Anyone successfully using titanium rods?
 

Hello all, I guess I'm new to the board.

I thought I'd poll you offshore powerboat endurance racers about titanium connecting rods. I'm hearing totally conflicting things about them, such as they break, or they don't break, back and forth and so on. I'd sure like to be able to figure out if they are suitable or not for an endurance engine that is supercharged, with the rods capable of handling 1000HP (I expect 800-850 in reality, but prefer rods that will live with no undue fears). I'm guessing that perhaps titanium rod technology has advanced over the old days, just like aluminum rods, with better alloys, better manufacturing processes, and better heat-treat processes. But before spending a wad on ti-rods, I really need to hear from those who are using or have tried them.

So, anyone here successfully (or unsuccessfully) using titanium rods? If so, what engine application exactly? How long have you been using the same set? RPM they see? Other specs of the engine? Type fuel? Manufacturer of the rods? How about bearing wear or bearing life? Any other things that should be discussed?


Thanks.

Let me preface this to say that I have NO EXPERIENCE with titanium rods.

What I do know, however, is that pound for pound, titanium is hard to beat for strength. With that said, it is notable to recognize that a lot of popular titanium alloys do not have as good of a fatigue life as high-chrome steel alloys such as those used in hi-perf steel rods.

For a sprint motor, titanium can offer a lot in terms of balancing strength against reciprocating weight and its associated loading cycles. For an endurance motor, I am not sure of whether a connecting rod is the best application.

Remember, I have ZERO experience with Ti rods, so I am only offering something for you to discuss with your builder/parts suppliers.

** Hopefully, this thread can bring positive information to us all.

With a boat motor the weak link is in the valvetrain. Bottom ends built with good components are good for 7500 rpms for hours on end. However the big roller cams required to feed a big engine at these rs will kill lifters and springs. Why spend all that money on something you won't get any benefit from?

Application I'm considering them for is a supercharged engine that will not be taken apart all the time, hence aluminum rods are out of the question. Being supercharged, lift will be no more than .650-.670 maximum, and is a shaft-mount setup, so valvetrain probelms should not be an issue.

Keep the input coming, thanks.

You can exceed a 1000 hp easily on quality "of the shelf" 4340 rods all day long from someone like Oliver, Lunati etc.

That being said, I agree with partiyacht

DAVE

How about Titanium Valves??? Would they be suitable for the marine environment??? Will they last???

The strength of the steel rods wasn't the question, those are obviously stronger than aluminum rods. The problem with the steel rods is the weight that is being slung around being very hard on the bottom end of the engine at 7000 RPM (which is one main reason why drag engines use aluminum rods).

Since aluminum rods will not be a good choice in an engine that is not torn apart regularly, and because of the weight of stel rods being a negative factor in a blown engine at 7000 RPM, this is why I am investigating the titanium rods.

I just need to determine what people's experiences have been with titanium rods. I've heard conflicting things, and I suspect there are differences in alloys, manufacturing processes, and heat treats, just as with any steel and aluminum rod. Not all rods are equal in steel and aluminum, so I suspect titanium won't be much different. But I have heard of a few reports of cracked ti-rods, which makes me nervous about investing in them until I can get some input from those who use them successfully.

Anyone have experience with Oliver's forged titanium rods which are of a different alloy than the typical 6-4 and are forged instead of billet? Anyone know of any endurance marine racing engines using titanium rods, or have any references I can contact?

How many hours do you anticipate between teardowns?

oh lord here we go. Marc biult a air fo 1000 and ran for godknows how many hours...

wasn't it somehting ridiculous like 500 before a rebiuld?

I personally would like an engine to last 1000 hours between tear-downs if possible. I certainly would hate to have to replace a $3800 set of rods every 1000 hours, or even 500 hours. But will still easily consider titanium over steel if they will hold up for 1000+ hours.

I spoke with a tech person at Sonny's Racing Engines today and he told me they have been using Crower Ti-rods exclusively for 10-11 years with no reports of any failures at all. He said Sonny's uses the Ti-rods exclusively in their 800+CID IHRA Pro Stock mountain motors. These engines have 5-1/2 to 5-3/4 strokes, run 800-8300 RPM, and produce 1700 HP. He said those engines run 80-90 passes per year, and several have had the same set of rods for 4-5 years. They only use the best high-priced rod bolt option, and they do change out the rod bolts at about the 3 year mark. He also stated there were no problems whatsoever with bearing wear and bearing life. So that makes me think they would definitely be suitable for a blown gas engine running a 4" stroke, 7200 RPM and 1000 HP.

