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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. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    FlyHiFlyLo,
    As Phil1934 said, this engine takes a neutral balance flywheel. The 28 oz will not work, unless it has removable weights. 240 and 300 inline 6 motors have the same bolt pattern and are neutral balance, but I have not found a flywheel for them that is 157 tooth. Internal balance SBF strokers are not uncommon so the flywheel is available somewhere. The stock SBF flywheel is lighter than the I6.
    https://www.amazon.com/Fidanza-Balance-Clutch-Flywheel-186501/dp/B01M3PSPCC

    https://www.amazon.com/PRW-1628980-...rd_wg=msZyB&psc=1&refRID=5TCAJWVP0PYDSHHS2P5R

    This one says 28oz or 50oz external balance but the weights are bolt on. Possibly it could be run without either weight as a 0 balance
    https://www.amazon.com/Procomp-Elec...rd_wg=id8Ep&psc=1&refRID=6C7A2JSR6D393VWH7SWH


    I agree with your thoughts of turning the crank rod bearings to BBC dimensions. If I go that route I will be putting a little more stroke into the crank. There are 460 Ford pistons available for that rod swap, but not at bargain prices. Since I am using the A460 head my pistons will be custom anyway.

    I don't believe the stock camshaft will be compatible with roller lifters. The material of construction is wrong and the aggressive lobe of a roller is larger than the current lobe on the cam. I wish it was that easy since the aftermarket roller blanks don't have the distributor drive gear on them creating ignition and oil pump issues.

    (Not proven, but my belief) Unless using keyed roller lifters the bolt bosses that retains the lifter cover need to be milled out of the block. The bolts will not clear the dog bones or lifter tie bars. See post 1325 on page 45 for more.

    Currently there are no provisions on the crank or the cam to install an internal seal for your belt drive rear cover. The cam is retained by a plate located directly behind the timing gear. The crank timing gear us seated against the front bearing boss. If you get these worked out count me in for a couple!

    I have been wanting to put a crank and cam into a block here to get a center measurement on the timing set, but have not had the time - soon though.
     
  2. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Good info, thanks,

    Jesel keyed lifters might be the call. I like running the large bore so it can get a larger roller and will add a point or two to the ratio.
     
  3. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Who has the cam blanks?
     
  4. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,642

    Phil1934
    Member

    With new front cover being considered, it would be nice to do it like old McGurk ones and have a place for ext. OEM oil pump, maybe Chrysler 340, that didn't cost $400+ like aftermarket ones, and dist., maybe '32-'48 flathead, so cam blank gear not a problem.
    250 6 flywheel is neutral balanced, SBF crank bolt pattern and 157 tooth for those not wanting an aftermarket SFI one.
     
    Last edited: Dec 20, 2016
  5. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    The cam blanks are something a few of us have talked about, but not done yet. See post 1480 & 1487 on page 50. GearheadsQCE is still trying to figure out what would be the best timing gear drive to put on the blank. If someone comes up with a good design I would like to purchase a few. If we would agree on a nose design it would be less expensive having several cut. 1 piece of steel stock is enough for 4 cams. If designing a new belt drive front cover I would wait until that was well underway to determine if the cam was going to need something special for it.

    Another acquaintance had 4 blanks made. 2 have been ground into camshafts already. He still has 1 blank and he gave me 1. These are the ones with the SBC timing gear pattern. They have a modified snout on them useable for an external oil pump drive or distributor drive. I have the drawings with dimensions for these blanks if anyone is interested. These are the drawings GearheadsQCE referred to in his posts.

    GearheadsQCE is in need of a motor to advance his research. If your in the Detroit area and know of a motor give him a shout. The motors are reasonably priced enough that it wouldn't pay to ship or drive one across a few states.
     
  6. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Beck, please get me those Dwgs. I can get the blanks cut and the dist gear too. I can do them in 300M. And yes... lets get the timing gear figured out. I'm trying to get info on lower/upper tooth count for all Jesel Ford/Chevy/Mopar drive belt gears. If we could use the SBF Lower and SBC upper. it would be great. We can get almost any belt tooth count. Also, I'm gonna do some stuff with Jesel and get some of their cam data. Roller cam bearings are totally worth the few bucks they cost. do you know the factory cam bearing bore on the block? I have a conference call with Jesel tomorrow.
     
  7. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,642

    Phil1934
    Member

    I said SBC might work as I pulled a sprocket out of my "I blew it up pile" and compared it to the cam bolt pattern and also to the size of a 460 sprocket in the same pile, but no accurate measure. I know talking to a man who raced one in a dragster he said the timing chain was a weak link so I was just pondering the possibilities.
     
  8. drtrcrV-8
    Joined: Jan 6, 2013
    Posts: 1,222

    drtrcrV-8
    Member

    If the problem with a roller camshaft is the gear for the distributor/oil pump, why not go dry-sump with a readily available 3,4, or 5 stage oil/fluids pump(see sprintcar technology) & crank trigger ignition? No more need for a gear on the camshaft! Oh, don't forget the plug in the hole where the distributor used to go. LOL! I brought this up much earlier, but now we've come to a point where it makes more sense, as the cost of the accessories(pump & Drive plus the crank trigger assy) is still less than the custom "gear-hobbing" required on the cam(& for EACH cam!!) Also, now experimental cams can be cut/ground from sections of round stock of the desired material at a MUCH more reasonable price.
     
