Looking to rebuild 351W motor

[tallnfast]

Hello;

Let me start by saying, i am still a novice at boats, well especially motors....however I have the "itch and desire" to learn more.

I want to find a ford 351w motor and do a complete rebuild and then put that new motor in my engine...however long it takes.

any suggestions on where to look, what to avoid, what needs to be done to ensure it is a "marine" motor.

Also someone told me that the process of building the motor is what makes it marine "approved"

could someone in novice terms explain to me the process...thanks again for all your help guys!

[OUI]

A motor is a motor. The only difference between marine and car is the exhaust manifolds, carburetor, generator and alternator. Everything else is the same. If you’re going to do a total rebuild, I would suggest you get a set of GT 40 heads from Skidim.com.

[wotan2525]

That's not exactly true.... some of the engine blocks (I believe only GM) are stamped as Marine castings. My machine shop told me that those have some reinforced sections but he didn't say it was crucial. You also want to make sure you use a marine cam as the operating RPMs of Marine engines is a lot different than what a car uses.

Other than that, though -- you should be good.

You can buy a junkyard 351 and rebuild it as a marine engine. You can use your existing accessories or buy new marine-rated ones.

I had never rebuilt an engine before I rebuilt the 454 in my boat. It was a fun project and I learned a lot. I had to buy quite a few tools and it probably cost me about the same as what hiring a professional to do it would have. I learned over the last 4 years of the small things I did wrong (knock on wood.... nothing catastrophic so far... just chasing oil leaks and improperly seated gaskets.)

I learned and followed the boxwrench.net engine building DVD and an old shop manual. I'd probably do it again if my engine took a crap on me.

[cadunkle]

There are other differences too, such as freeze plugs being brass, gasket material being different, marine distributor, etc..

If I were you I'd build it pretty much like a car engine, but with a marine cam making power in the range you want that will still have a smooth idle. I would also do a minor exhaust port cleanup on whatever heads you run. 5-10 minutes of grinding per exhaust port will make a world of difference, and is basically free power. If you want a better build outline let me know what engine you're starting with, the boat it's going in, and any performance of what it does now vs where you'd like it to be improved (hole shot, top end, fuel consumption, etc.), budget, etc.. As for marine parts obviously run marine carb, distributor, alternator. Aside from those definitely use brass freeze plugs (won't rust) and I'd probably use marine head gaskets. Not really a big deal if you run in fresh water only, but cheap insurance on a new engine build.

Building an engine is fairly straightforward, anyone with a little mechanical inclination can do it. It's more than mashing whatever parts together and hoping for the best, but a mild performance build should be no problem to get a bit more HP and broader torque curve than stock without the complications of high power builds.

If this is your first engine, first small block Ford, or even 5th or 10th... I highly recommend Tom Monroe's book How to rebuild small block ford engines. It walks you through the rebuild process with good pictures, helpful notes for beginners, and has proven to be an invaluable reference for me even after doing tens of small block Fords.

[tallnfast]

someone told me that a normal 351w would not work due to the rotation and that i would need to make a lot of modification to the camshaft/pistons....

like i said, i am a novice, do i need to find a specific "boat/marine" 351w?

[87SunSportMikeyD]

Depends on which way your current engine rotates. Most boats are Left-hand. Correct craft is RH. I have heard of a couple Supras that are RH, so ya gotta check! Just look at the prop and see which way it is designed to turn.

You are ok with any longblock 351W but the engines are slightly different through ranges of years. I replaced my 87 with an engine compatible with 86-89 351's. You could contact a major manufacturer of rebuilt engines for more information about what engine to select for your boat. What is your make/model/year again??

[rludtke]

The GM and Ford Marinized V-8's are based upon the GM and Ford truck engines. This typically means four-bolt main caps, forged crankshafts, and large valve heads. The marinizing companies (PCM, etc) most likely did some proprietery engineering from there to differ from the land-based OEM truck engines by selecting specialized camshaft grinds, intake manifolds etc etc.

Fourtunatly, the speed/power range for our inboards is fairly well defined- we need lower rpm tourque and power for pulling, and a broad tourque curve in the lower rpm ranges for our mission. We don't want peaky tourque curves. Plenty of data exists out their to help select the proper components (cam, cam followers, intake manifolds, valve dimensions, etc) to build an engine best suited for this mission.

[alelogman]

I'm still on the learning process and learned from some mistakes as well, specially for ripping off and trying to fix things without proper knowledge. Cars and boats are two different things though some used engines are the same. I'm good at cars but get rally crappy with boats and rebuilt engines so I hope to learn from the experts here though I'm also going through some kind of training.

[beast 496]

A good qualitly rebuild will cost you around 2k. Machine shop will have to bore, grind, head work ext. You can assemble, new pistons, rings, brgs. Remembler to also replace items such as, fuel pump and circulation pump. Good time to have the starter and alternator rebuilt also. Don't forget about the carb and distributer. I have rebuilt many engines in the past, the satifaction of doing something yourself is priceless. How many people do you know who have actually completely assembled and engine, not many I bet. Not many on this board have also. Go for it and have a blast. Make sure you find a really good machine shop, one which is familiar with the engine in question. Probably one locally, and it will have some sort of a basic name. It Terrys' automotive, or Sam's Machine, ect. Al