741 cam question
 

will i get more top end with the 741 cam in at 0 vs 4 degrees advanced. Mine is at 4 advanced and i think im losing top end power and speed vs being in at 0. Thanks

fixx
 

yes it will make more power in the upper end 5k+ ifd you can get pas the rev limiter.you will have to go to headers with dry exhaust tho..

Probably not but, if you want some valid info you'll need to post some specifics:
Engine specs: Size, compression ratio, heads, intake, carb size, or efi, exhaust type, rocker ratio, spring pressure, etc. Boat info: Gear ratio, prop size and type, type of boat, max rpm you want to turn.

Also, when you say 0, are you talking about straight up per the cam card, or retarding it 4 degrees? I don't know the specs on the 741 'cause I've never used one, but I'd guess it's got some advance ground in. Are you 4 degrees advanced of the recommended install now, or straight up? Please clarify.

fixx
 

he has his 741 cam advanced 4* because he waws getting reversion with his gil manifolds a few years back...i got 400 rpm by taking out the 4* that i advanced my cam to..

2000 32 active thunder 500hps with worked heads, carbs worked by nickerson marine, turn them 5400, 30 pitch b1s , 1.7 rollers, as fixx said i advanced them 4 degrees thought it was a reversion problem but it was not and im thinking i lost top end speed. Fixx you picked up 400 rpms turning back from 4 degrees advance to 0 is that correct.

fixx
 

400+ went from 5600 to 6+ at times lol...small block tho..my donzi is a lite boat and i really did not notice any low end loss..im going back to like 99 when i did it...i build the engine in 1997 in 1999 the pin came out of the comp cam and went through my timing chain and snapped it and exploaded my alunimum timing cover..i pulled it and had hent every valve in the heads..i ordered better valves and lapped them in..i put the cam back in at 112* and she has been rippin ever since..the idle is a little ruffer tho..

So you have it at 0 now no advance.

If you put it in at 4degrees advanced on the sprocket, which is in addition to the advance ground in to the cam, then you're probably
around 8 degrees advanced and would benefit from putting it back in straight up at the factory specs, which are likely 4 degrees advanced. Do you have a degree wheel? If you're truly only 4 degrees advanced total, then I don't think you'll gain anything by retarding it 4 degrees. If it runs stronger at 4 deg retarded then you could use a bigger cam.

So where is this cam installed now? ICL?

Loading them at the recommended ICL is always the best in my opinion unless you have the wrong cam for the application. So if your rev limiter will let you get to 55-5800rpm you should set it straight up. If you are limited to 51-5200 or so you probably need a more stump puller type cam. In that case I'd change the rev limiter and set the cam up to spin the Rpms it needs.

It is advance 4 on the sproket rather than on 0, and as for rpms i do have msd boxes set at 5800 and i spin them up to 5500 or so. Will i benefit more by just going back to 0 on the sproket or shoulsd i use a degree wheel and get it as close to 112 as possible. Thanks Guys

I want to say that straight up install should be around 107* with the 741. The cam has advance built into it. If you put a degree wheel on it, you should see 103* as it sits. I personally, would go back to where it needs to be (107). 112 would be 4-5* retarded if my assumption is correct on that cam. With a 502, that cam, I'd go straight up. That stick in a 540, I might go 2-4* retarded.

How much power are you giving up? IDK. I want to say general rule of thumb, and this is very general, is 20-25HP gains 100RPM in boats. I dont think by retarding it back to where it should be will net a 400RPM gain. Which in most boats will net 5, 6, 7 MPH in top speed. I think i'd be being realistic in assuming by putting it back to straight up, would net around 25hp'ish, at 5500-5600. Which may get ya 1-2mph at most. I dont see big gains happening, but Im no expert.

Really is a conversation to have with Bob Madera.

Specs for the Crane 16741 http://www.cranecams.com/product/car...detail&p=24283

IMO, I think that all the 4* advance is doing is moving the torque/hp band down 200-400rpms. If you want to run it up to higher rpms, like 5800, it would probably make more power up top, but it would probably lose a little torque in the 2500-3500rpm range. I doubt you will see more than a 100 rpm gain.

You should always use a degree wheel period. I think you are confusing the LSA with the ICL.