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Performance Cam

Thats not your opinion Matt, its your belief and is pretty close for a stock L65 around 1800RPM. However the horsepower plateaus at 2100 RPM so best spot for most efficient power and may be where your transmission is in torque converter lockup.
 
Thats some awesome reading, I receommend going to the second link first for the real skinny of it.

Too bad it is not installed in anything yet. Nice rocker assembly setup.

If I read it right he achieved slightly higher lift by using a longer rocker arm, greater travel on the spring side? Is that correct? Or was it some other combination?
 
buddy said:
Thats some awesome reading, I receommend going to the second link first for the real skinny of it.

Too bad it is not installed in anything yet. Nice rocker assembly setup.

If I read it right he achieved slightly higher lift by using a longer rocker arm, greater travel on the spring side? Is that correct? Or was it some other combination?
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something like that. he really did not talk in great detail about it. i like the way he dropped the compression ratio to 18:1 by doing something to the valves and prechambers. i forgot what it was since ive been reading so much on it. i guess thats a little easier than getting new pistons especially since mahle stop making them. too bad he didnt stay with the 6.5/6.2 engines. word is he is swapping in a cummins in his blazer
 
I believe he was using BBC rockers which are a 1.7 ratio compared to the 6.5 ratio of 1.5 .
 
he cut away the material around the valves that shroud them and pressed in hardened valve seats i think. Thats where his compression drop came from. Might wanna double check those threads to make sure i remember correctly.
 
The valves are called "dimpled valves" the faces are machined down in a dome shape to increase combustion chamber space.

The 1.7 rocker ratio will give you more lift, but also greatly increase valve opening rates. I'm not sure he used strong enough springs, but you'll need stronger springs if you want to do that.

He also complicated the roller rocker setup, it can be done much easier, but there is more than one way to skin a cat.
 
chevyinlinesix said:
The valves are called "dimpled valves" the faces are machined down in a dome shape to increase combustion chamber space.

The 1.7 rocker ratio will give you more lift, but also greatly increase valve opening rates. I'm not sure he used strong enough springs, but you'll need stronger springs if you want to do that.

He also complicated the roller rocker setup, it can be done much easier, but there is more than one way to skin a cat.
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so is this a similar setup that you are going to run
 
Similar as in roller rockers yes, he used Pro Magnum, and I am using the new Ultra Pro Magnum. I am not using a 1.5 or a 1.7 ratio though. I am also not using dimpled valves, but custom ones.
 
Max mentioned they actually are stock valves, but he cupped around where the valves seat. I guess they are recessed normally. So with his mod, at times of low lift there would be more gap and slighter longer duration I suppose too.

Not sure what he meant by retaining stock "squish" because compression ratio is compression ratio, lower ration being less comrpession or "squish". But I do like what he did, really neat idea.
 
I couldn't believe the time and detail and effort put into this build only to decide to sell it for a loss to run a cummins motor. I was very surprised when he sold it.
 
6.5coalroller said:
So with a increase in gap and duration would that increase performance at all?
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Hmnn dare I answer such a loaded question; it may or may not, could or could not, depends IMO what your targeted build is, also physical flow dynamics don't always mirror results in a calculation, many times math is wrong, a LOT of performance back in day was simple trial & error, I dare say most of it, NASCAR & "shine runners" started by a bunch of "good ole boys" trying this & that; we do have math & modeling tools that improve our success to failure ratios, but at end of day there is still a trial & error component to any idea.

I deal with "good engineered solutions" every day at work, something as simple as which vendor to buy a sensor from that results in a "crispy locomotive" or burnt up from a better oring design, remember space ship Challenger oring from some of the best & brightest engineering minds.

Cam swap for the 6.5 benefits have yet to be proven or disproven by some, but others that have looked into it were not impressed at work involved vs what is currently available, I think I read on some site or article that real substantive gains did not impact in a significant way in engines with much higher Hp potential than the 6.5 don't see cams as a benefit until 500+ Hp.

This is not an indictment of the work being done, please you explorers of the boundaries for the 6.5 go forth & produce the best cam & best valve geometry out there, we've bought stuff as 6.5ers only realizing 1-2 Hp gains so I encourage you to find whatever else is out there.

IMO to 6.5CR

Since we have a few willing to go there but haven't finished their work yet, I'd wait for the results were it my build, "performance cam" can be somewhat easily be installed later, as current off shelf offerings appear to be more good advertising than results, but that is just me.
 
6.5coalroller said:
So with a increase in gap and duration would that increase performance at all?
Click to expand...

Some people think they get better efficiency and power from a better flowing turbo and less restrictive air filters.

If your valves beome less restriction to flow and will expell more exhaust gases, then.....to be continued

Was much effort put into any 6.5 valvetrain project?? Not that I have seen documentation of, but recently there are a few projects of different flavors that involve increasing flow through the engine. Already proving to be fruitful in one project.
 
There is a lot more to good cam design - or really any engine performance enhancement - than meets the eye. A good primer in cam selection can be found here: www.popularhotrodding.com/tech/0607phr_camshaft_basics/index.html

Without some very expensive testing, I think a performance cam for these is not going to happen. You would need someone to design and grind up several profiles, then test them on an engine dyno. Each cam test would require the engine spec to be tuned for the specific grind, so you would need multiple test for each grind. Then you might find something that would work better- maybe. No one grind is going to provide the results everyone is looking for. Some would want outright power, others economy, some would want towing power, etc. Which is why every cam seller has several profiles for each engine. A cam for our engines would be a money looser, no commercial cam grinder is going to invest that kind of resources for the small market returns that a 6.5 cam would provide. And even a group of individuals could not afford the cost. Which is why I don't see a cheap way to find a real gain here. If there were, I think places like Peninsular would have pursued it already and I think all their engines use stock cams. I think they found the easy way to power is lower compression and more boost, not cam changes.
 
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