Except for two things:

1)Those IHRA pro stock engines are still drag engines, and the actual number of cycles on the rods are still low in comparison to an engine that is run for long periods of time such as in an endurance application, street application, or other non-drag applications.

2)He also stated that Sonny's does not use Ti-rods in NOS drag motors because of the severe shockload the rods receive on the launch of a NOS-assisted drag car. They use aluminum rods for those engines. Even still, he said there was a man in KY running a Sonny's ex-pro stock Ti-rod engine on NOS with no problems reported. Sonny's had no first-hand experience with supercharged engines, but did say that blown engines are easier on the bottom end at the launchpad in a drag car than NOS-assist since the RPM is not at max RPM and the blower is not yet being driven to its potential until a little later.

So, I'm still trying to nail it all down as to whether a high-quality Ti-rod will be suitable for a 1000HP blown gas engine that will be run for hours before being torn down, unlike drag-only engines. Any further input as to experiences of Ti-rods is still greatly appreciated, thanks.

I have personally used Carrillo Rods without a component related (or cycle test) failure since 1969 in Trans Am, Can Am, circle track, and marine applications. Here is a tech paper regarding their approach to reciprocating mass and connecting rods. I do not believe there is any advantage (or disadvantage) to be gained by the use of Ti in this application.
http://www.carrilloind.com/tech_archives5.html
Ti is much more relevant where acceleration is at a premium, which is not the case here.
Hope this helps,
Bob

Don't take this wrong, but do the math.

90 x 5 x 8 seconds = 1 hour

To me that is just barely off the dyno.

As pointed out by Patriyacht, the limiting factor to longevity is the valve train. It might very well be that titanium rods would work great, but what is the real benefit? As Bob pointed out acceleration is not an issue. Better to put some $$ aside for a lifter (roller) change every 50 - 75 hours and springs every other set of lifters. This assumes that you spend most of your time cruising at part throttle. Even though if 850 HP is your target a good set of heads and a flat hydraulic cam will do the job and last much longer. With a good pan, oil system and conventional premium components the bottom end should be OK for 400 hrs no problem.

I will add that I do not personally have any experience with ti rods.

Puder yu ready tp move south yet?

A 1000hp blown bigblock will NOT need to turn 7200 rpm. No reason to spin it that hard.

You'll see 1000hp at less than 6500rpm, and if you are running an optimized parts combination, you can see 1000hp on a 550" motor at less than 6000rpm and less than 9 pounds of boost.

You seem to be concerned about the life of the rods/bottom end, but you are going to run it silly by spinning it at 7200?

You have mentioned that you want input from marine sources, but haven't said whether this is a marine application. If you are talking about an automotive application with 7200 rpm shift points, then that makes far more sense than a marine application with a WOT rpm of 7200.

Just trying to understand..

exshaust valves and roller tappets also valve springs are your weakness in motors>

Thanks to all who have offered input so far.

Mcollinstin, your hunch is correct, and is why I have been hesitant to say exactly what the application is, since this is a marine board. The application I am considering them for is indeed an automotive application. It is a street-strip drag application in a '40-Ford. Since aluminum rods are not really suitable for street due to low cycle life (though they can handle thousands of horsepower), they would not be a good choice. I expect to place 2000 hard miles on the engine annually and because of that type of use as well as the fact that the engine will be run in drags, I am trying to research Ti-rods to see if they will hold up to long cycle lifes. The weight savings of Ti rods over steel rods should be obvious in any engine used for acceleration as well as any engine that has a little weaker main webbing. I figured there would certainly have been some offshore powerboats that have used the Ti-rods, either successfully or unsuccessfully that could give me input from actual experience with those. Anybody here?

Sounds like your in the oldies type drag racing. There is a co. called Good vibrations in Ca. They do a lot of blown nostalgia stuff. There in National dragster. also try Marv at The Blower Shop. He's up on the blower stuff.
We ran some Tit rods in a mud drag truck for a while . motor was real strong and raped quick .ran it about 3 years and a rod let go Or could of been the bolts.we where turning it 8800 though.:DChanged to the steel crower rod then.

