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Cam and valvetrain longevity....??? low duration high lift...

Old 10-03-2016, 07:29 AM
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[ATTACH=CONFIG]559973[/ATTACH][ATTACH=CONFIG]559972[/ATTACH]
Attached Thumbnails Cam and valvetrain longevity....??? low duration high lift...-image.png   Cam and valvetrain longevity....??? low duration high lift...-image.png  
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Old 10-03-2016, 07:29 AM
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Abones , i wonder if it has something to do with bob selling the 8.1L cam cores for every application. I wonder if something is different with them, ever so slightly, in how the nose is machined
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Old 10-03-2016, 07:33 AM
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Originally Posted by MILD THUNDER View Post
Abones , i wonder if it has something to do with bob selling the 8.1L cam cores for every application. I wonder if something is different with them, ever so slightly, in how the nose is machined
At this point in the investigation it seems likely that indeed is the case!! I think if there are more incidents like Tim and Budman show up that might seal that deal!!
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Old 10-03-2016, 07:36 AM
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Unjust worry how many guys install and don't check runout to know? It can spin but it's right so if you don't check runout and you don't spin can hear only when installed you would never catch it, I was more thorough on my builds then people know

Originally Posted by abones View Post
At this point in the investigation it seems likely that indeed is the case!! I think if there are more incidents like Tim and Budman show up that might seal that deal!!
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Old 10-03-2016, 07:36 AM
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Originally Posted by Black Baja View Post
Hey Tim, I just had a thought this morning and it might be worth looking into. B4 you purchase new cams. It would be nice to see if anyone has done any testing with LS vs non LS firing order with a center rise manifold such as yours... If you think about how the double swap firing order would pull on the runner with the manifold such as yours I would think the exhaust scavenging would totally suck. Did you happen to notice any carbon tracking in the intake runners of the heads or into the intake itself. I was burning some brain cells this morning and have to say with the first cam I got from Bob I had Carbon tracking 2-3"s up into the intake with that combo... This was with Geniii manifolds. Next go round with that setup I added 20*+ duration normal firing order bigger intake bigger carb and had no carbon tracking anywhere in the intake track whatsoever. And that motor idled much better. 500rpms in and out of gear...
One thing I've noticed with the ls firing order is it seems to be considerably more prone to reversion then the conventional firing order even with mild duration. I always assumed that the intake reversion from the Bob cams was probably a combination of the stupid exhaust timing events and possibly instability in the intake valve causing it to bounce on the seat. On engines with a bit of time on them you would start to see the heat and even more carbon tracking on the intake seat. I saw a couple that ended up loosing intake seal completely and looked like they werent far away from getting torched.
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Old 10-03-2016, 07:38 AM
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The good Cloyes timing sets come with the iwis chain too.
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Old 10-03-2016, 07:52 AM
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Originally Posted by MILD THUNDER View Post
What i find interesting is, in the thread I linked, budman clearly stated he called bob about the cam nose/retainer fitment issue . Explained it, and said that bob didnt think it was a problem. That was 2013.

Then you guys had the issue. Let me guess, bob acted like he had never heard of that before ?

Just like when orlandi found the issues with his valve seats and other various valvetrain issues. Him and bob were friends . When the topic came up, bob acted like he had never heard of such a thing. After brian had talked to a few other builders, who also presented these issues to bob, he pieced the puzzle together. Bob very well knew about the issues these builders were having, and never shared it with brian, his good customer and friend. Cost brian tens of thousands of dollars.

Engine development at its finest.
These are all issues that could have and should have easily been corrected. If you are selling a volume of parts like he was and there is a trend of issues I simple phone call to the Manufacturing side little adjustment in machining and the problem goes away. I remember a phone conversation to a well known Marine Engine builder I had some years ago. He explained to me the reason he used Bullet for his cams was they had CNC'd their cams and finished them off on a Cam grinder to get a better finish on the lobes and journals. I had a brief conversation with Bob about this and was assured the CNC finish with Cam Motions state of the art CNC was fine and finishing on a grinder was a waiste of time. Well I can tell you this. I have a Bullet cam with about 50hrs on it and there is know lifter tracking on any of the lobes the lobes are very shiny and almost have a mirror finish on them. The $700 Cam Motion/MK cam I have has track marks on the lobes after I spun the cam in the block by hand a dozen times with checker spring. So what's the deal? The finish on the CNC only cam look like crap. It looks like someone took a wire wheel to the lobes and journals on the cam. Differently far from a mirror like finish and it's kind of depressing when I think that I paid $700 for this piece of crap. I have some Sneider, Erson and a cast Comp Cam and none of these cams have such a poor finish on the. I wonder what would happen if you put a crankshaft in a motor that had a finish like this. Would it eat the bearings out of the motor? I'm sure if a CNC'd finish was acceptable on a Crankshaft that we would all have poorly finished dull looking journal cranks going in our engines. I was always told the more mirror like the finish on the crank the better. For that reason we would have our cranks sent out and wait weeks for them to come back because the finish we would get from the grinder two states away was so much better. And this is a part of the motor that has an oil wedge and no metal to metal contact. So, now we get back to the cam and lifter there is no oil wedge just splash oiling and direct metal to metal contact with lots of spring force being exherted but yet it's acceptable to have a sh!t finish hmmm. Sounds like a crock of sh!t to me.
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Old 10-03-2016, 07:55 AM
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Originally Posted by HaxbySpeed View Post
One thing I've noticed with the ls firing order is it seems to be considerably more prone to reversion then the conventional firing order even with mild duration. I always assumed that the intake reversion from the Bob cams was probably a combination of the stupid exhaust timing events and possibly instability in the intake valve causing it to bounce on the seat. On engines with a bit of time on them you would start to see the heat and even more carbon tracking on the intake seat. I saw a couple that ended up loosing intake seal completely and looked like they werent far away from getting torched.

So, it sounds like you have moved to tried and true Lunati Cams. Are you going with standard or LS firing order?
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Old 10-03-2016, 07:57 AM
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Calling RMBUILDER....
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Old 10-03-2016, 08:01 AM
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Originally Posted by Full Force View Post
Calling RMBUILDER....
He's not gonna answer. Has caller ID. Need to three way with an out of your state number...
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