4.3 Vortec to non Vortec

[slim6969]

Hello everyone so my boat an 1989 19’ tempest has a 4.3 l mercruiser engine Last fall I paid to have it winterized This year I took it out of storage and it has a cracked block So I’ve been on the hunt for a new engine. I’ve found a industrial 4.3 l Vortec engine my engine in non Vortec so my questions

because the intake manifolds are different I’m wondering if the stock Vortec one will work for a marine application.

will the exhaust manifolds bolt to the stock Vortec heads ?

my plan was to switch over the accessories and the exhaust manifolds to the Vortec is there going to be issues doing this

should I keep looking seems these engines 4.3l marine engines ( Atleast I’m my area ) are hard to find and worth $4000+

 

[achris]

Exhaust manifolds will bolt straight up. If the intake is cast iron, then that's all that is required to be 'marine'... As the old engine is non-balance shaft and the new engine is with a balance shaft, you may (read 'will') need to change the engine mounts.

Everything else should be plug and pray...

Chris........

 

[slim6969]

Thanks very much for your reply. I was reading that I’d need to switch to an electric fuel pump as well not a big deal I suppose

 

[achris]

Thanks very much for your reply. I was reading that I’d need to switch to an electric fuel pump as well not a big deal I suppose

Ah yes. You'll need an oil pressure switch (N.O.) for that, and a relay... (I forgot about the pump, sorry).

Chris........

 

[nola mike]

Assuming we're going with a 4bbl carb, same swap I'm working on
The old mounts will fit, but are fluid instead of solid.
You'll need a new water pump to clear the timing cover
Dipstick doesn't work with new oil pan
New block may be partially metric, in which case you'll need new hardware and either new starter or modify bolt holes on the old one
New throttle bracket that mounts to carb
Fuel pump as mentioned
New head gaskets, maybe new core plugs
May need to remove cps reluctor behind timing cover depending on vintage of new motor

 

[Rick Stephens]

And sometimes getting a harmonic balancer pulley, to match the older v-belt accessories instead of the newer serpentine belt, can be challenging.

 

[nola mike]

The pulley is swappable. The question (which I'm not sure of the answer) is whether the v belt balancer will seat fully on a block with a cps wheel behind the timing cover. I removed mine but am not sure if it was necessary. If you remove you need a new timing cover.

 

[slim6969]

Thanks very much for your reply.

so the engine I’m looking at is a 1994 4.3 Vortec

so let’s see if I have this right. I can take all the accessories off the non Vortec put them on the Vortec change the exhaust manifolds and add a electric fuel pump and I should be good to go ?

 

[Rick Stephens]

You will need to install the marine water pump, brass core plugs, along with all the bolt on accessories.

 

[slim6969]

One other thing though is the 94 4.3 does not have a carb but it does come with engine harness and stand alone comp. anyone see issues with this ?

 

[slim6969]

You will need to install the marine water pump, brass core plugs, along with all the bolt on accessories.

opps sorry I forgot about those thank you

 

[achris]

...so the engine I’m looking at is a 1994 4.3 Vortec...

1994 was NOT a vortec engine. It has 'Vortec' on the valve covers, but count the intake screws, there's 12. Vortec heads have 8.

Chris....

 

[nola mike]

One other thing though is the 94 4.3 does not have a carb but it does come with engine harness and stand alone comp. anyone see issues with this ?

Not sure what you're talking about here...is this a truck block or a marine block? What's a stand alone comp?

 

[achris]

Not sure what you're talking about here...is this a truck block or a marine block? What's a stand alone comp?

Truck engine, with a computer for the efi...

 

[nola mike]

Truck engine, with a computer for the efi...

That's what it sounded like, but was wondering why everybody let that slide

OP, you can't use any of the induction system from the truck. If you're sticking with pre vortec then you can reuse your old intake and carb. Vortec heads need a different intake.

 

[slim6969]

Not sure what you're talking about here...is this a truck block or a marine block? What's a stand alone comp?

Sorry for the confusion it’s a truck block with a stand alone Computer to run the Engine.

 

[slim6969]

That's what it sounded like, but was wondering why everybody let that slide

OP, you can't use any of the induction system from the truck. If you're sticking with pre vortec then you can reuse your old intake and carb. Vortec heads need a different intake.

Consider me new to this but why can’t the induction parts be used ? Gas vapor ?

 

[achris]

Anything related to the electrical system or the fuel system MUST be marine rated. It's a safety issue...

 

[slim6969]

Anything related to the electrical system or the fuel system MUST be marine rated. It's a safety issue...

thank you

 

[slim6969]

Thanks everyone for your reply’s and help it’s very much appreciated

I hope this post can also help others out as well