Dennis, cam question
09-27-2002, 10:28 AM
#12
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Location: Spicewood, Texas USA
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Kaama, I run an Ultradyne with those exact specs in my 555. It's an EFI engine, so I had it ground at 114. I have 140 hours on it so far. I run Stainless Marine exhaust with captains call. I've seen no signs of reversion and it idles very good at 700 RPM. On the dyno it made 608 HP @ 5300 RPM and 648 ft. lbs @ 4400 RPM. It fell off rapidly above 5300 RPM. I assume it was not nearly enough cam to pull beyond that, which is fine because 5300 was my target peak RPM.
09-27-2002, 10:40 AM
#13
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The 500EFI Cam Specs Crane Part Number 169621
230/236 Duration, .598/ .610 Lift on a 114 Lobe Center.
Has any one tried this cam in a 502 mag???
What changes are necessary?? I would assume reprog ecu(possibly bigger injectors ?), dif lifters because of the lift being greater than .56, dif springs
230/236 Duration, .598/ .610 Lift on a 114 Lobe Center.
Has any one tried this cam in a 502 mag???
What changes are necessary?? I would assume reprog ecu(possibly bigger injectors ?), dif lifters because of the lift being greater than .56, dif springs
Last edited by ursus; 09-27-2002 at 10:49 AM.
09-27-2002, 02:57 PM
#14
bobl,
What kind of heads are you running and what kind of port work if any? Thanks
By the way Dennis, thanks for your response. I was happy to hear that it was 112*. I have heard that when getting into the larger cubic inch engines that they tend to like wider LSA's---is that a fact or myth? If true why is it that they like the wider LSA's?
What kind of heads are you running and what kind of port work if any? Thanks
By the way Dennis, thanks for your response. I was happy to hear that it was 112*. I have heard that when getting into the larger cubic inch engines that they tend to like wider LSA's---is that a fact or myth? If true why is it that they like the wider LSA's?
Last edited by KAAMA; 09-27-2002 at 03:01 PM.
09-27-2002, 07:39 PM
#16
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Wider lobe separation
Kaama
I don't know, I have heard the same thing, I have also heard that automotive Pro Stock Drag Racing engines use 116 LSA and wider. I have heard that wider LSA increases performance at all rpm ranges including top rpm. Closer LSA angles increase performance only in the mid range (they do provide more midrange performance than a wide LSA). Could be that wide LSA is the best for extremely high rpm power.
I think 110 is optimal for a marine engine. Most camshaft designers believe that an automotive engines optimal LSA is 112. Automotive engines with large camshafts that need vacuum for power brakes and a smooth idle need 114 - 116. Not much difference between 110 and 112 but there is a difference between 110 and 114 in midrange performance.
Valve overlap is the reason for water entering the cylinders at an idle. I am a firm believer that a short duration camshaft (because the camshaft has less overlap) can use a closer LSA. Longer duration camshafts (because the camshaft has more overlap) need to use a wider LSA.
Hope this helps someone!
Dennis Moore
I don't know, I have heard the same thing, I have also heard that automotive Pro Stock Drag Racing engines use 116 LSA and wider. I have heard that wider LSA increases performance at all rpm ranges including top rpm. Closer LSA angles increase performance only in the mid range (they do provide more midrange performance than a wide LSA). Could be that wide LSA is the best for extremely high rpm power.
I think 110 is optimal for a marine engine. Most camshaft designers believe that an automotive engines optimal LSA is 112. Automotive engines with large camshafts that need vacuum for power brakes and a smooth idle need 114 - 116. Not much difference between 110 and 112 but there is a difference between 110 and 114 in midrange performance.
Valve overlap is the reason for water entering the cylinders at an idle. I am a firm believer that a short duration camshaft (because the camshaft has less overlap) can use a closer LSA. Longer duration camshafts (because the camshaft has more overlap) need to use a wider LSA.
Hope this helps someone!
Dennis Moore
09-27-2002, 09:06 PM
#17
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DonMan,
What model is your 454? Mag? Carb or EFI? Do you have silent choice or capt call exhaust?
I may wait to see how your cam swap works out. Despite the comments here, I'm very concerned that the 502/502 cam (with 9 degrees of overlap !!) will suck up water. No matter how "small" the cam is, it's the overlap that causes reversion. I simply cannot afford to destroy my engine, or even have to go back and put in a different cam later.
What model is your 454? Mag? Carb or EFI? Do you have silent choice or capt call exhaust?
I may wait to see how your cam swap works out. Despite the comments here, I'm very concerned that the 502/502 cam (with 9 degrees of overlap !!) will suck up water. No matter how "small" the cam is, it's the overlap that causes reversion. I simply cannot afford to destroy my engine, or even have to go back and put in a different cam later.
