Engine upgrade?

[FlattopXXX]

New to the forum but it looks like I'll be here often with many questions. I have an "89 Sea Ray 200 BR with a cracked 4.3. I also have some fiberglass work to do. My mechanic has come across a good, low hour 5.7 complete engine. What do I need to look for to make this swap smooth. I know some 20 ft Sea Rays came factory with a 5.7 L so I don't think that should be an issue. Any help will be greatly appreciated. Thanks

 

[lime4x4]

Re: Engine upgrade?

If it's alpha drive then your either going to have to change the upper gears or find another upper unit with the correct ratio 1.5:1 which is what a small block v8 uses

 

[Bifflefan]

Re: Engine upgrade?

Along with the above you will need exhaust manifolds, and a ton of other parts that you wont know of until you need them. Your better off getting a new block for the 4.3 and rebuilding it.

If you have a complete doner boat sitting there to get the parts off, then you can do it with reasonable difficulty. If not, stick with what you have.

This is just my opinion. Best of luck with your endever.

 

[zbnutcase]

Re: Engine upgrade?

If that 5.7 is a fully dressed engine, its dang near a bolt in, and yes you will have to change the gear ratio in the upper.

 

[HT32BSX115]

Re: Engine upgrade?

Along with the above you will need exhaust manifolds, and a ton of other parts that you wont know of until you need them.

.....


Well, I don't think you'd need a "TON" of other parts.....you would need new manifolds and a different drive.

A lot of your accessories would swap over. The V-6 is very similar to a 350.

I had a quick look at the alternator brackets (Doug Russell parts)for an 89 V-6 vs a V-8 and it appears that even the alternator brackets and starter motor are the same part number.


So your main difference might be the wrong ratio drive. Your drive is worth as much as any other Alpha drive for a V-6 and SBC v-8 so you could probably sell yours and easily find the right ratio OR just get a NEW SEI drive with a 3 year warranty.


I would do it. Don't get me wrong though, It's not completely a bolt/plug/play change but it's pretty close!



Cheers,


Rick









For example, the flywheel housing for an 89 4.3L V-6 is the same as that required for a V-8.

 

[180shabah]

Re: Engine upgrade?

I'm with Rick on this one. It one of the simpler upgrades...

 

[FlattopXXX]

Re: Engine upgrade?

Thanks for the responses. My understanding is that the whole engine and outdrive is being removed to install an outboard. So if everything is there it should be a pretty easy swap? If not what is my cheapest option for saving the 4.3. Use a truck l;ong block and rebuild what I have or purchase a longblock? Has anyone bought from US engine? In particular their upgraded 4.3?

 

[Bondo]

Re: Engine upgrade?

My understanding is that the whole engine and outdrive is being removed to install an outboard.

Ayuh,... Doesn't that mean it's Already Junk, for whatever reasons,..??

Up-grading the 4.3l is Possible, but there'll be Vintage type fitment issues...

 

[FlattopXXX]

Re: Engine upgrade?

Thanks Bondo, The mechanic is a friend and he says it is a low hrs replacement engine. He is going to let me hear it run up front before removing. The only reason I consider it is because he has it available and reasonable. Back to salvaging the 4.3. What is your opinion of the most economical and feasable way to do it? It will crank and run but started chugging and puking milky colored oil out the crank case vent tube.

 

[Bondo]

Re: Engine upgrade?

It will crank and run but started chugging and puking milky colored oil out the crank case vent tube.

Ayuh,.... Diagnose Why it's doin' what it's Doin' 1st off...

If it's a Cracked Block,...
Raul at Rapido is highly regarded, Give 'im a call for a Replacement...

 

[180shabah]

Re: Engine upgrade?

I have never dealt with US engine, but a quick glane at their website is a little disturbing.

We Guarantee Our Engines Are 100% Marine
NOT Auto Engines That Others Sell as Marine Engines
Automotive Engines Use More Fuel And Have Much Less Power !

WHAT????

I also question WHERE they are rating the hp. My guess is at the crank, which all by itself accounts for a 30hp "increase" vs the prop rating that merc uses.

50hp is a huge jump for a 4.3. With the older engines it is very easy to go from 155ish at the prop to well over 200hp, with vortec heads, a good intake and a 4bbl. That they also list the 50hp increase as being available for the post '96 engines that already had the vortec heads, is very suspect.

 

[wca_tim]

Re: Engine upgrade?

if youre going to replace the 4.3, rapido worked fine for me.

If you're going to swap in a 350, and I think you'll be pleased with the power increase, don't worry about the gear ratio. you can easily reprop. I've done it with good results. it's NOT that big of a difference.

 

[wca_tim]

Re: Engine upgrade?

if youre going to replace the 4.3, rapido worked fine for me.

If you're going to swap in a 350, and I think you'll be pleased with the power increase, don't worry about the gear ratio. you can easily reprop. I've done it with good results. it's NOT that big of a difference.