Well, I guess I'll find out whether they work on the street maybe late this year. I'm putting my "Nascar" heads on the 4.3 V6 AS-IS. Ti valves, and with the stock seats (changing to lighter springs for my street cam, however). AdioSS correctly points out these things have some THIN valve seats vs. a typical street head. Valve margins are not all that different, though. The heads I have use stock 11/32" valve stems on the valves (with some sort of alien high-tech friction coating on the stems).

Just to give you weekend warriors (like me) an idea how much lighter stuff like this is than typical steel parts check this out.....

Stock steel 1.94 intake valve: 108g
Titanium 2.08 race valve: 83g

Steel 1.45" reatiner: 32g
Titanium 1.55" retainer: 18g

Total difference: 39g and it's not even a fair comparison, obviously. That's like taking the weight of a small child out of your valvetrain!

Oh, this is gonna be fun! Even if it doesn't last long.

 

I predict it will last 499 miles, and blow up on the last lap lol..

Dave C.

 

A few things in life are like that...

 

That "groove" you guys mention...... do you think that has anything to do with the valve being made from titanium?

Cause guess what... I've seen the same thing on SS valves. Kinda looks like someone put a chamfer on the edge of the lock groove. It's caused by valve bounce. Not just something that happens to a valve because it happens to be made from titanium. Use a bead lock and find a better valvespring.

I've run titanium valves in many different applications... both street and strip... and my moderate running strip cars (marginally streetable and worth mentioning for this discussion) would run on a set of ti valves for 2-3 seasons with very little evidence of wear. Based on my experiences, I don't get where some of you are coming from.

I'd guess that there were other issues like poor seat concentricity, excessive guide wear, valve bounce, etc.. 99.9% of the time, I think the baby gets thrown out with the bath water.

contactpatch,

Yes, you're correct. Copper is a better seat in regards to heat transfer. Imperative when running Ti but also suitable for SS valves.

"C3PO & R2D2"



I can believe that one a little better.

Either that, or Bret gave in to the dark side of the force and bought a FORD!

-Mindgame

 

I didn't think Nascar could use exotic metals?
Also I think most Ti valves have a Hardened steel tip above the locks where the roller rides. CAuse Ti cannot be hardened to the extreme like steel.

 

Titanium is not a durable material. It is used for its weight properties in motorsports, period. It will last a weekend of cup racing and then its discarded. Titanium makes for a good spring material. It deforms easily. Titanuim rods have a life roughly 3 times longer than aluminum, way less than steel rods. Titanium retainers show wear after a good year of street driving. Titanium valves will have a seat indentation after some time of prolonged use. If you're set on buying some, just get the intakes. A stainless exhaust valve will be roughly the same weight as the intakes. There is a reason why you don't see titanium push rods, they deflect way too much. This should give you some idea.You used to see titanium valvesprings in blown alchohol and prostock, but not anymore. They are only good for about 2-3 passes before some would break, especially alchohol and at $1800 for 16 better stuff was developed.

And by the way, all titanuim valves are two piece.

 

Not as durable as hardened steel and less weight... I agree.

On the NASCAR weekend thing... how many cycles does your typical cup valve see in a 500 mile race anyways?
Is it really fair to compare a cup engine to a street/strip engine?

Well, I think your 1st reason... the weight... hit home a little better. Reduced mass and inertia is bound to do nice things for a spring's natural frequency. Ti springs also don't need as tight a coiling to do their job... usually having a larger wire diameter and fewer coils. They aren't stressed to the same level as a steel spring and they tend to be more resistant to taking a set.

They have their place, although I'd agree that the street aint one of those places.

Where did you get this from?

I had more than 200 passes on a set of GRP's in my old top sportsman car. A lifter failure shut that one down. The rods went into a friends car and I think it ran a couple of seasons on them.


That's the slow side of the valvetrain... why would the use of Titanium make any sense where stiffness, not weight, was of most importance?

There are still plenty of guys running Ti valvesprings. Not that it really means much cause some are still running "Pink" rods too.

Either way, I know of one very successful Pro Mod car running titanium valvesprings to this day. Went to Manley NexTek springs for testing, then right back to Ti for all of last season.

Can you show me a 2 piece titanium valve?

Manley, Victory, Ferrea and Del West are all very popular and they're also 1 piece.

