Off the shelf cam options for marine engines
#221
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#222
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Heres a good example of what sometimes works out as a basic combo, that yields good results. Sure we can talk about CSA's, valve job angles, throat diameters, area under the curve, .020 of valve lift, and all that stuff, all day friggin long.
Last year, a boater friend I had met a poker run, asked me for some engine input. He had a set of stock HP500 engines, with 250 blower shop blowers. Without getting into the fine details, I basically told him I would go with some aftermarket heads, Dart, AFR, Brodix, and swap the stock HP500 short duration narrow LSA cam, for the 525EFI merc/crane cam.
Today I get a text from him, saying thanks for the advice, as he just had that combo dyno'd. They were stock HP500s, with Dart 325 pro 1's, with 525EFI cam, and his little 250 blower shop blowers, and a single dominator. For a budget upgrade, I think it worked out nice, and should see a nice speed increase, in his smaller twin engine boat, that already was hauling azz with the old setup. Was it a super high tech build that needed several months to plan out, no. But what it should be, is a well running combo in his boat, and have a mild camshaft that should be very easy on parts. Is the 325cc head a bit large, maybe, but certainly isn't lacking in the torque department. 780HP with a very nice torque curve, with low boost, should work nicely.
Last year, a boater friend I had met a poker run, asked me for some engine input. He had a set of stock HP500 engines, with 250 blower shop blowers. Without getting into the fine details, I basically told him I would go with some aftermarket heads, Dart, AFR, Brodix, and swap the stock HP500 short duration narrow LSA cam, for the 525EFI merc/crane cam.
Today I get a text from him, saying thanks for the advice, as he just had that combo dyno'd. They were stock HP500s, with Dart 325 pro 1's, with 525EFI cam, and his little 250 blower shop blowers, and a single dominator. For a budget upgrade, I think it worked out nice, and should see a nice speed increase, in his smaller twin engine boat, that already was hauling azz with the old setup. Was it a super high tech build that needed several months to plan out, no. But what it should be, is a well running combo in his boat, and have a mild camshaft that should be very easy on parts. Is the 325cc head a bit large, maybe, but certainly isn't lacking in the torque department. 780HP with a very nice torque curve, with low boost, should work nicely.
#223
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No problems here.. 251/260 @ 0.050, .671/663 on a 114. My boat gained 100-200 rpm on top and 3 mph going from shelf Crane 138631 solid roller cams to to custom hydraulics. Used the old solid cams as a starting point to convert to hydraulic since I was happy with those cams.
I was happy with bolt the shelf and custom cams...I got tired of lashing valves every year.
I was happy with bolt the shelf and custom cams...I got tired of lashing valves every year.
That Crane solid roller profile, is VERY mild for a solid roller cam.
304/312, 254/262, .636/.636 valve lift (.374 lobe).
You switched it out for similar duration, .671/663 (.394 lobe) hydraulic roller.
Without having all of the camshaft details, I'd be willing to bet that the hydraulic roller you switched to, not only has more lift, probably also has a more aggressive lobe than that particular solid grind you mentioned.
Now, try putting that hydraulic roller up against a solid lobe, that is comparable, and I think you'd find the results would have been a bit different. Just because a cam is designed for a solid, doesnt make it more aggressive, and just because a cam is designed for a hydraulic, doesnt make it less aggressive. I'm not a cam guru, but plugging those basic numbers off the cam card from that solid crane there, into my simulator, shows its lifter acceleration to be, very tame. I've seen off the shelf hydraulics more aggressive than that as far as lifter acceleration goes. Its spring recommendation of 190lbs on the seat, kinda says something in my opinion as well.
#224
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Yes, and in my case, my builder sent a Callie's 3 pc core to Lunati to have ground. They have a state of the art Landis machine . The Voodoo lobes are slightly less lift versions of Harold Brookshire's later (or last) hydraulic roller designs and I'm pretty sure that Lunati could still grind them for you or tell you who owns the files. Brookshire had a wonderful reputatation as a cam/lobe designer, but it is VERY important that you are adept at degreeing a cam and use an adjustable timing set such as a hex-a-just....definitely not a cam you can line up timing dots on.
#225
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You just had to integrate that into your post..... ;-)
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not same dyno I get that, but I am told my exact combo made 716 hp with a dominator, I have 1050 carbs but 4150, also only using 870 CFM so I am way off that number....boat runs 73 mph as of now.
I am not trying to cry about my situation I just wonder why my fully custom build does not perform as good as the "standard recipe 540" builds... Cig rockets Mistress had 315 afr with 741 cams his engines made 687 HP I think it was and boat went 75 mph easily he said at 5350 rpm so it just proves shelf cams are just fine if not better in some cases...
I am not trying to cry about my situation I just wonder why my fully custom build does not perform as good as the "standard recipe 540" builds... Cig rockets Mistress had 315 afr with 741 cams his engines made 687 HP I think it was and boat went 75 mph easily he said at 5350 rpm so it just proves shelf cams are just fine if not better in some cases...
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with marine exhaust and accessories? I guess I also need to look at mine made that power with those things, not everyone dynos that way... so if not what kind of actual loss do they cause me?
The power curve of the engine will move upward as the duration does. Sometimes not as much as I would expect, especially with good cylinder heads. There's too many variables to determine exact hp. Running all your specs through a program like pipe max can certainly help get closer. Based off of other builds I've done and seen. I'd probably go with the 238 / 248. and look for around 650 hp at 5700 ish. Of the heads flow better then I guessed, peak rpm will move up a bit. It should make around 675 torque
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true thanks bud
Tim has a thread in the Cig section we should discuss more there.
http://www.offshoreonly.com/forums/c...-2-begins.html
http://www.offshoreonly.com/forums/c...-2-begins.html
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Yes, that would be fully dressed. I'm not familiar with the 310 head, but guessed it was probably close to an afr 305. That combo will make 675-685 with dyno headers and no accessories. Yours might pick up 25ish with headers, but it usually raises the rpm a couple hundred too. Your motors aren't complete turds, but it could make that power at 5200. I can't believe it's spinning almost 6k to make that number. Honestly, I've made similar power with a 509 at that rpm.
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correct, a buddy of mine made 621 hp similar rpm and 641 TQ with 502's so to me mine are nothing amazing at all, not horrible but not breaking records....
Yes, that would be fully dressed. I'm not familiar with the 310 head, but guessed it was probably close to an afr 305. That combo will make 675-685 with dyno headers and no accessories. Yours might pick up 25ish with headers, but it usually raises the rpm a couple hundred too. Your motors aren't complete turds, but it could make that power at 5200. I can't believe it's spinning almost 6k to make that number. Honestly, I've made similar power with a 509 at that rpm.