comp cams xtreme marine

duane.mosley

i am building a 377 stroker and found this comp xtreme marine cam that seems to be perfect with the power range being 1000-5000. does anyone here have experience with this cam? right now auto zone has 20% off ship to home which would bring their price to 663.99 with free shipping. the price is amazing so any thoughts on this cam before i make the purchase would be awesome. thanks in advance

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=201&sb=2

duane.mosley

but then again this one sounds very appealing as well. this engine will be going in an '06 250ec that weighs 6450 dry.

http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=202&sb=2

BellevilleMXZ

Whats stock cam specs, able to find any? I know Gi and Gxi are the same, Gxi used 1.6 rockers, instead of 1.5

duane.mosley

this is what i found on summit for the specs on the factory gm 7395 cam shaft. seems to be a considerable difference all around. between the first comp cam i listed.


https://m.summitracing.com/parts/nal-14097395

Handymans342

Wouldn't you want a cam that would make the motor a stump puller similar to a hole shot?

duane.mosley

Handymans342 said:

Wouldn't you want a cam that would make the motor a stump puller similar to a hole shot?

which cam is going to provide that?  i'm not an engine builder so that is why i'm asking questions from the guys that have been around the scene longer than myself. all i know is that my 250 would stand up with 6 people and 50% fluids in their tanks with the 5.7, trim tabs and drive all the way down. 2 people would have to go to the v-berth and a 3rd would have to stand in the door way to the cabin to get on plain. original engine is the 280hp 5.7 osi-ef volvo penta  DP with f-3 blades. boat would come out of the water good with 2 people but if i fill the fuel tank it was sluggish.

Handymans342

Where is Al?

NavyCTRC

I agree with Al.  Marine engines are different!  The tight tolerances alone tend to dissuade modification.  There are some builders out there that can do it, but it is VERY expensive to boost the HP on marine engines, once they reach a certain point HP wise, it is cheaper to get a new higher HP motor than attempt to squeeze the current block for every small HP gain.  Even then, they tend to not last long.

duane.mosley

i truly respect your opinions, i honestly do, that's why i post in this forum, but i have to ask. what is the difference in what I'm doing vs what the manufacturer is doing? i am taking a 350 marine block and converting it to a 377. I'm not porting and polishing heads, I'm not milling heads and decking  the block for CR increase(although i have been reading about "zero decking to get the perfect quench for helping to eliminate pre-detonation) , I'm not boring the cylinder walls on my block because it doesn't need it. i am not putting a radical cam into the engine(hence the reason for this post)i just want a cam that is going to do what i need it to do.  i am putting ALL brand new components into the engine that have been tried and tested by the people that sell them for this very application. isn't that the same thing that mercury marine is doing? why would i want to pay mercury marine twice the amount of what i can do it for myself? they want 9500 bucks for a drop in ready 6.2 and i can have it done myself, replace everything in my bilge, and still not be at 9500 bucks.  i know i am not the engineers at mercury by any means, nor is the man building my long block, but he is a reputable engine builder in my area. i don't understand why what I'm doing is any different?

Handymans342

I think it has to do with the computer

duane.mosley

Handymans342 said:

I think it has to do with the computer

Even if I buy a new Mercury ECM and harness, it's still cheaper than buying the one drop in ready. I started a new research agenda  of finding the factory specs for the mercruiser 6.2 mag camshaft. I will dig in more tonight when I get done working

Handymans342

Sounds like it will work. I did the same thing with my 350 truck motor. Crank and Cam that was it.

randy56

duane, Your on the right path man, anytime I've been around guys that try an Hot Rod there boat engine, it comes back to haunt them. Stick to specs. 

 Short story: Two guys each bought brand new 26 ft scarabs,  with the smallest big block they could get, both pulled engines out got rid of the whole engine,  started form scratch building hot rod motors.
Both with different ideas on how to use different cams and pistons, Heads, and carbs, ect. One guy ended up putting 5 motors in his boat in two years. They would run great on the dino, but when they put them in the boat. They blew up. Those motors cost more than he payed for the boat. Then he sold it for half what he paid for the boat. Smart guy's lost about $100k. each. And he did not get to go boating much. 

69fastback

Alswagg said:

Ok first off are you building a 383 or a 377?   Not the same.  What is you hp hopes?   320-330 hp? Ok fine.   390-400 no way will it be reliable with the load you are experiencing with a 250 Rinker. A 377 is a stroked 5.7 by Merc.  A 383 is bored out and stroked 5.7. Many have clearance issues.   

What kind of clearance issues? The crank counterweights clearing the block?

duane.mosley

randy56 said:

duane, Your on the right path man, anytime I've been around guys that try an Hot Rod there boat engine, it comes back to haunt them. Stick to specs. 

 Short story: Two guys each bought brand new 26 ft scarabs,  with the smallest big block they could get, both pulled engines out got rid of the whole engine,  started form scratch building hot rod motors.
Both with different ideas on how to use different cams and pistons, Heads, and carbs, ect. One guy ended up putting 5 motors in his boat in two years. They would run great on the dino, but when they put them in the boat. They blew up. Those motors cost more than he payed for the boat. Then he sold it for half what he paid for the boat. Smart guy's lost about $100k. each. And he did not get to go boating much. 

definitely not looking to hot rod. just looking for efficiency and torque and if i can get a few mile per hour on the top end i won't complain. if the cams in this thread are "too hot rod", that is why I'm asking. i am trying to absorb as much info as possible before i buy anything. the machine shop has all of my components and is going to give me an estimate on what he thinks based on the research that he has been doing(he is also a boat guy). i will combine the info i gain on my own and listen to what the machinist has come up with and make a final decision.

