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Mercruiser 3.7 Build, 1970 Cj5? Big Block Hurricane!

Discussion in 'Early CJ5 and CJ6 Tech' started by 70cj5134f, Sep 27, 2018.

  1. Oct 2, 2018
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
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    What do you want? What's your budget? Search old posts and you'll find pages and pages of discussion. The Novak site goes through the possibilities too.
     
  2. Oct 2, 2018
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    Jan 23, 2014
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    2,634
    I'm not aware of an aftermarket bellhousing that will bolt to the T90 and also bolt up to a Chevy pattern block. The adapters that require the T90J longer input shaft won't work unless you change the countershaft too, making your T90C into a T90A.
    Many transmissions will mate up to a stock Chevy bellhousing, and can be adapted to the D18. That may be the easiest route, but there will be nothing easy about building a 470 conversion. Have you checked out how the front of this engine mounts? The engine dangles from a "C" shaped bracket off the front. There are no engine mount bosses on the sides of the block to make things easy. Have you checked your crankshaft to see if there is even a bore for a pilot bearing?
    Just have both eyes open if you jump in. You'll be blazing a new trail, and yes, I'm planning on using a 470 too.
    -Donny
     
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  3. Oct 2, 2018
    gunner

    gunner Member

    Washington state...
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    Dec 4, 2012
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    This is the part- the bolt pattern- I found confusing with the Merc 470. The threads on HAMB etc had guys trying to build adapters to use Ford or Chevy bellhousings. More than one guy lost interest at that point, though they seem to have fewer machinist type guys there than we have on this forum so maybe that's why. Also, the HAMB-types don't stray too far off the reservation when it comes to conversions and adaptations. They'll do them, sure, but not to the extent ECJ5 or pirate guys will. That's why I say I'd have more faith in solutions to the 470 being found on these pages.
     
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  4. Oct 2, 2018
    gunner

    gunner Member

    Washington state...
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    Sums it up well. Yeah, more than one of the HAMB guys gave up on the 470 and went to the 2.5/3.0 Mercruiser (153/181 CID).

    Far as I know, most marine engines of this size class use that "C" bracket- I see it all the time with the 153/181 Mercruisers in boats. But most of them started out as car engines (or also used for forklifts, etc) so already have the bosses cast into the block (3 of the 4 153 blocks I have are marine- they all have the motor mount bosses). The 470 was a purpose built engine- strictly marine so there was no need to put motor mount bosses into the block casting. And that's just one of the oddities with this engine- the water pump and alternator were headaches for the guys wanting to adapt it into their jalopies. Also, as I recall, they found no hole in the crank for a pilot bushing. It's much like the 181 Merc marine cylinder head- it was designed for the cumbersome marine manifolds and there is no vehicle manifold to fit. Has to be fabricated. The 153 head, found stock, obviously on 153s but also sometimes on 181 marine engines, has aftermarket support. You can buy the exhaust manifolds on Rockauto (and SPA made/makes turbo manifolds for it).

    Donny, you sure a common 90* Chevy bellhousing bolts up to the 470?

    To the OP- have you see any sign of coolant contamination in the oil? It was a common problem with these engines and resulted in destroyed bearings.

    One last thing, years ago when looking into the 470, it was mentioned that new, replacement parts aren't being made for a number of systems on the engine. You have to source good takeoff parts. I can't recall which parts, but things like pistons, rods, cranks, cams, lifters etc might only be found used. The 460 Ford head is no problem, of course- tons of options there all the way up to high performance aluminum heads.
     
    Last edited: Oct 2, 2018
  5. Oct 2, 2018
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    Sep 22, 2002
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    These engines have an open deck design which in my mind is a bad idea with an aluminum block and cast iron head, that’s what’s causing most of the water leaks.

    This post here will tell you about the bell housing and such.

    The elusive 224/3.7 MerCruiser banger
     
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  6. Oct 2, 2018
    jhuey

    jhuey Michigan Jeeper!

    Indian River...
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    Apr 9, 2004
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    414
    Merc 470 should be avoided. Just my opinion. I worked as a marine mechanic for 15 years, I was Mercruiser trained. Out of all Merc engines produced the 470 had higher than average issues and higher cost. Sure much had to do with age, parts availability and poor maintenance practices. That engine was hot and cold when it came to reliably, I have worked on some that performed quite well, but bad running ones really took a lot to turn around. I never cared for the idle quality, it had a lot of mass moving for a four cylinder engine, and cold idle is very, very shaky. The cam drives the water circulation pump, the seals wear, or cam gets a groove and the cooling water ends up in the oil. Sure it fixable, but a common issue. I repowered many boats that had the 470 in them, the replacement engine we chose was the 4.3 v-6. The best engine (IMHO) I worked on as the Chevrolet small block in all cubic inch configurations. I always wondered if the 470 was designed on a bar napkin over Leinenkugels at a supper club in Fond du Lac WI.
     
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  7. Oct 2, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    730
    So, let's adapt to the jeep bell?
    Why not a plate type adapt?
    When home from vacation, I'll get some pics and measurements posted.
    And don't worry bout mounting the engine, I'll fab up something.
     
  8. Oct 2, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    I've been reading that?
    I'm on page 6 now, their is 64 pages.
     
  9. Oct 2, 2018
    gunner

    gunner Member

    Washington state...
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    :rofl:

    It'd be even funnier if I knew what the he** a leinenkugel was.

