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Repower planning for 37 Al Riviera

Discussion in 'Chris Craft Roamer Yacht' started by bolsado, Apr 2, 2010.

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  1. bolsado

    bolsado Member

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    I have been following Steenburgers repower post (repower 27') along with a few others and theres some good info similar to my planning.

    1) I am just planning at this time for a possible repower next fall

    2) Previous owner repowered once with 1200 hrs on engines since then, trannies are paragons. Dont know hp but assume probably currently HP 250-275 range

    3) I want to roughly target performance numbers of the OE 300 HP 427's as a basic guide as there is much published info
    - I understand HP calcs "back in the day" are diff then now but not excatly sure how to apply that knowledge
    - seems even the basic options today significantly exceed that baseline in HP/torque and weight is much less

    4) I will stick with gas 350 based blocks (diesel/other motors just seems too much effort and cost) considering two basic options and one outside the box idea

    a) 320 HP crusader, carb power pack (about $3800 std rot) as the most straight forward economical option, anybody done a recent gas repower?

    b) 330 HP Crusader MPFI power pack, (about $5800 std rot) as most "modern" conversion, anybody done an EFI conversion?

    c) 400 HP 383 stroker, carb, fully dressed crate motor (about $5000 std rot) as well if HP and torque are king as some say this baby has it, maybe too much
  2. Kiwipushrod

    Kiwipushrod New Member

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    Hey Bolsado, I like the why You're thinking, with the smallies.

    This is what I think I know, the original 300hp, 427's torque, peaked at 438 ft. lbs. @2900 rpm's, @shaft. For what your trying to figure out, You really dont care about HP, Torque is what You're worried about. That 427ci TQ figure is also @shaft, so that means after drive power loss. With todays TQ figures, I'd go for about 480 to 490 TQ peak @crankshaft.

    It's no coincidence that 2900-3000 rpm's, just happens to be the 37's cruise speed, an internal combustion motors peak fuel effiency, is about 100 rpm's above peak torque, so the props are factory figured for this rpm. A steel hull 37' Roamer,(3800 lbs heavier then alum.) runs about 19 staute miles per hour, depending on load and tanks. I wont go into if it's planing or not.

    Soo, heres the problem We come to. Can you build a small block produce 490 ft. lb. of TQ. Absolutley. Can You build a small block that has enough power on the low end to get over the hump before semi planeing speed, to get to peak TQ with stock props....Maybe. The small block peak TQ, will also be 3-500 rpm's higher. I also think that the weight savings between 427's and 350's is'nt that big a deal.

    Are You S.A.E. guys. gonna beat me up now?:D



    Kiwi
  3. bolsado

    bolsado Member

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    I searched the web and could not up with TQ number for crusaders (or mercruisers) so I went to the GM Marine Engine page and heres is what I found.

    Orig Chris Chraft #'s for GM based blocks

    HP @rpm TQ @rpm
    CC283F 165 4000 261 3000
    CC327F 210 4000 302 2600
    CC350Q 235 4000 330 3100
    CC427 300 4000 440 3000

    2010 GM Marine Engines
    HP @rpm TQ @rpm WT
    GM4.3 266 4800 268 4000 NA
    GM5.0 253 4800 302 3800 432
    GM5.7 292 4800 370 3200 NA
    6.0LY6 385 5600 400 4400 539
    6.2LS3 418 5400 424 4600 NA
    6.2LSA 530 5400 545 4000 467

    Across the board the max's are @ higher RPM's and of course the strokers are getting up there

    It would seem that the V6 would be good match for smaller disp blocks and probably very good economical alts for 35' and under boats.

    The 427 is a TQ monster and to beat that you have to go to the supercharged small block.
  4. Kiwipushrod

    Kiwipushrod New Member

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    There is one other smallblock that was rarely marinized, that everyone seems to have forgotten about.....The 400ci smallblock.

    I've built a few of these with junkyard shortblocks and their Stock 9.4:1 compression ratio pistons. To produce over 480 ft. lbs. of TQ around 3200 rpms, using GM stock Vortec cylinder heads (96' 00' 5.7ltr.) the heads only cost $225 apiece, brand new complete from any GM dealer. You can make over 500 TQ peak but you'd need some high dollar cylinder heads. All this TQ., with a not so wild cam, single carb and stock pistons.