69fastback

Well, crank to block clearance issues, are really a non issue. I've built multiple engines with more stroke than stock, and have had to clearance the block on all of them. There's really nothing to that. 

gtyee

Just turn the air cleaner over and put a pair of glasspacks on it! 

duane.mosley

Alswagg said:

Ok first off are you building a 383 or a 377? 

i edited my original post, sorry for the understandable confusion. my thoughts were to just keep it a 377 so that i didn't have to bore the block.                                                         

Alswagg said:
 What is you hp hopes?   320-330 hp? Ok fine. 

my HP hopes were in the 330-350 range. i am looking to get more low end torque than anything. i'm not looking to go 40mph in my 250 rinker, i just want to know that when i have 6 people on board with 50% fluids in the tanks and a cooler full of our favorite beverages, i can get on plain with more efficiency. i don't want to have to ask 3 of my 5 passengers to move forward so that i can plain out. i experienced that this year and i didn't like it. i'm perfectly fine cruising at 25-28mph but if i could move that to 30-32 i wouldn't complain. i just don't want it standing on it's stern trying to get on plain.

duane.mosley

Alswagg said:

When you get your motor completed I can give you some ideas for quicker plane times      

thanks AL. i always use trim tabs and drive all the way down. try to keep the cooler in the cabin and all safety gear stays under the seats in the cabin.

SeaHare

hey duane, keep us updated how the build goes. Im thinking about doing the same thing with my engines.. carbed 5.7 mercs. Would like to build them into 383 or 377's. 

duane.mosley

talked to the machine shop today. with purchase of the crank kit, all the machine work necessary and assembly of the long block, it is going to run me 2300 at the machine shop.  turns out 3 of my cylinders had some minor scratches and we are going to bore to .030. he said that it was border line that with the fact that i'm going ALL NEW on this build, he would feel better about his warranty if we bored it. with the purchase of new tins, new gaskets, cam and lifter kit with all new springs and push rods, i should fall in just under 3300 for the build from oil pan to intake. i am considering replacing my sensors and fuel injectors and haven't priced all that out yet. all and all, i'm thinking under 5000 and that's replacing bilge pump and float switch, both exhaust manifolds, both water pumps, a few hard to get hoses, motor mounts, bellows, and a few other things. i just did the shift cable beginning of this year. this of course is just to get everything back in the boat and ready to run, the ECM issue will be it's own animal once i get it back together.

randy56

sounds like you picked the right machine shop, You have saved as much as is gong to cost, by doing the labor.  Paint her up good make it pretty. 

Always in fresh water, I'm surprised the exhaust manifolds need replaced.

duane.mosley

randy56 said:

sounds like you picked the right machine shop, You have saved as much as is gong to cost, by doing the labor.  Paint her up good make it pretty. 

Always in fresh water, I'm surprised the exhaust manifolds need replaced.

  I've been dealing with this machine shop for quite a while. a good friend of mine has used them for 30 years . just one of them little hole in the walls that's been around a long time for a reason. with that said, he'll probably have my motor for 4-6 weeks from beginning to end. he has had it for 3weeks so far and i still have to order my cam kit. he says he can compete on prices for the cam but his guy is on vacation so I'll have to pull the trigger for a comp cam. I've been busy the last couple days and crashed right after dinner last night so i haven't purchased the cam yet.

  I  have always been a do it myself kind of person. i would be doing the assembly of the long block as well but he is only charging 275 bucks to assemble it, that to me is worth it for the 1 year warranty. for what I'm doing in the bilge compartment between cost of parts and time in cleaning, figure that I've saved a few grand in labor easy. not too mention the mark up on all the parts that I'm buying. i will certainly be painting it up and have it looking good. still debating on painting the bilge directly under the motor to clean it up and make it pop.
 
 i bought the boat out of Tennessee, but you can see the shadow of FL in the gel coat so not so sure it's stayed in fresh water. one of the manifolds is newer and one is looking borderline. i figure with where I'm going with this build, and our plans to keep the boat for a while, I'm going to get new manifolds so i know what I've got. hopefully set it and forget it for a while!

212rowboat

disregard.... 

Handymans342

Thanks Brofessor 212. I was wondering when you were going to write a chapter LOL

212rowboat

Nt

Handymans342

212rowboat said:

disregard.... 

What happened?

duane.mosley

212rowboat, where did your posts go? i read it from my phone and went to my pc to reply and it's gone? i honestly value your opinion, from your posts i can tell you know your stuff.

Handymans342

I think the EPA showed up and put him in jail lol

randy56

how much is bail, I'll bail him out, I read it also. 

duane.mosley

Alswagg said:

I would not recommend modifying these motors.  I have stated several times in the past.   Sorry.  

i decided to take your advice Alswagg.  i got the completed 5.7 engine back from the machine shop today. after all the reading and research that i've done, it would be a big headache trying to make the stroker work with the MPI. (if it were carb'd it would be a no brainer to go 6.2)

    spent 1900 at the machine shop with all new pistons, roller cam, lifters, crank, all necessary head work and assembled intake to oil pan, with a 12 month or 100 hour warranty.  after i replace everything that i plan on replacing and doing the work myself, we will have a new engine, bilge pump, float switch, blower motors, cleaned the fresh water tank and holding tank, cleaned the bilge,  in and out for less that 2500. got it all painted today and will start bolting on the brackets  and externals tomorrow.