    (Otherwise, exactly what I hear about the engine on this side of the country- the side with no clue about leinenkugels)
     
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  10. Oct 2, 2018
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    Summer Shandy!:beer:
     
    Last edited: Oct 2, 2018
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  11. Oct 2, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    So far the problems with engine, speedy sleve,or a new cam fixes 1,
    A mercrusier head gasket and not overheating (should not be a problem
    in a car which isn't loaded like on a dyno all the time), with a decent cooling system
    and thermostat , fixes the other . All the rest is fab work.
    To start with a 460 ex manifold, maby flipped for front exit if needed like the 134.
    Alt brackets.
    A fluiddamper and correct pulley on crank.
    Some fab work on hooking cooling system to a rad.
    I'll run stock carb, dist,and intake for now.
    My biggest concern as of now, is not spending more on hooking up the
    Tranny , than on the rest of the build?
    I can c the custom made decal on the valve cover now!
    BIG BLOCK HURRICANE 3.7
     
  12. Oct 3, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    Aug 18, 2018
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    Y'all ever heard of block posting?
    Used in blocks with open top cylinders.
    Check this out.
    Block Posting
     
  13. Oct 3, 2018
    70cj5134f

    70cj5134f Member

    East Tn
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    No oil in water, or water in oil, it ran right off the lake when I bought it.
    Engine seemed fine, the boat it was in needed tons of glass work.
    Bought the boat to restore, lost interest.
     
  14. Oct 3, 2018
    Keys5a

    Keys5a Sponsor

    Florida Keys
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    There are many variations of the 470 over the years. Yes, the water in the oil issue is directly related to the nose of the camshaft wearing, allowing the waterpump to leak into the crankcase. To my knowledge, there is not a speedy sleeve to address this. The open deck block doesn't present many issues with head gasket leaks because these were freshwater cooled, just use an OEM Mercruiser gasket. Some folks have cut the nose off the cam and plugged the timing cover, mounting a remote water pump.
    The balancer up front must be retained because it is an integral part of the rotating mass of this large displacement engine. The balancer is very heavy, maybe 18+ lbs. A Fluid Damper isn't going to cut it on this application.
    You can pull the alternator stator/guts out and mount a conventional alternator. Mine has a pulley sheave made on the balancer for driving accessories. Mine also has forward engine mount bosses cast on the block in the Chevy triangle pattern, but my crank is not bored to accept a pilot. This will be more difficult to overcome than it seems on the surface; the area needing to be bored is the center that otherwise is needed to turn the crank on a lathe.
    A standard Ford 429/460 iron exhaust manifold bolts right on, pick left or right for your preference of dump.
    The oil pan kind of has both front and rear sumps, so some attention may be required to clear the front diff.
    And yes, I have already bolted a Chevy 90 degree bellhousing onto my block. Even the dowels line up perfectly.
    Think the project through before you jump in with both feet!
    -Donny
     
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  15. Oct 3, 2018
    Mcruff

    Mcruff Earlycj5 Machinist

    Albertville, AL
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    Pilot bushing hole can probably be machined with the engine assembled sitting on a wooden frame. Fresh water cooled has nothing to do with the open deck , it has everything to do with that lightweight aluminum block and heavy cast iron head growing at different rates as it warms up. The head is stronger than the block. It’s one of the reasons you don’t see this in cars. It’s always the other way around, iron block aluminum head or all of one metal or another.
     
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  16. Oct 3, 2018
    colojeepguy

    colojeepguy Colorado Springs 2019 Sponsor

    At the foot of...
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    OK, I'm going to say what we're all thinking. Forget the Mercruiser engine and go with a 225 or a 3.8 or a 4.3 Chevy.
    Don't get me wrong, I LOVE oddball engine swaps. I spend lots of time at car shows checking out Nailheads, W motors, early hemis etc. But the Mercruiser engine seems like a problem child with no upside. (Just my impression, I have zero personal experience with one)
     
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  17. Oct 3, 2018
    ITLKSEZ

    ITLKSEZ Volvophilic

    Post Falls, ID
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    I sort of agree. I'm a huge fan of doing things that "shouldn't" be done, but to do it with an engine with questionable integrity on a jeep that's currently a driver seems like a bad path to go down. Just my $.02.
     
  18. Oct 3, 2018
    timgr

    timgr Jeepin' Nerd 2020 Sponsor 2019 Sponsor

    Medford Mass USA
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    Many things are popular for a reason.
     
  19. Oct 3, 2018
    Rich M.

    Rich M. Shoe pusher

    Maryland
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    Mar 23, 2008
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    746
    I like the mercruiser thing , after McRuffs post I think he just needs an aluminum head:sneak:
     
  20. Oct 3, 2018
    70cj5134f

    70cj5134f Member

    East Tn
    Joined:
    Aug 18, 2018
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    730
    The pilot bearing is the most difficult task left in my mind, besides mating it to the tranny?
    I really don't think with a stock rebuild, overheating will be a problem!
    And I'm considering block posting?(this keeps the cylinder stationary.)
    The vibration thing worries me a tad?
    And I'm using the stock water pump with a speedy sleeve or 2?
    May go with 1/2 in head bolts (or arp studs)nstead of 9/16 because of more stretch.
    And I got to find or fab some kind of oil pump line up tool or jig?
    I'm now on page 19, of. 64. And anyone considering this build, or if u just curious,
    Should read!
     
    Last edited: Oct 3, 2018

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