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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. From what I've seen on the internet, it is a 429 cobrajet rod. Those rods are listed as being two lengths 6.6050" [as in the 460] and 6.549"
  2. those numbers would give a static compression ratio of 8.73:1 . reasonably close to the specified 8.8:1 so something is just a little off. I tried 98.9cc head volume and the ratio came out 8.80. accepting your deck ht. number and changing the head gasket thickness gets us there [I assumed it was 0.040, perhaps it is 0.036"]
    Anyone have a figure for the mercruiser head gasket thickness[used]?

    A new Mercury gasket came this afternoon A brand new one is 0.048" thick [the thickness of the fibrous part]
    Last edited: Mar 29, 2010
  3. tjm73
    Joined: Feb 17, 2006
    Posts: 3,381


    According to Ford Racing Performance Parts all 429/460 BBF's had 6.605" rod lengths except the '69 BOSS 429 which was 6.549".
  4. Phil:
    How did you setup to mill the starter mount back 5/8"? I can't see how to get a cutter down in there against the block.
  5. Yes, we are in total agreement.
    Trethewey likes this.
  6. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,704


    I did not mill starter mount. Extra flywheel depth is to rear. I cut the bellhousing pocket from low on passenger side and moved to high on driver side. I just set ring gear to clear when disengaged, which is probably stock location on a std. flywheel.
  7. This morning I made rough measurements of the distance the transmission input shafts extended forward from the face of two 3 speed manual transmissions:
    Ford: 6 1/2"
    Chev: 6 3/4"
    this will make a difference in adapting one or the other to the merc 470
    The Merc 470 crankshaft already has rear centering hole but it is tapered so it will not take a bushing without machining.
    Last edited: Apr 6, 2010
  8. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,704


    A check of Lakewood housings show a depth of 6.45" for GM trans, 7.07" for Ford trans. Add about 5/8" extended bell of 470 block and you can see the problem. Put pilot bearing in flywheel.
  9. So we have a range of bellhousing lengths to work with:
    data from lakewood:
    7.885 ford borgwarner t5
    7.50 chrysler
    6.924 ford 4 speed and tremec 3550
    6.9211 early tremec tko
    6.45 Muncie, Saganaw, tremec tko, BW T10
    6.361 tremec tko, ford toploader, BW T10
    6.125 recent LS small block chevy
    [ these distances also have an allowance for some sort of plate that is between the block and the clutch]

    Maybe we could use a short bellhousing like that from an LS series chevy without resorting to an expensive special bellhousing. With its 7" rear hole it would need a centering adapter to adapt it down for the older transmissions. It might give us half of the needed distance. But the transmission is mounted rotated to the left.
    [I'll remeasure a couple of my transmissions]
    Last edited: Mar 31, 2010
  10. This afternoon I visited a autoparts house and compared their expensive flywheels to my mercruiser one.
    Car flywheels are considerably thicker. One for a ford 300 six has potential as although its OD is too much, its center pattern looks right and its greater thickness would all be in the direction to help on the needed 5/8". Or is that 5/8" figure already determined from an automotive flywheel?
    I'm off to a wrecking yard Monday to look at a "pile of flywheels".
    Trethewey likes this.
  11. randydupree
    Joined: May 19, 2005
    Posts: 649

    from archer fl

    all you have to do is mill 5/8'' off the block at the bell housing flange,then a chevy bell housing will work with a chevy trans.
    You still have to add a kickout for the mercruiser starter,thats easy,run a ford flywheel which is what most mercruisers came with,a 0 balance 302 flywheel.
    use a ford pressure plate,and a chevy disc,you will have to drill a pilot bushing hole in the crank for the chevy bushing.

    I have done this,many times.
  12. Thanks Randy:
    What you suggest makes great sense.
    The detail you provided is invaluable.
    Last edited: Apr 3, 2010
  13. I took my block in to get the 5/8" milled off today. There was a moment of stunned silence after my trunk opened.
    "Thats not a little block" said the tech. "I hope it will fit in our milling machine". [It didn't.]

    I finally found a heavy industrial shop with a really big vertical mill.
    Last edited: Apr 8, 2010
  14. I found that the pressure plate which fits my merc 470 flywheel.

    There are three kinds of 302 flywheels. The one from the 1990's holes did not match up and I did not try the one from the 1960's through the 1970's.

