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The elusive 224/3.7 MerCruiser banger

Discussion in 'The Hokey Ass Message Board' started by tjm73, Apr 9, 2008.

  1. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Johan G,

    The D series DOOE and D6VE Ford rods with ARP rod bolts at 200,000psi will work to 6500rpm.

    As I understand it Randy Dupree ran 186mph at about 5000rpm at the salt flats. Now he was probably running other rods at the time. He said that he didn't make the return run as his engine went south. He further stated that he had run that engine more than 6 years.

    The point I am trying to make is that with an engine that pulls bodacious (that means big) torque at 5000rpm with rods that go to 6500rpm whats to worry?

    I understand that with your loggin name of Turboclubnorth you are probably going to want to Turbo this engine.

    I have also thought about a street friendlyTurbo if any of my cars need more GO.

    With 8.8 to 1 compression I would think that about 4 to 5 lbs of boost would give me more than what I could handle on the street.

    Correct me if I am wrong but I understand that turbos can be tuned to come on at 2500-3000 rpm. If that is true then my engines with Mustang V6 T-5 transmissions should be able move the cars thru the gears just fine. And with these light cars that amount of boost should not cause precompustion with California premium fuel.

    I will wait and see how the engines handle in these cars without a turbo before making a decision.

    Johan, Sweden dosn't have the corner on people who will think you are crazy. Many of my friends think I'm crazy and a few of them know that I am.

    But a word of warning before you put too much boost on one of these and blow it up proving that they are right you might think of working up performance before going to an all out race engine.

    I like to bet on strengths rather than gamble on the unknowns.

    Good luck in Sweden.

    :) :) :) Dick :) :) :)
     
  2. randydupree
    Joined: May 19, 2005
    Posts: 649

    randydupree
    Member
    from archer fl

    don't drill the head for the water port,just drill the intake on each end and use a 1'' nipple to return the water to the rad,make a "Y" to run both 1'' lines together,then go to the radiator.
    This is better because it cools the back cylinder better.

    The engine we raced at B-ville had been raced at Maxton for 5-6 years,in a lakester and a comp. coupe,i still have the coupe.(minus the engine).
    B-ville put a 200 MPH speed limit on us that year because they didn't like our tires on the front,so we made an easy pass at 186 at 5000RPMs and the next day we spun a bearing and packed it in for that year,My fault on the engine problem,i narrowed the rod bearings up and un-covered the oil hole on number 4 crankpin,when you stroke a crank the oil holes move,and #4 moved way out.
    The skinny bearing un-covered the hole..
    we turned the motor 6500 rpm at maxton.
    good times..
     
  3. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Hi Randy,

    The problem that I am having with just drilling the intakes and putting 1" nipples is that the aluminum heads have a lot bigger water ports than the cast iron heads had. Neither the 2 barrel or the 4 barrel mercruiser aluminum manifolds quite cover the hole so I am going to fab a 1/4" aluminum spacer plate to fully cover the head and allow the original Mercruiser manifolds to work.

    The original Mercruiser Maniforld should flow good the way they are. The 2 barrel is a 500 Rochester and the 4 barrel is a 750 Quadrajet.
     

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    Last edited: Apr 28, 2010
  4. oldebob
    Joined: Oct 21, 2008
    Posts: 782

    oldebob
    Member
    from Spokane WA

    Be careful on this in the cold climates. Many inboard/outboard motors are changed out every spring because the owner never got around to draining the block in the fall.
     
  5. Dick:
    I used a 1976 post office Jeep. xxx for strong but also with some heavy parts. My reason for using it was that it had straight frame rails and I knew that the car would have to be lengthened. Yes the axles are narrower, but I lost ~4" of that in welding a plate into the ford wire wheels. Carquest's longest 9/16" studs worked well. Had to modify the wheels as I wanted to run the jeep drum brakes, but they were too big to fit into my 35 ford wheels.
    The outer ends of its front axles are quite good, but the main tube is way too thick. [ It is from the 4 wheel drive willys. Since it is straight splicing in a lighter center section is an easy option.
    With a very light body and its present Allis Chalmers engine it weighs 1900 lbs. 3" ground clearance under the engine has worked out well enough.
    I'd use the ford rear axles as there are so many ratios easily available. I'm using a Dana 44 which I've changed ring and pinion gears from 3.72 to 3.07. Its all jeep stuff that came on the chassis.

