10m mid cabin - power upgrade Crusader 8.1's

[BobCT]

I went from not much boat stuff going on for the past year to diving in deep again. I am picking up a pair of Crusader 8.1 HO (425 HP) engines tomorrow with Hurth 8 degree down angle transmissions. Has anyone here installed 8.1's in any International hull? I haven't found one person online. I have studied the drawings and know that they will fit but dying to know what my before/after numbers will be. I have made it a habit to video my helm underway at least a few times a year so I'll have hard evidence of my speed/fuel burn to compare after the fact.

My plan is to get them home and setup in my garage/running. Then go through each one top to bottom. Once I complete that phase, then I need to determine timing of removing my engines and making the swap. Timing is key, I don't want to push all (or most) of this work out to the spring and screw up next year. My 454's run great so I'm mentally prepared to run them through next season and maybe pull the boat out early (like this time next year). There's just so much to figure out and I've done enough "projects" to know I'm missing a bunch of details and sure I'm underestimating the details.

Anyone with firsthand 8.1 knowledge please chime in! Of particular interest are any weak points/things I should replace while I have these on the bench. I'll be doing belts/hoses/exhaust/cooling system/oil coolers so I'm thinking of more obscure parts like sensors, seals (oil pan?), fuel pump(s) that will either leave me stranded or be really hard to change installed.

thanks
Bob

[prowlersfish]

what ratio are the gears ?

[BobCT]

They're 2:1 and "think" I can use them but not 100% sure. Any thoughts there?

[prowlersfish]

They're 2:1 and "think" I can use them but not 100% sure. Any thoughts there?

You may have to use them . Its very possible both your new engines spin the same way so counter rotation is done through the gear box . Instead of forward and reverse many Hurth/ZF gears have A & B and can take full power in both positions . It would be a good idea to find out about the engine rotation . Do you know what model gear it is ? Down angle gears are nice as it lets the engines sit more level . The down side is the engine mounting will take a little more work to get it all in alignment

[todd brinkerhoff]

These are my favorite thread topics. I have an embarrassingly underpowered boat and cannot justify the price of a diesel returb, so these types of options are great to watch.

[BobCT]

Yes, the 8.1 engines are both normal rotation. I definitely need to use this style of transmission (ZF Hurth 630’s). My “think” comment was regarding the 2:1 ratio, I’m not 100% certain that is the right number just yet.

The 454’s do sit at a pretty steep angle so this should help access on some items. Getting the engine up in the rear should free up some room which is a plus.

Todd, I’ll have some hard/video evidence of the before and after numbers so you can follow my lead if this is a viable option. Or, watch an epic disaster unfold.

Bob

[todd brinkerhoff]

I’ve watched your other work...I’m pretty confident you got this.

[RWS]

I was real serious about the 8.1's when I did my repower.

At the time Crusader was offering them, NEW, with the gears, however, on the long shaft of the Express, the dealer recommended that I go to either a thicker shaft or replace the shafts with (?) aquamet 22's. (as I recall)

The shafts should not be an issue for you in a mid cabin, as they are not nearly as long.

That same Crusader dealer also told me I would need bigger raw water intakes and strainers - IN RETROSPECT, I REALLY WONDER IF THIS IS BOGUS ADVICE.

That said, once I added up the new Crusaders + raw water intakes, strainers & shafts the DIFFERENCE to go diesel became smaller

Suggest you verify the above in your case, just to be safe.

SOUNDS LIKE A FUN REPOWER - I believe the 8.1 is a great choice

BEST!

RWS

[RWS]

Hey Bob,

Attached below is some information I found in my files regarding the 8.1 Crusaders.

The info below is in regard to replacing 502's with the 8.1

Don't know if it will be of any help but here goes...

RWS
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Posted on Tuesday, December 07, 2004 - 01:28 pm:

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Getting ready to replace my 1990 crusader 502's with crusader 8.1 425 hp engine with Hurth 630v trans on my 40X Silverton. Would appreciate any comments regarding this particular engine/trans.

Also, should I delay receipt/installation of the engines to early spring, considering I won't be able to test them until I put my boat back in the water in April???


