Author Topic: Why Titanium Retainers over steel? What am I missing? (Read 3628 times)

BlackMax · « **on:** May 21, 2009, 05:18:15 PM »

I'm curious.... why would you ever replace stock steel retainers with titium??? I mean, titanium sounds very good; but, it's not stronger than steel. So, for a non 15,000RPM engine, why would you upgrade to titanium???

The reason I ask is because I'm about to get my head back from APE (hopefully). I've read that F2 heads are "notorious" for dropping valves due to failed retainers; and that, they should be upgraded to titanium, as soon as possible. Well, that sounds reasonable; and, I almost ordered up the retainers or called APE to tell them to add it to my order. But then I thought it through. Titanium isn't superior to steel in raw strength....just strength:weight, and corrosion. Plus, titanium is far, far less stiff than steel. So, why would the upgrade make a valve any less likely to drop?? What am I missing? Are the OE retainers made of some especially inferior alloy that is prone to failure? Is the design of the OE inferior and prone to failure??

kghost · « **Reply #1 on:** May 21, 2009, 05:24:56 PM »

Weight.

Ti is stronger than Aluminium and weighs less than steel.

Retainers fail not from lack of strength...but from float.

BlackMax · « **Reply #2 on:** May 21, 2009, 05:35:09 PM »

float causes retainers to fail? I'm sure you are correct, I'm just looking for rationale. Next, realistically, on an F2 head with the extra heavy springs, at what RPM would you expect float? 10,000+....minimum? Just trying to work this out....

MRieck · « **Reply #3 on:** May 21, 2009, 05:37:42 PM »

The APE retainers will not work with the F2 valve keepers. R/D makes Ti retainers for the F2 but they are very expensive.

mlinder · « **Reply #4 on:** May 21, 2009, 05:42:10 PM »

I've done 11k+ on a K regularly with no float.
I have ti retainers on the cb350t racebike, but expect to be hitting very near 15k for redline. As little reciprocating mass as possible is needed in that particular environment.

Not sure why ti retainers would be needed for a big bore bike that wouldn't be seeing anything over 10k regularly.

As far as being less still than steel, it's about the same stiffness in terms of mass. Meaning, objects of the same mass of the two materials will have similar stiffness. Ti has some superior fatigue properties in certain situations, though.

kghost · « **Reply #5 on:** May 21, 2009, 05:49:26 PM »

Quote from: BlackMax on May 21, 2009, 05:35:09 PM

float causes retainers to fail? I'm sure you are correct, I'm just looking for rationale. Next, realistically, on an F2 head with the extra heavy springs, at what RPM would you expect float? 10,000+....minimum? Just trying to work this out....

Yes float causes all sorts of things to fail.

Imagine for a minute the valve staying stationary...when the cam lobe rotates around it will give that valve a hell of a smack.

Bear in mind any engine is a study in compromise.

For example....if you have super stiff springs....the valve closes nice and fast...but valve seat wear increases...rocker wear increases...cam wear increases....

Stiff springs require different metalurgy...more prone to cracking...the higher the tensile strength of steel.

If you want something to move faster...make it lighter.

Oversimplification but you get the idea.

Another factor is harmonics.

MCRider · « **Reply #6 on:** May 21, 2009, 05:57:04 PM »

Quote from: kghost on May 21, 2009, 05:49:26 PM

Quote from: BlackMax on May 21, 2009, 05:35:09 PM
float causes retainers to fail? I'm sure you are correct, I'm just looking for rationale. Next, realistically, on an F2 head with the extra heavy springs, at what RPM would you expect float? 10,000+....minimum? Just trying to work this out....

Yes float causes all sorts of things to fail.

Imagine for a minute the valve staying stationary...when the cam lobe rotates around it will give that valve a hell of a smack.

Bear in mind any engine is a study in compromise.

For example....if you have super stiff springs....the valve closes nice and fast...but valve seat wear increases...rocker wear increases...cam wear increases....

Stiff springs require different metalurgy...more prone to cracking...the higher the tensile strength of steel.

If you want something to move faster...make it lighter.

Oversimplification but you get the idea.

Another factor is harmonics.

What he said.

BlackMax · « **Reply #7 on:** May 21, 2009, 06:05:02 PM »

Quote from: kghost on May 21, 2009, 05:49:26 PM

Quote from: BlackMax on May 21, 2009, 05:35:09 PM
float causes retainers to fail? I'm sure you are correct, I'm just looking for rationale. Next, realistically, on an F2 head with the extra heavy springs, at what RPM would you expect float? 10,000+....minimum? Just trying to work this out....

Yes float causes all sorts of things to fail.

Imagine for a minute the valve staying stationary...when the cam lobe rotates around it will give that valve a hell of a smack.

Bear in mind any engine is a study in compromise.

For example....if you have super stiff springs....the valve closes nice and fast...but valve seat wear increases...rocker wear increases...cam wear increases....

Stiff springs require different metalurgy...more prone to cracking...the higher the tensile strength of steel.

If you want something to move faster...make it lighter.

Oversimplification but you get the idea.

Another factor is harmonics.

I gotcha. But since the f2 heads have pretty massive and stiff springs....and considering I'm using stock F2/3 cam specs......I'm guessing I can stay with the stock retainers. This bike won't see 9,000 but for a blip here and there.

