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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. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Johan,

    I am not catching up. I am going to use small block Chevy or Ford electric water pumps that I will drill and tap 1/2" Pipe nipples into. As you will see the outlets on these are not much bigger than that anyway.

    I will mount the pump, motor up, on an aluminum plate with a block off gaskets covering the original outlets. I will then drill and tap 1/2" pipe nipples into the sides of the elbows. I will use 1 for the engine input and one for the heater input.

    The aluminum plate will serve as the mounting bracket.

    See picture which will not show the pipe nipples because I have not installed them yet.

    :) :) :) Dick :) :) :)
     

    Attached Files:

  2. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    The last week or so since I have found this forum I have spent more time on the computer than I have in the last year.

    It is now time for me to get to work on the projects.

    This forium has tied up a lot of loose ends for me and incouraged me to go forward.

    Thanks all for your input and keep it comming.

    :) :) :) Dick :) :) :)
     
  3. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    I thought my question might get lost in this thread so here it is again.

    My question is what is the easiest way to make multiple manifold plates out of the aluminum stock that I have. Can I get them laser or computer cut and if so where and how much. Remember that I live in So. Cal. I will probably have 6 or more cut if the price is right.

    I know that I can cut and drill them myself but that is a lot of work for me with my shop not fully set up yet. The gasket will serve as the pattern for the cad cam.

    Thanks for any suggestions.

    :) :) :) Dick :) :) :) <!-- / message --><!-- attachments -->
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  4. turboclubnorth
    Joined: Apr 7, 2010
    Posts: 28

    turboclubnorth
    Member
    from sweden

    Dick
    It's nice to talk to you, we sems to be in the same boat more or less. If I where you I would leave the jobb to the experts and cut them out someway, because I feel that there is so many parts to fabricate anyhow on a project like ours.

    Johan
     
    Last edited: May 2, 2010
  5. Dick, I made sets of manifold flanges last week [3 intake and two exhaust].
    It was not difficult and took less time as I became experienced. I used 2" hole saws for the intake openings as they were only slightly oval. For the exhaust holes I used a 1 5/8" hole saw to cut the top and the bottom of the hole and then I milled a straight line between the two holes on each side.
    My flanges are 3/8" thick mild steel [4" wide for the intake] Although the steel is heavy, it is easy to braze to the tubing.
    Your aluminum will be easier to cut than steel but welding it is much more of a problem as it tends to suddenly melt and disappear.
    I made manifolds last year [ different engine] and worked in steel then also. The main problem that I had was warping of the 1/2" flange due to my arc welding. As I could not mount them to mill flat I tried another method, I used pipe nipples screwed into my flanges. It was not pretty but there was no warping.
    This time, I made a frame to hold the welded manifolds while I mill them flat. I had to change the manifold design so that it was small enough so it could be held down to mill flat with a surfacer.

    As to the actual layout of your flange for cutting,
    The gasket is the easiest pattern to use. Give the aluminum a coat of layout fluid & hold the gasket to the plate with a couple spring clamps. Use transfer punches to mark the small holes.
    For the large ones just trace the holes.
    With the aluminum held in your vise line a hole saw up with the intake holes. You do not need a center drill for the saw in a milling machine as it holds it rigidly. For the bolt/stud holes just start out with a 1/8" pilot bit and work up to a bit slightly larger than 3/8".
    As the exhaust side is individual flanges, there should be less problem with heat changing the size of things.
    As I used steel as it came from the steel mill,I could not use layout fluid. I copied the gasket, got one good manifold and copied it by laying it in my vise atop the material being cut into exhaust flanges. I just did the intake by transfer punches and light paint sprayed through the pattern..
     
  6. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Dennis g,

    Thanks for the reply, My problem is that I want 5 or 6 of them and don't want the grief of having to duplicate my effort that many times if I can get a shop to cad cam and laser cut them all in the same process.

    I like your ideas for the exhaust manifolds. I have taken old gaskets and laid them flat over the metal and spray painted over them then drilled, cut out and off the painted areas living a perfect plate.

    I have also made gaskets in a similar fashon by laying the cover over the gasket material and lightly spraying primmer just enough to see the outlines then cutting and punching the gasket.