-Mindgame

 

Don't tell Honda and GM Ti rods and valves can't last. They may have to scrap the S2000 engine and the LS7. Oh heck, maybe they tested them for durability and found they could last.

A Cup engine turns over more than a million revs (1/2 mil valve actions) in a race weekend. 100,000 miles at an average speed of 40 mph and 2500 rpm is about 375 million revs or over 180 million valve actions. Even 50k miles is over 90 million valve actions.

Ti pushrods can work. A few series have banned them. When you are into 1/2 or 9/16 diameter double tapered pushrods at 10K, every few grams helps.

Hollow stem Ti valve must necessarily be multi-piece in order to gun drill the stem. Stem and head could be one piece though, which is probably what Mindgame meant.

FWIW, in addition to being light, Ti is pretty good at resisting heat also, and for a long time thru many heat cycles.

My $.02

 

GM also uses titanium for the pushrods and valve springs in the LS7.

 

I talked to Del-West before I assembled my last creation, and they told me there was no way to tell the life of ti valves. He said I could break a new one just as easy as my used cup ones. So he figured I'd be just as well off using what I had. Kinda sounded alot like any other metal out there. JFYI.

 

Indeed the limited production LS7 incorporates Ti intake valves as well as connecting rods. The jury will be out for a while on street durability.
My information on con rod life come directly from Crower and has been substantiated by a couple higher end engine builders that were customers of mine. Feel free to call Crower if you dispute the accuracy of my post.

Manley and Ferrea's Ti valves are indeed 2 piece. Call them too if you disagree. The heads are friction welded to the stems. I do not know why the material requires this to be so. This information comes from tech seminars I attended by both Manley and Ferrea. I can tell you that if you were to encounter valve float and touched a piston enough to slightly bend the valve the straghtening effect of the valve returning to its seat over and over would probably result in the head coming off. Obviously this is what you are trying to avoid by going to a Ti valve in the first place, but it should be noted. Ferrea displays its stainless valves at trade shows bent to look like a pretzel with no apparent damage to demonstate its toughness.

If pushrod side valvetrain weight weren't important there would be no such things as revkits and ceramic lifters. The absolute most important part of the valvetrain is to be as stiff and durable as possible, this is why Ti pushrods aren't considered. Even a 7/16 - 1/2" 4130 tapered pushrod on a tall deck IHRA prostock engine has enough flex to open up the head gasket holes and contact the block.

Ask any cylinder head shop that routinely sees Ti valves about valve seat wear on titanium (valve face). The margin can really get thin after some use. I have personally seen several examples as I had considered it for a project of mine myself.

I claim to be no expert on all aspects of performance, but I do back up my statements with my own real world professional experience/education and the experience of my customers. I do not make my tech up. If this board would rather I not share my information then I will remain silent but I refuse to be bashed in anonymity.

Mindgame: I have picked the pieces out of the cylinder heads of NHRA prostock, NHRA TAD, and IHRA promod titanium vavlesprings between rounds to replace them. The material has fairly high notch sensitivity and my feeling is that whoever is currenty winding them is unable to take the proper precautions to ensure long life. They also require the use of a teflon liner so they don't rub together.

 

Mark,

We're not trying to bash you here. Stick around and join in the fun!

Maybe what set some of us off are unsupported statements like:

Titanium is a very durable material. It is used extensively in jet engines, for which durabililty is a life/death matter. It has excellent fatigue resistance and is the strongest metal available in absolute strength per pound. It has an endurance limit approaching that of steel, unlike aluminum which has a very low endurance limit.

I suggest that Cup rotating or reciprocating parts are replaced after one race because they may be designed to last only that long (plus a safety factor) and because the teams cannot afford to chance having a part fail if replacing with an unused one is possible.

You are absolutely correct that stiffness is most critical in a valvetrain. The resistance to buckling of a tube in compression varies in direct proportion with the Young's Modulus (YM) of the material. That is the "elasticity" of the material or the proportionality coefficient between stress(load/area) and strain (deflection). Titanium has a YM of about 50% that of steel, any steel. Aluminum is about 33% of steel. Interestingly, the density of Titanium is about half that of steel and aluminum is about 1/3 that of steel.

