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  #1  
Old Nov 11th, 15, 05:29 AM
jp71ss jp71ss is offline
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Default Guess What I Will Be Doing Shortly!

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I know what it feels like now to start turning one up and have this happen!
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  #2  
Old Nov 11th, 15, 06:32 AM
62 NovaWagon 62 NovaWagon is offline
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Default Re: Guess What I Will Be Doing Shortly!

That sucks, hope there wasn't too much damage.
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  #3  
Old Nov 11th, 15, 08:50 AM
brian oneil brian oneil is offline
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Default Re: Guess What I Will Be Doing Shortly!

I would just replace them all. Comp Cams makes Ultra Pro and Ultra Pro XD. I use the Ultra Pro on my exhaust and Ultra Pro XD on my intake valves. rocker. Cost a bit more than those but I am not too worried about breaking rockers.
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  #4  
Old Nov 11th, 15, 09:52 AM
62 NovaWagon 62 NovaWagon is offline
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Default Re: Guess What I Will Be Doing Shortly!

Pays off in the long run, I used the Crower stainless for a long time never had a failure..
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Old Nov 11th, 15, 09:58 AM
Big Dave Big Dave is offline
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Default Re: Guess What I Will Be Doing Shortly!

Extruded aluminum rockers on race cars are replaced every race season or more frequently in higher RPM cars. This is why there are so many used sets for sale on line. Aluminum is very susceptible to work hardening. Once hardened it is only a matter of time until micro cracks become broken parts.

I also used cast chrome-moly rocker arms from Comp cams on my street driven cars and reserve the lighter but much more expensive extruded aluminum Crane Cam Gold roller rockers on my race only car. They go in the dumpster at the end of every year and are then replaced with a new set. If any cracks were visible on tear down they were replaced immediately. On the race car the springs were checked every twenty five passes (compared to two thousand miles on my street car) with the rockers removed and a pressure checker used to measure spring rate. On some of my higher RPM engines (those with four inch strokes or less motors) I also used Titanium valve spring retainers that are also replaced regularly as Titanium is even worse at work hardening, and high spring pressure erodes the thickness of the metal as they operate.

The factory used mild steel rockers because mild steel will run for 150,000 miles before failure from work hardening (all metals work harden if flexed). By definition if there is a pressure (force) applied then there will be deflection. We used to measure people's weight by having them step up on top of a fourteen inch thick steel I-beam suspended just off the floor as a three foot cantilever. We had a stress transducer glued to the top of the beam that measured the deflection of the beam by the change in the electrical conductivity of the metal due to the stress of someone standing on the end of the beam. It was accurate to half a Kg or less depending upon how stable our power supply was.

Big Dave
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Old Nov 11th, 15, 02:07 PM
jp71ss jp71ss is offline
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If you will look close you will see where I had to machine these for bigger springs. That is where it broke. Yeah I ordered new ones.
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  #7  
Old Nov 11th, 15, 02:28 PM
brian oneil brian oneil is offline
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Default Re: Guess What I Will Be Doing Shortly!

John that in itself is an issue especially with conical springs there is really no need to ever do that.
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  #8  
Old Nov 11th, 15, 06:04 PM
jp71ss jp71ss is offline
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Default Re: Guess What I Will Be Doing Shortly!

I didn't see any damage yet. No bent pushrod but havent checked compression yet either.
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Old Dec 24th, 15, 01:32 PM
jp71ss jp71ss is offline
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Default Re: Guess What I Will Be Doing Shortly!

Well I bought a set of scorpions per recommendation of local engine builder. I upgrade to 7/16 too. I called lunati ( voodoo solid roller cam) and asked what should be the initial valve lash cold with aluminum heads. They recommended subtracting .010" on each valve (.006" for my '016" hot lash). I have done this and when I check the lash after running the motor and it has cooled my lash varies from .018" to .025". Is this normal? I've readjusted per lunati spec (nothing was loose) and it repeats with loose lash. Any ideas where to start?
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Old Dec 24th, 15, 01:54 PM
Big Dave Big Dave is offline
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Default Re: Guess What I Will Be Doing Shortly!

Cold lash is irrelevant. What you are looking for is the lash when running hot. I lashed the engines running by using a dedicated (chewed up ) set of feeler gauges I only used to lash the valves. You can lash them equally well without the motor running it just has to be done while it is still hot!

Scorpion by the way manufactures the aluminum roller rockers for Comp Cams and Isky. I don't think the make them for Crane as the "Golds" are so much bigger (they are extruded through a die and cut up to width before machining). I think Lunati buys raw blanks from another source before they finish machining the parts, but I can't recall who it is.

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Last edited by Big Dave; Dec 24th, 15 at 02:06 PM.
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  #11  
Old Dec 24th, 15, 02:47 PM
jp71ss jp71ss is offline
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Default Re: Guess What I Will Be Doing Shortly!

What I am getting at is, shouldn't the valves come back to what I originally adjusted them to cold when I recheck them cold?
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  #12  
Old Dec 24th, 15, 02:51 PM
jp71ss jp71ss is offline
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Default Re: Guess What I Will Be Doing Shortly!

Here is what I hear when warm.
http://vid216.photobucket.com/albums...psg9c1qsom.mp4
Do you here the one pecking every once in awhile?
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  #13  
Old Dec 25th, 15, 02:34 PM
Philip Philip is offline
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Default Re: Guess What I Will Be Doing Shortly!

Scorpion is on my list of manufacturers to never again deal with. Had a set of their rockers on a sb 400. One day one of them developed a real loud tapping. When the covers were pulled to check the adjustment I was astonished at what I saw. The anodizing was lifting off the metal. That stuff is hard and would be as bad as metal particles going through the engine. Fortunately they were not in the engine long enough to cause damage. When I spoke with Scorpion they said 2 things that lost me as a customer. First that I had the only 16 rockers to ever do that. I know that is bull because they are made in bigger lots than 16 at a time. If mine were bad more than likely the whole run was. Second they would not investigate why it happened. I sold the replacement set and bought another brand.

These photos show the stress areas as well as the missing coating.









BTW the tapping was not from adjustment, at least one of them had something wrong. They were not taken apart so as not to void the warranty but the rollers on a few felt rough.
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  #14  
Old Dec 25th, 15, 03:03 PM
62 NovaWagon 62 NovaWagon is offline
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Default Re: Guess What I Will Be Doing Shortly!

Wow that sucks, looks like the top one has a crack too.
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  #15  
Old Dec 25th, 15, 05:57 PM
jp71ss jp71ss is offline
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Default Re: Guess What I Will Be Doing Shortly!

How long ago was that Philip?
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