Looks like titanium may be a good idea for a racebike that will see 10k+ on a regular basis. Since all retainers, regardless of material, will be of the same size, the steel ones are actually stronger, but heavier. Therefore, for lower RPM use.....advantage steel.

Good answers. I have it now.

RRRToolSolutions · « **Reply #8 on:** May 21, 2009, 06:07:30 PM »

Because Buzz told me I needed to give him my money

I had my K4 ported by Bobby Mcallister of Clements Racing Engines of Spartanburg fame back when I was building the bike. When talking with Buzz, he sold me the Kibble White stainless valves, their keeper system, springs, valve guides, and the titanium retainers. His reasoning for it was the weigt and rpm potential. I don't know if I needed them, but Buzz sure was glad I had them in the head.

Of course, he wound up talking me into a lot more. I think I made his house payments that year!

Gordon

kghost · « **Reply #9 on:** May 21, 2009, 06:13:26 PM »

BTW...I've not heard alot about F2's dropping valves....they have a reputation for wearing out the guides rapidly.

Mreick is the guy to ask about valves and heads....

sparty · « **Reply #10 on:** May 21, 2009, 06:13:38 PM »

Quote from: Ilbikes on May 21, 2009, 06:07:30 PM

Because Buzz told me I needed to give him my money

I had my K4 ported by Bobby Mcallister of Clements Racing Engines of Spartanburg fame back when I was building the bike. When talking with Buzz, he sold me the Kibble White stainless valves, their keeper system, springs, valve guides, and the titanium retainers. His reasoning for it was the weigt and rpm potential. I don't know if I needed them, but Buzz sure was glad I had them in the head.

Of course, he wound up talking me into a lot more. I think I made his house payments that year!

Gordon

You and me both Gordon. Since our engines are finished I hear Buzz is now living in a van down by the river.

Art

754 · « **Reply #11 on:** May 21, 2009, 06:28:14 PM »

Correct me if I am wrong,
I think the stock ones are stamped, not cut from bar, so I am guessing that the point of failure, would be in the cupped area where the keepers sit.

advantages I see,

new material,
easier revving
maybe lighter
built in offset to allow for longer spring pack for high lifts.

kghost · « **Reply #12 on:** May 21, 2009, 06:41:12 PM »

By the way....Titanium ALLOY is stronger than most steels.

For example:

Stainless steel has a yield around 520 MPA and ultimate strength of 860MPA weighing about 8.9 g/cm3

Ti Alloy has a yeild around 830 mpa and a ultimate yield of 900 weighing about 4.51 g/cm3

http://en.wikipedia.org/wiki/Tensile_strength

fuzzybutt · « **Reply #13 on:** May 21, 2009, 06:42:39 PM »

as i understand it, the lighter you can make your valve train, the less spring pressure you have to run.

kghost · « **Reply #14 on:** May 21, 2009, 06:47:13 PM »

Quote from: fuzzybutt on May 21, 2009, 06:42:39 PM

as i understand it, the lighter you can make your valve train, the less spring pressure you have to run.

Speaking of your valve train.....how is it?

fuzzybutt · « **Reply #15 on:** May 21, 2009, 06:50:10 PM »

going back together in the next day or so i think.

kghost · « **Reply #16 on:** May 21, 2009, 06:52:39 PM »

Quote from: fuzzybutt on May 21, 2009, 06:50:10 PM

going back together in the next day or so i think.

Figure out the oil issue?

Sam Green Racing · « **Reply #17 on:** May 21, 2009, 08:23:38 PM »

Timmy, here's an intresting bit of bumph for you.
Did you know that pureTitanium as a metal is 60% heavier than pure Aluminum.
When it is transformed into an aloy, it becomes lighter.
It seems strange that you can change a metal that is heavier than alumium and end up with an aloy that is lighter than pure alumium.

Sam.

Jerry Rxman Griffin aka MuthaF'er · « **Reply #18 on:** May 21, 2009, 10:53:48 PM »

I missed a power shift into 2nd, well past 10K, broke the head off my #2 intake valve when it floated, and obliterated a perfectly good 1 year old 750F0 engine. I rebuilt with stronger stainless intakes and stronger S & W springs. Wish I had deep pockets then. Budget rebuild with same stock retainers however. It spins past 10K and probably hasn't floated in 25,000 miles since.

I have 1 ported head waiting for a 1000 engine. All Kibblewhite top end with 33.5mm intakes. Obviously stronger springs and lighter titanium retainers. I have another head that MRieck has that'll go into my same bike with a 900 kit. It will have full Kibblewhite top end with 34mm heads and 5mm stems. Cost is approximately $5000 just for an engine for full pop with all goodies. Rationale: Stronger AND lighter. WAY TOO expensive to skrimp on springs and retainers.

kghost · « **Reply #19 on:** May 22, 2009, 09:00:22 AM »

Quote from: Samcr750 on May 21, 2009, 08:23:38 PM

Timmy, here's an intresting bit of bumph for you.
Did you know that pureTitanium as a metal is 60% heavier than pure Aluminum.
When it is transformed into an aloy, it becomes lighter.
It seems strange that you can change a metal that is heavier than alumium and end up with an aloy that is lighter than pure alumium.

Sam.

Did you know Australia is the biggest producer?

News:

Author Topic: Why Titanium Retainers over steel? What am I missing? (Read 3628 times)

fuzzybutt

fuzzybutt