Cam and valvetrain longevity....??? low duration high lift...
09-19-2016, 07:36 PM
#182
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My buddy had a lengthy talk with the MP chief, he was a decent guy to deal with. Since he brought the boat into compliance within a week they dropped the $310 fine. However, if he modifies the exhaust from the state it was in that passed the test within one year there is a huge fine associated with it.
09-19-2016, 07:44 PM
#183
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Wow !
09-19-2016, 07:46 PM
#184
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Shop by me recently built a 496 ci. 10.2:1, GM Rect port iron heads with a nice valve job, no port work. Cams were hyd roller 242/254 112 LSA, .679/.679 lift. Victor JR intake, holley EFI . Peak was 645HP at 6200, 595FT lbs at 5000, still making 575ft lbs at 4000. Pretty darn good considering the GM iron heads , not even ported imo.
Wonder what it made at 5,800? I hit my realistic goal on a known dyno that is consistantly 25 to 50 hp lower than all others. It was more of a tune thing than happy numbers. Maybe Tim ought to throw away his engines and build some $5k 496's.
Oh forgot to mention Super Chevy must worked some real magic on a pump gas 700 hp @ 6,200 with 642 torque @ 4,600. That's totally bad to the bone RIGHT. Lol.
Last edited by getrdunn; 09-19-2016 at 08:46 PM.
09-19-2016, 07:51 PM
#185
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Tat minds me and not about you, just all over the world basically,
Everyone says they dyno on stingy dyno's and their heads are flowed on low reading benches.
Funny how it works.
Everyone says they dyno on stingy dyno's and their heads are flowed on low reading benches.
Funny how it works.
Last edited by SB; 09-19-2016 at 07:53 PM.
09-19-2016, 08:00 PM
#186
Registered
I've had a few friends run the 651 cranes in blown 540's. Icdedppl, mike tkach, Kvogt, etc.
For an off the shelf cam, they work very well. With that being said, it basically is a supercharger /nitrous cam. If I were building a N/A 540, with good exhaust, good cylinder heads, it wouldn't be my pick of cams.
The 651, with 12 degrees of split, can kinda hurt the torque. It will hold on better in the upper rpm, vs say a 244/248 cam, but will more than likely give up some midrange power. Single pattern cams can make great street cams. They really build some torque. But they tend to die off in the upper rpms, as the blowdown phase is simply not as good. Works great with a blower, when you need that extra time to evacuate the cylinder.
With that being said, that 651 cam, might have worked substantially better in tims build, where if in fact, his exhaust system, isn't up to par. I think you SB, had mentioned that scenerio before. You can really dial an engine combo in, when the engine has the proper designed exhaust. You can then take advantage of scavenging, overlap, and so on. But if the exhaust is crap, the cam really needs to be adjusted for it.
For an off the shelf cam, they work very well. With that being said, it basically is a supercharger /nitrous cam. If I were building a N/A 540, with good exhaust, good cylinder heads, it wouldn't be my pick of cams.
The 651, with 12 degrees of split, can kinda hurt the torque. It will hold on better in the upper rpm, vs say a 244/248 cam, but will more than likely give up some midrange power. Single pattern cams can make great street cams. They really build some torque. But they tend to die off in the upper rpms, as the blowdown phase is simply not as good. Works great with a blower, when you need that extra time to evacuate the cylinder.
With that being said, that 651 cam, might have worked substantially better in tims build, where if in fact, his exhaust system, isn't up to par. I think you SB, had mentioned that scenerio before. You can really dial an engine combo in, when the engine has the proper designed exhaust. You can then take advantage of scavenging, overlap, and so on. But if the exhaust is crap, the cam really needs to be adjusted for it.
I also find it hard to believe how much power valako is making with such a small cam. Makes ya wonder what he knows that many don't with his NA 784 hp @ 6,000.
09-19-2016, 08:10 PM
#187
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I've seen some engines ran on dynos from 50 years ago, with god knows what for calibration, no data aquisition whatsoever.
Obviously a builder can skew dyno results with correction factors and so on. However, building a good dyno cell, is another deep topic. Theres way more to it, than simply strapping on a dyno, some exhaust pipes, and a blower fan. A chitty dyno cell, with poor air supply/venting, poor exhaust plumbing, and so on, can certainly have an effect on the power output, uncorrected.
09-19-2016, 08:45 PM
#188
Registered
Yea, pretty much anyone who doesn't make the number they want, or as good as another combo, its a stingy dyno. Those who make a number higher than others, that dyno is called optimistic.
I've seen some engines ran on dynos from 50 years ago, with god knows what for calibration, no data aquisition whatsoever.
Obviously a builder can skew dyno results with correction factors and so on. However, building a good dyno cell, is another deep topic. Theres way more to it, than simply strapping on a dyno, some exhaust pipes, and a blower fan. A chitty dyno cell, with poor air supply/venting, poor exhaust plumbing, and so on, can certainly have an effect on the power output, uncorrected.
I've seen some engines ran on dynos from 50 years ago, with god knows what for calibration, no data aquisition whatsoever.
Obviously a builder can skew dyno results with correction factors and so on. However, building a good dyno cell, is another deep topic. Theres way more to it, than simply strapping on a dyno, some exhaust pipes, and a blower fan. A chitty dyno cell, with poor air supply/venting, poor exhaust plumbing, and so on, can certainly have an effect on the power output, uncorrected.
I'm curious, how much does a guy like haxby, mer, or the other top builders squeeze out out of a build, using like parts, besides the reliability that comes with it. They all have their recipes and trade secrets to do what they do but never chime in on threads like this to toss out a bone. Too bad...
09-19-2016, 09:31 PM
#190
Registered
As far as cams, the answer prob lies in the .100.,200.and higher lift duration #'s.along with tons of valve train stability techniques.
