Titanium pushrods anyone?

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Norman_John
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Titanium pushrods anyone?

Post by Norman_John » Fri Aug 16, 2013 11:08 pm

Noticed these but didn't think to post them here.

Titanium = nice and light and very strong, but have the wrong thermal expansion rates for an alloy barrel...

http://www.ebay.co.uk/itm/321183386029? ... 1423.l2649

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steve m
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Re: Titanium pushrods anyone?

Post by steve m » Sat Aug 17, 2013 12:32 am

not being an engineer, i would like to know why you would keep the Ti rod diam. the same as the standard Al ones :?: anybody :?:

steve

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Re: Titanium pushrods anyone?

Post by skippy » Sat Aug 17, 2013 1:36 am

Interesting Steve the atomic weight of aluminium is 26.9 and titanium is 47.8 so to be lighter there would need to be a lot less titanium in the rod, but of course titanium is so much stronger it would work with the rod being hollow and thin.
Doug
Should never have sold them old motorbikes

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steve m
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Re: Titanium pushrods anyone?

Post by steve m » Sat Aug 17, 2013 3:38 am

aha, another person who frequents the periodic table :thumb
looking at the taper on the bottom end, these look to be similar diam. to the standard Al ones, and solid.
skippy wrote: but of course titanium is so much stronger it would work with the rod being hollow and thin.
therein lies the whole purpose of the exercise, i would have thought - they don't need to be anywhere near as thick, just somewhat stronger than the Al ones.
if the std. ones are approx. 3/8" then Ti ones could be approx. 7/32" for a similar strength - if we assume weight=strength( :?: ). i'm stopping now, my little brain is hurting.
i guess the standard ones are ok for most of us, but i wonder what Stan uses in his 12,000rpm B25 flattracker, or Redspanner uses in his B25 grasstracker. i don't think there is enough room in the tunnel for barreled aluminium ones.

steve

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Re: Titanium pushrods anyone?

Post by bill davidson » Mon Aug 19, 2013 9:50 pm

Titanium is the worst material you could use as a push rod it acts as giant spring and causes bad valve train harmonics
and will lower your max rpm potential and my cause possible valve train damage . chrome moly tube push rods are used in all high performance and racing push rod engines ,also never reduce the diameter of push rods for the same reasons mentioned above,just because there exotic and expensive will not make them any better for this application.


Hope that saves you a few quid regards Bill Davidson

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Re: Titanium pushrods anyone?

Post by RichieP » Mon Sep 30, 2013 8:27 pm

this thread makes me almost bring up the carbon pushrod idea (I've plenty of ultra-light 8mm rod, but never got round to doing anything with it.....yet)!

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Re: Titanium pushrods anyone?

Post by HPbyStan » Tue Oct 01, 2013 2:13 am

Titanium by itself is almost useless but when alloyed correctly can be used in many applications. One of the 1st posts would be my worry ( about the rate of expansion ) BUT, I haven't kept up on things the way I used to and that may have changed by now. Remember, there are NO facts, only the sum total of our current knowledge and when / if we get smarter the "facts" sometimes change. Heck, at one time intelligent people used Castrol "R" cutting oil as a lubricant and in my youth the world was supposed to be flat.

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Re: Titanium pushrods anyone?

Post by steve m » Tue Oct 01, 2013 8:23 am

:laugh :laugh :laugh
thanks Stan :thumb

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Re: Titanium pushrods anyone?

Post by denis » Wed Oct 23, 2013 5:06 am

bill davidson wrote:Titanium is the worst material you could use as a push rod it acts as giant spring and causes bad valve train harmonics
and will lower your max rpm potential and my cause possible valve train damage . chrome moly tube push rods are used in all high performance and racing push rod engines ,also never reduce the diameter of push rods for the same reasons mentioned above,just because there exotic and expensive will not make them any better for this application.


Hope that saves you a few quid regards Bill Davidson

Look to information from David Vizard. Titanium as a rocker or pushrod is a quick way to spend lots of money to loose horsepower. Ti makes excellent valves and valve springs (speaking only in valvetrain)
My 2 pennies
Denis J
Mechanic @ The Vintage Monkey

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Re: Titanium pushrods anyone?

Post by koncretekid » Sun Nov 10, 2013 1:23 pm

Pushrods are columns and that fail according to Euler's formula. Strength of material does not enter this equation, but modulus of elasticity does. Steel has a relative modulus of 29, titanium 17, and aluminum, 10. Because steel has a modulus of nearly twice that of titanium and three times that of aluminum, it is 2 to 3 times stronger than either of the other two metals as a column. Furthermore, the other element of the formula involves the moment of inertia of the column which uses the square root of the ( I.D. of the tube to the 4th power subtracted from the O.D. to the 4th power). All this means that tubes of a given diameter are almost as strong as a solid round when used as a column. So if you use a steel tube, it can be as light as a solid aluminum round of the same O.D., and 3 times as stiff. That's why steel is the best material for pushrods.
Tom
life's uncertain - go fast now

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