2.5 vs 3.0 swap differences... Mad Scientist stuff

[DieselDood]

So I spend way to much time driving. This leads to my mind wandering. When my mind wanders I think of things... and well things like this come to mind.


I currently have a 2.5L 200hp EFI on my 1998 Triton TR21. 95% of these boats came with a 225hp which is a 3.0. So I'm underpowered and I know it. Sooner or later I plan to get a rebuildable 3.0 and swap them out.


A friend of mine hit something and the lower unit left the chat at 65mph, also breaking the leg. (yes he went on the wild spinny, wet ride! But still sacked up 16lbs for the day and made the regional team)

The shop told the insurance company they think the bottom of the crank is probably damaged, possibly even bent the crank, so the motor was totaled and he now has a new/used motor.


Soooo.....
That got me thinking, and Google did not help, so here I am to ask the experts.

Will the Leg and lower unit from a 2.5 bolt up to the 3.0?
Could I pull the 2.5 powerhead and covers, seal it the motor up, and put it on the shelf. Then drop the 3.0 on with covers in it's place? Kind of like the bellhousing on a vehicle, a 350 will bolt in where a 305 was very easily. At least that is my thoughts... my 2.5 uses the bigger lower gear housing even. Are the splines the same? I find some contradicting posts on that, so I'm not sure there. Again Google really didn't help, it actually muddied the water more for me.

Even if I have to replace the crankshaft on his old motor, it was well cared for, and ran great. Swapping out the crank and putting the powerhead on my leg/lower could happen in a weekend. Although, really I'd probably do it right and more than likely (hopefully, be able to) hone the cylinders and put new rings in it, just to make sure everything is good. (send injectors in to get checked....etc... its apart... do it right)

IF I can get it for the right price, I don't mind putting in the work. Then I know what I have. I potentially could take what is currently an anchor and turn it into a good solid running motor. At least that's my thinking.

I do know that the controls/wiring may be different, but when I do make the move from the 200 to a 225, I would need that anyway, so no harm no foul there. It would be really slick if it didn't even need that changed... but that's not really a huge worry at the moment. The physical motors are where I'm at.


So... back to the real question at hand... if I can get his old motor for cheap... can I drop his old 225 3.0 (I believe 03) onto my 98 200 2.5 Leg/Lower and swap the upper and lower covers?

[kllr bee]

Simple answer is no. Way different bolt pattern. I would not try to rebuild a powerhead that has a bent crank either because the block has more than likely been compromised.
Richard aka Kllr Bee

[DieselDood]

I thought the bolt pattern may be different. Dang. That's to bad.

I guess I didn't think about the block side of things. I guess I'd have to do a WHOLE lot of measuring! lol. Who knows, it may not actually be bent... it may have just been what they said happened.

I'll ask him if they actually tore it down before I try to pick it up. Although for cheap enough, even as a parts unit, it could be worth grabbing.

[JOE54]

your overthinking this your controls and wiring will work fine , GRAB IT find a blown 3.0L and install that powerhead and proceed to explore the world of fuel consumption

[EuropeanAM]

your overthinking this your controls and wiring will work fine , GRAB IT find a blown 3.0L and install that powerhead and proceed to explore the world of fuel consumption

^^^^ This. Controls and rigging will work (you may need an adapter, depending on the serial number of that 3L).

You will, however, need a 3L Midsection and gearcase suitable for the Vintage/Type the powerhead originated on (do your best to get that original serial number and hang onto it as it identified everything under the hood).

[DieselDood]

Thanks guys! Another gentleman about 6.5 hours from me is looking for a 2.5 and has a 3.0 225 Opti he's looking to trade. I think I may go that route, and... if I can get my friends motor I'll grab it too. Spare parts have saved me a BUNCH in the past!

[JOE54]

what year vintage on the trader be careful now on that , ser numbers help us a lot

[DieselDood]

what year vintage on the trader be careful now on that , ser numbers help us a lot

He is a pretty well known member of another forum and knows a few guys that I know. I know it's a 225 Optimax. (and a blown up 225EFI)
I'll post up the serial number once I pick it up and get it home.

[JOE54]