85-3.8l cracked block options and 3.8 to 4.3 conversion

[Canadian thundercraft]

Hello Everyone, Great site and glad to be aboard. I have an 19' 85 Thundercraft that has a 3.8l with a cracked block. I am in the process of removing the engine from the boat. Basically I am at the stage where everything is stripped down and we are ready to pull the motor and would have gotten it out last night if not for darkness. We tried to separate the engine and have it about 1/2" apart but were feeling some resistance. We are thinking its a spline shaft that is tight but didn't want to pry to hard on it last night.
1) Any tricks to getting it apart?
Once it is out we will inspect the cracked area and perhaps try some JB Weld as option 1 if crack is not to bad.
(2)Anyone have input on the success/failure of this method of repair on a 3.8l?
I have been searching for a replacement 3.8l short (or long) block but am not having much success due to its limited production years (80-85 I think) and that availability number is even lower here in Canada I'm sure.
(3) The 3.8l to 4.3l conversion...worth considering or not and why?
Thanks in advance to all that reply.
Regards

 

[Levinz11]

Re: 85-3.8l cracked block options and 3.8 to 4.3 conversion

Did you remove the drive before trying to pull the engine??

Read this...http://forums.iboats.com/mercruiser...-8l-4-3l-omc-stringer-engine-swap-454476.html

 

[doral1985]

Re: 85-3.8l cracked block options and 3.8 to 4.3 conversion

I had a similar situation when I bought my scow, the 3.8L was shot but the buddy gave me a 4.3 and said it was all good, Not! the 4.3 was wore out and the other major thing was my OMC manifolds wouldnt fit, the heads of the 4.3 had a wider lower lip with interefered with the manifolds fitting flush against the heads. We lucked in with finding a 84 Malibu with very low mileage and tore it down to make sure it was all good and then replaced all the auto externals with the marine parts from the 3.8 engine, cam, dist,starter,alternator, carb.
She works like a good 3.8 should. I heard that a spacer might help with the manifolds fitting the heads but abandoned that idea when we found the 3.8. Im in Canada too and 3.8's are scarce as hens teeth for sure. Hope you find something that will work.

 

[Canadian thundercraft]

Re: 85-3.8l cracked block options and 3.8 to 4.3 conversion

Thanks for the replys so far.
Levins11: Yes i had read that thread but was hoping it would slide forward.

Doral85: I didn't think it would be an easy or even possible swap but had to ask.

looking to get some time in the next day or so to get back at it. I am still hoping a JB weld fix will do the trick. If it dosen't hold its only a couple of bucks and a bit of time. I will also continue the search for a running early 80's 3.8l.