Enginetamer
Member
Username: Enginetamer

Post Number: 12
Registered: 10-2004

Posted on Tuesday, December 07, 2004 - 02:35 pm:

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I was going to sell ans install one of the 8.1 to one of my boat customers. i found out that the fuel use numbers are better, and the engine seems smoother. BUT. Look at the pictures. Study the manual. these engines are literaly encased in wiring harnesses, sensors, unpainted steel fuel lines,etc. As these components quit, corrode, go out of warrnty, etc., the Marine environment is going to eat them up. I suggest you have a great relationship with the dealer regarding warranty,and that you make sure that the environment for these engines is dry, well ventilated, etc. Because the potential for high maintenance costs are big.// cheers.


linesix
Visitor

Posted on Tuesday, December 07, 2004 - 10:15 pm:

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I don't agree. When you get your new 8.1s installed, you'll throw rocks at the 502s. A few notes: Keep in mind Silverton uses the return type fuel system. Cursader offers the engine with both returnless and returnable fuel system engines. Make sure you order the return type. The fuel pick-up locations on the 8.1 is different that the 502, so you will meed to redo some of the fuel lines. Make sure you use the 1/2" line, as was originally installed. The ZF gear is a good choice. Most likely ration is 2.70:1, but match is up to what you have now keeping in mind that if you currently have a Velvet Drive gear, the ratio will be slightly different. The engine mounts and mufflers will bolt right up.
I wouldn't wait until spring. You are going to get three seasons (with Captains Choice) of warranty no matter how you look at it. As far as the unpainted fuel lines go, they are aircraft quality stainless steel flex lines. They have been in use for several years now with virtually no failures. Manifolds and brackets are powder coated, not just painted. The finish is much better than that of your 502s. One last thing. The operating range of the 8.1 is higher than the 502, so you may well end up needing some prop work before you are finished. That's another reason to get it done now. Both the marinas and the prop shops get really busy in the spring and will probably make it worth your while financially to do it during the "slow" months. Good luck
Rick


Enginetamer
Member
Username: Enginetamer

Post Number: 13
Registered: 10-2004

Posted on Tuesday, December 07, 2004 - 11:15 pm:

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All true, line 6, about the 502's but they are simple. He still needs a damn good mechanic for the warranty period, and maybe keep it in his pocket after that, because the electronics on this engine are very complex. And he needs to be honest about the environment that this engine is going in. We';re talking about 35K or so. after installation. If his 502's are rebuildable, he could save about 25K. that's a lot of gas. Maybe for the money he ought to go for diesels. What say?


linesix
Visitor

Posted on Friday, December 10, 2004 - 11:11 pm:

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I would have to say that if LadyLove were in the process of shopping for replacment engines, he has already considered the option of rebuilding. Rebuilding a 15 year old carburated engine will save dollars, no doubt, but I have customers who replace their boat every year or so, just to have the newest and best. Everyone's situation and priorities are different. If the 502s were fuel injected, I would give much more weight to the rebuilding option, but technology on these powerplants has advanced so much in the past 15 years I would have to lean toward repower. Albeit expensive, they are much more fuel efficient, smoother, quieter, easier starting, safer and emit much less emmisions, not to mention the decreased maintenance requirements since they no longer have a distributor. I also feel that due to the increased value of the updated boat, there is a very high recovery percentage on this money should you decide to sell in the future. As far as the diesel option goes. It's cheaper and easier to upgrade the whole boat. Silverton uses a more aggressive lamination schedule, heavier stringers, larger shafts and struts on the diesel version of this boat. The engine air induction vents in the diesel boat are also larger to accomidate the greater volume of air ingested by the diesel engines. The batteries and cables will need to be upgraded, the list goes on. By the time you refit the boat to properly and safely accept the diesel engines, the total cost goes way beyond the price of the engines. Don't be intimidated by the "complicated" electronics. Although similar, they are actually much less complicated than the system on your car. Consider the failure rate of components on your automobile engine versus the miles you put on it, then relate that to the actual hours you put on your boat. If you keep your filters clean, maintain it properly and poke your head down in the engineroom more than once a season, you'll find these engines as maintenance free as anything you could ask for. And failures will be very minimum, much less than you're dealing with now. I hope this information has been helpful to anyone considering such a change and feel free to post any further questions or concerns.