    PS, I'm impressed with what you are doing, and Randy is legendary, I need say no more.
     
    Last edited: Apr 28, 2010
  6. Johan we are crazy but that is a lot better than being boring.
    dennis
     
  7. Dick show us a side view photo of your manifold with the water jacket off. I nearly milled mine off but stopped as the water jacket did not seem harmful.
     
  8. Excellent, thanks, I'll do it your way... the merc way seems much less strong and more plugged up.
     
    Last edited: Apr 29, 2010
  9. Gizzy
    Joined: Jan 20, 2008
    Posts: 684

    Gizzy
    Member
    from N.W,Ohio

    Fuc#ers cool dude!
     
  10. BigChief
    Joined: Jan 14, 2003
    Posts: 2,077

    BigChief
    Member

    Good advice regardless....however, the 3.7 Mercruisers have a closed cooling system that uses antifreeze. Assuming the coolant wasn't swapped out with water the only thing that usually bites the bullet if one were to improperly winterize the boat is the (very expensive) heat exchanger.

    -Bigchief.
     
  11. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Oldebob,

    Fortunetly Mercruiser used a closed loop heat exchange sustem with antifrieze so winter cold and sea water aren't usually a problem.

    Dennis G,

    I found the 4 barrel manifold and I apparently didn't mess with the water jacket or the oil cooler. I think I will initially leave them alone in case I need the heat for warmup.

    It would also be a kick to run ice water thur it if I install a Turbo later.

    Here ar the pictures you asked for.

    :) :) :) Dick :) :) :)
     

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  12. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    If you guys haven't already found this already Search : RPU guys.

    There are many similar posts there.

    Sorry I haven't figured out how to post the HAMB address yet.

    :) :) :) Dick :) :) :)
     
    Last edited: Apr 29, 2010
  13. turboclubnorth
    Joined: Apr 7, 2010
    Posts: 28

    turboclubnorth
    Member
    from sweden

    Hi again from Sweden, the reason why I'm building a new engine is, because I have a 1965 Volvo Amazon 121 that I had a turbocharged 153,5 CID (2,5l) engine custom made intake, exaust manifold up to 30 PSI of boost, and that's my limit. Therefore I'm building a new big 4 banger to get the car through the inspection, because I drive it on the dragstrip and also on the streets.

    dawford / Like you say, reliable engine. "Low" rpm with "low" boost, but high performance. my set up, custom made intake with injection,custom exaust manifold, dry sump, scat rods, forged pistons, regrind camshafts and of course turbo

    randydupree / thank you for the tip about the water return, I planed to plug the return in the back. How much did you stroke the crank?
     
    Last edited: Apr 29, 2010
  14. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Johan,

    Here is a thread that I copied from "turbo on a 235 inline.

    It was authored by Mart3406.

    If you want a cheap and 'near bolt on' turbo set up
    for your 235, maybe think about a complete set-up
    off of a late '70's carburated turbo-Buick V6.
    These were used on 3.8 itre V6's in late 70's. I
    picked up one in a boneyard a few years ago from
    a '78 Buick Regal and put it on an otherwise stock
    slant-6, in an in O.T. '81 Dodge D100 pick-up. The
    late-'70's Buick set-up is a 'draw through' system,
    with a Rochester Q-jet mounted to the inlet of the
    turbo, via a cast aluminum adaptor.The size and
    layout of the Buick turbo set-up happens to be
    just about perfect for adapting to an inline-6. To
    fit it to the Dodge, I used short piece of 2-inch
    diamiter stainless steel exhaust tubing, with
    flanges welded on the ends. The turbo mounted
    to the stock slant-6 intake manifold, sitting just
    above it, with the stainless exhaust tubing
    connecting the turbo's compressor outlet to
    the carb mounting pad on the slant-6 intake. For
    the exhaust, I had another piece of stainless
    exhaust tubing - this time 2 1/4 inch diamiter
    - bent in a "U" shape, with flanges welded on
    the ends to connect the outlet on the stock
    slant-6 exhaust manifold to the inlet of the
    turbo's exhaust turbine.

