Simple cam swap on Gen V 454

[bigsbetter]

I'm gonna do a cam swap on my engine. The engine will remain in the boat. My curent engine consist of a bone stock 330 horse 454, with a Weiand 177 Supercharger and CMI headers. I want a little more radical/lopey idle. I've done some research and thought that going with what Mercruiser has allready done would be a good move. The cam they used in their 525SC is the same cam they used in their 400 & 420 horsepower 454's. It is Crane part number 132561. My engine has oval port heads, and I'm sure all these other engines that had this cam had the larger rectangle port heads. Is this a simple cam/lifter swap? I'm not familiar with the big blocks as much as I am with the small blocks. Will I need new push rods? Rocker arms? Should my valve springs be ok?

 

[ezstriper]

Ok, first running that blower you do not want much overlap and you will need something with a lobe separation of 114 or so, my advice is to call weiand's tech line, talk to Tom on the blower side, let him help, as you know I have the same boat as you and am building a complete 489 with that blower. I have talked to them and Tom knows whats going on, I don't think you are going get that racy sound without loosing some power with that blower, I had another cam I wanted to run but he told me not to. as far as the came change no big deal, should be a factory roller, you can change just the cam if thats the case and the factory lifters are in good shape, springs I would change and set the installed height. I'm going to be running a blower specific cam from comp, and running oval port heads as well, I think they work great in a boat for the RPM you run, even though the HP big blocks go to rect ports. you will need a balancer puller/installer and have to cut the front oil pan seal, just use RTV there when you go back together, hope this helps, Rob

 

[bigsbetter]

This cam does have a 114 degree lobe separation. The 525SC was mercruisers 454 that they had the same 177 Blower as I have installed. That's why I chose this cam because it worked pretty well on the factory built 525SC with the same blower. Mine is not a roller, it's standard flat tappet.

 

[ezstriper]

Ok, then you will need cam/lifters, but I would still give Tom a call, wern't the 525's a 502 ? that may make that choice still more than you need, also going to have to very carefull on assembly lube as all the oils now days have taken all the good break in additives out, and the first 3o min on a new flat tappet are critical. heard some diesel oils may still have the good stuff in them..not sure which ones.

 

[ezstriper]

I went to cranes website, looked at that cam, it's not a lot different than the blower cam from comp that I have, so it does look to me that should be fine...Vinny may be able to lend his expertise here....Rob

 

[ezstriper]

One other thing is going to be the pushrods, if the stocks ones are the 5/16 you are going to need to change them and the guide plates to 3/8's as those will not cut it, again I run the comp moly ones, stock lenth, Rob

 

[bigsbetter]

Rob, I was thinking about your engine set up. Those 177 blowers are designed for a basically stock engine. Is yours going to be to 'hot' for that small of a blower? You might be better off going with the 256.? Do you think I'll have to change my valve springs with the new cam?

 

[Kary]

What lift are you running on the cam?
If going to 3/8 pushrods, I have run into a problem where the ball end at the rocker arm breaks out the pivot socket in the rocker arm.
Are you running stock rocker arms?
You will definitely have to run some different springs if the lift is different. it may have some valve float on top end due to a steeper lobe profile and higher lift.

 

[bigsbetter]

Oh Man!! I knew I couldn't just do a simple 300.00 cam swap!! New Push Rods....New Rockers...... New Springs....... Screw in studs......Guide plates...... I should just leave it alone and get a different pulley for more boost!

 

[Kary]

... I should just leave it alone and get a different pulley for more boost!

That would be a lot easier and still handle it. Just make sure you use the right fuel.

 

[Old Navy]

Is a 330 Hp bottom end all cast parts, similar to the 310 hp non mag engines? If it is you may be shooting yourself in the foot here. If you are unsure keep your boost low and don't get greedy until the shortblock is up to the task. 525 SC motors have forged bottom ends, 088 heads (Gen V), big pushrods, roller rockers, and about 5 pounds of boost stock. Paddles suck.

 

[bigsbetter]

Mine is a GEN V engine, but it's not the mag so I'm assuming it has cast inerds. Currently I'm getting about 4lbs of boost, and 28 degrees of total timing...to be safe. If I swapped the cam, my guess is that the boost will probably go down to 3.5 or 3.0 lbs because of the increased air flow.

 

[bigsbetter]

OLD NAVY, What kind of GPS speed numbers are you getting with your boat? Is it stock? What prop/RPM? What year is it?

