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Old 03-07-2013, 08:08 PM   #136
supershaft
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Quote:
Originally Posted by bmweuro View Post
I have run these chromeoly pushrods before. They are under $100 for 2 bikes worth https://www.wolfgangint.com/store/pr...uncut-1109302/
but at the end of the day unless your turning 7500 plus RPM's stock works fine.
They work just fine at rpm's higher than that in my experience but they flex a lot even at low rpm's as evidenced by the scrap marks they almost always have from getting into the pushrod tubes. If you want rods that don't flex for more power, steel alone isn't the ticket. Steel pushrods of just a few years back turned out to flex a lot. Nowadays the big money pushrod boys are running MUCH heavier steel rods for more rigidity and power. Two to three times heavier than steel rods of just a few years back.
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Old 03-07-2013, 08:34 PM   #137
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Originally Posted by supershaft View Post
They work just fine at rpm's higher than that in my experience but they flex a lot even at low rpm's as evidenced by the scrap marks they almost always have from getting into the pushrod tubes. If you want rods that don't flex for more power, steel alone isn't the ticket. Steel pushrods of just a few years back turned out to flex a lot. Nowadays the big money pushrod boys are running MUCH heavier steel rods for more rigidity and power. Two to three times heavier than steel rods of just a few years back.
Back in the 90's when I was building campaigning three R75/5's the biggest problem was breaking rockers and rarely a push rod problem.
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Old 03-07-2013, 10:44 PM   #138
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Originally Posted by bmweuro View Post
Back in the 90's when I was building campaigning three R75/5's the biggest problem was breaking rockers and rarely a push rod problem.
I have taken aluminum pushrods out of a lot of airheads. Almost every one of them had rub marks where they flex and get into the ends of the pushrod tubes at the top of the cylinders and the bottom of the heads. IF you are looking for all the power you can get out of your setup, that much pushrod flex is a problem since it slows the valve opening and perhaps even reduces valve lift. Just about any pushrod flex is a problem as far as peak performance is concerned and even if pushrods are not flexing enough to get into the tubes that doesn't mean they aren't flexing. At least that is a lot of the buzz lately in performance pushrod engines.
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Old 03-07-2013, 10:56 PM   #139
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Originally Posted by supershaft View Post
I have taken aluminum pushrods out of a lot of airheads. Almost every one of them had rub marks where they flex and get into the ends of the pushrod tubes at the top of the cylinders and the bottom of the heads. IF you are looking for all the power you can get out of your setup, that much pushrod flex is a problem since it slows the valve opening and perhaps even reduces valve lift. Just about any pushrod flex is a problem as far as peak performance is concerned and even if pushrods are not flexing enough to get into the tubes that doesn't mean they aren't flexing. At least that is a lot of the buzz lately in performance pushrod engines.
f you are talking about a worn shinny ring around the push rod right about where the edge of the oil return tube is pressed into the cylinder? I think it is created by poor rocker arm alignment. How would you have a prefect ring if it was flexing?
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Old 03-07-2013, 11:16 PM   #140
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Originally Posted by bmweuro View Post
f you are talking about a worn shinny ring around the push rod right about where the edge of the oil return tube is pressed into the cylinder? I think it is created by poor rocker arm alignment. How would you have a prefect ring if it was flexing?
I have seen the same polished rings around the pushrods. I've taken the rocker covers off and turned the engine by hand and the push rods have plenty of clearance to the tubes, but after they've been run, there are polished marks round them. From this I deduce that the pushrods are flexing and touching the sides of their tubes. I don't see how they can get polished like that without flexing.
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Old 03-08-2013, 12:49 AM   #141
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Quote:
Originally Posted by bmweuro View Post
f you are talking about a worn shinny ring around the push rod right about where the edge of the oil return tube is pressed into the cylinder? I think it is created by poor rocker arm alignment. How would you have a prefect ring if it was flexing?
The lifters rotate due to offset with the cam lobes right? Even though the pushrods have polished ball and socket unions, I'd reckon they'd rotate to some degree with the lifters. And who's to say they flex in the same direction all the time. All sorts of modes of vibration would be going on. Keeps the balls and sockets nice and concentric and polished too! In fact, wouldn't be surprised if they are designed to rotate for that reason..
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Old 03-08-2013, 02:16 AM   #142
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Dear Gentleman,

First of all please know that it is ok for me if anyone on this great earth is doing something better and / or cheaper then us at Edelweiss Motorsport.

I'm surrounded by plagiators and people like mr. i know it all and my guy can make it cheaper...go ahead and do it because you can.

I share a lot of information all time and if someone is buying a product he will be informed about all specifics he ever wants anyhow.

There are company's with nice webshops just selling whatever they can copy and whatever they can get their hands on. They do no developement no research no racing no nothing to bring this beautiful engines on to an other level.

They not even have a dyno so all they can do is telling a sweet story about products they know nothing about.

All they have is a mail account and a guy who can make it cheaper....

As i learned it here in this forum one of this company's is well known in the states as a source for camshafts for example and I was really surprised....obviously they have the time to do marketing when we where working.

But also this is very much ok for me since there was the same story here in Germany before - then it turned out that you just can answer the question if you have invented the product.

So whatever innovation it was in the last 20 years - asymmetrical cams, longer conrods, big bore kits, long stroke crankshafts, ratio rockers, programmable ignition systems, the specifics that make a sr exhaust working....etc. it was all coming from the same spot making it available to the freaks, fans and dudes.

In the long run innovation beats imitation.

As I said it - and whatever it sounds like and yes it is a pain now and then, under the line it is ok for me !