    The Vortec heads have a different intake manifold bolt pattern, which require a different intake, in order to use the heads, but the same exaust manifold bolt pattern as every other smallie has had for the last 50 years. I dont know if You'd try any of this but it gives You an idea of how it all works. The GM marine 5.7ltr. are already using the the Vortec heads but dont have the Displacement You need, to do it cheap.

    Also check out Comp Cams Extreme Marine series of camshafts, on their site for some better TQ graphs.


    Kiwi
  5. bolsado

    bolsado Member

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    Re 400

    There are so many GM variants, historically Ive been a Ford guy (cars & trucks) but you pay $$ as a ford or even worse as a mopar and finally been sold on go with the masses ie GM=Microsoft.

    Are these 400's the ones used in the 70's-80's in the light truck line.

    Here is the crate outfit claiming 400/435 I based my stroker idea on

    Block:
    Seasoned 4-bolt main
    Max .040 bore
    One piece rear main seal
    Sonic tested to assure wall thickness
    Align honed main bearing bore


    Rotating Assembly:
    New SCAT premium crank
    Keith Black Hypereutectic pistons
    New COMP CAMS roller camshaft

    Cylinder Heads:
    Cast Iron Vortec
    1.25 dia. valve springs, hardened retainers and keepers
    2.02 swirl polished intake valves
    1.60 swirl polished exhaust valves
    Elgin hardened push rods
    Long slot rockers with positive lock adjusting nuts



    New Brezinski cast iron marine intake
    Edelbrock Fuel Pump
    Edelbrock stainless steel fuel line and filter
    Cast iron circulating pump
    Edelbrock 750 electric choke carburetor
    Professional Products harmonic balancer
    MSD Pro-billet distributor
    MSD Blaster SS coil
    AC Delco spark plugs
    MSD wire looms
    MSD Super Conductor plug wires
    Blueprint "Signature Series" polished aluminum valve covers
    Rubber coated steel oil pan
    Brass freeze plugs
    All engines are dyno tested on a state of the art DTS dyno and ship with a complete spec sheet

    Attached Files:

  6. bolsado

    bolsado Member

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    RE 400 pt 2

    Kiwi,

    Checking into the 400 youre right its the best SBC TQ motor out there. Biggest isssue and not really is steam ports on the heads as it seems any set of 350 heads will match. The do say they are prone to over heating.

    I assume you could find junkers but just to check I found the following remans long blocks so they are out there

    CHEVY 6.6 400 V8 - 70-78 Small Block, 6 bolt heads 2 bolt block

    CHEVY 6.6 400 V8 - 70-78 Small Block,6 bolt heads 4 bolt block

    CHEVY 6.6 400 V8 - 79-80 Small Block, 7 bolt exhaust, 2 bolt block

    The consensus seems to be the 2 bolt is better???

    Chevy performance with the parts listed claims 450HP/500TQ

    What would you do to "marinize this set up"?

    Attached Files:

  7. Ormond Bert54

    Ormond Bert54 Senior Member

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    My understanding is that the 383 stroker does not really produce 400 hp even though that is advertised by some of the companies ... 375hp ... yes ... and it is available in an MPI version. That is the engine I'm looking at for my Bertram 28. And ... of course, it's not producing anywhere near that at the 3800 rpm or so cruise so it is the torque number that is so important. ... and the 383 performs well in this area. The more I have looked into it, the more I'm inclined to choose the 383 as my next power choice.

    Isn't the issue with the 400 CI Chevy that the cylinder walls are too thin or that there were no cooling veins around the cylinders because the bore was too large to allow for the cooling veins?

    Sorry ... I'm no expert.
  8. Kiwipushrod

    Kiwipushrod New Member

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    More of what I think I know.

    Hey Bert28, thanks for joining the thread, nobody knows everything!