Enginetamer
Member
Username: Enginetamer

Post Number: 15
Registered: 10-2004

Posted on Saturday, December 11, 2004 - 12:41 pm:

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Hi Ladylove and Linesix/ It is alwys hard to argue against more technnology and money, but I would argue the reliability issue because of the marine environment. Most of my customers are Commercial watermen and Sportfishers, who use a lot of fuel and they like to go fast. Some of them have gotten excellent hours out of carburated engines, like 17,000 and 12 years. Carb never replaced, and distributor at $75.00 replaced only once. Plugs three or four times, and many, many Amsoil and filter changes. So what's the problem with this?why put 30-35K in engines and installation, plus the time, into the boat, and still only get a modest trade-in when it's time to move on or move up? Another thing, if Ladylove's mehanic can't deal with these simple 502's, in terms of making them purr like kittens, who can he turn to to hlep him set up and check out these new ones, properly. We all know that warranties are mostly a joke, at lest in most parts of the country. We don't even now where Ladylove hails from or who he is thinking of buying these 8.1's from?. Buying new motors is a BIG DEAL, especially when such big money is involved.// Cheers// Paul R.


Jackman
Visitor

Posted on Monday, December 13, 2004 - 11:51 am:

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I agree with Enginetamer 100%. Can't add anything other than this tibit...I can't count how many times I've run into people at the marnia who were sitting at the docks waiting for a mechanic because their "computer brain" on their new fuel injected angines failed because of salt or some other electronic part failed. My crusaders are carbed. Went over 2300hrs without major issues before I just decided to rebuild because I knew their "routine documented life span" was coming to an end and I noticed some mechanical issues begininng to show up.

I wouldn't have done it any other way than to rebuild. These Crusader engines are very reliable and with a very good rebuilder/machinist they can run better than a crate engine because the rebuilder pays more attention to tolerances than a factory thats making hundreds of them.

I'm sure I'll see some people sitting at the docks this year again because of electronic as I pass them by for a nice day on the water.


linesix
Visitor

Posted on Friday, December 17, 2004 - 10:47 pm:

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Jack, that may be true, but on the other hand, I've seen boats explode and burn to the waterline from leaky carbs and stuck floats, but that's a topic for another day. And Paul, there should be no reason to expect any less engine life on this new technonogy, vs. the old 502s. The cooling system and oil system are much improved over the old design, and should therefore actually run much longer. GM really did their homework when they came up with this new design. The old 502 had siamese cylinders, which did not allow for coolant in the block to completely surround the cylinders. This creates hot spots in the cylinders. For this reason GM was forced to oversize the cylinders to keep the pistons from burning or expanding too fast and seizing. This additional piston to wall clearence is what creates the high oil consumption these engines are famous for. These engines defined the term "Fill the oil and check the gas". Furthermore, I don't recall Ladylove complaining about problems with service. A dealer or marina compitant enough to properly do this job most certainly should be able to do the needed maintenance and repairs. Crusader now has in place a new "Premium Dealer" program which rewards dealers to stay up-to-date with tools and training. These Premium dealers have the knowledge and experience to troubleshoot and repair all systems on these engines. The technology is there, the dealer support is there, the only issue left is the cost, and I didn't see mention by Ladylove of cost being an issue.

Rick

[RWS]

additional performance info (from my files)

keep in mind, these performance figures may be skewed by the manufacturer loading the boat as lightly as possible, etc

I'd certainly consider this with a grain or TEN of salt

FWIW


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Looks like 3500 RPM will be the sweet spot on the 8.1

If it can push this 18,000 lb vessel at nearly 24 kts @.92 nmpg (1.06 mpg) I might do just a bit better !

RWS should be all the way up on the delta portion of the hull at that rpm/speed.

Your thoughts ?
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Base price: $229,077 with 2/375-hp Volvo Penta 8.1Gi gasoline inboards
Optional power: 2/370-hp Volvo Penta TAMD 63P or 2/385-hp Caterpillar 3126E diesel inboards: 2/420-hp Volvo Penta 8.1GXi gasoline inboards; 2/370-hp MerCruiser MC8.1S or 2/420-hp MerCruiser MC8.1SHO gasoline inboards; 2/385-hp Crusader CR8.1MPI or 2/425-hp Crusader CR8.1HO gasoline inboards
Standard equipment: extended swim platform, cockpit table, ice maker, camper canvas, central vac, and entertainment center with DVD, CD-changer, and flat-screen TV
SPECIFICATIONS
LOA: 41'3"
Beam: 12'9"
Draft: 3'6"
Weight: 18,000 lbs. (dry)
Fuel capacity: 300 gal.
Water capacity: 66 gal.
Test engines: 2/375-hp Volvo Penta 8.1Gi gasoline inboards
Transmission/ratio: ZF-Hurth/2.5:1
Props: Acme 21 x 24 3-blade bronze
Steering: Teleflex hydraulic
Controls: Morse mechanical
Optional equipment on test boat: 1/7.3-kW Kohler genset w/hushbox, freshwater cooling system, vapor detector, fire extinguishing system, deck sunpads, Raymarine RC520 GPS/plotter, 210 VHF, and ST60 Tri-data
Price as tested: $248,768

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[RWS]

but wait, there's more...….

