Logo
FULL SITE MENU

Ford 302 - Mercruiser 888 Engine Work

J

justid2

New member
I recently picked up a houseboat on the cheap in great shape but the motor had freeze damage, hence the cheap price tag. I have an entire 302 long block, with enverything still on it that I bought that was pickled out of a badly damaged boat. The the engine is in good shape block wise but I am thinking of freshing up the top end with new pistons and rings, or just new rings and taking a look at the head to make sure everything is in good working order since pulling the houseboat down the road is something that I don't want to do, I also only plan on keeping it a few years anyhow.

My question is, has anyone rebuilt these or freshed them up? I know there are "marine" parts sold everyday but the price tag between marine parts such as gaskets, pistons, rings, etc seem outragious to some of the car varients that are using the exact sameblock and heads! So I know someone out there has some experience as to what to use, and what to not do, etc. Thanks, Justin
 
Ayuh,.... For what yer doin', the necessary "Marine" parts include the head gaskets, brass core plugs, 'n the cam,...

Quality pistons, 'n rings are just Quality pistons, 'n rings,...
 
Fair enough. The motor I have is pretty low time so I'm going to checkout the can before I put a new one in it. But thanks, just was trying to see what options I had. We all know you can spend to the moon and back if you want haha
 
As I recall, the Marine 302 (5.0L) Fords used the 5.8L Ford cylinder heads!

Either of these heads are similar to the SBC, in that they offer a Quench surface of to the side of the main chamber.
Most of these that I have torn into have been fitted with the flat top pistons.
Flat Tops, with the correct piston to deck clearance, and the correct compressed head gasket thickness, can offer you a good Quench dimension.
However, you must make certain that the flat tops are being accompanied with the correct combustion chamber volume...... (spelled correct Static Compression Ratio!)

A good quench will also allow for a bit higher C/R!

Build a good quench into this, and you will have a good Marine Engine.

If it will be "closed system cooled", you can use a high-quality automotive head gasket set, and save a few dollars without compromising.



.
 
Last edited:
Oops ...... Spelling boo-boo correction.
That should have read:
Either of these heads are similar to the SBC, in that they offer a Quench surface off to the side of the main chamber.

I don't think that the picture is loading properly.
Look here to see this surface.
http://www.google.com/search?q=ford...wIGgBA&ved=0CAkQ_AUoAA&biw=320&bih=356&dpr=2#

imagejpeg



.
 
Last edited:
Thanks for the info. Started tearing into the motor and I think I may get off with just doing gaskets and rings and a hone, pistons look pretty solid. They are not full flat top pistons, they have a bit of a center dish with some cut circular groves toward the edge. I do believe I'm going to do the heads though and freshen them up and you are correct it has 351w heads.
 
Best to steer clear of a dished piston in this engine.
A dished piston offers zero quench potential when used underneath this style cylinder head.
You are needing a "Marine" build, not an automotive build.

Your call!
 
justid2 said:
Fair enough. The motor I have is pretty low time so I'm going to checkout the can before I put a new one in it. But thanks, just was trying to see what options I had. We all know you can spend to the moon and back if you want haha
Click to expand...


Yes marine rated parts are typically more expensive. You have to purchase said parts from a marine dealer who is a middle man taking there cut.
Some have a coast guard number therefore that cost more to meet that specification.

As Bondo said, everything internal is standard motor parts as used in a automotive situation. The cams are typically a different specification to give a lower rpm torque and HP band as boats rarely run over 4800 rpms.......

A few things to consider,

1. Exhaust valaves are NOT hardened seats..........Very much needed for unleaded fuel......
2. this motor was made back when 94 octane and above and leaded was available.
3. Timing will most likely be a few degress BTDC lower than original spec. Example, was 10 BTDC now should be 6-8 BTDC.

Lower quality fuels and higher combustion temps..........But if the correct parts are selected you may be able to keep it at 10 or even higher.

There is no magic to a great running good power 302.......

If you choose to rebiuld it your self I would at a minimum have the heads reworked with hardened seats and a good valve job/seals/guides!!

Also do some research in your area, There are always hard core ford guys around who know how to biuld good motors. Try to find one and ask some questions.......Maybe a better piston and cam combo would wake this motor up a bit with no sacrifice in durability.....Instead of 200 or so hp you could/should be able to get 270-300hp with not much effort.

Also take a good look at the oil pump make sure it is up to the task.

One last thing is to upgrade to a full electronic ignition. Look for a simple all in one type MARINE distributor with a external coil.

Good quality wires and a fresh set of plugs........

Dont get to hung up on head/piston design as what you have worked just fine when manufactured. May not be the best combo today but can surfice.
If you do seek out a ford motor guy I am sure he can suggest a great combo for your application.

JMHO
 
Back
Top