    Yes I'm talking about the 400ci smallblock from the GM pickup line in the 80's.
    The "overheat" problem is overrated. On the 400ci block, the cylinders are siamesed because they, (GM) had reached the max bore allowed by the legendary blocks castings dimention. This siamese cylinder setup, does not allow block coolant to pass between the cyls. resulting in hot spots near the top (combustion area) of them. The hottrodders fix was to drill small holes into the cylinder head just above this hot spot in order to pull more coolant thru the area, they're called "steam holes". They do help.

    A 383ci "Stroker" motor is just a 350ci block with a 400ci motors, crankshaft installed. Again figured out by motor heads on the street without factory support. Imagine that.

    The biggest benefit of going MPI or any Marine electronic injection is drivebility, easier hot and cold starts. You will Not gain much in fuel effiency. The reason is, that the Marine injection systems are not a feedback system, in other words they dont read O2 content of the exaust stream, so they cant adjust injector dwell to compensate for a lean or rich mixture. Why not? Because of the USCG requirement for a water cooled exaust, water and O2 sensors dont mix well. (There are a few people working on this right now.) But without feedback from the exaust stream, You're stuck with PROM fuel maps. Which means big fat marine fuel mixes that keep a motor from burning down during long periods @WOT. Personally I'd rather have a carb for the tuneability.

    I took an almost worn out Mercury 270hp 350ci, in a 28' Bayliner (I know) command bridge single. And installed a Comp extreme marine cam and timing chain in it, I then rejetted the primarys in the carb, much leaner. With a 4 bladed prop, the boat averaged 2.3 mpg at 20mph. I also took it on a 900mi Mississippi river trip. I avoided WOT like the plague and never had a problem with the motor. I also think there was more to be had, but for redneck mpg "science" the results were acceptable.

    As far as "Marinizing" an automobile engine, You'll need alternator spark screens which you can buy separetly, Water cooled exaust manifolds, (any smallie marine engine takeoffs) marine thermostat housing to feed the exaust, a marine approved distributer and cap and an approved closed switch starter, it's all about sparks. This is off the top of My head so I'd do some more research of course.

    I don't know if 400's are Your way to go, but they would be interesting and have better fuel efficiency over the GM 454 based bigblocks, which seem to Me, to make more heat then power. As always just My opinion.

    Kiwi
  9. bolsado

    bolsado Member

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    Sbc 400

    The info I am finding on the net seems to center on the cooling issue for the The SBC 400 engine.

    The steam holes, which have to be drilled out may get plugged up rather quickly followed by a blown head gasket. If you do choose the 400 engine for marine use then its suggested to use the maximum diameter steam holes may help. Also a solution may be to run a closed water system.

    There seem to be many that indicate they have not had overheating problems though.

    I found on the Junk yard searchs there seem to be many SBC400's you can get pulled, Most seem to come from 4x4 trucks, suburbans and vans.

    There are EGR and Non EGR models which probably becomes mute for a marine engine as you would swap out all the fuel/ex components anyway.
  10. Henning

    Henning Senior Member

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    The reason very few of the 400 blocks were used in marine applications is because of the Siamese cylinder walls. If you are running a freshwater set up with a heat exchanger, it's not much of an issue. If you are running raw water, it becomes an issue quickly as silt and salt cake into the corners insulating the heat and causing hot spot issues where the cylinders are conjoined. I use the 400 blocks a lot with a 3 1/4 stroke crank and 6.3" rods. Makes for a very efficient and torquy 350.
  11. bolsado

    bolsado Member

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    RE marinization

    Thanks for the 400 info,

    Let me restate I am not experineced in this but am learning a great deal of info from feed back you all have given.

    I have gotten a lot of info looking into this and here has what I have come up with. Forum members let me know if you think this is bunk info.

    Marinization of a engine is focused on 3 principle points of cooling, spark arresting and performance. In this post Ill cover the first 2.

    If you can accomplish the above three and connect it to a marine drive train in theory any auto engine could work.

    Cooling is the main point with most older boats raw water cooled (sticking to cruisers and SF relevent to this forum) for the engine and exhaust manifolds. Newer engines already seem to be making the conversion to closed cooling systems.