    Thanks, :) :) :) Dick :) :) :)
     
  7. The Speedi Sleeve needed to smooth out the camshaft where the seals rub on it is an odd size , 7/8" and a hard one to find.

    I cut the "Gordian knot" by turning the front of the camshaft nose down to the next smaller commonly available size [ 20mm]. Speedi sleeves are available for that size when the need arises. Seal life should be a little longer too.

    Got my block back from the machine shop this morning. It looks great. I checked the visitor log and saw that customers Ingersoll Rand, Lockheed and Boeing had visited just before me. Made me feel good to be right in there with the "big boys".
    Dennis
     
  8. Looking at the block to bellhousing dowel pins, I will need stepped ones unless there is a better way. Possibly bush the bellhousing holes down. What would you suggest?
    It looks like mercruiser also has larger diameter holes in the casting that bolts on the rear of the block.
     
    Last edited: May 4, 2010
  9. Dick, they are not that hard to make and there is the advantage that you can improve on them as you progress through the series. I usually toss the first one or two attempts at making a new part because I learn as I go along.

    The problem in making them as a batch is that, if there is something you do not foresee in the design, all of them are screwed up.

    Dennis
     
  10. Hit & run....

    [​IMG]

    [​IMG]

    [​IMG]

    JH
     
  11. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    dennis g,

    You are right and I usually do as you suggest but these spacer plates will look perfect if they are laser cut and in this instance for these parts I know exactly how they will work.

    They will use a gasket on each side. The gasket between the spacer plate and the head will use a stock gasket thus sealing off the large water jacket hole.

    The gasket between the intake manifold and the spacer plate will be cut off at each end to follow the lines of the midified Intake manifold.

    I will drill and tape and install a 1/2" pipe nipple in the spacer plate that lines up with the water jaclet.

    I will then drill a hole in the Mercruiser intake manifold just large enough to allow the 1/2" pipe nipple to pass thru into the spacer plate.

    The only function of the spacer plate is to make up for the fact that the Mercruiser manifold isn't quite big enough to cover the large water jacket hole in the aluminum head.

    If you click on the second and third photo and look at the upper right and left hand corners of the manifold you can just see the small gap where the manifold dosn't quite cover the gasket.

    An added benifit to the plate is that it might keep the intake a little cooler because of the 2 gaskets.

    If I was a perfectionist I could make the head side more perfectly match up with the head and the manifold side match the manifold. As it is they are different dimensions both heighth and width.

    It is funny how my mind works after I measured them, I measured the head gasket then it struck me that after making the plate all I have to do is hog out the head and manifold to match the plate. Then the flow will be as good as the head gasket which has a hole that is larger than both the head and the manifold.

    Obviously this is the forst time I have put together a head and manifold of diverse origins.

    :) :) :) Dick :) :) :)
     

    Attached Files:

    Last edited: May 4, 2010
  12. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Harrison,

    Your installation and your RPU is far superior to anything I am capable of creating. This Thread has inspired me to get on the stick and redouble my efforts to finish at least the RPU before the summer is over.

    As I said before, I just found HAMB 2 Sundays ago while attending the Orange Co. Model A Pancake Breakfast, when someone suggested I look on here to find out more about my Mercruiser plans.

    Untill that time the only contact that I had was with Sarge Nichols of the Inliners who wrote an article a couple of years ago in the Inliners about the 3.7 Mercruiser. He has built several that he used in dragsters. He is an interesting guy but the engines that he builds wouldn't be good in street cars.

    He did however publish good photos and some information on the right kind of flywheels, balancers and other peripherals that will work well on this engine.

    One thing that I noticed about your installation is that you mounted your engine at the front which looks good for your application. I may use that method or I may use the 3 bolts that are between the oil filter and the fuel pump block off shown in your second picture.

    It will depend on where the Vega steering ends up mounting. I will mount it first and then position a stripped block to see how I will position the engine mounts

    Any way your project has inspired me to get with it.

    Thanks, :) :) :) Dick :) :) :)
     
  13. That forward mount is only temporary. It will get a mount at the stock location later.

    The PRU belongs to a friend.

    JH
     
  14. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Harrison,

    Have him build one for you.

    After all what are friends for anyway?

