tale of 2 engines!

M

merc40

Member
#1 engine. 39-40 merc. 99 stamped block. it is out to 296 c.i.. the center main let loose an broke crank in two. bored to 3 3/8. relived, adj. tappets, ss valves, unknown cam. webber alum. f. wheel. crab dizzy. i guess the crank. must be 4 3/8 to get to 296 c,i. it has sat for a few year#sbefore i got it. cam and valves move free. no sign of cracks yet.

#2engine 40 merc. 99 stamped block. 255 c.i. bored .125 adj. tappets ss valves 4inch crank. cracked block #7 cly. an valve seat.
removed this engine from my 40 merc. last august an put in a 59 a-b.
it runs great but not as much pep as the 255. it is a new rebuild, so i guess i have to give it a little time to breakin.

now the big ?
can i take #2 engine crank rods, an maines an put in #1 using 3 3/8 pistons. what will the the end be an is it worth it. i read the barn every day,an learn something new every time. reguards dick t. i will come back with any more info. if needed.
 
I think the pin height in the stroker pistons is different than stock to make up for the extra 1/8th inch stroke. So with 4 inch throw they'll be sitting 1/8 inch down in the block at top center. Think you'll have to get a piston set or get the crank stroked.
 
Bottom line is yes will need the piston out of engine #2 and will need to have the mains line bored. Better to just change the center and get it line bored. Whether it is worth depends how badly worn cyc are in engine number one. Putting a sleve in engine number two might be cheaper if the cyc are not badly worn and a new value seat.
 
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