Engine replacement

[Mbyzfr6]

I am in need of some recommendations for places to get a reman engine. What I have is a 1992 Seaswirl 180se with a 4.3l omc engine. Also would it make a difference if I go with a pre vortech or a vortech engine? This is my first boat and I am mechanically inclined. Any help would be greatly appreciated

 

[Scott Danforth]

welcome aboard

vortec motors are post 1996. you get a bit more power with the vortec heads

your boat should be a non-balance shaft motor

here is some reading

http://forums.iboats.com/forum/engi...history-of-the-4-3-liter-with-casting-numbers

I would rebuild the block you have, buy new vortec heads, rotating assembly and be back boating with a new motor.

 

[Mbyzfr6]

Thanks for the link. I will do some reading up. As for rebuilding the engine, that as my first thought but I removed the heads and noticed a nice scrape on the one cylinder wall.
Here is what happened:
I had bought the boat with everything in working order and a supposed rebuilt engine. I had it out on the lake and it over heated.
First thing I checked was the impeller and noticed it was shot.
So I also just did a compression check on internals and it was reading low on the one bank, so I decided to pull the heads and when I did I noticed the nice scrape.
And I am thinking it is too deep to be repaired

 

[Scott Danforth]

first thing you should have done is the maintenance items like changing the impeller when you bought the boat.

unless the scratch is over .030" deep, it can be fixed with a bore/hone/rebuild

 

[Mbyzfr6]

Yeah I should have checked it even though the guy had the papers from a shop charging for a new impeller. My dumb mistake.

 

[Keaton]

if you are going to replace the motor I would look at a junk yard for a 1996+ jimmy/blazer/gmc sonoma. Take the motor, wiring harness, ECU. 1996+ should be a MAF based system so o2 sensors are not extremely important, speed density systems really needs o2. you can ad o2 to your exhaust for ~$200 ($95 for the adapter + $60 for the sensor + some machining time)
http://howellefi.com/general-motors...accessories/adaptor-o2-sensor-for-marine-use/

pull the motor swap exhaust, starter, alt, over to the new motor.

vortecs should come with a hydro roller cam that is basically the same as a boat cam, there will be a few that say you can't use it, specs are with in a few degrees.

you will also need a high pressure pump and tank return.

http://www.onedirt.com/tech-stories/engine/a-guide-to-vortec-vs-oe-small-block-chevy-heads/


this sounds like a bit more work but you don't have to deal with a F***ing carb.

if you are gonna rebuild your current motor look at a set of votrec heads, good for a ~+20-30hp & tq increase better low speed burn. note the center bolt angles will be different depending on the heads (junk yard vs new castings from jeggs/summit) so that is an intake change as well. basic port clean up goes along way on either sets of heads, don't forget the intake manifold. see youtube for how to

 

[Scott Danforth]

No Title

automotive EFI is not SAE 1171 compliant. so while some people do not understand the simplicity of a carb, suggesting using automotive EFI in a boat is simply bad advise

 

[ab59]

My two cents- if you find a good engine for an auto and you replace the cam, freeze plugs with brass plugs , distributor with marine dis. and I guess you can get away with not changing head gaskets to Marine as long as you will be operating in FRESH water. I would add up all those costs to see if it is worth while but I'm not a professional mechanic by any means, just common sense .

 

[Keaton]

automotive EFI is not SAE 1171 compliant. so while some people do not understand the simplicity of a carb, suggesting using automotive EFI in a boat is simply bad advise

I do understand carb. I also know EFI is superior, and safer.

your photo is showing a boat exploding, something that can happen when you get an explosive mixture of fuel in the air in a contained space and an spark sets it off.
a carb has several vents to atmosphere the biggest being the bowel, a warm engine will aid this liquid in from becoming a liquid to vapor and then you get above. that's why you turn the blower on for a few minutes before you start the motor. most carb boat smell like fuel for this reason.

with EFI you have a high pressure pump that sucks it from the tank and pressurizes it up to a closed valve (the injector) and a return pressure regulator that goes to the tank. no vent to atmosphere. in the case of the 4.3L vortec it's just like its big brother with spider injection located inside the intake manifold behind the throttle body. A leak here would be sucked into the motor, if the motor dies from to much fuel the computer shuts the pump off... so how are you going to get a leak of fuel vapor that can cause an explosion? you have to use the correct fuel line for this because you are now at 60psi vs 8psi, there is your other fail point. so give me a more scientific reason why EFI is unsafe

when you are setting a carb, you set the to run rich at idle so when you put it in gear the load will not stall the motor. then you have to play the game of setting your jets and metering rods to give you a good hall shot, throttle response, and tip in and top end. and you have to pick what you prefer the most.

with EFI you don't have these problems you have a computer running 20+ million instruction per second (20MHz) who's whole job is to read the sensors (TPS,IAT, MAP, MAF, RPM, o2, Coolant, oil pressure) on the motor, look up tables, do math and spit out an answer (injectors & Timing). rinse, wash, repeat. the computer is mapped to cover large engine operation conditions. better fuel econ and power output.


so other than saying it wont work and point to a spec, give me a more scientific reason why you can't use it.

do you worry about your car/truck exploding and or catching fire when you take it out every day? didn't think so.