Back to the push rods:

In the beginning you have to find out when and why they are flexing - so go ahead and build a simulation, take a stroposkope light and look on the valve train as a complete system. Then understand it do a analysation and try to fix the problem.

Next step find out the right material, the right heat treatment, the correct machining process, the perfect balance between weight and stiffness and then you just need the correct steel ends to make it last forever because you have to take responsibility for what you sell and people expect warranty for a good reason.

After years you know why several things that are in discussion in this thread are not right and are not working alt all - and then at the end try to find a Chinese company to do the production on the same quality level as we do it here.

All we sell is strictly made in Germany, and believe it or not we will not get rich by selling this pushrods.

If then you have the product ready to go it will do miracles to the airheads solving a very specific problem.

They are able to transport the cam information 1:1 from the cam to the valve...and this is more then essential and makes it perform like an overhead cam engine. Very silent, very smooth and very strong.

Some more little hints -

You brake rockers and you think your valve train is ok ?

No need for better push rods ?

The std. ones are ok ?

Think it over and please know that in all that decades we have not one broken rocker in all this race, sport, street engines - whatever power they do and whatever they rev.

If you brake a rocker something is totally wrong !

Have a wonderful day - remaining with best reg.

Dirk
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Old 03-08-2013, 02:30 AM   #143
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Haha, Beautifully said Dirk!
Mr. know it all means well, he just rubs people the wrong way

On another note, aluminum is stiffer than steel, a lot stiffer, so it seems it would not flex much as a pushrod of any alloy of steel. The other issue is that aluminum will crack if cycled/flexed very many times. This leads me to believe they can't be flexing much, or they would rapidly fail.
That said the only explanation I can find for the rub marks, is that because aluminum is much weaker than steel, it must be made larger in diameter than the steel rods (wall thickness has almost zero to do with tube stiffness) causing them to make contact even with less flex than the steel push rods.

Peace!
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Old 03-08-2013, 02:38 AM   #144
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Quote:
Originally Posted by Edelweiss-Motorsport View Post
Think it over and please know that in all that decades we have not one broken rocker in all this race, sport, street engines - whatever power they do and whatever they rev.

If you brake a rocker something is totally wrong !

Have a wonderful day - remaining with best reg.

Dirk

Hi Dirk

Thanks for all the excellent information you've given us.

I broke a rocker once.. at Chimay where you spend a lot of time at high rpm. But it was a rocker that I had lightened. My fault :)
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Old 03-08-2013, 03:36 AM   #145
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The one and only?

Servus Dirk!

I remember a thread about push rods in the 2-ventiler forum several years ago. You then recommended convex aluminium push rods for roads engines and chrome-moly push rods for sports/race engines.
You also wrote that several factors would influence the selection of push rods. And that from the technical point of view the chrome moly push rod would be superior over the aluminium push rods.
Are these news from yesterday?

So are the push rods you offer now the proper choice for any kind of application? Or are there still limitations?

Best regards

Rudi
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Old 03-08-2013, 03:55 AM   #146
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Hey Rudi my dear friend !

Yes this is right - it was a time when we where not able to generate the stiffness that we need from the aluminium versions.

So we where going with the chromo's taking all their suboptimal behavior as a compromise to make sure the reliability was 100 % .

Now we are one step ahead of this time and can use the aluminium pushrods in all application.

Have a nice weekend - here the sun is shining, what about bavaria ?

Yours in sport

Dirk
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Old 03-08-2013, 04:02 AM   #147
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Now we are one step ahead of this time and can use the aluminium pushrods in all application.

Have a nice weekend - here the sun is shining, what about bavaria ?
Thanks for these info.
Weather is splendid here, too.

Have a nice weekend

Rudi
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Old 03-08-2013, 04:36 AM   #148
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Originally Posted by Houseoffubar View Post
Haha, Beautifully said Dirk!
Mr. know it all means well, he just rubs people the wrong way

On another note, aluminum is stiffer than steel, a lot stiffer, so it seems it would not flex much as a pushrod of any alloy of steel. The other issue is that aluminum will crack if cycled/flexed very many times. This leads me to believe they can't be flexing much, or they would rapidly fail.
That said the only explanation I can find for the rub marks, is that because aluminum is much weaker than steel, it must be made larger in diameter than the steel rods (wall thickness has almost zero to do with tube stiffness) causing them to make contact even with less flex than the steel push rods.



Peace!

ya gots that backwards partner. The modulus of elasticity of aluminum is around 10 million. it's 30 million for steels. The steel is 3 times stiffer. That's why aluminum bicycle frames use such fat tubes. You need to make the tubes a LOT bigger to get the stiffness of a steel tube. What can be confusing is the failure mode. Steel will bend where aluminum will fracture. This a function of ductility, not stiffness.

if the pushrods are flexing, they will be doing it under pressure. Under those circumstances the rods are also moving longitudinally. You you would expect the rub mark be almost as wide as the longitudinal travel of the rod 9not quite as much as the rod might only be touching at max pressure which is only part of it's stroke). Are the rub marks that wide?

Under a purely compressive load, a beam won't flex. But one end of the pushrod moves in an arc while the other doesn't. So you can't keep the load purely compressive. You can calculate what the load is if you measure the angle. You know the weight of the valve spring and can measure the length of the rod. Down load a free program called BeamBoy and play with it.

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Old 03-08-2013, 05:11 AM   #149
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Hi Plaka - yes you are so right !!!


Dirk
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Old 03-08-2013, 06:24 AM   #150
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Before - after measurement?

Hallo Dirk,

yet another question.
Can the effect of your pushrods be quantified?
Is there a measurable increase of torque?
Does this increase differ for different configurations (valve accelerations, selected springs, ...)

Best regards

Rudi

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