So, you would think that you'd need twice as much titanium as steel to accomplish the same stiffness, so there would be no weight savings for a pushrod. Almost, but not quite.

A tube's resistance to buckling also depends more strongly on its wall thickness. As a result, a small increase in wall thickness makes up for a large reduction in YM. If we want to assign a number that reflects a particular tube material's sensitivity to buckling, we need to divide, not the Young's Modulus by the material's density, but rather the square root of the Young's Modulus by the density.

If the YM of steel is approx. 30 (million psi) and it's density is approx .30 (lb/cubic inch)and titanium's YM is approx. 15 and it's density .15, dividing (sqr rt 30) by .3 = 18.26 and (sqr rt 15) by .15 = 25.82 or about 40% stiffer for the titanium tube based on weight.

(See Race Car Chassis Design and Construction by Forbes Aird, Race Car Engineering and Mechanics by Paul Van Valkenburgh and Engineer To Win by Carroll Smith. All are very understandable non-texbook style presentations.)

You might not understand what kind of durability testing OEMs subject any production engine to. Ask some OEM engineers who post here. It's been a long while since I was personally involved, but I am assured that durability testing today is as least as rigorous, and most often more rigorous than in years past. While it's true that some customers find ways to operate their engines that even the very insidious test engineers didn't envision, I don't believe that you, or me, the potential customers for an LS7, will be the beta testers.

Again, not trying to bust your chops (all evidence to the contrary ), but you need to support your claims.

Stay around, please.


Jon

 

Ive got to chime in on this with my slightly offtopic[as usual] two cents.
-NASA's X-15, all time speed and altitude records for manned flight[still standing] of Mach 6.72[4,534mph] and 354,200 ft.Titanium/inconel-x intensive construction.
-Lockheed SR71 Blackbird,manned production aircraft records, speed and level altitude flight, 2,193.167mph and 85,068.997ft,respectively.
Titanium intensive construction.

FWIW,I dont think you, markinck69, should leave this forum.I only registered a couple mos. ago but have been following ad. tech for over a year and the reason the discussions are so interesting and involved is because there are so many opinions and information from members who are sharing their own experience..Like a big tech bench race session,you take what you want from it,leave what you dont,and maybe get an insight or approach to a problem you hadnt thought of, or information you didnt have before.

 

Looks to me like this has become a moot point.

If I were to take anything from this post it would be from Jon (oldstroker) being a metallurgist and all, not to mention ME. Sounds like Mindgame has experience with them, but all the experiences have been different between who you talk to, so.....

 

First off.... Mark, welcome to the forum.

I didn't mean to dispense with all formalities but I am a too-the-point kinda guy and your statements just didn't/don't seem well founded to me. Like OS said earlier... you have to back these up with facts and I'm sorry, but I haven't seen many here.

Mark, there are still a number of Acura NSX's running around and they all came with Ti conecting rods. The Ferrari F40 is another, although most F40 owmers aren't members of the high mileage club.
Hey, if I can complete a 24 Hours of LeMans with a set of Ti connecting rods, why wouldn't they last 100,000+ miles in my street car?
If they are durable enough for GM's endurance tests, why are we saying they aren't durable enough?

Makes absolutely no sense to me that a company would forge a valve head, friction weld the stem to it, then build a webpage that states... "Forged one piece construction with grain flow
(Not a head welded to a stem.)"

http://www.manleyperformance.com/titvlvs.html

I'll ask Don Losito the next time I see him. The talks I've had on this issue all trace back to seat concentricity (#1) and controlling valve bounce (#2). The concentricity is a machining issue and from what I understand, many "good" heads aren't even very good in this area. The valve bounce is easier to control as the valve-side of the valvetrain gets lighter. Springs, retainers, valves... everything as a system.

The guys I know, who are using Ti valvesprings for instance, are using them because they have a higher resonating frequency. It's not that things get bad at some arbitrary rpm, then stay bad from there up... it's that there's a "bad spot" somewhere along the way. Titanium, may be the ticket to pushing that bad harmonic further up the rpm scale...... somewhere the engine will never reach.

You'll find that the same is true of the people on this forum. We all come here to share our experiences and once you look around a while you'll come to find that many of us aren't exactly new to this stuff. So welcome.. I hope you continue to contribute well founded facts to the forum.

-Mindgame