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Crusader 454 vs. the Crusader 8.1 which would you repower with???

contender31

Regular Contributor
I have 2 tired 1990 454 Carbureted Crusader 350 model engines in my 1990 Tiara 33 open. I have an option to repower with long block 454's with the same specs or with the 8.1's. Cost of the conversion is not the only factor in my decision. The considerations I have are quickness to plane, fuel economy, technology, serviceability, parts and longevity.

Any thoughts or experiences? Has anyone made the conversion to the 8.1's in this vessel or a similiar vessel in size and displacement? The Tiara is 15,000 lbs loaded and a 12 foot beam.

Thanks in advance
 
Did you try to find 8.1's? As you probably know, they don't make them anymore -discontinued last year with no BB replacement. Seems like NEW 7.4 "Crusader" long blocks are scarce as well. IMHO the 8.1's would be the better choice for every reason you listed.

I'd be curious to know what you end up doing as I would like to repower in the next year or two. I had always planned on going with Crusader 8.1s but now it seems like the Mercruiser 8.1 Horizon's are the only thing close to them. They are very costly and I'm not a big Mercruiser fan. From what I've read on this and other boards, opinions are that the Crusaders are highly preferred over the Mercruisers.
 
I will advise once I make the decision. I called Crusader and they said the same thing as you mention. They basically said that the 8.1 was a far superior engine than the 454 however they discontinued as you mentioned. There only comment was that replacements may be problematic down the road but the engine it self was superior in pretty much all aspects. What I would really like to do is replace them with diesels but the difference in the cost doesnt warrant the extra fuel. I would have to burn alot of gas to offset the cost of the difference in cost.

Thanks for the feedback
 
Repowered my 35 ft Viking with Crusader 8.1s, 3 seasons ago replacing tired 454's. Very satisfied with the results. Like a new boat, cruise & top end went up, fuel burn rate went down.
 
I did see them and spoke to the owner - 1100 hrs and many parts missing. The owner was vague as if he appeared to be hiding something. I asked if I could send someone over to start them and do compression and leak down and avoided the question. He couldnt tell me the history so I moved on as I dont buy amnything unless the feeling is right. He said he bought the engines last summer from a guy who had them in storage when in fact these engines had been on ebay last summer so not sure about the stories. Seems like he is hiding something.

Thanks
 
I might as well keep my engines than do all the work and expense of the conversion on engines that are almost as tired as mine. Besides after speaking to Crusader they recommended that I stay away from the 8.1 engines as they are discontinued and replacements engines and parts will be tough to find down the road. The 454 was out so long the engines and parts are plentifull.
 
Contender31,

Why not freshen up the engines you have? Rings, bearings, valve jobs, gaskets & seals, hoses, impeller, etc. Likely both can be done complete parts wise, for the price of one longblock.
 
The Question was, "Which one would you repower with?" This is a question that in reality only you can answer, perhaps after extensive investigation. Yes, it is true that GM stopped producing the 8.1L engine, however, many were produced. The 8.1L is a superior engine. Some are begining to show up at engine rebuilders. I think parts will be available for many years. I went thru the decision process of rebuilding my 454's or replacing with new 8.1s. If I rebuilt my 454's, I would still have old technology. I considered converting to diesels but could not justify the cost (would have to keep the boat forever). Regarding these specific engines, most likely the seller does not know much of the history and may be a position of wanting to get out from under them and needing the cash. My opinion (for what it's worth) is that the sellers current price is very reasonable. Even if these engines would happen to need some work, they are more modern technology . I guess like any other decision, "You pay your money and take your chance". I have no regrets about repowering my boat with Crusader 8.1L engines.
 
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Yes, it is true, no counter-rotating. This can be (usually is), counter rotating props are provided by the transmissions (Hurth) or Velvet drive with different ratios (also different pitch props). When repowering my boat, for clearance issues, I had to use down angle (Hurth) trans which also provided L& R rotating props. The new 8.1L is configured different from the 454 which requires greater verticle clearance. The down angle trans helped to provide greater clearance and counter rotating props (engine sits more level). The inline tranys would not allow for adequate clearance (set the engine at the wrong angle) . The cost difference was not much greater than purchasing a new trans to provide the counter rotating prop (plus rebuilding my existing/old trans). I did converse with an engine rebuilder who could build for me a reverse rotating 8.1L engine. However, my concern was then having od-ball enginene that may be difficult to support in the future. The cost for the custom engine was not all that different then buying a new standard engine. Two new engines and tranys was the route I decided to go. I did a lot of research before my decision. No regrets!
 
