I think eng-tips has a good discussion on Ti vs other materials on their list.

I think I would like a Ti set of rods, but deep down I know that the a nice set of billet ones will wind up being the better bet. As mentioned earlier the Z06 vett' motor has Ti rods, but I'm not sure all the reasons, might just be a cool marketing ploy from GM

Sandy

 

[Rick]

I once saw some Ti rods that were claimed to be from John Forces Funny Car, it was after some sort of R&D excercise. Recently at The Monterey historics one of the vendors had on display 2 conrods and attached pistons from one of Schumachers F1 car from a couple of years ago. The entire piston and rod wasn't much over 4 -4.5 inches tall, and it is cetainly made of some sort of unobtanium.

 

[Rick]

oooops

 

[Nathan]

Think a few others mentioned it already but after doing some reading it seems you need to be aware of titaniums wear factor when coming into contact with other parts. I have read of people having parts fail withing 20k miles because a valve spring wore a retainer down and such.