New 540 Combo
 

So I'm looking for advise on my winter project. The boat is a 2001 single engine 28' stepped vee bottom bravo 1 believed to weigh somewhere around 6500 lbs loaded. It had a 502 mpi that I said I was going to leave stock :D. The plan is to install the 540 N/A for now and at some point add a Vortech/Procharger. I come from the car world and this will be my first attempt at a marine engine so let me know if something is out of place or not matched.

Stock GM block 4.5 x 4.25 +.005 decked flat top 9.3:1, .040 cometics
2200 cfm throttle body, Holley single plane 4500 efi manifold and Micro Squirt controller
AFR 315 cnc W/Inconel exhaust valves, scorpion rockers with girdle
Imco power flow's through transom no mufflers
Johnson or Morel lifters
I'm not 100% sure on the cam but thinking .640ish [email protected] intake and 249 exhaust
hoping for peak power around 5800-6000

Thanks for looking.

should be a nice engine, i think a crane 139651 cam would work great.

johnson lifters,the above cam and I'd change the exhaust manifolds to stainless marine gen 3's.

I'd go with a .051 gasket if the piston is out of the hole .005.

I hadn't seen that cam in my searching, do you think it needs that much exhaust duration for the blower or the small exhaust pipes?

On the head gaskets, the piston at full tilt was something like .018 which I'll have to double check but that would give a .022 quench before thermal expansion. I always thought the tighter the quench the more resistant it would be to detonation?

The exhaust and drive will definitely be upgraded before the blower goes on.

Thanks for the comments, keep them coming.

In a bbc marine build with steel rods, i personally would go with .040 as a minimum, .060 as a maximum for an NA build.

If the cam you posted, and the 651 were my only two choices, i would go with your cam out of the two, with a 112LSA. Jmo.

The 651 cam from crane is a 244/256 114 LSA 632/632 lift

I assume the heads were surfaced also, in prep for the desirable, in that app.mls gaskets?
Should be a runner , quadrouple check your comp ratio calculations would be curious what your finished chamber volume is on that one .

The cam and lifters haven't been ordered yet so they are still a blank sheet of paper..
The heads are box stock and Afr claims they are 121cc so if the surface checks out good for mls gaskets they won't be surfaced.

I can pass on some info on what my motors are...
547's...10.3.1 pistons..
CFE heads, completely reworked, new everything
isky solid roller 710 lift, 286/294 adv duration red ball lifters needless
4500 carb...deck height was zero
new comp cam rockers
think clambers were 118???
mls head gasket...

going take boat out for first run since rebuild boat sat morning

i am confused,is the piston .018 below the deck or above the deck.also on my cam,the 651 has been used in hundreds of 540s,i have used it in my own 540,s with great results but the max power will be closer to 6400 rpm.

The center of the piston is .005 above the deck but with piston rock it could be as much as .018 above the deck.

I like the 651 cam in a blower motor. Ive seen it used in a NA 540 with afr cnc heads, and wasnt all that impressed. It didnt pull quite as high without the blower helping,

Reason i say id go with the 243/249 cam over the 244/256, is because i dont feel he needs the 12* of split with a cnc ported head, and assuming hes not going to be running a ton of boost with a 9.25:1 engine that will start out as Naturally aspirated.

The 651 cam in the afr cnc headed NA 540, made 660ft lbs peak at 5000rpm, and 670hp at 5700. Not bad. But, the torque from 3000 to 4000 rpm, was down quite a bit. Like 70-80ft lbs from peak. ..

If youre interested in a procharged engine build, you certainly dont want a cam thats weak until you start building the boost as rpm increases. Thats exactly what you'll get when you have a huge split in duration. Not really an issue with a roots or whipple..

By shortening up the split, and tightening the lsa a little, youll have an engine thats a little happier off boost..... when you have a procharged engine, making 1000hp at 6000 per say, and capable of turning say a 36p prop, last thing you want is an engine that is gutless at planing speeds trying to turn that big wheel. Pretty much why nobody builds a 7.5:1 long duration engine for a procharger boat engine.