    Going to a closed cooling system, ie heat exchanger, cooling box or keel cooler eliminates the need for corossion resistent engine internals such as brass plugs, head gaskets etc..

    What is gained, for a price of the closed cooling system is:
    - more optimal engine performance due to optimal coolant temp flowing through the block
    - longer engine life due to elimination of the corrisive water factor
    - lower replacemnt cost as corossive elements are restriced to the heat exchanger elements and/or exhast manifolds depending on system vs replacing expensive engine components
    - reduced risk of major engine freeze related issues and I assume slightly less winterization needs for cold weather climes
    - extended boating season in mild to cold water climes
    - ability to run a cabin/cockpit heating circuit ( unrelated but I guess you could do an AC on any boat as well while engines, including generator, were running)
    - with a heater circuit, if heating problems do develop you have expanded heat release capacity
    - additionally a raw water circuit could be isolated to heater exchanger, cool box, ex manifolds and with a cutin circuit for emergency cooling

    On spark arresting that is taken with the use of standard marine carbs, alternators, distributors and either use of marine or insolation of misc elec pumps and motors which one may be utilizing.

    Am I missing something non performance related (ie not cams, compression ratio, torque, rpm range, variable prop loading etc...)
  12. Kiwipushrod

    Kiwipushrod New Member

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    Hey bolsado,

    What motors do You have now? Are they closed cooling? Why not build what You already have?

    I went back thru the Chris-Craft 37' Roamer literature, off of the old "geocities" site and came up with this.

    Top Speeds for offered engine options

    27 knots, 283s, 200hp.
    29 knots, 327s, 210hp.
    38 knots, 427s, 300hp.
    30 knots, 6V53s, 197hp. (Diesels)


    37' Weights.
    Aluminium, 16,000 lbs.
    Steel, 20,300 lbs

    I'd guess the speed specs were taken from an Aluminium hull, with 5 gallons of gas, gutted cabin, 110# pilot and a 30 knot tail wind on glass.:D

    Kiwi
  13. bolsado

    bolsado Member

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    What I have now

    Kiwi,

    The setup now is conventional raw water cooling on rebuilt 350's by previous owner. They run well, the boat seems sluggish to me but I have no reference point to relate that to from the limited previous experience and time I have spent on the boat. When I bought it the mental planning was to do a repower-reelectrical job w/in first 2-3 seasons, which is were I am at now. I am absoultely no expert now which the reasons for this thread but I want to be sure to know eactly what I want to do when the time comes.

    Closed cooling just seems to be the way to go regardless in a gas 28'-40' cruiser/SF even though its an incremental cost increase. No one has posted any negative comments so far but I still need to do some more research. As it sits now I would use closed cool system for the engines and raw water cool the exhaust for any SBC marine setup.

    I have the old website info as well, as you pointed out CC figures are pretty glossy. My boat on the travel lift with nearly full fuel & water pegged out at about 19,000 lbs. This season Ill spend some time getting baseline performance figures. The 350 has an advantage in that is what the masses know and understand.

    Thus in the Bertram 28, at 12,000 lbs displacement those 383's would be just fine to be in the very top end of the performance range for that boat or for the economy minded cruiser go to the other end and elect V6's.

    In the 37' roamer you are looking to bring/keep down the compression and optimal RPM range and bring up the CI from a higher winding 383 SBC when looking to be at the top of the performance range for the boat to move the additional 7,000 lbs. The paper numbers on the 383 come really close or even exceeed the target of the stock 427 which is were I basically started in this thread.

    Thus, I really appreciate the 400 insight as I have started really looking hard into it and had already commited to a 350+ CI SBC any way, balancing performance, cost and reliability.

    Were I am at to date is not to use a salvage block/cylinder head set up. No big deal really but issue there is the realiability over cost. Cheaper the salvage route but taking higher risk of component failure, dosent matter if its a 327, 350 or a 400. In the end it seems the savings are pretty minimal overall and comes down to the faith in the engine builders skills unless its the boat owners own hands doing all the rebuild work and considers his a labor of love, he provides the warranty and effort is completely gratis.

