Off the shelf cam options for marine engines
02-14-2016, 12:30 AM
#61
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This thread has been a completely peaceful exchange of info and I am asking questions in an attempt to learn. take whatever the f your problem is elsewhere or we'll get this one locked down also. I'm about to ask mt what the hell a .400 lobe is because I don't know wth that means. All I know about lift is .550 .600 etc.
Carry on
02-14-2016, 12:35 AM
#62
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I'm dynoing multiple carbs and intakes and 2 compression ratios. I might even throw my old super secret cams back in as well. I'm spending days on the dyno and will have lots of info to provide when it's done. This isn't that thread. Right now I'm trying to learn about cams.
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Straight bottoms and flat decks
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02-14-2016, 12:36 AM
#63
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This thread has been a completely peaceful exchange of info and I am asking questions in an attempt to learn. take whatever the f your problem is elsewhere or we'll get this one locked down also. I'm about to ask mt what the hell a .400 lobe is because I don't know wth that means. All I know about lift is .550 .600 etc.
.400 lobe times 1.7 equals 680 lift at valve.
02-14-2016, 12:41 AM
#64
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Listen pal, I am not trying to start issues, you were asked for cam specs and you want a discussion about specs, yet you won't post them... And I am the issue? I have here to learn also but if you want to learn and discuss put up the info.... I have every right to ask for specs as you do...
Carry on
Carry on
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Straight bottoms and flat decks
Straight bottoms and flat decks
02-14-2016, 12:43 AM
#65
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One person- mt asked the specs in a flurry of back and forth I didn't even see because I'm doing this on a phone and before I even have a chance to respond you're on here accusing me of avoiding. I don't even know what the hell a 400 lobe is or what is considered high lift and you expect me to remember a page of dozens of numbers I looked at for a minute over a week ago at the builders shop
02-14-2016, 12:48 AM
#66
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Heres comp's MARINE lobes from their master lobe list. See .400 lobes anywhere here? I don't.
But, lets look at something. Take a look at the 236 cam lobes, in standard, and hi lift profiles. Rated duration same, .050 duration same, .200 duration NOT same. Why?
Heres what Kip Fabre says on that
Someone came up with this statement and it stuck, “THE MORE AGGRESSIVE THE RAMP RATE, THE MORE OVERALL AND UNDER THE CURVE POWER”. It was probably some cam lobe designer trying to BS people. Ramp rate? What is that? Velocity? Acceleration? Degrees from .006” to .050”? You must have high acceleration and jerk to have a lobe that has a low .006” to .050” number like 49 degrees, and that will beat the snot out of the lifters and be noisy. We use a smoother ramp of about 55 degrees. The .050” to .200” can be pushed if you want a high duration @.200”, but you will have higher accelerations before and at the nose which will float sooner. If you have two cams, both having [email protected]”, one with .340” lobe lift, one with .360” lobe lift, the lobe with the higher lobe lift (.360”) will always have a higher .200” duration.
But, lets look at something. Take a look at the 236 cam lobes, in standard, and hi lift profiles. Rated duration same, .050 duration same, .200 duration NOT same. Why?
Heres what Kip Fabre says on that
Someone came up with this statement and it stuck, “THE MORE AGGRESSIVE THE RAMP RATE, THE MORE OVERALL AND UNDER THE CURVE POWER”. It was probably some cam lobe designer trying to BS people. Ramp rate? What is that? Velocity? Acceleration? Degrees from .006” to .050”? You must have high acceleration and jerk to have a lobe that has a low .006” to .050” number like 49 degrees, and that will beat the snot out of the lifters and be noisy. We use a smoother ramp of about 55 degrees. The .050” to .200” can be pushed if you want a high duration @.200”, but you will have higher accelerations before and at the nose which will float sooner. If you have two cams, both having [email protected]”, one with .340” lobe lift, one with .360” lobe lift, the lobe with the higher lobe lift (.360”) will always have a higher .200” duration.
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Straight bottoms and flat decks
Straight bottoms and flat decks
02-14-2016, 12:54 AM
#67
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See it how you like, but I can tell you my goal is NOT to cause issues. Myself having concerns on this thread because for 1, I have not even come close to power goals, and 2 I could possibly have a recipe for issues in my engines now... So yes cam specs linked to a failure is a big deal to us
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Straight bottoms and flat decks
Straight bottoms and flat decks
02-14-2016, 01:13 AM
#69
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this thread has been a good one with a lot of good information.lets not fuk it up and get it locked or removed.also,imo if you have 16 lifters in a engine and one fails[colapse]soon after startup i think the problem is that lifter,not the cam lobe.i had this happen on 3 different engines on the dyno,twice with 5w30 oil.all 3 had different cams.bck,throw all 16 of your old lifters in the trash.they can only cause you problems that you don,t need.jmo.
02-14-2016, 01:13 AM
#70
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My old cams were specd for wet exhaust, low compression (so I could run cheap gas) and because I didn't want drive problems I wanted to keep the rpm low. When the engines went south I decided to try to get some more power out of them because the boat they are in now doesn't have any of the old limitations. I can't afford to change blocks or cranks or heads so I decided to change the cams.
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Straight bottoms and flat decks
Straight bottoms and flat decks