    Mustang 302 flywheels made in the 1980's have the same hole pattern as mine and that pressure plate fits my Mercruiser 470 flywheel with no modification to either.
    Last edited: Apr 7, 2010
  15. turboclubnorth
    Joined: Apr 7, 2010
    Posts: 28

    from sweden

    Hi I just throwing in some facts of my new engine project. Turbocharged mercrusier 227 3.7 l engine with scat rods, edelbrock rpm cyl. head, forged pistons. I`m wonder if somebody had have problems with the stability of the aluminium blocks.
    Last edited: Apr 8, 2010
  16. what it actually cost
    I have spent:
    $100 ....nearly complete basket case engine with a few good parts [with newly reground crank. bored block, old pistons
    ,flywheel, water pump, cam, oil pan ,valve cover & 1 engine mount]
    $130.... sierra engine gasket set and merc.seal set
    $ 39.....mercury headgasket
    $106......main & rod bearings [-.010]
    $ 44.....Ford piston ring set
    $ 3....pilot bearing
    $ 3 ...freshly rekitted Mercruiser carb
    $ 75.. manifold, tubing
    $ 6...exhaust manifold studs
    $ 75... Ford 460 head[used]
    $105.... timing chain/sprockets/tensioner[like new]
    $ 18....distributor [used]
    $ 40... oil pump[used]
    $ 19... cam retaining plate
    $ 25... Mustang pressure plate ebay
    $ 53... Chevrolet clutch disk
    $ 20...aluminum Chevrolet bell housing
    $ 50....drill crank for pilot bearing [he saw me coming]
    $100... machine 5/8" off block
    $297.....pre-assembly shop work:
    [align hone main bearings, polish crank, resize rods, clean block, clean crank] ___
    $ 28 new rod bolts
    $218 deck block, surface head, hot tank head
    $159 four new pistons
    $100 balance crank rods pistons & pressure plate
    $ 25 press in wristpins
    $50 grind cam ______________________________________________________
    $1048 total for materials
    $840 subtotal for labor
    $1888 total

    So It will cost me about $2000.
    You can easily find good running engines for this much.
    but you will have to add on the expense of stripping and reassembling the engine plus the parts in the above list.
    Last edited: Jan 20, 2020
  17. I was told that you can fill the water jacket within about 5cm of the top as the bottom of the water jacket is much less important for cooling. Tilt the engine while adding the epoxy so the water pump is away from the glue. As to what you should use to fill it, I don't know as I've never done it but I'd guess a heat-resisting epoxy which is stiff up to 125C. check the following post, it has the right block filling material.
    Last edited: Apr 8, 2010
  18. BigChief
    Joined: Jan 14, 2003
    Posts: 2,077

  19. boo
    Joined: Jul 6, 2005
    Posts: 546

    from stuart,fl.

    i belive this is the 1/2 460 eng that a boss 429 head will fit on..
  20. Buying clutch parts:
    The pressure plate from a 1984 mustang V8 fits my flywheel.

    As the bellhousing is Chevrolet and the transmission is therefore Chevrolet, the matching clutch disk is for a 283 chevrolet. It is a 10" disk with ten splines on a 1.25 shaft. The NAPA part number is RCF 470 and it costs $53.

    {A larger 10.4" disk is on the more recent Chevrolet cars. It is the more common one. I do not know if it will fit into the Mustang pressure plate assembly as that Mustang uses a 10" disk.}

    Individual clutch parts are becoming harder to find anywhere but on Ebay and craigslist. I was lucky in being able to find a pressureplate for $25 [ ebay] and the disk at NAPA. The other parts stores here can not get just a disk.

    It might be an idea to buy a clutch disk soon if you want to put a Mercruiser in a car and not have to buy some parts that you've no need for.
    Last edited: Apr 12, 2010
  21. Does anyone know what sealant/adhesive Mercruiser used for the water tube in the head? ( I have used an aviation sealant called "proseal" which looks and feels like it)
    Last edited: Apr 16, 2010
  22. Mercruiser factory service 405-743-6570 said that locktite 271 is used to secure the water sleeve to the head. My merc head must have developed a leak there and had proseal added to seal it.
    Last edited: Apr 19, 2010
  23. FoMoCoPower
    Joined: Feb 2, 2007
    Posts: 2,490


    subscribing......buddy finally wants to sell the pos boat he has with the running 470
  24. dawford
    Joined: Apr 25, 2010
    Posts: 498


    Hi, I'm new to this forum so please bare with me.

    I have read these 5 pages of threads and wish I had found this forium years ago. I am building 3 of these engines with T-5 transmissions and I am just about to put the first one together.

    I am using aluminum high performance heads similar to the Trick Flow Street heads. These heads cost a little over $500.00 each and my dealer will sell them one at a time. I am using an electric fan, water pump and fuel pump, a Powergen alternator and an IMI High Torque compact starter that dosn't have the long nose and large heavy body of the Mercruiser starter.

    These engines are going into Model A Fords. I figure that with the better heads and roller rocker arms the 2 barrel 500fpm carb should give out about 200hp and the 750cfm Quadrajet should give out about 225hp.

    The Quadrajet engine is going into a 1500/1600lb Model A Roadster Pickup. The others will go in 2300lb Model A's. With these power to weight ratios they will be great sleepers as the bodies will look pretty stock except for the roadster pickup that will have a ford 8N tractor hood and grill. Having fun with old Fords.

    Thanks for the great posts, Dick
  25. It sounds very nice indeed Dick and doing 3 motors makes sense too.

