Cams & cam regrind discussion as a performance adder

[buddy]

And what I summarize a lot of that to mean is that our camshaft design is innefficient and that a better one that had less negative overlap would improve efficiency and power significantly. Of course to achieve this new piston designs have valve reliefs and simply lower compression with larger combustion chambers (newer direct injection engines). This has been suggested before with less than warm reception here. This technical sticky pretty much explains it though. Higher lift, longer duration, and valve reliefs sounds like a wonderful plan for a 6.5 build up. Although, I may have to think about getting the intake valve closed a little earlier than previously planning for, and attempt to figure out at what degree after TDC fuel combustion stops being helpful and opening the exhaust valve can be done without being wasteful.

 

[Turbine Doc]

Reason it's gotten lackluster enthusiasm for cam rework, many have tried and bottom line even with the assistance of some big names in the cam bidness, a lot of work with marginal gain over the cam GM supplier the 6.5 with, it was a topic under consideration for the Heath LSR but after much R&D they are still running a stock cam, if any ride were to benefit from a regrind, that would be the one.

Now a cam with opened up precups and some tweaks possibly another ball of wax, rather than dilute information thread with theory talk let's take that discussion to the performance area where if it is wished to be expanded the discussion can be picked up there.

 

[Turbine Doc]

If ya'll want to discuss the cam talk carried from this thread Buddy was referencing http://www.thetruckstop.us/forum/showthread.php?27096-IDI-tecchie-info-courtesy-of-Great-White have at it;

I didn't want it to detract from the information purpose of a reference thread, it's a good topic for discussion just better suited here than in a reference post.

 

[Turbine Doc]

Bill's ride isn't only game in town albeit it is the worlds fastest 6.5 and running std precups, a wicked tune, twins, but has a stock cam, a hybrid cam tried still not getting the job done last time I talked to Bill.

Another Diesel gearhead Dennis Garmon of Garmon performance I met at a dyno day had tried some special cam work on his 12V Cummins 500rwhp #2 fuel only ride, said special cams for him weren't good power adders either and suspected for my 6.5 it would not do much, but said try it; only way to know for sure is to try.

 

[buddy]

If you read the info in the thread I posted in, it had all the justification, it tells you why our cam design is inefficient, its like something the industry just accepted to maintain the high compression engines. Something they brainwashed so many in the industry to accept as well. I also highly doubt there was any extensive R&D done on cams for the 6.5. Meaning who actually ground one and ran it, vs maybe thinking about it and the additional trouble you would have to go through, and giving up on the idea. Just because someone said they looked into it may be giving them a little too much credit as R&D, meaning where is the development part of that? I would like to hear from the horses mouth how much R&D was done, rather than dismissing as second hand knowledge, which is like limiting innovation to the realm of the understood.

I'm already running more fuel from a stock DS4 than your industry experts have been providing you the option for, so how much faith do you put in them for innovative thinking? It is a limited return on investment to do R&D, so do you think much gets done outside tinkering enthusiasts?

And my idea of a real cam job is not just a grind, because we are limited so much by the high compression, you can't really change a whole lot, so just a cam regrind is not going far enough.

 

[Turbine Doc]

I had started a lengthy response but figured what the heck, go for it do your cam thing if it works we'll all celebrate, FWIW more than just a grind has been attempted including springs, lifters, timing etc. required for a complete review of making a different/better cam work. Fuel is limited for a reason for tunes available to the mass public you ought to be able to figure out why.

Good night Buddy

 

[buddy]

Thanks, I plan to, one test cam has already been ground, but if I could get a billet one that would be a lot better, because they can make the lobe rises anything you want and not limited to working with the lobes already there.

 

[Woody35]

I really like what your doing buddy. not trying to bash you TD because you have done some great things for this engine but i think r&ding of stuff that hasnt been tested or new ideas really can get the ball rolling so more ideas can be brought to light to make a more powerful and efficent engine even after being out of production after 10 years

 

[turbonator]

Continue on, you certainly have our attention. This is one direction that we have seen a lot of talk and not very much actual work done nor cams tried.

Heck, even Peninsular is starting to look at this part of the process with their new valve train. Although only to look at in pics so far......apparently had a geometrical problem in the first production.

So, we are subscribed.....

 

[ak diesel driver]

penn has a new valve train? I'll have to check that out

 

[turbonator]

they had some issues with the first production, but they are working on it..... it is a direct bolt in piece... no machining required...... should be a nice addition to a hotter cam..... a little pricey at 600.00 a set, but the price will come down with time....

Now back to cams.....

 

[buddy]

Well, since it was brought up, I did a quick search on Cummins cams not being fruitful.

This company, although perhaps using more of a brute force method with trial and error is producing camshafts to the delight of Cummins owners.
http://www.coltcams.com/html/cummins_5_9_camshafts/

The one I had ground for an eventual engine project is kind of a cross between their "Big Stick" and Stage 5, but causes all kinds of clearance issues on a 6.5.

The stock Cummins and 6.5 cams obviously differ, having the Cummins valve events timing would be good for comparison.

On a Cummins site, the expert mod there said this of the cam modifications:
"Nut shell, more power below 2400 rpm, very small gains in overall power on a mild application, big gains for large slow spooling turbo or turbos, specs vary as there are several grinds we have tried. More boost early in the power range, more boost at cruise speeds, some egt reduction and fuel mileage gains, quicker throttle response, cleaner sounding exhaust note. All pluses, if you don't mind the labor intensive installation."

There was a 6.5 owner with Delta's biggest direct replacemet cam that commented similarly about faster spooling and throttle response.

