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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. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    This is the boogieman for my application:
    From the research I have done the only problem(s) with these engines is the water pump system will weep because the cam seal will fail, the alternator sucks and if you over heat it with the iron head it will leak the head gasket. So in stock form if you solve the first two issues that leaves the head sealing issue if it overheats. Decking filling or block reinforcement could be a death-nail to my build. I will be running this thing for up to 24 hours strait. When you consider closed course road racing you are essentially running two drag races per lap down the front and rear stretches. We can easily run 450-650 laps per race. That is 1000 hard pulls per race. My boogieman is if I screw with the water jackets and cause hot spots in the cylinders or restrict the general cooling capacity I might be throwing well over a 1000.00 in other block machining tricks in the trash. My build is about freeing up frictional horsepower rather than increasing the RPM it was tested and designed for. Yes, I will be slightly increasing cylinder pressures but I want to do this at the designed piston speeds and with great reluctance on the turbo side of things...

    I'm getting closer and closer to just copper o-ringing the head and EPDM o-ringing the block with the stock cylinders.

    But at this point and time... I'm in the realm of listening to the most experienced 470 guy on this forum and just running the FACTORY head gasket. Whom made lots of power and reliability with that setup and went 186mph. lol.
     
  2. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Has anyone EVER seen any dyno numbers on a 470 build? The only numbers I have ever seen was the dragster that got 470HP@7500 on meth.
     
  3. Boss9 Brian
    Joined: Jul 29, 2015
    Posts: 73

    Boss9 Brian

    I havent even heard videos of one running besides mine. We put all the specs in to and engine building program and that is how i got my numbers.
     
  4. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Here's some videos...












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

    FlyHiFlyLo
    Member

    Wow! I just found this post on another forum- from 2003 by none other than Jon Kaase himself.

    "We built one of these in 1982. It was 243 inch with a 4.020 stroke(offset ground stock crank to 2.200). We used a nascar boss 429 hemi head and ended up having to use Webber carbs. The vibration and intake pulses were too severe for Holleys. It shook so bad I had to get rid of the Crower steel rods and use BME aluminum. Also had to weld straps to the counterweights. We reground the flat tappet cam and got by with the stock chain and gears.
    It made 400 ft/lbs @ 6000 and 400 HP @ 8000. Woody Mays ran it in a dragster for a few years. 8.70's I think. It changed hands a few times and ended up in Il. I saw it a few years ago at Cordova in a roadster. After 20 years I think it still runs.
    I orginally built this engine to test cylinder heads cheap. This was when I learned my lesson that nothing is the same with a four banger as a V-8!
    Kaase"
     
  6. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    It's valuable hearing what Kaase says about the Holley. So maybe the draw thru turbo even at low boost will actually help smooth out the intake pulses. Because I really want to run my Holley setups.
     
  7. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,642

    Phil1934
    Member

    Holley sells off road conversion kits to handle fuel slosh
     
  8. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Yes that is solved with spring loaded seats and raised bowel venting. However, nothing can solve the intake pulse that messes with the metering. A large plenum helps the pulse but you lose low-end tq.

    Sent from my SM-G920P using The H.A.M.B. mobile app
     
  9. Boss9 Brian
    Joined: Jul 29, 2015
    Posts: 73

    Boss9 Brian

    I was referring to no one on the forum posting personal videos. I can go on youtube all day long. And my engine is just a bigger version of kaases with two holley 500s. Works perfectly fine. Oh also, do you still need a roller cam since kaase used a reground flat tappet? Because i used a flat tappet also and i was told that it wasnt going to work well.
     
  10. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    There was tcheer posted a vid. Yeah, I have to run a roller. I wont make the level of power and economy I need without it.

    Sent from my SM-G920P using The H.A.M.B. mobile app
     
  11. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Brian, have you put a load on that engine yet? In a car? Can't wait to see it run.

    Sent from my SM-G920P using The H.A.M.B. mobile app
     
  12. Boss9 Brian
    Joined: Jul 29, 2015
    Posts: 73

    Boss9 Brian

    Not yet. Just got it bolted in the car though. It barely fits. The whole car has been a 5 year project and the engine has been 3 years so its coming close now. [​IMG][​IMG][​IMG]
     
  13.  
  14. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    So damn cool!
     
  15. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Dennis, great to know... Did you ever get a new block? Yours running again?
     
  16. I rebuilt a Mercruiser "120" and ran it in my car until it was time to change its break in oil but was surprised at how much less power it made. I'm presently working on it but I bought another 170 for the car. The best thing I can say about the smaller engine is that it has no tendency to knock but that engine is small and too heavy for its power. I have a supercharger for it but the larger 170 engine is far better. ( I'v another car ready for my 120.)

    Scott, I am quite impressed with your engine, your car and its performance. Revs really, really well
    Dennis
     
  17. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    You seen it?
     
  18. Boss9 Brian
    Joined: Jul 29, 2015
    Posts: 73

    Boss9 Brian

    Have you posted about your car? I dont remember seeing a video or anything of it.
     
  19. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

  20. skip57
    Joined: Sep 8, 2012
    Posts: 13

    skip57
    Member
    from md.

    Just watching and taking note's
     
  21. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Been swamped at work for the last two weeks... Just wanted to touch base.
     
  22. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 2,241

    GearheadsQCE
    Member

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

    FlyHiFlyLo
    Member

    So having off thread discussions: Vibration issues were discussed. I always knew piston speed increased at the bottom of stroke and helped with the intake charge. However, I never related it to balance and vibration specifically increased on 4cyl engines...

    I have done some looking on the intrawebz and found this valuable info.

    Piston speed
    An even-firing inline-four engine is in primary balance because the pistons are moving in pairs, and one pair of pistons is always moving up at the same time as the other pair is moving down. However, piston acceleration and deceleration is greater in the top half of the crankshaft rotation than in the bottom half, because the connecting rods are not infinitely long, resulting in a non-sinusoidal motion. As a result, two pistons are always accelerating faster in one direction, while the other two are accelerating more slowly in the other direction, which leads to a secondary dynamic imbalance that causes an up-and-down vibration at twice crankshaft speed. This imbalance is common among all piston engines, but the effect is particularly strong on inline-four because of the two pistons always moving together.

    The reason for the piston's higher speed during the 180° rotation from mid-stroke through top-dead-center, and back to mid-stroke, is that the minor contribution to the piston's up/down movement from the connecting rod's change of angle here has the same direction as the major contribution to the piston's up/down movement from the up/down movement of the crank pin. By contrast, during the 180° rotation from mid-stroke through bottom-dead-center and back to mid-stroke, the minor contribution to the piston's up/down movement from the connecting rod's change of angle has the opposite direction of the major contribution to the piston's up/down movement from the up/down movement of the crank pin.

    The strength of this imbalance is determined by 1. Reciprocating mass, 2. Ratio of connecting rod length to stroke, and 3. Acceleration of piston movement. So small displacement engines with light pistons show little effect, and racing engines use long connecting rods. However, the effect grows exponentially with crankshaft rotational speed.


    SO:
    Finding all my power (tq)under 5500RPM will help keep this under control.

    However, I'm gonna do a few tweaks. I'm sticking with the 4.39 overbore (+.030) but doing a slight destroked crank grind. I'm gonna go to 3.65 from 3.75. This is a 218ci combination or 3572cc. This reduced stroke will slightly slow BDC piston speed.

    Then I will go to a 6.800 aluminum rod. This will stand the rod up more in the cylinder and reduce the harmonic of the varied piston speeds. Also, I'm not going to run the BBC 2.20 journal dia I was going with and go to a SBC journal of 2.100 (stock 2.50) . This will reduce the journal side weight of the crank by 5.97 .oz at each location. This is not reciprocation weight but it will free up some weight off the counter weight side that can be used for knife edging to reduce windage. There will be additional weight saving in the smaller rod bearing. And the aluminum rod's big end that counts towards rotating weight reduction during balancing.

    On the reciprocating side I will run very light pistons with with the help of the .150 higher pin location in the piston, light weight wrist pins and thin rings.

    And another trade off; I want to keep a significant piston skirt but have it coated. This will help with piston rocking that puts force on the cast cylinder sleeves.

    What years did these engines come with a steel crank?
     
  24. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 2,241

    GearheadsQCE
    Member

    Very interesting stuff. Long ago, I found some similar information and seeing a graph of piston acceleration/deceleration was quite an eye opener for me. What I didn't think about was the effect of two piston/rod assemblies having twice the force acting together on the crank at any given time. I did know about the different rates but hadn't thought about them in relation to pairs of pistons in an inline 4. No wonder that these cranks are so beefy.
    Also amazing to me, was how small changes can have such large effects on the internal stresses in an engine.
    I'm also a subscriber to the long rod, light reciprocating mass approach.

    From what I have read, Randy Dupree is right about the pulsing, but the dynamic imbalance contributes to the harmonics, and shouldn't be ignored. I think this engine would benefit from tuned port injection. Signals to carburetors must be huge.

    I don't know when the forged cranks were made. The one I have was a gift from an unknown engine.
     
  25. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Can you do me a favor and find a PN on it?
     
  26. beck
    Joined: Sep 20, 2008
    Posts: 165

    beck
    Member

    I read somewhere, possibly on this forum, that the forged cranks were used in the very early motors. I believe the same person suggested the cast cranks may have helped with vibration control.
     
  27. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 2,241

    GearheadsQCE
    Member

    Here is the number on my crank
    IMG_0306.JPG
    4565327
     
  28. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    You know for a fact it's steel? Not say'n you don't know how to check... Just say'n I'm gonna turn the intrawebz up side down looking for a few. LOL
     
  29. FlyHiFlyLo
    Joined: Dec 5, 2016
    Posts: 107

    FlyHiFlyLo
    Member

    Are there any other markings on it?
     

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