That "GUT" feeling goes a long way sometime... and while it may be the best bargain of the year, it never pays if you don't feel right about it. They look like they are brand new ...that might make me think like something should be looked into. I bought way too many vintage motorcycles that in unrestored condition...really looked unrestored. Others were played with beyond their value and took more to get it right. They do look sweet but sweet wont make 'em run great if ...

My 93 year old father always tells me..."when in doubt, do nothing"
 
Your question was pretty basic. I think just about anyone would choose the 8.1 engine, including me,but not this pair !Too many unanswered questions about these engines to take a chance on, you may have better ones already in your boat, if you were happy with your existing engines for all these years then why not either rebuild yours or buy rebuilds and go from there. If I were in your position , I think I would have my own engines rebuilt and have the transes gone over, you will probably spend less money doing that , you'll definitely know what you have and you'll enjoy another 20 years ....Lee
 
Six of one; a half dozen of the rest.

The 8.1s are modern, so motors and new parts ($$$) will be plentiful for decades. The 454s are old, but rebuilt long blocks will be avaialble--and cheaper--for decades.

Jeff
 
The 8.1's had a relatively short lifetime though not a bad as GM's TBI system. So the market economics will drive parts prices for them much higher than the MarkIV-GenVI commodity parts. The big pay-off is their injection system was common across the suite of V-8s so that should be one expection, pricewise.
 
All great thoughts and ideas - you guys are great - great website observed by great people - I passed on the engines based on the last question answered which I have cut and paste below. I think I will run these 454's til they run no more then re think my options. The great thing about these 454's is the popularity they have with the muscle cars.

Dear jelliottjr,

Thanks for responding - can you tell me everything the engines need to complete them for install other than the transmissions.

Gary

Dear limitout31contender,

No I can?t. I am not a marine mechanic nor do I know your application. They are basically dressed long blocks.

- jelliottjr



Appreciate all your feedback


Thanks
 
Too bad they did not work out for you. I have one of the last Crusader 8.1 HOs that I put in to replace a Merc 454. Nice upgrade. ...Not only more power but better ecconomy (given the same speeds). But if the ones you were looking at are no good, then it's a moot point.

Bruce Clarkson
 
I have 2 tired 1990 454 Carbureted Crusader 350 model engines in my 1990 Tiara 33 open. I have an option to repower with long block 454's with the same specs or with the 8.1's. Cost of the conversion is not the only factor in my decision. The considerations I have are quickness to plane, fuel economy, technology, serviceability, parts and longevity.

Any thoughts or experiences? Has anyone made the conversion to the 8.1's in this vessel or a similiar vessel in size and displacement? The Tiara is 15,000 lbs loaded and a 12 foot beam.

Thanks in advance
I repowered my Trojan F-36 (had Chrysler 440's, similar to your 454's) with 8.1's.
Only similarity to 454's is bore centers. EVERYTHING ELSE IS DIFFERENT AND BETTER.
8.1's are stroker motors, Vortec EFI, with MUCH MORE TORQUE AND EFFICIENCY = 420HP X 550 ft-lbs torque.
EVERYBODY TOLD ME THEY WOULDN'T FIT, but they fit nicely with ZF 8* down angle xmissions (ya' hafta change trannies cuz both engines rotate the same direction, so for counter-rotation, one trans in reverse, one fwd).
My old WOT (30mph) is now an easy cruise, with wot above 40. Fuel economy doubled.
PS: get SmartCraft instrumentation with them701717_0_230620101437_1.jpg701717_0_230620101437_32.jpg
 
I repowered my Trojan F-36 (had Chrysler 440's, similar to your 454's) with 8.1's.
Only similarity to 454's is bore centers. EVERYTHING ELSE IS DIFFERENT AND BETTER.
8.1's are stroker motors, Vortec EFI, with MUCH MORE TORQUE AND EFFICIENCY = 420HP X 550 ft-lbs torque.
EVERYBODY TOLD ME THEY WOULDN'T FIT, but they fit nicely with ZF 8* down angle xmissions (ya' hafta change trannies cuz both engines rotate the same direction, so for counter-rotation, one trans in reverse, one fwd).
My old WOT (30mph) is now an easy cruise, with wot above 40. Fuel economy doubled.
PS: get SmartCraft instrumentation with themView attachment 8262View attachment 8263
Also, check with Tiarra to see if you may be overpowering your boat with 8.1's. My F-36 has lifting strakes like yours, and really gets up on top with added 10mph (pic). It comes close to chine walking, and trim tabs & rudders work as fast as ailerons on a stunt plane.
If you have to change your prop shaft angle down (as I did, from 12* to 8), it's easy with a solid fiberglass bottom. I'd be happy to help you with sketches, etc.
 