    Plus, there are can be a few more details to the 400 buildup beyond the head cooling involved with cam small circle issue and a few other items, so I am really investigating the new short-long block combos already available from outfits such as Dart. You can get very high quality, low compression setups up to 450 CI from the 400 block with years of racing experience built in.

    Research to date indicates a build is pretty competetive with the commercial hi-po 350-383's marine engines available with a lot more performance upside. You dont have to address the head cooling issue either if one elects a non vortec setup.

    I am out of time for today but will keep getting into the weeds on a 400 based marine build and hopefully this will wind up on being a valuable resource to the forum on what you can do, maybe what one should do and hopefully, what one should not do without paying a cash price for the lifes lesson.
  14. Attached Files:

  15. Henning

    Henning Senior Member

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    Just bite the bullet and put in a pair of 6BT Cummins or find a set of used 3208 Cats. If you plan on keeping the boat, the fuel savings will pay the difference in not too long.
  16. Henning

    Henning Senior Member

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    Explain what you mean by "salvage".... If you mean buying new block and heads, that's not particularly the best way to go. Metal parts settle and shift with use. When we build performance engines for endurance, we take used "first run" blocks or "season" them with a large rosebud "flame thrower" bringing them to high temps and cooling them several times before doing our machine work.

    Again, I suggest you bite the bullet and go diesel.
  17. Kiwipushrod

    Kiwipushrod New Member

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    Hey Henning, I'm doing My income taxes right now, can I borrow Your calculator?:D

    Salvage means junkyard, boneyard, used, old or wrecked stuff.


    Kiwi
  18. Henning

    Henning Senior Member

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    You can buy a good set of 3208s with gears out of Boats and Harbors for about $10k a side, figure by the time you do everything involved, you'll be into the repower for $40k. I used to operate 425hp 3208s on 8gph at about 70% power. He could easily get away with 355hp units, lets still call it 20 gph. What does red diesel cost stateside these days? Haven't bought any there in a while, still going to be cheaper than gasoline. Figure a pair of gasoline engines pushing that boat at the same speed are going to be using twice that fuel if not more, but we'll call it 40 gph. He's going to spend at least $12,000 by the time he's done with his gas engine repower. That's a savings of $28,000. Let's call both fuels $2.25 a gallon (though red diesel will be cheaper). Using those numbers it will take 623 hrs of operating to break even. For my average boater client, that's less than 2 years, most of them run about 400 hrs a year. To me, that's not a long time to pay off, especially since you'll run through 4 sets of SBCs pushing that boat in the time it takes to wear out a set of 3208s which get pushed past 12,000hrs on a pretty regular basis. In order to get 3000hrs on a SBC pushing that boat at speed you'll be spending $15k building it properly (billet crank, steel or titanium rods, angle bolt 4 bolt mains...). The engines he's looking at won't make 1000 hrs pushing that boat at speed, even though they are reasonably cheap to repair when you blow them up. We won't get into resale value, or even resellability/desireability in soft markets and economies, nor the safety factors of operating diesel inboards vs. gasoline. Find five identical boats, one powered with diesels, and see which one sells first and for the most money, and see which ones need to be given away at fire sale prices just to unload.
  19. K1W1

    K1W1 Senior Member

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    Hi,

    As an example there is a pair of 210 HP with 800Hrs on there now for 14k for the pair.

    http://www.pagegangster.com/p/b5SdP/44/
  20. Kiwipushrod

    Kiwipushrod New Member

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    Mr. Henning, Your math is good and your reasoning sound. However, most Roamers are in the midwest and are used for weekend recreation, which means maybe 100 hrs use, per very short season.

    Diesel is .10 -.15 cents more per gallon here, then gasoline. You also did'nt mention the cost difference when servicing a diesel, which is considerable.

    Would a 37' Roamer benefit from a diesel conversion?...Absolutely. But I dont think You would recover more then 40% of the refit cost, at resale. Used Cat 3208's would also, not be My choice. There is a reason why they're cheap.

    This is an old debate and if My boat had 400 hr seasons, of course I would go diesel in order to take advantage of it's BTU content and longer lived motors but in a short season climate where most engine wear occurs from layup, I just don't think it pays.

    Respectfully, Kiwi