    For an an exhaust system, I had a 3 inch diamiter
    'downpipe' made up, that went from the exhaust
    outlet on the turbo and connected under the truck
    ito to a homemade 3 inch inlet and two - 2 1/2
    inch outlets "Y" pipe that fed into a pair of
    2 1/2 inch inlet & outlet X 30 inch-long resonators
    and a pair of turnouts, exiting just ahead of the left
    rear wheel. Even with two side by side, straight-through
    resonators and turnouts, the turbo acted enough as a
    miffler, that until you were really on it and making
    boosrt, the system was still resonably quiet and not
    a whole lot louder than stock.

    I had the downpipe and turbo mounting and exhaust
    tubing bent up for me at a local mufler shop and a
    little trick I used to get the bends right, was to use
    exhaust 'flex flex pipe' to mock everything up. When
    I had the flex pipe bent the way I needed it, I
    brushed on some epoxy cement and let it harden. Then
    I took the pieces of flex pipe to the muffler shop and
    got them to rplicate them in stainless steel exhaust
    tubing. I made the flanges up myself at work, from
    some scrap 5/16 304 stainless plate

    To lube the turbo,I found an unused oil port on the
    side of the block. I plumbed into it by removing the
    stock pipe plug from it and replacing it with an NPT
    to AN adaptor fitting. Then I used a length of braided
    hose, -also from work - to connect to the oil inlet on
    the turbo. For the oil outlet, I simply ran a line from
    the turbo into a brass hose fitting that I epoxyied
    into the the side of the valve cover. The only other
    even 'semi-major' mod I made was changing the carb.
    The stock Buick Q-Jet is an electronic "feed-back" carb
    and used a computor.whiich I didn't have and wouldnrt
    have wanted to try messing with anyway. Probably any
    old style 'non-feed-back' Q-Jet could be made to work,
    but I had a 'Holley 'list 80552' 650 cfm 'sreadbore
    replacement' marine carb collecting dust on a shelf that
    I rebuilt and used. The carb worked great almost
    'as is' with only some linkage fabrication and
    going 3 jet sizes richer on the secondaries required.
    I also added an electric fuel pump at the back of the
    truck to push fuel up to the stock slant- 6 mechanical
    pump , "just in case" to ward off any chance of fuel
    starvation and lean-out under boost. After a bit of
    tweeking with the timing to limit the total advanvve
    to 30 degrees, the system worked great. With the
    turbo, at low speeds, the truck drove pretty much
    as stock. In fact you'd hardly know that it had been
    modified. But when the scondaries kicked and it
    started making boost, hang on! I kept the boost
    limted it to 6lbs, which was probably about the
    mazimun safe limit for the stock cast pistons and
    stock, 80,000-plus mile slant-6 bottom end, but
    what a difference even just 6 lbs. made!. I never
    tried dynoing it or running it at the track, but
    just 'seat of the pants' guesstimating from driving
    it, I'm sure the stock 115 horsepower was at least
    - and probably more than - doubled! Besides
    everything being basically "bolt on", it was cheap too.
    Including buying the complete Buick turbo set-up from
    a boneyard, having the tubing bent at a muffler shop
    and buying or making the assorted small bits and
    pieces, I still had less than $350 tied up in the whole
    system. I''m sure that you could adapt the Buick turbo
    set-up to a 235 Chevy - or any other any similarrly
    sized inline-6 - and have simillar results.

    Mart3406


    Here is a Picture posted by 6cf Pony in that same thread.


    I think that you might have a hard time finding a late 70s Buick V6 turbo in sweeden but you might be able to get one shipped to you from here.

    It looks like it might be a natural for this engine.


    :) :) :) Dick :) :) :)
     

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  15. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Johan,

    The advantages of this set up are that the Buick is about the same displacement 3.8 liters.

    The Buick V6 without the turbo probably didn't make any more HP than the Mercruiser 3.7 liter.

    And the earley Buick turbo used a QuadraJet similar to the 188 model Mercruiser that made 190hp with the stock cast iron head.

    I think that you could get a pretty reliable 300hp out of this engine with the aluminum heads and the turbo.

    You might want to go to other rods because if you figure that if this is 1/2 of a 460 ford it would put out 600hp as a V8.

