1988 Weekender 300 - repower with Crusader 454's . Questions

[mrboatfinder]

So I need to replace the engines in my Weekender 300. It has Mercruiser 454's 330hp , straight inboards. I have found a pair of used drop-in Crusader 454's that are totally rebuilt and 100% guaranteed. My questions have to do with what will be required to use the Crusaders where the Mercruisers were.

1. I believe they should be a direct bolt in match for footprint and pairing with the drives. Anyone have an opinion on this?

2. Just looking at them (haven't had a chance to measure) it would appear the Crusaders exhaust riser/elbow outlet is a bit lower than the current Mercs. Some have said I should re-use the Merc Manifolds/risers to make it match up. However, I think the Crusader manifold/risers are in better shape and would prefer to use them. Any ideas how this is done if they aren't the same height?

Any other info from experience or knowledge of this would be appreciated. Does anyone have a Weekender 300 with Crusaders I could see a photo of the engines?

Thx.

 

[moparlvr4406]

the fresh water pumps are different on the crusaders also
I assume you are doing counter rotational ??

 

[speakrdude]

One (engine) should be a counter rotator. Is in my 88 300WE, but I have 5.7's.

 

[mrboatfinder]

Yep, the starboard engine is counter rotation. The different pumps shouldn't matter as the crusaders are complete engines so ready to plug and play. I just need to make sure things line up properly.

 

[moparlvr4406]

is one of your mercs counter rotating ?

 

[hottoddie]

The risk in using the Crusader manifolds and riser is the risk of water reversion if the engines sit lower than the manifold/riser combinations were designed for. Using the Mercruiser manifolds/risers should eliminate that risk. The Crusader sea water pump is different and you need to check the clearance but they are usually Sherwood pumps and better than Mercuiser. Also Crusader mounts are different but if you Mercruiser mounts are in good shape they will bolt right up.

What Generation are the Crusaders (Gen 4 or Gen 5). Your 1988's are Gen 4 and if the same the rest of the parts will swap easily. Good luck.

PS. If your blocks are in good shape I would find a really good shop and have then rebuilt to my specs.

 

[mrboatfinder]

Yes, both the current Mercs and the Crusaders are gen IV . I'll have to do some measuring to see how far above the water line the crusader risers would sit and also make sure we have a slope to the exhaust muffler.

Another question : The Crusaders I am considering a fresh water cooled but my current engines are raw water cooled. I boat in the Great Lakes so most have raw water cooling. Do I want to keep the Crusaders asfreshwater set up or convert to raw water and sell the heat exchanger, etc.? DO you use the same manifolds either way?

Thx

 

[hottoddie]

Re: the manifolds. Crusaders use 4" outlets and Mercruisers run either 3" or 4". I would prefer 4". Either manifold will work the Crusader heat exchanger but some hoses may be different lengths. You can get different Crusader elbows that will increase the height of the outlet if you need that. I would keep the FWC as they are easier to winterize, run hotter and more efficient and the resale on them would be better. JMHO.

 

[1956olds]

I would keep the fwc if you have room in the bilge for it.

 

[mrboatfinder]

OK, yes, I think there's plenty of room for the FWC accessories. As for the elbow, I tried to upload a photo of the engine but no luck so far so I will try to describe it. It's very typical of Crusaders I've seen where the manifold goes to a riser which reaches the max height then an elbow back down 6-8 unches, maybe about the height of the top of the manifold, then the elbow goes to the exhaust hose. I believe the elbow is where the raw cooling water comes in and then exits so it is cooled. Whereas Mercruiser has the hose attached to the riser at the max height of the system.

All I'd need is some sort of elbow back up, I think. I don't think I can attach the exhaust hose directly to the Crusader riser as there'd be no elbow for the raw cooling water.

Anjyone ever re-plumb this sort of thing?

 

[Saverio]

Both your mercs failed?

 

[hottoddie]

The important consideration is that the Crusader elbow reach the same "elevation" as the Merc elbows did in order to ensure that water will not flow back into the engine upon shutdown or while backing down in reverse. The Crusader elbow will have a fitting or an adapter with a fitting to connect the raw water hose to.

 

[mrboatfinder]

Thanks for the help so far. One engine has a cracked block from improper winterization. The other engine runs OK but is rusty and has seen some brackish water and with raw water cooling is likely on it's last legs. I can get a pair of nice used Crusaders for a good price and have two engines I trust.

I think I'll have to wait until I get the Crusader engines then measure where the exhaust hose fitting is and see how far off it is going to be.