RWS

---------------------------------------------

Interesting post to Egg Harbor website

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Posted 16 June 2004 10:55 PM 16 June 2004 09:55 PM
Have any members with a 88-89 35' SF repowered with any of the new Crusader or Mercruiser 8.1 (496 CI) engines? Would like to know performance compared to 454's and changes in prop size, shafts & gear ratio. Would like to also hear your pros and cons.
Posts: 6 | Location: Long Island NY | Registered: 16 June 2004



Smitty

Posted 28 June 2004 10:51 PM 28 June 2004 09:51 PM
Thank you Sam and Bob. I will most likely be doing the repower in a few weeks. I will keep you posted with the results.
Posts: 6 | Location: Long Island NY | Registered: 16 June 2004



Bob Cronin

Posted 28 June 2004 09:53 AM 28 June 2004 08:53 AM
Smitty,
I have a customer a 37 Sport Fisherman who repowered with the new 8.1 Crusaders and he too experienced a significant reduction in fuel consumption (something like 20%!). He also purchased 4 blades to accomodate the new engines. The increase in speed was dramatic.

Bob Cronin
Posts: 6 | Registered: 27 May 2004



"TIGHTROPE"

Posted 26 June 2004 07:55 PM 26 June 2004 06:55 PM
Hi Smitty,
Just finished installing 8.1 Capts. Choice "496" in my 35ft 1988 Sportfisherman. I only have about 12 hours on the engines but so far I am thrilled. I went with 4 blade props as suggested by Dan and we went with 20x18. Now for the best part,last year with my old "454" my top end was 24kts. With these new engines not yet broken in, 30.4 kts with full water and fuel tanks and 2 people on board. I do not know the ammount of fuel consumption as yet but I am told it should be 20% less but I am so happy with the performance that if it is true that would be nice to add to the package. We are going to the rendezvous in Cuttyhunk Ma. on July 31 and would be happy to share any conservation with you .
Good luck,
Sam "TIGHTROPE"
Posts: 8 | Registered: 07 June 2004

[BobCT]

Harris, good stuff! I appreciate it. The cat is out of the bag, they’re sitting in my garage now. I easily have a months worth of work to go through before I figure out my next step. I’m going to take my time and should know them inside/out by the time I am done. On your prior post, I agree on the shafts being ok given the length but will confirm that. I know that the one shaft I replaced a few years ago is already aquamet 22 not positive on the other but I had that dye tested within the past two years.


More to follow!

Bob

[RWS]

Hey Bob,

Please confirm with Crusader the diameter of your raw water inlet system.

They told me mine was going to be an issue...… seacocks & strainers for the 454 too small.

This combined with the shaft issues & props were the factors pushing me into diesel land, as the difference was getting smaller.

Too bad you cannot purchase a reasonably priced lightweight mechanical marine diesel anymore, THANKS TO THE NEW STRINGENT BEYOND REDICULOUS US EPA REQUIREMENTS

RWS

[todd brinkerhoff]

The diesel fantasy is my favorite to think about, but by far the hardest to justify. Everything would need to be changed, and high horsepower lightweight diesels are so expensive I’d need to take out another mortgage. It’s just not possible. Doing what Bob is doing or finding a good engine builder are my only 2 options. I’m almost as excited to see the results as Bob.

[BobCT]

Agreed, I didn’t initially rule out diesels but it really came down to overall initial cost. Plus the thought of reworking my helm panel to add the necessary gauges was a non starter. I spent probably 100 hours rewiring and rehabbing that a couple of years ago.

At this point (it will be interesting to read this post again in about 6 months), I think I’ll be around $17-18k total with the 8.1’s ready to install. That’s the initial purchase plus about 3-4k in preventative maintenance while I have them “on the bench”. That’s assuming re-use of my existing shafts and no raw water intake changes. I know that won’t be my grand total but that’s my guess on where I’ll be with them sitting next to the boat ready to install.

I’m also going to add dripless and a million other things to the list that I don’t even know about yet.

Bob