Switch motor from 3.0L to 4.3L. Is it possible?
glennfam2003 Member Posts: 7 ✭
edited March 2018 in Rinker Custom Projects
We have a 2001 Rinker bowrider 180 with the 3.0L engine that is gutless. I hear that there was a sport option that came with a 4.3L engine. Is it possible to switch my 3.0L for the 4.3L?
Most economical way: sell your boat and buy the boat with the powerplant you want.
Second most economical way: buy a donor boat with the 4.3 and frankenstein them together.
guessing your 3.0 uses the alpha1gen2, right? just like a vehicle, the gearing can be done on either end (overall gear ratio on a car/truck is impacted by diameter of tire, which is roughly equiv to prop selection) - either through the drives gearbox OR through the prop. obviously, the prop is the easiest and less expensive to do... for instance:
if i had a gearbox of 1.82:1 and could swing a 21p prop within the engines spec'd RPM range, if i dropped to 1.5:1 i could likely only swing a 17p prop to meet the engine spec'd RPM range. it translates to roughly the same forward speed, though... weird, huh?
as far as the engine itself- you have to pull the 3.0 and PROPERLY fill the vacant holes in the engine mount blocks by drilling them out slightly, using a dowel of proper wood and diameter, then seal it... your 'new' engine will be hoisted in and sat atop the blocks, aligned to the outdrive as if you're doing a 'final alignment', then the feet of the mounts properly seated, marked carefully, engine pulled and new mount location drilled- return engine... it sounds hard, but it's really not.
seeing as how 4.3's are often swapped for V8's, you can usually find one pretty easy... you can find a gear box easily too- only the upper will gearbox will need to be swapped to find the ratio you need. but again, it can also be done from the prop, too, and which is the way i'd go beyond doubt. cheaper, and easier.
as it turns out, i have an entire Alpha1Gen2 drive in 1.82:1 I'm willing to sell if you want it. It needs a new seal, but that is all- it's in perfect working order otherwise. I'd be happy to sell it to you, but................ prop, man- account for the ratio on the prop side.
i have a 4.3 sitting on a pallet right now. it would need some top end work- such as carb and intake manifold, and it needs exhaust manifolds, risers, and elbows... you're welcome to it, though, if you want it. it simply didn't have enough gogo for what i wanted. it's an 05 Mercruiser... had about 300 hours on it when i pulled it. shipping, and it's yours. compression is good and it ran fine when i pulled it- though i'd consider a timing chain and probably a water pump (engine mounted) if i was going to use it again. I kept it with intent to use it as a stationary generator- but this is before i knew that power heads for a generator cost as much as an entire generator does- it's only in my collection because i kept waiting for a used powerhead to present itself...
2002 FV 342 on Lake St. Clair - Past Commodore SHC - Vessel Examiner USCGAUX
I remember back in the day OMC using Ford 351 marine engines.
On a 180 the 3.0 isn't a bad engine choice, I have skied behind many boats with 3-4 people with decent performance. That being said I owned a new bayliner 180 with a 4.3 and was happy with it. I was however disappointed with the factory props, way to high of a pitch for a good hole shot and lower speed control. Once I changed the prop from a three blade 23 to a four blade 21 it made a huge difference. Lots of fellows go to the stainless 19 but I went with a happy medium for my driving preference.
With your boat being older, a tune up and engine compression check may be in order... are you getting the most out of the engine, is it healthy? Maybe a rebuild of the current 3.0 is in order vs swaping it out.