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Thread: Announcing the Merc 888

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    Default Announcing the Merc 888

    To all Mercury enthusiasts, engine builders, racers, and collectors,

    This site has been to quiet lately, so it's time to liven it up. Following the AOMCI show at Mark Suter's, I decided to pull out the stops for 2016. Name:  888 Star side.JPG
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    Feast your eyes and explain what's going on.......

    Tim

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    Tim Weber
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    Ok, I'll bite. You have two blocks opposed. Now the fun begins. Where do the carbs go? How do you get 8 rods on a 44 crank? Interesting!

    Tim

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    Default The business side

    Quote Originally Posted by Tim Weber View Post
    Ok, I'll bite. You have two blocks opposed. Now the fun begins. Where do the carbs go? How do you get 8 rods on a 44 crank? Interesting!

    Tim
    One carb (not shown) in front of the turbo. Custom rods, two per journal, for the prototype enables directly opposed cylinders.

    TimName:  IMG_0817.JPG
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    Team Member R Austin's Avatar
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    How will you start it. You have no pumping action from the pistons which cancel each other out. No fuel air flow until turbo up.

    PS, You could do like the old GMC Diesels and run a positive displacement blower. However I think you will have a problem with 2 rods articulating in opposite directions on the same roller bearings. I think they tried to resolve that same problem in the 30's on the flat head V8's with a full floating shared bearing and it worked so well (not) that they went to individual rod bearings.

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    Default Leaf blower

    Quote Originally Posted by R Austin View Post
    How will you start it. You have no pumping action from the pistons which cancel each other out. No fuel air flow until turbo up.

    PS, You could do like the old GMC Diesels and run a positive displacement blower. However I think you will have a problem with 2 rods articulating in opposite directions on the same roller bearings. I think they tried to resolve that same problem in the 30's on the flat head V8's with a full floating shared bearing and it worked so well (not) that they went to individual rod bearings.
    A SeaDoo blower was considered, but not large enough to provide for 88 cubic inches. Also, there was no reasonable way to install a gear drive to deliver the needed 1:7.25 step up.

    For the purposes of the proof-of-concept prototype, custom .250" thick rods will be made of 954 aluminum bronze or bronze plated 4140 steel running directly on the crank (with 8:1 fuel/oil ratio.

    For starting, two potential methods are envisioned:

    1) Lucky: Crank the engine with the electric starter, inject prime through the starboard side (aft bank) port covers, and hope the exhaust gust is enough to spin-up the (undersized) turbo and provide scavenge flow.

    2) Not so lucky: Crank the engine with the electric starter, apply airflow through the carb with a leaf blower, and prime the aft bank. This will most certainly provide enough flow to spin-up the turbo and provide scavenge flow.

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    I was going to ask how are the needle bearings at each journal kept separate from each other, but they are rolling the same way for each bank, so...

    Assembly has gonna be a b*tch!

    Jeff

    PS: Another fascinating project.
    "We live at the bottom of an ocean of air." - General Marvage Slatington

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    Default No needle bearings

    Quote Originally Posted by Fastjeff57 View Post
    I was going to ask how are the needle bearings at each journal kept separate from each other, but they are rolling the same way for each bank, so...

    Assembly has gonna be a b*tch!

    Jeff

    PS: Another fascinating project.
    For the prototype, no needle bearings will be used. If they were, there's assembly grease. The crank will be assembled vertically with all 8 pistons and rods, lowered into the aft bank, then the fore bank will be lowered onto it. It will take two people and/or a counterbalanced jib crane.

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    Love to watch that being done. Watch it, now, not participate!

    You sure have some interesting projects.

    Jeff

    PS: Could you needle bearings that are captured in the cage (like the later Mercs and some OMCs)? Using sleeve bearings with that violent pull-push action going on would scare me. I appreciate what a Chinese Fire Drill it would be to attempt to use the stock needles in this case.
    "We live at the bottom of an ocean of air." - General Marvage Slatington

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    Default Proof-of-concept

    Quote Originally Posted by Fastjeff57 View Post
    Love to watch that being done. Watch it, now, not participate!

    You sure have some interesting projects.

    Jeff

    PS: Could you needle bearings that are captured in the cage (like the later Mercs and some OMCs)? Using sleeve bearings with that violent pull-push action going on would scare me. I appreciate what a Chinese Fire Drill it would be to attempt to use the stock needles in this case.

    Hi Jeff,

    Images will be posted as work is completed so all can follow along. This one will look especially cool because of the plugs forward and aft.

    There are no sleeve bearings, only bronze on steel and lots of oil. The objective is to learn if the turbo scavenged concept (no reed cages) will even work. My guess is it will.......

    Tim

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    It works fine with EMD two strokes, You'll have to be careful backfires, however; they would be very violent.

    Jeff
    "We live at the bottom of an ocean of air." - General Marvage Slatington

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