    The bottom end will hold up because it is heavier than the 460 because the throws are only 1/2 the width of the V8 crank and the ballance weights are wider making the crank probably one of the strongest of any 4 cylinder around. The mains are 2 3/4" and the rod bearings are 2 1/2"

    Let me know what you think.

    :) :) :) Dick :) :) :)
     
  16. randydupree
    Joined: May 19, 2005
    Posts: 649

    randydupree
    Member
    from archer fl

    I never used the stock manifold or head either,the spacer should work fine foor you,or,just build an intake like I did.
     
  17. randydupree
    Joined: May 19, 2005
    Posts: 649

    randydupree
    Member
    from archer fl

    i stroked one crank .200 and destroked another .200.
    so,i had a 3.95o stroke on one and 3.550 on the other.
     
  18. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    I think the stock Mercruiser manifolds look good and I would think Mercury Marine engineers would have the flow down pretty good judging from what they get out of their Mercury Outboards.

    I have cut the water jacket off of the bottom of a couple of the 2 barrel manifolds and they look better.

    I might set up some electric valves hooked up to the hot water return so that warm water flows thru the manifold untill the engine warms up. Then temp switches would turn off the flow thru the intake manifold after the engine gets up to running temp.

    In So. Cal this might not be necessary so I will wait and see after I get them installed. I still have a couple of manifolds that have the water jacket on them and I just bought another 4 barrel manifold yesterday.

    They are hard to find. But for a Buick Turbo setup they are unnecessary as the 2 barrel manifold has ports the size of lemons, will flow very well and it looks like the buick turbo would bolt up quite easily.

    I am starting with the mild stock setup with just the mild aluminum performance heads and roller rocker arms as I want them to be bullet proof and the light model A's do not need more than 200-230hp.

    Down the line I might turbo the open wheeled roadster pickup that is setup with a 8N front end.

    Here is a picture of one back in NY built by Elis that gave me the Idea. Imitation is the finest form of flattery.

    My RPU won't have a blower sticking out of the hood and should be way cool.

    I added some pictures of the 2 barrel manifold with the water jacket removed from the bottom and the Rochester 500cfm carb that is standard on the Mercruiser 170hp engine.


    :) :) :) Dick :) :) :)
     

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    Last edited: Apr 30, 2010
  19. I used a 1 1/8" hole saw and 1" pipe tap on 4 manifolds today. It worked out really well.
    I was concerned that the hole would not be large enough, but a 1" pipe nipple is the largest one that is an easy one to use on these manifolds. I did one hole at a time and it worked well in my little mill. I sawed the hole from the engine side of the manifold and then cut threads from the other side of it.

    I was surprised at how thick the manifold flange was. There is lots of aluminum there for good coupling to the pipe. It looks considerably thicker than my 3/8" steel manifold flanges.
    note that the manifold is not symetrical so it is only going to fit one way with the gasket.
     
  20. Dick, your cut down manifold looks quite nice. I was also surprised that how nice your "tractor" based car looks I tried an Allis-chamlers nose on my car and it looked like an airplane tug so I didn't use it.
     
  21. Randy, how did the stroked and destroked versions of your engines compare? [ useful power etc]
     
  22. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Dennis G.

    Thanks for the compliment on the picture that I sent of Eli's RPU. I have just got the bare chassis set up now so it will be a while before I get any pictures of mine.

    I have cut off the front of the camshaft just in front of the cam gear and have removed the water seals from the cam cover and epoxied the hole closed thus solving the seal problem.

    I also cut a small section of the water pump impeller cover and epoxied it to cover the front water inlet to the block. I then drilled and tapped a 1/2" pipe thread hole into the side of the cam cover to allow water to inter the block from the side. This shortens the engine and allows more room for the electric radiator fan.

