Off the shelf cam options for marine engines
02-14-2016, 12:09 PM
#91
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I sure wish this thread would have popped up last year before I dropped a bunch of coin on a custom cam setup. It's got my attention and making me second guess if what I have is worth a chit or not. Lucky for me I haven't fired it up or put it in the boat yet, maybe I need to do a little more homework before I go any further.
02-14-2016, 12:21 PM
#92
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02-14-2016, 12:27 PM
#93
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And when the valves are slamming shut and bouncing off their seats, power goes down, heat goes up. Even on what should have been milder cams, the unstable custom lobes caused significant damage to the valve seast. New AFR heads with less then 100 hours needed major work to fix the exhaust seats that had been pounded in to the head. The problem gets worse when the seat moves from the extreme heat and the valve seal gets worse. These were on 4400 max rpm engines. It was on two different engines and made me question the quality of the AFR heads before I realized completely what was going on.
02-14-2016, 12:29 PM
#94
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Sometimes you can tell right off the bat, just based on the specs. Other times the specs look good, and you won't know until you try it. Essentially your engine becomes the spintron machine, on your dollar. Roll the dice.
02-14-2016, 12:37 PM
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Absolutely. The engine that rattled the tie bars off the lifters was in a guide boat. The rpm history showed the majority of the engine hours were between 3200 and 3400 rpm. Obviously there was something in that rpm range that was causing issues. The heads were hurt, and you could see the heat wasn't getting out like it should. That engine has over 700 hours on it now with a shelf cam. I just recently took apart another one, that was almost an identical build and it had popped the tie bar off one pair, and was about to lose another. I put it back together with a take out 500 efi cam and it's working well. Made a bit more power then the original cam too.
Last edited by HaxbySpeed; 02-14-2016 at 12:43 PM.
02-14-2016, 01:23 PM
#97
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The best cam is going to be junk if all the supporting cast members aren't in the show. I'd love to see the geometry on some of these engines that have valve train problems and the cam is being blamed. Spring selection and set up can be really critical from some of these builds and the geometry on some of these after market rockers really sucks. We're fixing that. 
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3/8 x .080 wall pushrods aren't going to cut it either on most of these builds.
.3/8 x .080 wall pushrods aren't going to cut it either on most of these builds.
Last edited by horsepower1; 02-14-2016 at 01:26 PM.
02-14-2016, 01:32 PM
#98
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The best cam is going to be junk if all the supporting cast members aren't in the show. I'd love to see the geometry on some of these engines that have valve train problems and the cam is being blamed. Spring selection and set up can be really critical from some of these builds and the geometry on some of these after market rockers really sucks. We're fixing that. .
3/8 x .080 wall pushrods aren't going to cut it either on most of these builds.
.3/8 x .080 wall pushrods aren't going to cut it either on most of these builds.
02-14-2016, 01:37 PM
#99
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I see the morel lifter name getting tossed around on this thread. Just had a set put in our 500's. They seem to be the company of choice by many of the top builders. Not just in the marine world but also the car game.
02-14-2016, 02:08 PM
#100
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The best cam is going to be junk if all the supporting cast members aren't in the show. I'd love to see the geometry on some of these engines that have valve train problems and the cam is being blamed. Spring selection and set up can be really critical from some of these builds and the geometry on some of these after market rockers really sucks. We're fixing that. .
3/8 x .080 wall pushrods aren't going to cut it either on most of these builds.
.3/8 x .080 wall pushrods aren't going to cut it either on most of these builds.
