I think spring pressures have alot to do with the expected life of the rocker, probably more than anything else

I've got a set of erson forged aluminum roller rockers on a brand-x engine and the engine maybe has 10,000 miles on it, the rockers are shot to poop. Theres a butt load of play at the trunion, however the roller at the tip is in pretty good shape.

They are 1.6 rockers on a solid roller with fairly high spring pressure. the cam is not to aggressive, but its 278 degrees of advertised intake duration with a gross lift of .599 with some pretty heavy springs. The engine has seen 9,000 on the tach and a bit past it on more than one occasion (one time I lost my temper and floored the SOB for a good 15 seconds trying to blow the engine up. no bad luck though, its still together)

Hey Chris...I don't think a whole lot of people understand the Rotary motor, how do two piecs of spinning metal that look like pieces of cheese make power...I have no idea.

I love my MAC and we argue about this at work all the time but since I need to run CAD..it runs much better on the PC and not through Virtual PC like I had on the MAC.

Let me know if you get any info from the SEMA on Top Gun N2O..rhawver@strouse.com

Take Care,

Rick

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Spring pressure, hmm we may be on to something here.

I had this thought last night, what about the 96 LT-4 engine in Vettes or in some 97 F bodies. They have Alu rollers from the factory, would seem hard to imagine less than 100K mile durability for a factory install, but maybe they figure nobody will notice the trunion wear?? Maybe valvetrain geometry has a role, I know the LT-4 motor uses a very light valve/spring/retainer setup

I am puzzled now

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I put in a call to Crane Cams to ask about the life expectancy of their aluminum rockers after Ford Racing told me to call them. They manufacture the Ford M-6564-A351 rockers. I told the guy at Crane that I called Ford about the life expectancy of their rockers and before I could say that the Ford guy didn't have an answer, the guy at Crane sarcastically said, "They said 20 thousand miles, right?" That Summit catalog generated a lot of calls for them and he seemed annoyed. He told me that they can and should last a long time in a daily driven car if they are properly installed and the oil is kept clean, but that if I was worried I should check them.

The Ford Racing guy wouldn't put a life expectancy number on them, but he did say that in the 8 years he's been working at Ford Racing that he's never seen one fail.

I just thought I would let you guys know what the manufacturer said. I still plan to check them when I pull my engine next spring.

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351W 89 Mustang GT Convertible

Pressure plays a very big role. Think about it... the closer you get to the center, the less movement there is, so it's not necessarily wear from routine use. However, under excessive load, the trunion would suffer stress whether it moved or not, but especially under heavy load, which most systems with a high lift cam and stiffer springs will routinely see. I can say that the rollers that I have replaced for customers or on the Sprint car were under alot of load. Keep in mind, though, that the real reason aluminum rollers were put to use was for racing, not for longevity. A race engine, and it's parts, rarely have to go for more than 500 miles, and sometimes as few as 1/4 mile. Also, you get what you pay for. No offense intended, but Sig Erson, for example, is K-mart quality. The ford rollers are actually top of the line Crane rollers that Crane customized for Ford. GM uses top quality rollers as well, but still lists them as a part to replace at 100k miles as routine maintenance. In my opinion, based on what I've seen, I wouldn't really recommend aluminum rollers for a daily driver. The difference between aluminum rollers and steel rollers isn't noticable in a mild street engine. But, steel rollers wear faster than sled-fulcrumed rockers too.

Take care,
-Chris

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Heh, dug this thread up for an update. My rockers are trashed. There's too much side to side play so the roller doesn't stay centered on the valve stem. The rollers feel a bit gritty, too. I have to order a new set tomorrow if one of the local FRPP dealers doesn't have them. I guess it's for the best since I have new springs and a cam shaft.


Just thought I'd give you guys an update.

I decided to go ahead and order a set of Comp Cams Pro Magnum steel RRs. They're guaranteed for life and are rebuildable. I'll hopefully get them on Friday.

the main reason why aluminum RR's wear faster is because( i think someone already mentioned this) of the hardened steel against a softer metal(aluminum). since it is not depending on an oil wedge, there is more friction. a good example would be an overhead cam motor. notice their isnt any cam bearings on an OHC aluminum head. aluminum is a decent material for a camshaft as long as it holds a true line bore and good oil wedge. many cars have this and have hundreds of thousands of miles on them with little or no wear. i will use my 87 Toyota truck as an example with 182k on it. now put needle bearings in place of the oil wedge and see what happens.

also let me give you another example. i was doing an intake job on a 97-98 Chevy Venture van with a 3.1(maybe a 3.4). from the factory it has a roller cam and roller rockers which were Steel, not aluminum. this van had 125k on it. no signs of play at all with the rockers.

of course other factors do contribute to wear of aluminum RR's, like heat, maintenence, and to much spring pressure to name a few.

but what do i know........:rolleyes:

kind of makes you wonder why 93 cobras came with them stock? interesting

Answer: Trick Question, women don't make any sense

Answer: Heating and cooling in the atmosphere. Deserts hold no heat at night...



Answer: Air has mass. Mass is affected by gravity. Mass and velocity (don't ask how the air got velocity, it would take me awhile to explain :) ) create momentum. The vector sum of the momentum and the gravity keep air moving at the same speed as the earth.

Pictures are nothing more than images of light, just like when you take a picture of your car. We just have to use much more sensitive tools to capture light from these great distances. Of course our own atmosphere makes getting these pictures a little more difficult. Once we lauched a space-based camera we can get much better pictures as there is nothing to obstruct the light on it's path to earth.

By rotating octagonal mirror reflecting light to a concave mirror located about 35 km away. The light reflecting back from the concave mirror struck another face of the octagonal mirror, and could only be seen by an observer if the octagonal mirror was rotating at certain speeds. (To allow the mirror to make the minimum one-eighth rotation in the time it took the light to make the return trip required the octagonal mirror to make slightly more than 32 000 revolutions per minute.) From the round trip distance the light travelled, and the period of rotation of the octagonal mirror, the speed of light was determined.

Now of course they can use a shorter distance and use very precise instruments to get a more exact answer. :)


1. Heat evaporates moisture
2. Ground water can not permate the surrounding rock (at all or fast enough to replace evaporating moisture)


:)

smartypants:p

Who me? :rolleyes: ;)

Oh. Okay. There's not gonna be a test or anything, is there?

Take care,
~Chris

Test? No, no test. You asked, I answered. Kind of like when I ask a question about my car. I don't want you to have to always give the answers around here ;) :D

What a dude!

:)

Take care,
~Chris

for the love of God...
 

You guys make me want to go find an oil leak...or at least drink beer.

Re: for the love of God...
 

Ahh wussy American Beer. I really developed a taste for Coors Light when I lived in Dallas. Of couse now it's Molson Canadian :)

Damn Canucks!!
 

Easy on the Coors...(gulp) I mean it's really(slurp) great stuff...ahhhhh.