    I also machined off the alternator stator mountings around the crank shaft to allow a shorter zero ballance harmonic balancer to fit. This also shortens the engine: See pictures

    I use ebay IH Scout IMI High Torque Starters as they are smaller, lighter, more powerful, draw less current and can be rotated for clearance. This starter also dos'nt require cutting or messing with the bellhousing. : See pictures

    :) :) :) Dick :) :) :)
     

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    Last edited: May 2, 2010
  23. turboclubnorth
    Joined: Apr 7, 2010
    Posts: 28

    turboclubnorth
    Member
    from sweden

    Dick /I also have had my eyes on that type on engine, but I wanted a inline 4 cyl. because of the the car inspektion here in Sweden. Anyway I already bought a mercruiser 3,7 and started my engine building projekt. I custom making a intake manifold plenum with centerd placed injektors, and also a exhaust manifold for the turbo. I try to send some pictures.
    / Johan
     

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  24. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    I have a piece of .25" aluminum that I want to use for a spacer to fully cover the water jacket hole in the Intake side of the aluminum. The Mercruser manifolds don't quite cover the larger holes on the aluminum heads. This way I can drill and tap the plate with 1/2" pipe threads to install 1/2' water nipples for the front and rear of the head. These will provide the return to the radiator.

    I am sure that there will be those that think that 1/2' water lines won't be big enough to cool this engine but if they look at the 3 small slots in a thermostat that restrict the flow of a 1 1/2" hose on most cars they will probibly see that the .60" hole will flow plenty of water when fed with a larger hose necked down at the nipple. There will be 2 return lines out of the head front and rear that will also feed into a larger return line to the radiator.

    This aluminum engine with its open deck and aluminum head should shed heat very well.

    My question is what is the easiest way to make multiple manifold plates out of the aluminum stock that I have. Can I get them laser or computer cut and if so where and how much. Remember that I live in So. Cal. I will probably have 6 or more cut if the price is right.

    I know that I can cut and drill them myself but that is a lot of work for me with my shop not fully set up yet. The gasket will serve as the pattern for the cad cam.

    Thanks for any suggestions.

    :) :) :) Dick :) :) :)
     

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    Last edited: May 2, 2010
  25. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    WOW Johan,

    Your manifolds looks great. The first picture looks like a bunch of worms fighting it out but I can see that you thought it out perfectly and I know that it will work great for you. Nice work.

    It also appears that your head has the smaller water jacket holes like the cast Iron Ford heads. Your heads would not require the extra plate that I will need for Mercruiser intake manifold.

    :) :) :) Dick :) :) :)
     
    Last edited: May 2, 2010
  26. turboclubnorth
    Joined: Apr 7, 2010
    Posts: 28

    turboclubnorth
    Member
    from sweden

    Thanks Dick / What type of flywheel do you use? chevy or ford, I going to use a powerglide, and wondering about the small starter you used. It looks like a nice solution to the problem.
    / Johan
     
  27. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Johan,

    I wasn't suggesting that you put a Buick V6 turbo engine in your car but rather I wanted you to see the Buick V6 turbo setup as a possible installation on your Mercruiser.

    However I see that you can fabricate your own system that with your fuel injection will undoubtedly give better performance and milage.

    I am not that sophisticated in my abilities or my approach to this project.

    Again Good job.

    :) :) :) Dick :) :) :)
     
  28. turboclubnorth
    Joined: Apr 7, 2010
    Posts: 28

    turboclubnorth
    Member
    from sweden

    Dick
    Sorry, I didn't understand you right. Don't be shy I think your projekt looks very nice in all terms, we just have diffrent goals in the end, and that's a good thing that everybody have diffrent dreams. What type of water pump are you going to use for coling.

    Johan
     
  29. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Johan,

    I am a slow typest and I usually edit my posts so I am usually a post or 2 behind when there is someone on the other end of the thread.

    I am using small block ford zero balance flyweels, clutch and presssure plate and I am using WC T-5 V6 Mustang transmissions. They have good ratios and they have long input shafts that don't require shortining the Mercruiser bellhousing.

    The small starter will work fine on any flywheel with the original number or teeth. I think they are 157 tooth. I don't remember and I am too lazy to count them right now.

    Anyway the starter will not hit the bellhousing because it does not have the end bearing support sticking out the end like the Delco starter. You can see that on one of the pictures that I posted earlier.

    :) :) :) Dick :) :) :)
     
  30. turboclubnorth
    Joined: Apr 7, 2010
    Posts: 28

    turboclubnorth
    Member
    from sweden

    Dick
    I'm also a slow typest, and I don't sit by the computer every day at all. I should look into the problem with the starter it sounds like an good and easy solution.

    Johan
     

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