    :) :) :) Dick :) :) :)
     
  15. Dick, I forgot that you are making a spacer plate. You are completely right, it will give you no trouble. The manifold flange needs to be more rigid.
     
    Last edited: May 4, 2010
  16. Here are my 1" spigots screwed into an otherwise stock manifold. Also the cut off end of my newly milled block.
     

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  17. I have my present engine mounted at the front and the bellhousing adapter plate. I'm going to use the mid-engine mounts as they offer much more flexibility in height than putting the front of the engine on the middle of crossmember. I do not know if there needs to be a brace at the mounts to keep the engine from twisting the frame rails.
     
  18. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    dennis g,

    That is what I intended to do to my manifolds when I found that the amuninum head that I bought had a water jacket about 3/16" larger than the cast Iron ford head. Yours look good.

    Looking at the webs on your block reminds me of the times I have smiled when someone wrote that the lower end of this engine is weak or that they had a cracking problem. The sheer mass of the crank would come close to holding itself in place under power. I'm exaggerating of course but it does play a part in the overall physics of the engine.

    I have been reading about these engines on the net for more than 3 years and have read about many failures. Almost all of them have to do with over heating and head leaking probably caused by too advanced spark with bad gas, water in the crankcase caused by failure to replace the leaking first seal on the end of the camshaft waterpump shaft or failure of the water cooled rectifier for the harmonic balancer alternator.

    I have never heard anyone complane about bottom end failure. Even when Randy Dupre's engine let go he said that it was his own fault for not alligning the oil hole on a rod bearing after turning the crank down on a destroked crank. Then it took 5 or 6 years for it to fail on a 186mph run at Bonneville. I believe he was the one who said that he had seen about 25 of these engines and that he had yet to see one with a cracked lower block. The steel main caps are very robust.

    The first 3.7 Mercruiser I bought about 3 years ago was from a guy who had just bought a nice used boat with what was supposed to be a newly rebuilt engine.

    He said that the first time he took it out he had just cleared the Long Beach brakewater when it started to sound bad. He turned around and started in when it started to sound really bad he shut it off and could not restart it. He had to be pulled in by the Coastguard.

    When I went to pick it up he was just finishing up installing a 3.0 Mercruiser 3.0 140 hp engine.

    When I got home I pulled the pan and saw the problem. The engine had just been rebuilt but the guy that did the job must have been the original owner. A Weekend mechanic who probibly had had a few beers as he worked on the rebuild. He had forgotten to tighten down the boltes on the bottom of the oil pump and when they fell out the oil stopped flowing.

    I suspect that he sold the boat to the unsuspecting buyer when he noticed the oil pressure started going down as the bolts loosened.

    Anyway the end result was that the number 3 connection rod cap let loose and the netx time the crank came around it knocked the bottom of the connecting rod thru the side of the block in between 2 of the cast reinforcing webs and above the skirt of the block. It couldn't have been in a more convenient place because when I run out of blocks I will repair this block and rebuild it also.

    The poor guy that I got this first engine from probably got on the web and read one of the many posts put up by people who had had bad luck with the engine. Many had also replaced the 3.7 with a 3.0.

    Too bad for them because they gave up 170 to 190hp of high torque power for an engine that is mediocre at best in a boat.

    My friend who workes for mercruiser told me that the 3.0 was heavier and not nearly the engine that the 3.7 is. He further stated that it was better that the 250ci Chevy I6 that is rated at 165hp.

    Keep me posted on your progress and I will do the same.

    :) :) :) Dick :) :) :)
     
  19. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    dennis g,

    Even if you have already boxed your frame I would cut the plate off with a hand grinder and some Harbor Freight 4 1/4" metal cut off wheels and box girder at least the front half of uour frame.

    I have cut and pasted my post yesterday from the "Model A frame capabilities" Thread. SEE BELOW

    I have boxed and girdered 2 model A frames and they are stiff.

    I take 1 1/2" strap of stock of similar thickness to the original and cut it into 6" length pieces.

    I then start at the top of the front cross member and weld the pieces top to bottom then bottom to top inside the frame all of the way to the back of the center cross member then from the center cross member back to the rear crossmember.

    I sometimes shorten the pieces to avoid any frame holes that I want to use later.

