merc 302 trouble

meversole6

Recruit
Joined
Jun 29, 2010
Messages
5
i have a complete merc 302 with a cracked block and a good ford 302 out of a truck. does anyone know what all would have to be changed to make it work?
 

Bt Doctur

Supreme Mariner
Joined
Aug 29, 2004
Messages
19,111
Re: merc 302 trouble

brass core plugs unless FWC, cast iron timing cover, marine carb, starter, alt.
 

Bondo

Moderator
Staff member
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Apr 17, 2002
Messages
70,513
Re: merc 302 trouble

Ayuh,... I wouldn't,... It'll be just Fine....
 

zbnutcase

Commander
Joined
Sep 19, 2009
Messages
2,055
Re: merc 302 trouble

And these engines are externally balanced, and Ford changed the amounts of weigh carried in the flywheel and damper. If the truck engine is 81 or newer, you MUST use 81 and newer damper AND flywheel with it.
 

haulnazz15

Captain
Joined
Mar 9, 2009
Messages
3,720
Re: merc 302 trouble

And these engines are externally balanced, and Ford changed the amounts of weigh carried in the flywheel and damper. If the truck engine is 81 or newer, you MUST use 81 and newer damper AND flywheel with it.

^Yup, 50oz counterweight was used for the later models, early models were a 28.2oz.
 

sully73

Cadet
Joined
Jun 21, 2008
Messages
24
Re: merc 302 trouble

im kinda in the same boat, no pun intended lol. i have a 72 302 thats messed up, but have a crown vic police car motor i want to switch out. are you saying that the donor will be fine as long as we use the newer motors balancer and flexplate, or do we need to find some off of a 81 or newer boat?
 

Niedhogg

Seaman Apprentice
Joined
Jun 29, 2010
Messages
41
Re: merc 302 trouble

im kinda in the same boat, no pun intended lol. i have a 72 302 thats messed up, but have a crown vic police car motor i want to switch out. are you saying that the donor will be fine as long as we use the newer motors balancer and flexplate, or do we need to find some off of a 81 or newer boat?

My take on it is that you need the balancer and flexplate off of whatever year block you will be using. And why the brass core plugs? Is this so you can pull them out to drain the block? They don't corrode I take it?
 

zbnutcase

Commander
Joined
Sep 19, 2009
Messages
2,055
Re: merc 302 trouble

im kinda in the same boat, no pun intended lol. i have a 72 302 thats messed up, but have a crown vic police car motor i want to switch out. are you saying that the donor will be fine as long as we use the newer motors balancer and flexplate, or do we need to find some off of a 81 or newer boat?

Forget it. The modular engines were never used in a marine app, and cannot be used to replace a 302, even if somebody did make exhaust manifolds for them, which they don't.
 

haulnazz15

Captain
Joined
Mar 9, 2009
Messages
3,720
Re: merc 302 trouble

Forget it. The modular engines were never used in a marine app, and cannot be used to replace a 302, even if somebody did make exhaust manifolds for them, which they don't.

A 302 is a 302. 302's are not "modular" engines, I believe you are thinking of the 4.6/5.4L Triton engines.
 

Niedhogg

Seaman Apprentice
Joined
Jun 29, 2010
Messages
41
Re: merc 302 trouble

Forget it. The modular engines were never used in a marine app, and cannot be used to replace a 302, even if somebody did make exhaust manifolds for them, which they don't.

Please expand on your answer, we are obviosly new to the marine vs. automobile thing. I don't know much about ford blocks either and the modular thing has me stumped too. Why would the blocks be any different? I understand the heads, intake, carb, and all the other external components, but enlighten us on the differences in the blocks.
 
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