Marine engines

[BADASS38CHEVY]

Is there any engine building books out the that will give engine specs for building different size motors.Say I wanted to build a marine engine 700hp injected engine ,would it give me crank size , cam size ,valves springs,head sizes you know what I mean.I have been in the auto repair business for 23 years and have built mainly stock hp motors and wanted to know the difference in marine engines,like cam and spring choices etc..

[Moneypitt]

Sure there are books. Although finding one that deals exclusivly with a specific size or purpose is tough, if not impossible. You've been doing this long enough to have a handle on most of the basics, so do the math, and design an engine of the size you want, then make it breathe. Crank size? Do you mean stroke? To reach a certain cu in with a particular bore size? There a formulas for that.(PM me) Then the cam would be spec'd to let it breathe. Head cc and valve size, intake/exhaust flow etc. If you could be a little more specific there are about 100 builders here on a regular basis that can and will help you. As well as the cam grinders recomendations for particular use.....I would highly recomend the "how to hotrod" series of books by HP performance, very easily understood basic performance ideas and recomendations, and a good base line to start from. Piston manufacurers will spec clearances for different uses, and the HP books layout the tricks to make the bottom ends live. Just don't forget the "heart" of the oil system, the pump, and in a boat, the oil management in the pan...........An engine is just an air pump with fuel and spark mixed in, in some cases bigger is better, but not always.......MP

[BADASS38CHEVY]

This is a motor that I would like to build but run on 87 octane fuel.So Im assuming that would lower the horsepower a little.how would I find the exact internals .http://www.pfaffengines.net/700na.html.

[Rocket-J]

That motor is nearly identical to mine. For 87 octane I am only guessing that 8.5:1 compression ratio is necessary, maybe not, but it is a start. When I change only the compression ratio and run it on Desk Top Dino, there is a 40hp drop. About the same drop on torque. This is not the perfect way to make a judgement, but it is a quick ball park for you. Al

[BADASS38CHEVY]

Did you build yours?

[Rocket-J]

I built it from a management point of view. I researched what I wanted, like you are. Checked many marine engine builders for what they had and what parts they used in their motors. I already had an HTM built 565cid/670hp motor with a lot of quality parts in it. The rings went bad at 160hr. Also, was getting water in the combustion chamber. Teague wanted $25K for their short block. Not in my price range, but that is what I wanted.
Callies sold me a complete rotating assembley, crank, Oliver rods, JE pistons, rings, bearings, etc. but didn't have a block that was Gen VI compatibale. I bought a Bow Tie block from Fitzpatrick Chev, GM Performance Parts dealer (John 925-570-5220 cell) for $200 over cost. I also bought their hyd. roller cam that is used in the 572cid GM motor. Out of 80,000 combinations on the Desk Top Dyno interator program, that cam was #5 in the top 10 grind choices for my 565 motor with my Victor CNC heads. My mechanic at Pleasure Boat Specialties, sent the block to Pashoda (sp) in Sacramento to be bored and clearanced. My HTM motor was a 502 block bored 4.530" with a 4.375 stroke. My new Bow Tie is bored 4.600" with a 4.25" stroke to slow the pistons down and maybe save ring wear and give a better rod angle.
There are many opinions on motor building, as you will find out. Go to people you respect and that have a track record for a good product. Decide what you can afford and make compromises the best you can. I think that Teague has a very good reputation and I wanted their motor but I can't afford $25K for a short block. My package cost about $7K for all the parts.
Keep doing your research and Good Luck. Al

[SmokinLowriderSS]

As posted above, there are a lot of good sources, both on the boards, and in your local bookstore. The exact info in my "How to hotrod the Big Block Chevy" is dated as all of it predates the GenV block family, but the facts of what the engines need to survive a hard service life and make power are there. Marine engines are nothing radically special (I MAY just start a fight there) and their build isn't magic, but they do require a somewhat altered mindset from auto engines, especially as you build serious muscle.
Clearance specs are best set (in my humble and emminently correctable opinion) in the middle range of factory specs (ring end gap and bearing clearances). Due to the opperating conditions, you usually have a relatively cold engine (due to raw water cooling) with very hot parts from the much heavier loads applied (pistons). If the clearances are too tight, things will bind, expensive things. The sustained higher than auto RPM's also has it's demands, which is where I think lower end bearings being too close will bite you (in the wallet seccond, elsewhere first).
Many folks use high-volume oil pumps, many (like me) do not. I am running nothing special, a 400 HP 454 plus nitrous but idle oil pressure is 23 pounds hot, 55 pounds cold, 55 pounds hot, screaming down the lake for miles at 4800 in my jet drive Taylor (my avatar). The oil pump is GM standard, the pan is 5 qts. I DO think that any boat, but especially a jet, needs a REAR sump oil pan (the ford guys). Hard acceleration that many boats manage WILL cause starvation problems, lower end bearings get testy about this phenomena.
Power generation takes a different mindset from cars as there may be no ability to "wind the motor out" if the "fit" is bad, an example:
A man came in here last fall looking for advice with a dyno'd 502, making 718 HP, 600+ 'lbs torque, but could only spin his Berkley jet pump/"A" impeller to 4400 RPM and the boat was slow. My 454, making 350HP last summer (new exhaust this year) was spinning the same setup 4,800RPM and running 62mph on a badly scarred hull. I got his specs, loaded them to Desktop Dyno, and found his engine way optomized for high-rpm howling, but his jet pump shut him down before he could make his power. I was making more HP than him, untill 4,000 RPM, and FAR more torque. I could fight the pump to 4,800 where his won out at 4,400rpm.
He had a steep roller cam, ported rectangle port heads, oversized valves, headers, single plane manifold, all high-rpm goodies.
I'm running a .565" lift 280* hydraulic custom grind, unported (until next year) large oval port stock heads, stock std valves, restrictive log manifold exhausts, an Edelbrock Performer RPM Air Gap manifold, all good RPM but mid-range grunt parts.
I was ahead of him in power production (torque and HP) thru 4,000 rpm. Nothing wrong with his engine, just the aplication he had it built for was wrong. Would have been holly hell in a street car, MAYBE in a v-drive prop, not in a jet boat without going to a smaller impeller to get the engine ahead of the pump pull as it pressurizes.
Just figure out what you NEED to build to get what you want. I have a working lake boat, Skiis, Tubes, outruns bassmasters & Bajas & lice, and, as I complete the upgrades, will be able to run 80+ I believe from where I am & what I have planned. I'll make the 2% of folks who can beat me, work for it. :crossx: Besides, when I get outrun by a raceboat, I can blame the full interior, the 2 anchors, the 2 sets of skiis, the beer cooler, only 1 engine, no blower, and (most of all) the Admiral screaming "SLOW THE F*** DOWN!". :cry: :idea:
Good luck to you.

[Rocket-J]

I agree with everything you said Smoke, except the oil pump. For you, 55lbs is fine. Most performance engine builders say 10lbs per 1000rpm minimum pressure. For your 4800rpm motor, you are fine. If you are turning a BBC (500cid to 600+cid) over 6500rpm, you need a lot more oil. I would be nervious with less than 70psi on a WOT run. Oil cools those hot parts you are talking about and even though the water temps are low (100 degree range) piston tops are hitting 1450 degrees. More oil does help. Al

[Moneypitt]

Do not confuse high pressure with high volume, there is a difference.......MP

[BADASS38CHEVY]

Thanks for the info.