    I was talking with a friend who raced model a based cars and his comment was that they broke front spindles and rear axles fairly easily [while racing]. You may want to use other axles. My rear and front axles are jeep axles and no they do not look like model A axles but the Dana 44 is a good rear end, and I've changed gears but given the choice it is much easier using a rear end with a removable carrier. The jeep front end came with the frame I used and neither is light but they are very strong. With work the old wheels can be made to fit as the bolt pattern is the same.

    Which electric water pump are you using on your 470's? I think I'll use the stock pump and am putting a speedy sleeve on the camshaft's front end.

    I may use the stock intake manifold as it is heated, but I'm making one up out of tubes so I can use an updraft carb. as it takes less room But I'll only know when I try to get my steering shaft around them.
    How are you cutting the "water sleeve" hole in your heads? I've an old head to get the method worked out on. At present I anticipate using some sort of a "hole saw"[ or a precision milling cutter] and boring it to finish size.
  26. dawford
    Joined: Apr 25, 2010
    Posts: 498


    Hi, Dennis,

    I'm using early F-1 spindles and brakes on the front and a 9" ford pickup rear end with 5 on 5 1/2" lugs on the open wheeled 29 roadster PU and 87 Ford Ranger rear ends with 5 1/2" adapters in the extended cap 30 PU and 30 Woodie. I am using 16" Kelsey Hayes wheels with radial blackwalls on all of them. The open wheel Roadster PU is going to have an 8N hood and grill and be painted grey over red like the 8N tractor kind of a very clean Rat Rod. The others are going to look as stock as possable considering the 4 bar front and rear suspensions and the truck rear ends which will only be apparent to those familiar with Model A Fords.

    I am modifing a chevy small block electric water pump to work as a stand alone water pump as it seems that the only stand alone water pumps are very pricey.

    I have modified the front cover to block off the water pump and cut off the cam shaft pump extension. I further modified the cover to eliminate the 2 additional front covers and allow the water inlet to come into the block thru the front cover from the driver side. This combined with a zero balance harmonic balancer allowes the somewhat longer Mercruiser to fit a little further forward without hitting the radiator electric fan. I will still have to modify the firewall to accept the longer engine and bellhousing even though I am setting the engine as low in the frame as possible allowing for reasonable ground clearance.

    I am making a 1/4" aluminum plate to go between the aluminum intake manifolds and the aluminum heads that will have outlets to correspond with the water ports in the manifold side of the head. As it is the mercruiser Manifolds don't quite cover the enlarged ports in the after market aluminum heads anyway. I want the water pump to pump into the front of the block and return to the radiator from the higher head water jacket ports thus insuring a good flow thru the block. I have removed the water jacket from the bottom 2 of the Mercruiser intake manifolds and they look good but I have rethought this approach and I am wondering about warmup problems in cold weather. "So Cal" I have some manifolds that still have the water jacket on the bottom. In a boat the lake or sea was the radiator and I am sure Mercury Marine had it right for that application. I will see which works best later.

    I like your jeep axle idea as they are narrower than the Ford PU 9" and they are also probably lighter. What year and model jeep works best?
  27. ScottV
    Joined: Jul 18, 2009
    Posts: 819


    I wonder if you could use one of those new Kaase Boss '9 heads on there ???!!!???
  28. shmoozo
    Joined: Aug 14, 2007
    Posts: 672

    from Media, PA

    It sounds like using one in a lightweight roadster would put a lot less stress on the engine than using it in a boat, so a lot of the problems you'd experience running it in a boat would simply never manifest themselves in the car.
  29. dawford
    Joined: Apr 25, 2010
    Posts: 498


    This engine block was going to be sold by Ford Motorsport back in the winter of 1986 but the deal fell thru between Ford and Mercury Marine.

    That fact indicates that Ford Motorsport recognized the potential for these engines as high performance light weight (75lb stripped block) engines. The Ford Motorsport flier listed the engine as a 224 CID Aluminum Block ... M-6010-A224 and listed "Crankshafts, Camshafts and other components as available from Mercury Marine."

    The fact that this engine running in a light weight car will probably eliminate the preignition problem. In a boat there are extreme loads of getting on plane pulling two skiers out of the water or running all day long pushing a big prop against water to the limit of the Torque available. If a problem does arise it may require premium gas or octane Booster.

    Extreme high performance heads sometimes require special head bolts and pushrods. The heads I am using are not nearly as expensive or as demanding to install and still give a significant boost in performance over the stock engine. I am also using aluminum roller rocker arms to reduce friction and add a couple of HP.

    The main difference in a model A is how fast you want to wear out your tires.

    I want a fun sleeper that handles well and is bullet proof.

    Others want drag cars or speed record breakers. Thats what makes us all unique.

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

    from sweden

    It's fun to find out that there is more people who build on this type of engines, because where I live in Sweden they think I'm crazy ( but I will show them in the end ). I wonder how high rpm anyone has tried in this blocks? I don't talk about a standard rod and piston setup, I talk about stronger and lighter in parts.
    / Johan G

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