To compliment it with roller rockers and new springs was the plan, and the custom Rhoads lifters I have that bleed down and reach full lift/duration between 3000 and 3500rpm. Now Peninsular and other engine companies can do these things with some ease, definately have the upper hand. I dont even have a candidate engine yet.

 

[turbonator]

dont worry buddy... penn. was only .385 out of spec on their roller rockers( when i seen the add i phoned them immediatly) it is still in development over there..... it comes to mind that somebody should be fired for an f-up like that...

x-2 on the billet cam to grind whatever you want with it... it must be a little pricy though.... maybe time to pass around the ol R&D collection plate....lol

 

[Turbine Doc]

I really like what your doing buddy. not trying to bash you TD because you have done some great things for this engine but i think r&ding of stuff that hasnt been tested or new ideas really can get the ball rolling so more ideas can be brought to light to make a more powerful and efficent engine even after being out of production after 10 years

No problem Woody my point evidently I wasn't effective in the communication of it, is a lot of this is water that has been charted before, and found to be a lot of bang for low buck return.

That said man wasn't meant to fly or go to the moon either, nor was ATT supposed to work.

So by all means it should be explored if folks feel led to do it, realistically though we have folks that try to eek out the odd $$ here or there for the lowest cost of things griping about high cost of this & that & aren't going to want to shell out the $$$ for a special cam, lifter, or rockers so market niche would be small.

Hot rodders out for performance are in a different ball game & tend to overlook this; hats off to them as their R&D is where we get some good stuff for our daily drivers if it has a good fit.

Reason I created this forum was to have a place to discuss performance & perf. theories for the 6.5 is sort of along the same lines.

Many folks said in past the 6.5 can't be a performance engine so no need to discuss it, some folks even considered me creating this section as a place to "pigeon hole" & "hide" this discussion, far from it, as it turns out IMO it was a good decision as it doesn't muddy down & detract from the discussions in the normal 6.5 troubleshooting threads were folks wanted to run before learning to make their 6.5s walk.

We are the only site with a 6.5 performance section and it's well visited another thing I had hoped for, performance discussions often lead to "spirited" debate on which way is best to "skin the cat" as is the nature any time "gear-heads" congregate & study over an issue, so as far as I'm concerned it's "game on" for the quest for a better cam if that is your passion.

 

[randomid25]

Oh, I like those roller rockers!

 

[buddy]

I still doubt that extensive R&D was done. I have no doubt that a few people have tried one or two grinds based on some software that told them what would be best. And by all accounts I am fairly sure I have read the results were, faster spooling, that would work better with a larger turbo, higher RPM gains could be achieved. Now fast forward 2 or 3 years and you have guys thinking a larger turbo might work well on the 6.5. A lot of so called "experts" said it won't pair well, but you do it anyway and find that it works pretty well. You also have more people realizing great gains from opening up their exhaust, and even greater gains from making custom headers or honing the manifolds. And because of these advancements you have people running to higher RPMs and finding power there. These modfications employ a lot of the same principles and scientific calculations. I have actually spent many hours doing scientific calculations, not sure many others care to, its kind of a pain in the ass.

So there are more and more people willing to do all these other mods, those that can afford it of course. Engine rebuilds could easily incorporate a camshaft upgrade. So how many times do we have to read about the great turbo experiment, while not recognizing the potential benefits of other modifications. You look at the programming that everyone was doing back in that timeframe and they are incredibly basic, disappointing in my eyes. Some of them have made leaps and bounds in the last few years. Combine a larger turbo, with ported heads and manifolds, and larger exhaust, a good PCM program and a larger cam and now you are in business. As you have always said, its a combination of mods, that have to compliment eachother. Well more pieces of the pie are being used today that were not being used when most of this so-called R&D was being done.

The grind for 6.5s to date do not even come close to what I would like to do, because it is more trouble, but only time and effort will tell if the science and math pays off. And then probably only enthusiasts would care. But if you could get another 5mpg or 50 horsepower from your truck would it then be worth it? You dont know what its worth to others until you quantify it. Biggest gripe I have heard about the ATT is no quantifiable results, but so much qualitative information. Not everything produces 100hp but it just works better anyway.

The anecdotal evidence on cams from a Cummins enthusiast was obviously misleading informtiaon based on one man's preferences. I think its time to stop saying so much R&D has already been done that this is a closed book, unless the specs of the cams that were developed can be provided.

 

[6.2 turbo]

I would like to try a cam sometime. I believe with a lot of fuel and boost the right cam could make a huge difference. Probably not so much on a close to stock motor ?

 

[dragogt]

Could you use a 454 cam blank for this??

 

[Woody35]

what i dont get is the fact that everybody who has been doing 6.5 perfromance since way back in the day is saying that if you change the cam profile for a little better top end that you will lose tons of low end torque. im looking at the dmax and cummins cam swaps and the reason they do it is for better low end spooling of bigger turbos and better response. Why cant we do it for the 6.5? is it the gm engineers just did a better job then the guys at cummins and izuzu?

I know we dont have very big turbos compared to other light duty diesels but why cant we design a cam to spool an ATT, hx-35, or twin GM-Xs as fast as the stock single GM-X but still have the top end there that these bigger turbos provide?

I agree with you TD that a cam is a high dollar low return investment if you just throw into parts that werent designed to work together but if you get parts that compliment each other like Buddy said i really think they could make a bigger difference than they have in the past.

 

[6.2 turbo]

Probably because they ground it like a gas cam . Or it could be an idi thing,and very sensitive to any lost compression,which would explain low end power loss. If you have enough fuel you will light a h1c below 2000 rpms,not just spool,like normal fueling.