    I weld the pieces top and bottom and to the outside of the frame in the middle of the piece both sides about 1 1/2".

    Since I could not weld the boxing plate to the girder plates from the inside I had to mark and grind slots thru the plate exposing the girders so that I could weld the 4th side of the girders top, bottom and in the middle.

    This process took me an additional 6 hours of work but it effectively created a series of triangulated boxes that tremendously inhanced the rigidity of the frame in all axes.

    To illistrate this I use a match box. Imagine that you just box the frame. You get a rectangular box like the matchbox lid. The torsional strength is the bending strength at the 4 corners of the box.

    The second match box picture illistrates the strength of an ungirdered box.

    Now imagine that you girder the box. The cardboard strip is just standing on its side not even glued in but it easily supports the weight. Now in order to have any torsional movement you will have to stretch the girder in one dimension and compress it in the other.

    This illistration of the box top alone not supporting the Model A u-joint and the top supporting it with just the insertion of the strip of cardboard is the best illustration I could think of.

    The torsional rigidity of the frame depends as much on the rigidity of the frame rails as it does on the cross bracing.

    The 2 frames that I have done this way are very rigid in all axis and the additional 6lbs of steel was steel well used.

    See Pictures :

    :) :) :) Dick :) :) :) <!-- / message --><!-- attachments -->
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    Last edited: May 4, 2010
  20. Not much to contribute on the MerCruisers, except to say that you guys are NUTS (in a good way); BUT there are a number of OEM "stand alone" belt water pump designs out there if you know where to look. Toyota inline 6cyls used a good one IIRC, and it will cool a 450hp small block Chevy if geared correctly.

    I'll see if I can find a good pic of the one I had adapted on my old dirt car.
     
  21. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    exwestracer,

    I looked on ebay and but couldn't find one for a Toyota. Please give us more information or a photo.

    I would be interested and could use one with a return hose Model A thermostat.

    I planned to use an electric water pump because I could set it up with thermo switches to come on and shut off as the engine heats and cools.

    I planned to have an override switch to turn the pump on if the engine got hot.

    I also planned to have a high temp switch hooked to a loud (I'm very hard of hearing) buzzer to warn me if the engine was getting too hot.

    But a belt driven water pump is worthy of consideration.

    Thanks for the input.

    :) :) :) Dick :) :) :)
     
  22. Super88
    Joined: Nov 21, 2001
    Posts: 386

    Super88
    Member

    Other than it says MerCruiser on it, I don't have any other info on this motor other than it was listed as 140 h.p., so I apologize if it's not what you're looking for.
     

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  23. Dick, You will not hear the buzzer. We [ I'm hard of hearing too] might hear a car horn, but it would startle, so use a clearance light it mounts easily is big and is impossible to miss. I changed to that for my oil pressure light as a red light came on and I'd forgotten what it was for. I wrote "OIL" on the lens of the clearance lamp.
    I'd use belt-driven water pump as failures come on slowly. Some tractors used pumps which could be made stand-alone. Allis Chalmers would probably do.
    That is not to say that the electric pump would not be good. It could save power but I can see more ways for it to fail.
    I'm impressed with your frame bracing. You could haul a yard of concrete on it. [My frame came boxed from the factory.]
    Dennis
     
    Last edited: May 5, 2010
  24. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    dennis g,

    You haven't heard the buzzer that I have in mind.

    If you are worried about the frame flexing that far back on the frame (about 12 to 16" behind the front cross member you could build a 2X2 square girdle to go under the engine and connect to the frame under the motor mounts but I dont think that will be necessary with a factory built frame.

    You are right a yard of concrete weighs about 3900 lbs and I believe this frame would haul that kind of load, now the springs are another question.

    A Model A pickup was rated at 1/4 ton but most contractors hauled 1/2 ton of sand if they could get it in and they didn't even have a boxed frame.

    The abuses that the average surviving Model A Ford have had would boggle the mind. In their day most roads weren't even paved. Lucky to be gravel. Some City streets were brick, cobblestone or concrete but many were still dirt or gravel. A very few country highways were paved at all.

    They called the Model T a Tin Lizzie but Henry made his cars out of very good tin.