    Last edited: Dec 20, 2016
  9. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    We don't have to run the gear but it would be great for all who want to build a 470 to use the stock dist/oil pump.
     
  10. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

  11. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    The SBC bolt pattern is slightly larger than the Mercruiser bolt pattern
     
  12. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    The cam measures 2.125" at the bearing. I don't know what the clearance is.
     
  13. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    That's the block bore? Is there a cam bearing?
     
  14. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Do you need my email for the Dwgs? Are they CAD? I would prefer that. Otherwise, I'll redraw from the info.
     
  15. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    I refer to this photo often. Look on page 40, post # 1193.
    Doug is using a dry sump like you suggest. I don't have the room for a tank in my application so I plan to use just use the remote pump. It draws from the pan and there is no suction section to it.
    Doug is using a crank trigger ignition. I am going to use a Holley Dominator EFI. It controls ignition along with the injectors.
    Notice where Doug has mounted the oil pump from. There is an insert going into the distributor hole with the brackets coming from that. Ingenious!

    FlyHiFlyLo, I agree that a cam gear would be great, but we will need to source a distributor gear that will be compatible. The stock one will not work. See the link in post #1511 above.
     
  16. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    There is NO cam bearing. It runs direct to the aluminum block and works well.
     
  17. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    Ha! These were drawn on a piece of note book paper. Doug Lee made the sketch, from which his blanks were cut.
    Yes private message me your email.

    For those that are just planning to copy the measurements from a stock cam to cut a roller core... STOP. That won't work. The flat tappet cam is designed to rotate the lifters. That means the lobes are not centered on the lifters. On a roller cam the lifters ARE centered on the lobes. SO the lobes need to be moved for a roller cam. If you want the drawings just PM me. OR if FlyHiFlyLo will share his CAD file when it is done that would be great. I wouldn't know what to do with a CAD file. I don't have anything to open it with. Doug and I are old school.
     
    Last edited: Dec 20, 2016
  18. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    I can take care of the dist gear. We can cut the cam to match a composite gear we source. (Just read your link while writing this post) Yup... Had gear failure before from billet cams. Good info.
    For my application a dry sump pump will raise eyebrows. I need to run the wet system. But if not I'm sure a single stage pump could pressurize this engine.
     
  19. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Great! I can draw them up. I'll send you back a PDF when I get it drawn.
     
  20. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 2,242

    GearheadsQCE
    Member

    Wow! That escalated quickly. Sounds like it could get pretty exotic. My vote is to use the BBC Ford Cam gear if possible. Then, the guys that aren't up for dry sumps and crank triggers can participate. If a 460 timing set can be used it could cut costs for the little guys. (That's me, by the way.)
     
  21. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    I hate to leave all this cam/timing gear conversation, but....
    My intake manifold if finally about finished. I think it should move a LOT of air.
    intake bottom view small.jpg
     
  22. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

  23. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    It all depends on the cam/crank CL spacing.
     
  24. oj
    Joined: Jul 27, 2008
    Posts: 6,199

    oj
    Member

    I need to start all over reading this thread, I'm going to use one of these in a tank too. Let me ask, couldn't a V8 rollercam fit?
    I have Inventor 2012 and need engine stuff, I'm working on the spaceframe if that'll help anybody.
     
    lothiandon1940 likes this.
  25. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    As you know a lot of this motor is based off the 460 Ford. Unfortunately the cam bearings are not in the same location as those of a 460, so no it isn't possible.
     
  26. oj
    Joined: Jul 27, 2008
    Posts: 6,199

    oj
    Member

    Figures. What about a 460 crank? Would it work?
     
  27. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    The 460 is the BBF I was referring to.. No it doesn't work.
     
  28. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Here is a first blush on the Cam blank. Still need dist gear info, snout and some bla bla bla. [​IMG]
     
  29. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    I just found a 488 which has not been ran in a couple of years. The last time it was fired was with gas down the carb and it ran rough. It's still in the boat with a trailer. The outdrive has been sold already. I could have everything left or just the motor for the same $$. The guy values his time for pulling it out with a Bobcat. I don't want to mess with disposing of the hull. The owner runs a tow company. He was called to tow it from the roadside. The trailer had blown a tire. The owner didn't want to pay the tow/storage bill so the tow guy now owns it. I doubt there are titles.

    The neat thing about the 488 is it has the 4bbl carb and the larger cam. They are 188 hp. The owner will not guarantee it is a runner at this time. I would like to have this motors bigger cam and another 4 bbl setup. This one has the alternator conversion on it too. I have one motor with a rough crank snout...another needs to be bored to .060" over... Hmmmm... What to do?? Should this be #5 in my garage? It may be time to start replacing some of my costly to rebuild parts.

    I may be nuts, but I really have a thing for these little buggers.
     
  30. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Score... The guys parting these out do well.
     

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