Theoretical Motor Build Up!
 

I'm bored and sick of winter! So lets have some fun and kick around some ideas and theories for something different. Here is what I am thinking. 1000 HP naturally aspirated marine engine. It can run on 110 octane and can be 632". Max RPM can be 6700 RPM and it must be able to idle at 1000 RPM. Assume full length headers and it must be capable of 20 hrs between lifter / spring changes and 200 hrs on the bottom end. I am thinking a good start will be a 12:1 compression 632". Which heads? AFR, Dart Big M, Big Chief? What about induction and cam specs? This is only a BS motor for now, but this is something I think would be very cool in my 23' cat. :drink:

Craig

Re: Theoretical Motor Build Up!
 

How about you start with the new 10.6 Dart block so you can have a decent rod to stroke ratio. Make 9.0 compression so you can run pump gas, use Big Duke 388cc runner heads to keep your bottom end. Use EFI so you can run a 280/ 288 @ .050 110ls cam that will idle around 900rpm. and blow your outdrive at will. HP would be over 1000.

Re: Theoretical Motor Build Up!
 

With the 10.6 block what kind of cubes are we talking? Probably looking at some custom dished pistons, but that is no big deal. EFI would be sweet and allow good idle quality. 1000 HP NA pumped gas motor would be pretty sick!! Paint it blue and call it a stock HP 500! :D

Re: Theoretical Motor Build Up!
 

I figured stay at 632 and use a 7.1 rod so you can turn it up, I think you would end up with around a 43 cc dish in the piston. The block isn't available for a little while yet, but it could be fun. I guess you better look into a sheet metal tunnel ram and a couple of 1600 cfm throttle bodies. A Weldon 2025 fuel pump and a set of 72 lb injectors should do the job.

Re: Theoretical Motor Build Up!
 

That cam is too big for a 632" GPM :rolleyes: since were going to keep the r's around 6500 a hydralic roller would be the ticket.....call Crane and get a 651! :p :p :D :D Besides these big inch motors are not good boat motors and you can't make power without a blower Wette Vette.....

I got another idea Vette...sit those flat tops on the shelf get a set of 13:1's coming from JE, oh yeah and a little more cam...Wholah 1000+ on 110. Your minimuim idle restriction would be the toughest nut to crack :drink:

Re: Theoretical Motor Build Up!
 

No wimpy hydraulics in the imaginary motor, I ran the solid roller 280/288 in my 598.

Re: Theoretical Motor Build Up!
 

Exact same cam I ran in my 632 except it was on 115 to give it a chance to idle with a tunnel ram. This big HP fuel injection is finally getting there it seems.

Re: Theoretical Motor Build Up!
 

The one I ran was in a blown application so it was cut on a 112, with the EFI it idled at 1000 rpm. It was a little big for the 598 so I cut back to a 276/284. I would think the 4.75 crank could use the larger one. What are the other specs on your cam?

Re: Theoretical Motor Build Up!
 

Are the big chief type heads that superior to conventional that 1000+ HP could be expected at 9:1 compression? I have seen a 632 make 900 HP with 10.5:1 compression at 6600 RPM with fully ported Dart 360's. That is why I thought it would take at least 12:1 and a couple of dominators on either a custom sheet metal intake or at least a fully hand ported tunnel ram. The stick I like for this application is one that Erson advertises as "easy on parts" for marine race use. 276/284 @ .050" lift with .731" lift on a 114 with a 4/7 firing order swap. Now for another debate. Is the EFI or dual dominators goning to make more peak HP? The benefits of EFI speak for themselves, but I feel the wet manifold may actually make more peak HP and be better for a motor intended primarily for high RPM use. Aren't the Pro Stock guys still running carbs? :cool:

Re: Theoretical Motor Build Up!
 

Yes Pro Stockers are still running carbs. The last I heard, they were running them split in half. I believe this was to spread the carbs out enough to straighten the intake runners.

Re: Theoretical Motor Build Up!
 