Depends on which crank you go with . The tit rods are pretty lite. We were at daytona for Industry week .before the daytona 500 and one of the Manuf .had a Titanium crank . Nascar outlawed it not cost effective $10.000 was the estimated price WD. bet it wound up in the Sprint Cars World of out outlaws .Could you imagine a little sbc 400 something ci with a 25 lbs crank.
Crower is what we run ,they are usually higher that everybody . They have a light weight bill-it 4340 rod that might be something to consider or the maxi lite or just call the crower tech line you can ask for Dave Crower himself .Have your ducks inarow ,he's short with ya on the phone

http://crower.com/pdf/173.pdf

http://crower.com/misc/m_cat.shtml

I use to run theCrower 6 inch 4340 small block mid weight billet rod and put 13000 street miles and a bunch of NOS passes. the 358 dynoed at 540 hp on pump gas and we went as high as 475 hp of nitrous on it . The Crower rods and crank held up great . the bearings were always very good , even on detonation and burning pistons they never showed any flexing that would show up on the bearings.
For the price of the tit rods you can get 3 sets of the steel ones ,That is at the jobber price .

in an automotive engien i'd think 1000hp shodul eb way easier. No worries abotu reversion and finiky low speed perforamcne spo you can run radical cams PLUS you can run way more oost becasue you aren;t running at 5000rpm for 45 minutes.

sombody wa stellign me the otehr day in a some kind of alchohal dragster they are runnign liek 46psi of boost. and making over 2000hp. SOmthing relaly silly granted that engien gest rebiult pretty often but still.

Olds,

I do understand your figures better, now that I see they aren't marine figures.

Furthermore, if we are talking about OLDS motors, then your weak block issues can be partially offset by going with a custom crank with LOTS of mallory metal in it for a good internal balance. This does a better job of offsetting the balance issue AT THE SOURCE rather than on the ends. This spares a lot of the cyclic loading on the block itself. And that crank and a set of polished billet steel rods will cost a bunch less than Ti rods.

Not trying to talk you out of anything, just hate to see you trash a good block by running exotic parts beyond their fatigue cycle limits..

Titanium Valves???
 

Has anyone used these in a marine motor and do they have benefits???

Lighter valves ALWAYS will offer benefits, but ion the case of a BB Chevy, the other valvetrain components (lifters, pushrods, rockers) carry a significant amount of mass which must be controlled. Overhead Cam motors obviously benefit the most from valve mass reduction and see huge benefits from unltra light valves (they can run lighter springs due to the light valves and that helps too).

It's always a cost issue. If you could mfr the entire valvetrain out of ultralight components then you'd be really doing something, but you gotta balance it with the pocketbook.

I ran the Del West Titaniums in Pontiac heads with 9.0:1 and had some problems with exhausts. Del West advised not to use them on the exhuast due to the hotter burn of the lower compression. Left the intakes in and changed the exhaust to the Ferra Super Alloys and life was good.

I'd also be interested in knowing about the titanium rods. Anyone else know anything?

Ti rods work to a point. They are strong and light, but have a finite life cycle.
Unlike aluminum rods, which will stretch during use and can be measured to predict the life cycle, Ti rods will not stretch, but will become brittle over time. this is difficult if not impossible to measure.
Usually your only idea that a ti rod is beyond it's limits is when it is sticking through the side of the block.
Therefore, you must wiegh other's experience and your best guess to determine replacement time.
In hours and hours upon more hours of dyno time, Pro Stock builders do not find a significant performance (ie-accelaration) advantage with Ti rods. They do last twice as long as aluminum, but are twice the price.
The above is on 500" motors. For IHRA stuff (813ci) the strength of Ti rods on such a long stroke, high RPM motor justifies Ti rods.
In a street application, Ti rods would last a long time I would think.

Now, Ti valve springs....that's another story. They are junk. They never get weak, but they break without losing seat pressure, once again, very unpredictable.

Ti valves, I have no idea in a marine environment. They are the ONLY valves used in high rpm race appications.

500 ci, 9800 RPM, Many, many laps, and never had a valve failure.