Yikes. This with flat top with a 3cc or so valve relief? Personally I've never done a build with anything less than .005 in the hole and like to see .008 but that's just me. Not knowing exactly what gaskets you'd be using I come up with a little more comp than you. If your going to add a procharger wouldn't 9:1 comp max be more of a target? Just curious. Can always open up chambers to 125-126 but to lose a little if need be.

Yeah it's a 3cc relief. With the 502 rotating assembly it was .003 in the hole and now it's .005 out with the new stuff. If I go to a .051 gasket it will be 9.15:1 which is probably the right thing to do, I just didn't want it to be a dog N/A.

Thanks mild thunder, a lot of good info there. The 243-249 cam is a Howard's 120666-12 so it is on a 112 separation.

Is a tighter quench more resistant to detonation? I always understood it to be that way but not a 100% sure. Just wondering best way to achieve what you need and considering future add on. I'm kinda in the same dilemma with my builds. I wanted to max out 565 aluminum head builds with 10.5 CR however am considering super chargers at a later date which really kinda sucks for cam selection etc if I build for future SC. So dish or dome? I just know after a season or two of NA, chit will get old. Maybe dish and blowers when time for rebuild.

Btw when you have like hours to kill and wanna read up on cam thread check out full forces recent. Lots of good info.

I assumed it was a howards grind when you gave those specs.

Id go with the .051 gaskets. It wont hurt a thing , and you wont be knocking the carbon off the quench pad of the piston .

My little bit of advice....

Buy heads BARE and have them done by someone you trust... especially for marine use, after what I went through I will never buy assembled heads again..

Research cams and combos, you will need to know if you are going to boost it or not and cam accordingly, or find a middle of the road cam that works well both ways.

Recent convos with marine builders guys are steering away from Aluminum rockers, yes Cranes were used for years and years, but seems the quality is not what it once was with aluminum, Look at the Comp or crower stainless, I am replacing mine this winter with them to be safer...

Johnson lifters offer axle oiling and a great lifter, guys love Morel also, recently I read a lot of plunger issues but not sure if that's lifter caused or otherwise...

Good luck and post results!!

Definitely, the best cylinder head guy in the state is a good friend of mine so I have no doubt that they will be right when I bolt them on. The whole idea of stud mounted rockers is a step back in time for me but at hydraulic roller pressures I don't think shaft mounted rockers are necessary. I could only find one dyno sheet with the Howards cam I'm looking at and it made right at 700hp @ 5950 rpm (more compression and smaller heads though)

http://www.chevelles.com/forums/89-e...install-2.html

I read the link from your above post and did I read correctly that the OP ended up with the edelbrock e street oval port heads. 290cc. Maybe 300-305 after port work. Would like to have seen what those heads flowed after port work and assuming lager valves. I thought I read at one point he made 694 hp at 5350???? Yet dyno sheet showed 682 at 6,000 however claimed to make over 700. Unless there was another posted dyno sheet I didn't see. I will go back and read from the start 1-4. Regardless good results. Your 315's will offset the CR hp loss I would think easily.

with the use of imco powerflow manifolds i think the extra exhaust duration might be a plus and with 9.2 to 1 c/r it should plane pretty quick.i put a much larger cam in a m3 pro charged 565 and it has a little trouble plaining but it is in a heavy cat with a 1.30 drive gear.what a computer program pits out does not always equil real world results.i do agree that the other cam in question would be a good choice but it might leave some power on the table.EDIT IN,for me a pro charger for marine use is my last choice.

That's some great power coming from edelbrock oval port heads. Somebody evidently worked some magic with them to get those kind of numbers. Although headers and water pump only..

i would use a head gasket at least .060 thick.

I did a similar build..

Ran 82 mph in my 26 Corsa naturally aspirated...

Haven't run it in a boat with the blower yet, I bought a different boat and haven't had a chance to install this engine..

N/A dyno...
https://drive.google.com/file/d/0B8O...ew?usp=sharing

https://drive.google.com/file/d/0B8O...ew?usp=sharing




Link to my build...

http://www.offshoreonly.com/forums/g...o-results.html

Nice work. Cam specs look familiar for some reason. Btw any flaws with injectors etc or has it been pretty stable.

That forum post was a little hard to follow but either way it made decent power.

