1988 Mercruiser 454 inboard. Can I replace with Crusader

[tmh]

Hi. I'm looking for a replacement engine for my 1988 twin engine 1988 Sea Ray. It has Merc 454 Inboards, Gen 4. I have found a couple nice Crusaders of the same era - 1988 also. I'm wondering how easily they drop in as replacements for the Mercs.

 

[Scott Danforth]

Re: 1988 Mercruiser 454 inboard. Can I replace with Crusader

the blocks and heads are the same. Crusader has different intake and exhaust manifolds.

I would probably just install the motor and swap over your mercruiser exhaust manifolds (or buy new). to match up the remainder of your exhaust system.

 

[tmh]

OK, thanks for that info. I want to make sure I understand how a Crusader 454 would work on my Sea Ray 300 with inboards. I have gen IV Mercruiser MIE engines one of which has a cracked block and both are a bit rusty looking so maybe other issues coming soon. If I buy two used complete Crusader 454's (pulled running perfectly) of the same vintage will they:

1. Be able to use the same bolt holes for mounting?

2. Fit correctly with my Velvet drives without modification?

3. What about my exhaust hoses? Would I use my Mercruiser manifolds so they line up correctly?

4. Anything I'm missing here?

Basically, I'd plan to have mechanic pull current Mercruiser engines and install the Crusader engines with as little parts changing as is practical. I'd then sell the running engine and parts from the cracked one (or give to mechanic if he can use them to pay for work done). I'm looking for info on what complications there are in doing this.

Thanks.

 

[Bt Doctur]

are your motors both standard rotation, are the crusaders standard rotation?
1 yes
2 yes
3 yes
4 no

 

[tmh]

Thx Doctur, sounds like a fairly straightforward swap out to nicer engines. To answer your question, existing engines are one standard one reverse rotation, same with the crusaders. I believe the Crusaders came from a V-Drive application - shouldn't matter though, right? I will make sure 100% on the rotation prior to purchase, of course.

 

[tmh]

OK, I had a chance to check out the Crusader 454's and hear them run. All looks great. These are freshwater cooled Crusaders from a freshwater lake boat. My current Mercruisers were raw water cooled. Anyways, the Crusaders look in great shape, start great and have proper compression, so as best I can tell they check out. I have one more question though, regarding the exhaust manifolds, risers and hoses.

1. Can I use the Crusader as is and have some sort of adapter to the exhaust hoses? My current manifolds/risers do not appear to be in nearly the condition the Crusader ones are in so I'd much prefer to use the Crusader as-is. However, it doesn't look like they'd line up with my current exhaust hoses. If this boat had originally had Crusaders would the hoses have been lower to match up and no other changes? What are my options on this?

Thanks for any help on this. I plan to make the engine purchase by the end of the weekend and want to know what I'm doing.

 

[Bondo]

OK, I had a chance to check out the Crusader 454's and hear them run. All looks great. These are freshwater cooled Crusaders from a freshwater lake boat. My current Mercruisers were raw water cooled. Anyways, the Crusaders look in great shape, start great and have proper compression, so as best I can tell they check out. I have one more question though, regarding the exhaust manifolds, risers and hoses.

1. Can I use the Crusader as is and have some sort of adapter to the exhaust hoses? My current manifolds/risers do not appear to be in nearly the condition the Crusader ones are in so I'd much prefer to use the Crusader as-is. However, it doesn't look like they'd line up with my current exhaust hoses. If this boat had originally had Crusaders would the hoses have been lower to match up and no other changes? What are my options on this?

Thanks for any help on this. I plan to make the engine purchase by the end of the weekend and want to know what I'm doing.

Ayuh,.... Ya might need to buy different risers/ elbows to make 'em fit,.....

 

[tmh]

OK< thanks Bondo. Would you recommend using crusader parts to make them fit or using the mercruiser manifold and risers? I may want to replace the merc manifolds/risers anyhow so no savings re-using them.

 

[tmh]

Well, I'm still trying to iron down exactly how to use the Crusader 454 if the outlet from the exhaust elbow (has end for exhaust hose) doesn't line up with the hose. Can we just use an "S" shaped piece of some sort to match them up? The elbow on the Crusader is cooled so clearly I can' not have it in there. Does anyone know if it has to be a curved piece (downward "S" shape, which puts it too low) or if there's a straight piece I can have off the riser to the exhaust hose? Unlike my current mercruiser, it looks like the riser on the Crusader does not have a fitting to the exhaust hose - maybe I need to use a riser that goes direct to the hose like the Merc does. I did look at various risers/elbows for sale but haven't really seen for sure what I need.

Thanks for the help, btw, I'm getting there!

 

[Bondo]

Well, I'm still trying to iron down exactly how to use the Crusader 454 if the outlet from the exhaust elbow (has end for exhaust hose) doesn't line up with the hose. Can we just use an "S" shaped piece of some sort to match them up? The elbow on the Crusader is cooled so clearly I can' not have it in there. Does anyone know if it has to be a curved piece (downward "S" shape, which puts it too low) or if there's a straight piece I can have off the riser to the exhaust hose? Unlike my current mercruiser, it looks like the riser on the Crusader does not have a fitting to the exhaust hose - maybe I need to use a riser that goes direct to the hose like the Merc does. I did look at various risers/elbows for sale but haven't really seen for sure what I need.

Thanks for the help, btw, I'm getting there!

Ayuh,.... The easiest answer is adapt the Mercruiser manifolds, 'n risers,....

As I said before,... Different risers at different angles, 'n lengths can be bought for most manifolds,...
The motor side of the manifold don't care, the plumbin' will also need to be adapted I imagine, but donno, can't see any of it,...

 

[tmh]

Thanks again Bondo and others. I've looked around a bit and have concluded I just have to wait until I can measure the two engines and my exhaust hose layout and see what's needed to make the Crusaders fit. I assume it will be a center riser manifold to a riser direct to the hose, which is what my Mercruisers have. I am hesitant to re-use the Merc manifolds/risers because the boat spent some time in brackish water and is raw water cooled (although I know these aren't original manifolds I don't know when they were last changed). I bought it from a freshwater lake but it clearly has seen salt at some point not too long ago, IMO.

My best guess is I'll be buying the center rise manifolds/risers (maybe OEM, maybe not) and maybe selling the ones that come with the engine on eBay or whatever. We'll see when I get the engines and have a look see.

 

[Bondo]

Thanks again Bondo and others. I've looked around a bit and have concluded I just have to wait until I can measure the two engines and my exhaust hose layout and see what's needed to make the Crusaders fit. I assume it will be a center riser manifold to a riser direct to the hose, which is what my Mercruisers have. I am hesitant to re-use the Merc manifolds/risers because the boat spent some time in brackish water and is raw water cooled (although I know these aren't original manifolds I don't know when they were last changed). I bought it from a freshwater lake but it clearly has seen salt at some point not too long ago, IMO.

My best guess is I'll be buying the center rise manifolds/risers (maybe OEM, maybe not) and maybe selling the ones that come with the engine on eBay or whatever. We'll see when I get the engines and have a look see.

Ayuh,.... Ya Gotta have the motors pretty much side by side to do what yer doin',...

Another thing to watch out for with the manifolds is the accessory bolt holes ain't always the same, application to application,...

To know whether the Merc manifolds are viable, Pull 'em apart, 'n Look,....