 

[Scott Danforth]

so other than saying it wont work and point to a spec, give me a more scientific reason why you can't use it.

do you worry about your car/truck exploding and or catching fire when you take it out every day? didn't think so.

Because automotive EFI does not comply with SAE 1171. The extra sealing of the trhrottle shafts is not there. Not to mention the whole difference in fuel mapping for marine applications and the EGR and carbon canister purge systems are an ignition source and a bomb if you encase them in a bilge

Automotive EFI has no place in a boat.

Marine EFI is developed for boats

And no, when my cars EFI suffers a fuel leak, i dont worry about it, because unlike a boat where the leaking fuel becomes explosive, there is no bilge on a car

Your miscellaneous ramblings are not supporting the OP's quest to get his boat back in the water

 

[Mbyzfr6]

Since my engine is the 4.3l w/o the balance shaft would a later 4.3 w/ balance shaft work?

 

[bruceb58]

Since my engine is the 4.3l w/o the balance shaft would a later 4.3 w/ balance shaft work?

Yes...you will just need a new intake manifold to clear the balance shaft. You will need a new intake manifold anyway since newer engines are Vortec and the intakes are also different.

 

[Mbyzfr6]

Ok thanks. Also if I were to get a good used auto engine. Besides changing the freeze plugs, would I have to change the cam and the head gasket also? I am thinking about just replacing the long block because everything is good on it.

 

[ab59]

marine engines use a different cam then an auto . The cam in a marine engine is made to deliver a quicker response than an auto. think about how you drive a car and how you drive a boat , with an auto it is a much more mundane slower acceleration but with a boat you are going from 0 to 40 with WOT to get on plane that puts a lot more demand on your engine and you do not want to lug an engine that you want to keep around for a while.
Again , I am not a professional so some one else can explain this better that is. Y could probably get away with an auto engine as is but don't plan on a long life.

 

[bruceb58]

Any late model 4.3L engine that you find will be out of a truck and you can just use the cam that's in there.

 

[ab59]

58-- I would like to start another thread about this subject because I don't understand your statement as it is contrary to my research or I simply misunderstood the research . Is there already a post on this subject ? I don't want to sidetrack this mans post and would like to know for future needs.
thanks -- a.b.

 

[Yarecky3]

Hi. Just to say few words about getting engine done.
I have my own rebored by .060" got set of pistons with rings from US (to Ireland) for 80usd. I paid 200euro in machine shop for cylinder bore. Set of gaskets I think 100euro incl 2x head gaskets. New main bearings cam bearings and rod bearings for as far i remember 80euro. And i have a new engine now. So i think its worthed to fix it. A block had some hidtory and it was welded before under inlet manifold and all is great.
So if you didn't get new enginevyet think about fixing it.
Cheers j

 

[Lou C]

There are a few other considerations as far as sticking with the old non Vortec vs the Vortec...
​1) if you plan on sticking with the pre Vortec, keep in mind that the carb intakes for these are no longer made and can be hard to find if yours is not in good shape (freeze damage, corrosion or warped). You can find them on e-bay but the condition is hit and miss....
​2) the Vortec will give you the balance shaft and better flowing heads for a bit more power and smoothness
​3) the Vortec has no provision for a mechanical fuel pump (which I prefer, reliable and inexpensive) if you want to stick with a marine carb set up. So you will have to use an electric marine rated pump

​I think the best but most expensive plan with the greatest probability for success is to buy a new GM marine long block 4.3 Vortec. You then have to decide on if you will go with a 2bbl or a 4bbl carb since that determines which intake you must buy. Personally I'd go with a 4bbl, if you had a Q-Jet on the old engine, you'd have to convert it to an electric choke because there is no exhaust crossover passage on the Vortec engines like on the pre Vortec. I think by the time OMC was making the '92s they had switched to Holleys for the 4bbl with electric choke.

​As far as EFI in boats, unless it is a marine certified system I would stick with a carb. Carbs are simple, they can be easily replaced, and there are no $700 mystery boxes to run the system that can become NLA years down the road. You can still buy brand new marine Holley 4bbls and 2bbls or a number of other carb brands.