    Ford wasn't very well educated but he educated himself. He very earley on studied
    European steel plants and discovered that Vanadium steel was very durable and had great strength. He thus figured out that he could build light weight frames that were stronger than his competitors.

    The added cost of the alloy was almost completely offset by the reduction in the amount of steel he had to use.

    The added benifit was that his cars were durable in comparison to most others. That is why the April Hemmings Motor News has less than 2 pages of 1911-1954 chevrolets and 7 pages of 1928-1953 fords. 31 chevys from 1917 to 1940 and 192 1919 to 1940 fords.

    I'm not knocking Chevy's I love them to and would like to find a nice early 6 cylinder chevy to put a clifford equiped 292ci in.

    Star made millions of cars and was a major producer in the Model T days but I have only seen 1 ever and it was a wreck.

    I love old cars.

    :) :) :) Dick :) :) :)
     
    Last edited: May 5, 2010
  25. Dawford,
    [​IMG]

    I just Googled "Toyota water pump" images... There are others like this as well, but this is pretty close to the one I used years ago. I just used a restrictor in the return line to the rad instead of a thermostat, but there are a number of inline stat housings available too.
     
  26. tjm73
    Joined: Feb 17, 2006
    Posts: 3,381

    tjm73
    Member

    4.6 Fords have nice small water pumps that flow lots of water. There are also nice electric water pumps that might work too. You could even hide it someplace.
     
  27. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    exwestracer,

    What does the other side of that pump look like and what model does it fit?

    I have been trying to avoid having too many pulleys on the front of the crankshaft so as to keep the engine as far forward as possible.

    However when I layed the pan which has the oil pump forward in approximate position yesterday I found that the limiting factor won't be the front pullies but rather the pan clearing the cross stearing rod.

    The good news was that I will be able to use the 525 steering box rather than the vega box because there is plenty of clearance between the frame rail and the engine. This box has a quicker ratio than the vega box and since it is going into the light weight RPU it should work very well.


    This is a 160 degree hose thermostat for a Model A Ford.

    :) :) :) Dick :) :) :)
     

    Attached Files:

    Last edited: May 5, 2010
  28. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    Supper88,

    The engine that you posted pictures of is the 3.0 chevrolet commercial engine that Mercruiser installs in their 140hp stearndrives. It is not as easily modified for performance as is the 3.7.

    I recommend the 3.0 for those who are seeking reliability and reasonable performance for their Model A.

    If you want an easy to install 4 cylinder engine in your light car the 3.0 is very good. It is what I planed to install untill I saw the potential of the 3.7.

    The 3.7 Mercruiser is the kind of the sleeping giant of the big block 4 cylinder world. It can be modified greatly and still have reasonable reliability and it is lighter and much more robust than the 3.0.

    The 3.7 will provide the kind of torque that is really fun in a car of this weight.

    It is not going to go in a streight line as fast as a blown Chrysler. But I won't have to have 12" rear tires and it won't sound like a thrashing machine or have the engine sticking out of the hood either.

    If you want to look fast and go extremely fast go with an overhead V8.

    If you want to look slow and go very fast go with the 3.7 Mercruiser.

    Good pictures.

    :) :) :) Dick :) :) :)
     
    Last edited: May 5, 2010
  29. Dick, the back of the housing is rounded and the only attachment point is through a flange where the water flows into the front of the block (at top in the previous photo. I believe the one I had came off the old 7M series inline 6 engines (Supra), but I can't remember for sure.
    [​IMG]
    In this photo, you can see the water pump sitting next to the block just above the alternator. PLEASE pardon the bling photo! I just cribbed it from Google. Most of the pics of these engines are in the car, showing off their giant turbos....

    One thing I liked about these pumps is they can be indexed and mounted anywhere. I had designed one for a project that mounted it back along the block (like the REALLY old cars) and drove through a rag joint and steering intermediate shaft with an industrial shaft pulley. We never went that route with the build, though...
     
  30. dawford
    Joined: Apr 25, 2010
    Posts: 498

    dawford
    Member

    exwestracer,

    Thanks for the info and the great picture that looks like a winner if I choose to go with a belt driven water pump.

    Thanks again, :) :) :) Dick :) :) :)
     

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