Awesome, exactly what I have been looking for.Thank you! I bet those injectors were about tapped out.:D

Don't know yet.. I've only put about 10 hours on it in the Corsa without the blower and decided not to continue with that hull....

Bought a Velocity 290sc, Hopefully be installing the 555 before next summer...

I noticed those IAT temperatures on your dyno sheet. Pretty cool info. I always thought the prochargers were soooooo much cooler running , and how you could run way more boost than a roots. Those IAT readings, are basically the same , if not a little hotter, than my 420 Mega Blower making 8lbs boost with a superchiller on the dyno. I love actual data, rather than "heresay" or someones "opinion'' based on sales and marketing claims.

You made that power with a 239/246 cam in full marine dress with EMI manifolds with an M4 and only 9 lbs boost, thats pretty good.. Maybe the 244/256 crane 651 would have been better. I don't know. You also dyno'ed that engine without the procharger as well didn't you?

You won't get .018 above the deck under operating conditions. The piston grows when its hot.

With a .051 gasket, and even with the piston rock at max, you'd still have .033 of clearance. Once the piston grows, the rock will be less. If you were to average the measurement, say .018 above deck when rocked cold, and say, .012 below deck when rocked the other way, you can say, the piston is .004 above the deck, and use that for your measurment. Thats how I was taught to do it, using a deck bridge and a dial indicator. So far it seems to work.

I guess my point was why buy the heads assembled and spend more making them right, that's why I said bare, the rockers I listed are not shaft mount, still a stud mount just steel over aluminum..

Scorpion stud mount .612" @ valve 700+hrs and still going. Very surprised the roller tips aren't getting flattened out because of the hydraulic rollers. But they still look new...

651??? made by crane???
curious what are the numbers on this cam??

Sure did... :)

http://i130.photobucket.com/albums/p...psjc8p7gin.jpg



Would the 651 cam have caused reversion with my wet exhaust ? Seems many who run it run dry exhaust .


As far as the IAT, it was close to 100° in the shop when we dynod and I was feeding the intercooler off the bypass port on the crossover , so the water was heated some by the block.. When it finally goes in the boat it'll likely have its own pickup...

Thank you all. I find it interesting that the power curve of th SC just keeps climbing with that small of a cam and NA it falls off around 5500.

May have pulled even more with the SC we didn't try..
I chickened out due to my Eagle rotating assembly, AND due to the fact it was already well above my target hp anyways..

Sure doesn't sound like 1000+ hp at idle.. ;)

https://www.youtube.com/watch?v=kprKxCUKvz4

A SC and Turbo supplies more air then the motor does NA, thus able to feed the motor at higher rpm's than NA.

My gosh.... It's gotta be hilarious when some fool pulls up to you with his ratty sounding 454/502/540 and you drop the hammer. I would swear that sounds like a 330 or ok maybe a mag but... Good for you. That's awesome.

if the center of the piston is .005 above deck and has .018 out of the bore during cold rock it is .018 above and below center line of piston with a flat top.yes as the piston gets to operating temp it is growing so the .018 rock will be less when at operating temp.so lets say the rock goes to .008 at operating temp,now add .010 for carbon buildup you still need to allow .018 when figuring what head gasket to use.this is why i said i would use a .060 thick gasket.a little extra clearance won,t hurt but not enough clearance will cause all kinds of problem,s.this is how i have done it for 40 years so i guess it is working.don,t forget that the piston rock is .018 during cold running until the piston starts to grow and with the build up of carbon on the piston top one must allow clearance for it.

info is in post 6.

One thing to look at is his IAT is without fuel so he don't show any cooling effect VS a roots supercharger with fuel.

For sure. It still is what it is though. It be pretty cool to see what a non intercooled procharger does, vs a non intercooled roots. I know what the temps are with a non intercooled carb'd 1071 roots at 6k rpm. Still no where near as hot as the internet claims, but about 25-30 degrees hotter than the intercooled version. Im not super impressed with the "superchiller" brand intercooler results. Maybe the whipple ones work better, but they are sure expensive.

The Port EFI isn't getting the fuel cooling effect, but it should offer some help in the fuel distribution if its tuned right.