 

[SneakyPete]

Charlie,
I recomend Bob Madera of MarineKinetics in Rochester, NY. Give him your specs and he'll cut you a cam to suit, although he only does roller cams. if you want to stick with flat tappet, make sure you use Shell Rotella Diesel oil with GM EOS or Comp or Crane cam break-in suplement also in. Also, if you change springs, and you are using a double spring, you should use only the outside spring while breaking it in. I used a flat tappet cam with a single beehive spring, with a lot of spring pressure, and I follwed the above steps, along with a thorough priming, and the cam broke in fine, and looked great when I removed it. I have since changed to a MarineKinetics roller cam, and although it was almost a $1k with the retro fit roller lifters, I have much greater piece of mind.

 

[bigsbetter]

Pete,Shell Rotella huh? 15-40? I wouldn't have thought of that. A friend at work uses that in his boat ( just because he steals it for free) I didn't think the diesel oil would have been a good thing in a gas boat engine. I've always used Mobile 1 full synthetic. I need to find out what spring is recommended for this new cam and compare the specs to a stock spring. I don't think it's going to call for a double spring or anything, it's not a radical cam and I'm not going to be turning over 5000 rpm.

 

[Kary]

If you reboost and repitch the prop, you will still be running the same RPMs. I would not run more than 10 psi. It will give you as much as a simple cam swap without doing anything else. Everything works together. Higher lift=more flow=more hp it is a never ending cycle. The real solution is to throw a 1250HP Crockett in there. Mods eventually lead to a failure which in turn forces us into upgrading to what we should have done in the first place. Porting the heads would be a nice option also.

 

[bigsbetter]

Took a valve cover off. I do have the wimpy 5/16 push rods. Here are some other numbers for someone to decode for me...date code-L193, casting number is-10114156, on the guide plates says-MARK V PE, and in big letters on the head it says GM 6. Tell me what you know about these heads.

 

[Old Navy]

OLD NAVY, What kind of GPS speed numbers are you getting with your boat? Is it stock? What prop/RPM? What year is it?

My boat is not a good case study, hull wise. It has cabinetry and a refrigerator all of which are very heavy and slow it down. The mild blower motor works good and is "turn key" . My 1995 283 Convincor with a "Merc Racing" Labbed 26P Bravo 1 prop will go 5400 rpm's, which I feel is too much because of the speed the blower is spinning. Future plans include a labbed 28P B1. Those little blowers are what they are, and have limits of boost and rpm capability. With a 7" lower pulley and a 2.85 top pulley at WOT I see about 6.2 pounds of boost below the chiller. Good flowing heads will reduce the amount of boost the engine "sees" because all you see on the gage is what is backing up in the intake, basically waiting to flow into the cylinder that has the next intake valve open up. Also the chiller will cause a restriction and drop boost a pound or so. Get a crane ignition and use the curve for the 525 sc, stab a 525 cam in it-with matching springs and 3/8 pushrods, give it adequate fuel, keep the boost moderate and save money for your new drive!

 

[ezstriper]

A 454 does have all cast stuff in it..have two apart here now, also a 454 ho that has forged pistons, big rods and rect port heads, also I have seen merc 454 with 2 bolt mains..although that is not a big deal as I'm running a 9 sec outlaw pro street car with a 2 bolt 9-1 motor right now. when I was talked to Tom at wiend, he was saying with 8-1 comp. running 7 psi of boost = over 11-1 static comp. so be carefull on the boost with marina gas....one reason I'm going to run water injection as a little insurance, Rob

 

[SneakyPete]

The Rotella has more Zinc in than other oils, which helps the cam survive break in. Also make sure you prime the motor with the proper tool (the kind with the bushing that pushes oil to the valvetrain), and prime it until you see oil flowing out of every rocker. You may have to turn the motor over by hand a few times as well. Make sure you slather on plenty of that white "whale sperm" cam break in lubricant onto the cam and the bottom of the lifters. That red cam lube is no good, it drips off the cam almost immediately.
I have a Crane box and love it, it is digital as opposed to the MSD which is analog, has a built in adjustable rev limiter (great thing to have to save the motor if you scatter an outdrive) , has 9 different advance curves (including a locked out feature), has inputs for retard if you have a knock sensor, and many other features. IT is about the same price wise as an MSD box. I did have to buy a tach translator from MSD to get the Crane Box to work with my tach. You will not be dissapointed with this ignition and its many capabilities.