My opinion, you're going to need a head that flows 485 cfm each runner to reach 1000 hp. I think you will need a cam with more lift,and duration, somewhere around .780.280/288. You may need to stay with the smaller cam with the carbs so it will idle. I doubt the smaller cam will flow enough to make 1000 hp. The 10.5 compression would definatly help the theoretical engine reach it's goal.

Re: Theoretical Motor Build Up!
 

The first cam I ran in the motor was Erson 272/278 .770/.760" on 114 CL. Cam worked well all around but was totally done @6100. made 860HP there, ~805 Tq @5000. Motor was 10.2:1 with this cam. When I changed lifters I decided to step the cam up a little more and went to a Comp 280/288 .785/.772" on 115 CL, bumped CR to 10.5:1 Power jumped to 901 @6500 torque also went up slightly ~820 @5100. Both tq and power curves were long and flat..no peakiness at all with either cam. The idle was very rough but managable with both cams....noticably rougher with the latter cam even on the 115.

The ramps on the 280/288 cam were much more aggressive @.200 and it munched a lifter after 6hrs. (comp thought it was defective because the rest looked perfect, they took care of new cam and lifters, small token but I didn't turn it down!!) The boat gained no speed even with the extra 40HP and propped to turn 6500 vs 6100 with the smaller cam.

I ran a dart tunnel ram and 2X775 Race demons, aluminum flywheel. Response and acceleration was wicked in the mid range alll the way through 6000+

I switched to the Schubeck radius lifters after many talks with Joe and several circle track guys who'd had great luck with them. Its a totally different cam due to the 1" radius but it was ground by Bullet racing cams 276/284 .730/.730" lift on 115 C/L. The motor made right at 895HP@6400 and the same tq. I purposly took a little lift out of it just to tone things down a tad....everything else stayed exactly the same other than valve springs. Both myself and my builder were really impressed with the power the Schubeck system made...you can run a lot less valve spring because the lifters weigh less than half of a solid roller lifter.

Corey

Re: Theoretical Motor Build Up!
 

Very nice! do you recall the initial duration on the cams, curious how they match up with mine. What heads did you run?

Re: Theoretical Motor Build Up!
 

It looks like Chief Engines goes 705CI with the Super Tall Deck

Re: Theoretical Motor Build Up!
 

The smaller cam was 298/304 and the bigger was 311/325. Heads were fully ported and polished Dart 360's. I think they ended up around 393 and flowed ~425 .800" lift on the intake and ~315 on exhaust.....My memory is a little foggy on the flow but those #'s are close.

Craig and I spoke to the guys from Sonnys at the PRI show a couple of years ago and they "guaranteed" a minimum 125HP pick-up by going to their chief style heads with 73cc chambers on my motor staying on pump gas....Sounded cool until I thought about everything that would need to be changed, concluded I'd be better off to start over with a different motor. :D

Re: Theoretical Motor Build Up!
 

I really can't compare apples to apples here because I was playing with a Procharged 598. I tried 5 different solid rollers, rangeing from 272 to 280 @ .050 intake duration 280 to 288 exhaust. .748 to .782 lift. 112 and 114 lobe seperation installed in the motor from 106 thru 112 center line. I also tried cnc BB2 xtra and cnc Big Duke. both combos at 9 to 1 compression, and EFI.

Re: Theoretical Motor Build Up!
 

We played the advance on mine also...went from +6 to -2 retard....Predictively the less advance the more power...it just kept wanting more cam! I ended up running them both straight up.

Re: Theoretical Motor Build Up!
 

Both of my combos made their best power with the 112 lobe sereration set in at 108. The BB 2 xtra lost 60 hp and 75 lb of torque at 112 lobe center.peak hp moved up from 6200 to 6500.rpm.

Re: Theoretical Motor Build Up!
 

Craig

BLOWER MOTOR

that's all you need
:drink:

Re: Theoretical Motor Build Up!
 

Blowers make it too easy!!!! :p

Re: Theoretical Motor Build Up!
 

you'll convert one day
what's that saying " work smart not hard " :eek: :D :D