Mercruiser 470

[Dhodge23]

Hey I’m new to the boating world this is my second boat in 2 years and I don’t know what to do the boat is a 89 well craft with the mercruiser 470 in it I had a friend who is a good mechanic take it apart at his house because it has 30lbs compression on cylinder 2 he says it’s irreparable so what do I do now? Swap it out but for what motor? Help please?

 

[jhamblett]

Hey I’m new to the boating world this is my second boat in 2 years and I don’t know what to do the boat is a 89 well craft with the mercruiser 470 in it I had a friend who is a good mechanic take it apart at his house because it has 30lbs compression on cylinder 2 he says it’s irreparable so what do I do now? Swap it out but for what motor? Help please?

4.3 is a direct replacment without having to deal with outdrive swap and it will use the same transom plate. Might be a simple as a head gasket change. Use the search feature for the 3.7 470

 

[Dhodge23]

Okay thanks!! I have been doing a ton of reading and that’s what I thought that the 4.3 would work. But does it have to be carbureted? Can it be fuel injected? Does it have to be certain years?

 

[Eric 3.7LX Alpha 1]

4.3 is a direct replacment without having to deal with outdrive swap and it will use the same transom plate. Might be a simple as a head gasket change. Use the search feature for the 3.7 470

The 4.3 is the closest replacement, I wouldn't call it a direct replacement. Your going from an inline 4 with a single front engine mount to a V6 with two front mounts. There's going to be some measuring and fabrication possibly involved.

 

[Scott Danforth]

You have to change the input yoke in front of the universals when you go from inline to a V6

You can do carb, TBI or MPI. Its up to you

Would have to know what is wrong with the 470 before I would make a statement that the ebgine is irreparable

 

[nola mike]

You have to change the input yoke in front of the universals when you go from inline to a V6

Not on an 89

 

[Bondo]

Not on an 89

Ayuh,..... 'n only for GM in-lines, with MC-1 drives,......

 

[Dhodge23]

You have to change the input yoke in front of the universals when you go from inline to a V6

You can do carb, TBI or MPI. Its up to you

Would have to know what is wrong with the 470 before I would make a statement that the ebgine is irreparable

I’m told cylinder 2 is messed up in the block that it’s not able to be machined and the other cylinders are not far from it

 

[Eric 3.7LX Alpha 1]

Even if the cylinder is scored it's a sleeved cylinder. With an aluminum block, the cylinders are sleeved. Meaning the pistons rings aren't riding on aluminum but steel sleeves pressed in the bores them honed to the correct diameter. Sleeves can be pressed out and the block re sleeved if necessary

 

[QBhoy]

4.3 is a direct replacment without having to deal with outdrive swap and it will use the same transom plate. Might be a simple as a head gasket change. Use the search feature for the 3.7 470

I’m afraid it’s not at all. He will need to get new engine mounts glassed in and exhaust components at the very least.

 

[Scott Danforth]

I’m told cylinder 2 is messed up in the block that it’s not able to be machined and the other cylinders are not far from it

you have to sleeve the block to rebuild it.

 

[trimoon]

you have to sleeve the block to rebuild it.

Thes pictures may help from when i did mine.

I had very poor compression but was lucky there was enough metal left that i had bored out to a bigger size piston (.030) and replaced the pistons and rings


New pistons and rings: