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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. turboclubnorth
    Joined: Apr 7, 2010
    Posts: 28

    turboclubnorth
    Member
    from sweden

    Hi again Dennis

    The shape of the gasket is really the same as Ford 460.

    I am not worried i´am confused about the design.

    In your case it´s not a problem. In my case with 30 psi boost it might be a problem with pressure in the crankcase.
    Anyway It want be a problem. I was just wondering.

    I think I just machine a narrow slot on the block to get a edge for the seal to grip. I also think it will be a nice transition to the headgasket.

    again thank you Dennis // Johan
     
  2. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 2,203

    GearheadsQCE
    Member

    Could one of you post a picture of the area you are talking about? I'm trying to understand.

    Thanx,
     
  3. Johan, you would be best off without much crankcase pressure, if it becomes a problem, you can increase the ventilation. Some older vehicles had a breather from the lifter gallery so pressure could be released directly there.
    Be careful about the water jacket sealing surface inboard from the one with no gasket as it is a known sealing problem area on these engines.
    I see no harm in grooving the outer surface, you could put "O" ring material into it for a gasket and I hear it is available by the meter for those making special "O" rings that are spliced to complete.
     

  4. It is the upper surface at the top outer edge of the block above the lifter gallery. My orange paint ends right there.
     

    Attached Files:

  5. GearheadsQCE
    Joined: Mar 23, 2011
    Posts: 2,203

    GearheadsQCE
    Member

    Oh, I see now. The only thing I have gathered for my build is a crankshaft.

    (Heavy bugger, ain't it?)
     
  6. turboclubnorth
    Joined: Apr 7, 2010
    Posts: 28

    turboclubnorth
    Member
    from sweden

    Hi Dennis
    It want be a problem for me because I learned the lesson by the years building turbocharged engines for 20 years. I just reacted, I think the mercruiser design people could have put in some effort in the design of the headgasket. I already consider the o-ring sealing and I think I go ahead with that design. Thank you Dennis you are awake.

    Johan
     
  7. tjm73
    Joined: Feb 17, 2006
    Posts: 3,315

    tjm73
    Member

    What's a complete 170hp version of the 3.7 worth?
     
  8. I see running engines on ebay for $1000 + . One can get them cheap in partly decayed boats. $ 100 and up. but then they would probably not be running.

    I bought a complete engine ( all apart) with a newly reground crank for $100. Then I spent well over $2000 rebuilding it, I detailed the cost early in this thread. I was later told that my rebuild was inexpensive as Mercruiser 470 rebuilds go.

    If looking for an inexpensive engine, buy a running one. But the probability is that the cam will be worn, particularly in the water pump seal area. Any used engine is a gamble.
     
  9. The crank and the head are the two heaviest parts in the engine.
     
  10. As the Mercruiser 470 is a flat tappet engine. It is critical to use an oil which has a high level of ZDDP (about 1200 ppm) which will protect the camshaft.
    Using an oil made for modern engines can damage a mercruiser 470 camshaft. The oils which must not be used are labeled SM or SN. But oils vary widely.
    Choose your oil with care as you do not want to destroy the camshaft as they are expensive and hard to get.

    I have seen a lot written on this and have concluded that hard and fast rules are difficult to come by as there are several anti wear compounds in an oil
     
    Last edited: Apr 24, 2013
  11. I measured my engine's valve lift this afternoon and bought a new camshaft this evening. The engine has 600 miles on it. So a camshaft can be worn out very quickly. I was using a diesel oil, but even their ZDDP is much lower now. It seems it was not enough.
     
  12. tjm73
    Joined: Feb 17, 2006
    Posts: 3,315

    tjm73
    Member

    Run "off road/racing oil". It's the old formula from what I've been able to read.
     
  13. BuiltFerComfort
    Joined: Jan 24, 2007
    Posts: 1,620

    BuiltFerComfort
    Member

    I think adding a zinc additive to good oil may be the way to go. From another site: "

    I was also disappointed in the amount of zddp in the QS Defy VOA that was posted here a while back. I think your plan of adding a zinc supplement to a quality, readily available oil is fine. It adds maybe $12 to the cost of an oil change, but it's cheap insurance over having to rebuild an engine.

    http://www.zddplus.com/

    Also, check out the above link. ZDDPlus has a lot of articles on their website about using zinc supplements versus other options for protecting slider-follower valvetrains.


    From
    http://www.bobistheoilguy.com/forums/ubbthreads.php?ubb=showflat&Number=2628751


    Posted from the TJJ App for iPhone & iPad
     
  14. tjm73
    Joined: Feb 17, 2006
    Posts: 3,315

    tjm73
    Member

  15. Thanks guys. I'm learning about lifter and cam break in. I used Redline ZDDP supplement in Rotella T the first 100 miles and Rotella T oil for the next 500. The only thing that I did not know about was to cut a groove in the lifter bores on one side for more cam oiling. The cam and lifters were both reground ones. There may have been poor hardening.


    I wrongly calculated that the wear cost some 60 horsepower. Although it came on the cam at 4000 rpm, it got anemic much over that. A third more power will make a big difference.

    I will be using a new 1989 4bbl carb cam.
    ...........................
    the lifters looked ok, the motor was clean inside and one lobe was worn 20 thousandths.
    measurements a few posts below.
     
    Last edited: May 16, 2013
  16. Redline Oil company said that the ZDDP in their oil has never been reduced.
    They said break the rings in first (1500 miles) as their synthetic will keep the piston rings from breaking in. I'm using plain cast iron rings and they broke in right away. I also use a 5 micron filter so perhaps the sub 5 micron cam metal sped things up. There was no visible metal in the oil filter at 100 miles.

    No visible metal in the filter at 700 miles, very little in the sump ( I pulled it to inspect).
    Checked the sump residue with a magnet, picked up a little iron (not much).
    but I did find that the engine must be jacked up at the front and right to drain the last remaining cup of oil.
     
    Last edited: May 16, 2013
  17. turboclubnorth
    Joined: Apr 7, 2010
    Posts: 28

    turboclubnorth
    Member
    from sweden

    Hi, Dennis what is the lift/ numbers on that camshaft.

    // Johan
     
  18. D-Rail
    Joined: Dec 15, 2012
    Posts: 16

    D-Rail
    Member

    It might be known already, but quite a bit of performance ideas can be found on 460ford.com about the mer cruiser. I was very surprised when I found it in their tech section.
     
  19. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,639

    Phil1934
    Member

    I posted cam lifts in post #16
     
  20. dawford
    Joined: Apr 25, 2010
    Posts: 499

    dawford
    Member

    Almost everybody seems to want to change the cam and thats fine but I think that the Mercruiser engineers knew how to get good torque over a wide range of rpm.

    I also will use the carburetor and intake that they use for the same reason.

    If I were building a dragster I would probably start screwing with things but changing the head to an inexpensive performance aluminum head and resolving the water pump and alternator weaknesses seems like the easiest way to insure a reliable engine swap.

    200 hp+ in a 300 lb package installed in a light vehicle should be fun enough with the added bonus of reliability.

    These engines also sound good, not like much else but just good.

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

    turboclubnorth
    Member
    from sweden

    forgott thank you Phil 1934
     
  22. I have two cams which I just measured between centers in my lathe:

    1. a locally reground cam made for my application (rv cam profile)
    I requested that it be a supercharged application cam:

    data from the cam card:

    intake lobe lift 263 thousandths x 1.73 rocker arm ratio = 456 thousandths
    exhaust lobe lift 296 thousandths x 1.73 = 492 thousandths

    lobe sep. 115 degrees
    overlap 27 degrees
    exhaust opens 40 degrees BBDC
    intake opens 13 degrees BTDC
    exhaust closes 10 degrees ATDC
    intake closes 32 degrees ABDC
    all figures at 050 tappet rise
    exhaust duration 210 degrees at 50 thousandths (advertised duration 262)
    intake duration 203 degrees at 50 thousandths (advertised duration 260

    ........................................................................................................
    my measurements (worn supercharger cam) showed
    exhaust lobe lift 278,278,281,279
    intake lobe lift 262,259,256,242
    ..........................................................

    2. an Elgin Mercruiser 470LX replacement cam I bought new last week

    intake lobe lift 287 thousandths x 1.73 = 497 th
    exhaust lobe lift 290 thousandths x 1.73 = 502 th


    exhaust 289,292,290,291 average lobe lift is 290
    intake 285,287,288,288 average lobe lift is 287

    I made no other measurements
     
    Last edited: May 17, 2013
  23. To assemble the engine 3 years ago I bought a used timing chain and sprockets on Ebay. That was not wise as although my timing chain is barely within spec, it is worn to the point of having a lot of deflection (7/8") and even a new chain tensioner is whimpy at best .

    I saw a new chain on EBay $70 and it seemed like too much money so I looked around with my chain in hand. It is a #35 duplex roller chain. Ten feet of which comes for $30. One would use a master link (two included with the chain) to put it together. I was advised by automotive people not to use a master link chain so I called a chain company (Cloyes), they also said don't use a master link, they knew about Mercruiser 470s, I was impresed. they also gave two chain numbers for it : C1608 or C3024

    The 470 chain is a big block Chevy "performance" chain. I bought one today from NAPA $22. It has a surprising amount of play in it. Not up to the highest standards but it is all rivited.
     
    Last edited: May 18, 2013
  24. Phil, What is "MR" an abbreviation for in your post?
     
  25. Phil1934
    Joined: Jun 24, 2001
    Posts: 2,639

    Phil1934
    Member

    It's just the model of the stern drive. It falls between the R and Alpha models.
     
  26. Johan I will read the "stock" cam and make a cam card.
    So far I'm getting too much variation in my numbers to post them.
    but it looks like the stock aftermarket replacement has valve lift
    of about half an inch and lobe centers about 115 degrees apart.
    It is almost the same as the cam I had ground except for having 30 degrees more intake duration.
    dennis
     
    Last edited: May 18, 2013
  27. I agree Dick. Mercruiser had extensive resources that we lack, but our situation is different. If the engine was run with car oil made in the last several years its camshaft may been destroyed. The cam which came with my motor could not be used without regrinding. I requested a moderate grind, a RV grind like my beloved Crower cam which brought a small block chevy back to life. It had great torque, turned up well and got good gas mileage too.
    Phil has shown that Mercruiser used several cams so they were looking closely at that. A used mercruiser cam, still to factory specs, would be a very good choice. I contacted a guy selling one on ebay, he had no idea at all of how to measure a cam so he could not know if it was good or not. He was a good enough guy, he just did not know. Unless it is terrible, a cam needing to be reground looks much like a good one.

    By far the best and cheapest way to use one of these engines is to buy one which is running well and just fix the few design errors in it. I would have used its alternator but the magnets fell out on the floor. I was going to use the original carb, but as it would not work (I had two) so I used a similar one which I knew to be excellent in operation and easy to work with and commonly available. There is no need to change from things that you have which are working well (mine weren't).

    There must be a harmony with the cam, the head and etc.
     
  28. In spite of its good basic design, the stock Ford head is heavy and does not breathe well.
    A well designed aluminum head like the Krause P51 would be an excellent choice. Making use of it would mean cam and carb would have to have more capacity to flow air.
     
    Last edited: May 18, 2013
  29. Here is the cam data that I have from measurements that I made for the Mercruiser replacement cam by Elgin. "zit" was easy to spell and I used it to mean all lift stops there.
     

    Attached Files:

  30. The timing chain is that of a big block Chevrolet or Ford, it is a #35 duplex chain. I read that the sprockets were Ford ones.
     

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