My 8.1's were rescued from warranty scrap, and repaired by Derebery Marine. One never ran (bad computer harness), and the other had 40 hours before the early issue head gasket blew. Both were gone thru entirely, and I witnessed Dyno tests (427 HP & 418 HP (twins within 5% are acceptable, mine are 2%).
The torque is almost flat from 2600 rpm-4100rpm, so pick your speed anywhere in that range for max efficiency (24mph-40+). Hull seems to be most comfortable prox 3200/32mph, which is exactly 75% = designed cruise for gas engines.
My cost was $7500 + $2K tranny ea. , & I helped with shaft angles, cleaned & refinished bilge, linkages, shaft seals, wiring, etc. + $9K yard labor +$2K SmartCraft instrumentation (2 stations) - $1K for 440 cores = $29K turnkey.
 
I've been an engine freak since childhood (from lawnmower engines to my Gampa's late 1800's Fairbanks-Morse lake water pump engine).
The BIG advantage to the 8.1, is it provides torque over a wide band, prox 1.5 X HP, much like a diesel, 1.7 X HP.
Sadly, it's been discontinued, due to GM's LS engines developing more HP per lb. If you look @ the torque curve on the small blocks, it climbs @ a 45* angle thru 5,000 rpm (not a mid-range engine). The 454's have the same tendency, i.e., needing to run between 3500-5500 for peak efficiency range, and only HP = Torque.
That's because 454, 502 is "oversquare", = bore greater than stroke.
Stroke = Leverage = Torque.
Small block engines have always been O/S, yielding higher (safe) rpm potential for total HP.
Diesels and "work engines" are always undersquare (stroke longer than bore), which means a broad range of high torque, better "air pumping" efficiecy, and lower RPM limits.
Have y'all seen the new 557 HP Outboard motor by Seven Marine?
It uses a stock Cadillac LSA V8, and basically operates between 4K - 6K rpm.
How'd you like to operate @ cruise 4K-5K rpm all day?
My 8.1's are quiet thru 3800 rpm.
Most diesels and large "work engines" are "undersquare", meaning stroke longer than bore (some large ship engines are 2X undersquare).
A continuous flat band of torque, @ peak design efficiency, is what marine (continuous) duty needs.
High RPM, High HP = race cars.
PS: look up David Pascoe's (FL Marine Surveyor) article; "Gas VS Diesel".
For midsize boats like ours, stay gas. Or, multiply fuel mileage X .7 (due to the price of marine diesel, and limited availability), and diesel engine maintenance costs (I could replace a 8.1 long block for the price of one 3208 head rebuild).
 
By the way, my re-powered F36 is (sadly) for sale.
WE, IN TEXAS, HAVE MAJOR WATER PROBLEMS.
I live in Austin, now, but Lake Travis is 57 feet low (no longer a lake, only the CO River). The boat is on Lake Texoma, but the water is dropping so fast I now have only 2 ft. under the props (Dallas is starting to draw city water).
THE ONLY WATER WE HAVE TO MOVE THE BOAT to IS SALT, and I've already had my fill of saltwater damage on other ventures, and the freezing winters in MI.
I guess I have to rent (charter), or buy a trailerable boat for the remainder of my boating (SurfSide Five is my 20th boat).
 
By the way, my re-powered F36 is (sadly) for sale.
WE, IN TEXAS, HAVE MAJOR WATER PROBLEMS.
I live in Austin, now, but Lake Travis is 57 feet low (no longer a lake, only the CO River). The boat is on Lake Texoma, but the water is dropping so fast I now have only 2 ft. under the props (Dallas is starting to draw city water).
THE ONLY WATER WE HAVE TO MOVE THE BOAT to IS SALT, and I've already had my fill of saltwater damage on other ventures, and the freezing winters in MI.
I guess I have to rent (charter), or buy a trailerable boat for the remainder of my boating (SurfSide Five is my 20th boat).

Your 8.1 are fwc. No worries with the salt.
 
I'm a little confused....I just checked pricing for manifolds and risers for the 8.1 and the Osco part numbers are the same as the 7.4 and 454 crusader number. Is this a mistake? If this is true, why couldn't a guy buy a couple of truck motors and fit them up with the crusader gear much cheaper? You can find these motors on ebay fairly reasonable.
 
The 8.1's are not available counter-rotating, i.e; one trannie needs to run in reverse for c'rotating props. Is your Crusader trannie capable of long term full throttle in reverse?
Also, the 8.1 is much taller than the 454, hence, mounting it @ the same prox 12* angle of propshafts, it won't fit below floorboards.
I used the ZF 8* down-angle trannies, which are designed for full load either fwd or rev. Additionally, to mount the engines flat on the stringers, I dropped shaft angle to 8*, making them fit snugly under the floorboards.
 
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