Page 1 of 4 1234 LastLast
Results 1 to 10 of 31

Thread: Halved v-6 three cylinder

  1. #1
    Team Member
    Join Date
    Jun 2010
    Location
    Panama City, Florida
    Posts
    61
    Post Thanks / Like

    Default Halved v-6 three cylinder

    I've heard of but have not seen pictures of people taking a v-6 merc 2.5 L and removing a bank of cylinders to make an inline 3 cylinder. I've been asking Mitch Hardee questions but he did the build in 97 and doesn't have much documentation. He also isn't incredibly forthcoming with details.

    Does anyone know of an example of this that I can learn from? I'm not afraid of learning as I go but the fewer mistakes I can make the better.

    -Jim

  2. #2
    BoatRacingFacts VIP John Schubert T*A*R*T's Avatar
    Join Date
    Dec 2004
    Location
    East Galesburg, IL
    Posts
    862
    Post Thanks / Like

    Default

    Quote Originally Posted by slowJEEP View Post
    I've heard of but have not seen pictures of people taking a v-6 merc 2.5 L and removing a bank of cylinders to make an inline 3 cylinder. I've been asking Mitch Hardee questions but he did the build in 97 and doesn't have much documentation. He also isn't incredibly forthcoming with details.

    Does anyone know of an example of this that I can learn from? I'm not afraid of learning as I go but the fewer mistakes I can make the better.

    -Jim
    Contact Bill Gohr, APBA OPC category chairperson. He has done it, many times.

  3. #3
    BoatRacingFacts VIP John Schubert T*A*R*T's Avatar
    Join Date
    Dec 2004
    Location
    East Galesburg, IL
    Posts
    862
    Post Thanks / Like

    Default

    Quote Originally Posted by slowJEEP View Post
    I've heard of but have not seen pictures of people taking a v-6 merc 2.5 L and removing a bank of cylinders to make an inline 3 cylinder. I've been asking Mitch Hardee questions but he did the build in 97 and doesn't have much documentation. He also isn't incredibly forthcoming with details.

    Does anyone know of an example of this that I can learn from? I'm not afraid of learning as I go but the fewer mistakes I can make the better.

    -Jim
    Contact Bill Gohr, maybe on here, APBA OPC category Chairperson. Around Fox Lake, IL

  4. #4
    Team Member
    Join Date
    Jun 2010
    Location
    Panama City, Florida
    Posts
    61
    Post Thanks / Like

    Default

    Thanks John!

    I got ahold of Bill at Gohr Performance. Neat guy. He informed me that the SST 70 class was started from running a single bank of cylinders of the motors from the sst 140 class. That helped me find some info. Turns out they, pulled the pistons and rods but didn't remove the empty bank.

    I picked up a 2004 Mercury 2.5 carbed 150. Has a hole in a piston so the other three should be good. I'll post progress pictures as they manifest.

    -Jim
    Thanks Ron Hill thanked for this post

  5. #5
    Team Member
    Join Date
    Aug 2017
    Posts
    45
    Post Thanks / Like

    Default 1/2 v-6

    Quote Originally Posted by slowJEEP View Post
    I've heard of but have not seen pictures of people taking a v-6 merc 2.5 L and removing a bank of cylinders to make an inline 3 cylinder. I've been asking Mitch Hardee questions but he did the build in 97 and doesn't have much documentation. He also isn't incredibly forthcoming with details.

    Does anyone know of an example of this that I can learn from? I'm not afraid of learning as I go but the fewer mistakes I can make the better.

    -Jim
    I built them and raced many very successfully. SST 70 class was 75 cubic inch and below. Used a 2.4 Bridgeport as it had better porting than any three cylinder. I still have two engines. 2.4 Stock block and a 2.5 full Mod. They are great fun.
    Took PVC tube and glued a cap on one end. Turn that in a lathe so it will just slide in to the bore to block off the bottom of the case and all the ports. Full length like a sleeve. That three reed blocks and fill them with epoxy. Use one venturi of the two barrel carb. Replace one head with 1/4 plate. Use one switch box and ground the other side of the stator. Tunes great. Runs great. 15' tunnel boat runs 7200 rpms with 14:15 gears. The hot setup is the old mod 50 gears 13:16 engine will run 8600 with 15 pitch prop.
    The 2.5L 1/2 V-6 was full mod and would run 8500 with 16 pitch and 14:15 gears, what a ride.
    I never ran these with both venturies going into the same reed block Does not carb well. I have all my notes, the best props yet and extra gears yet. Just no tower or gearcase anymore. Wish I did. great stuff Won SST 70 Nationals and Mod 110 Nationals Very popular in mid/late 80s
    Thanks Ron Hill, Powerabout thanked for this post
    Likes Ron Hill, slowJEEP liked this post

  6. #6
    Team Member
    Join Date
    Aug 2017
    Posts
    45
    Post Thanks / Like

    Default

    The SST 70 class was stock block with tighter head and any tuner.
    mine made about 126 hp. the 2.5 I built was with small reed block as I needed great hole shot and the rest was like a mod u engine. Large carbs with big Air Horn but still just one venturi. this made 160 hp.
    Thanks Ron Hill, Powerabout thanked for this post

  7. #7
    Team Member
    Join Date
    Sep 2008
    Location
    Singapore/Melbourne/Italy
    Posts
    1,164
    Post Thanks / Like

    Default

    Quote Originally Posted by Mike Wienandt View Post
    The SST 70 class was stock block with tighter head and any tuner.
    mine made about 126 hp. the 2.5 I built was with small reed block as I needed great hole shot and the rest was like a mod u engine. Large carbs with big Air Horn but still just one venturi. this made 160 hp.
    one of those questions without answers, OMC raced a 3 cyl looper and Merc used a xflow, move to V6 and Merc ran a looper and OMC ran a xflow

  8. #8
    Team Member
    Join Date
    Aug 2017
    Posts
    45
    Post Thanks / Like

    Default

    The SST 70 class was a later evolution of Mod 50. But guys got fatter so the size went up. OMC Mod 50 was a looper, 650-700X Merc was cross flow. The V-6 was nice Looper the you could just leave one bank empty and it ran like an inline three with good pulse tuning. It was the dominant engine in the engine. As the boats got older and heaver, along the the drivers, the Mod SST60 was very strong. We build those for the inflatable guys at 115 hp with stock carbs.

  9. #9
    Team Member
    Join Date
    Aug 2017
    Posts
    45
    Post Thanks / Like

    Default

    We also built a Force 95 crossflow. In some Mod porting it was very strong down low but could not run the top speed for solid wins. Would not turn any rpms so needed 17 prop with 14:15 gears in #6 speedmaster.

  10. #10
    Team Member Roflhat's Avatar
    Join Date
    Jul 2011
    Location
    Scotland
    Posts
    283
    Post Thanks / Like

    Default

    Quote Originally Posted by Mike Wienandt View Post
    The SST 70 class was a later evolution of Mod 50. But guys got fatter so the size went up. OMC Mod 50 was a looper, 650-700X Merc was cross flow. The V-6 was nice Looper the you could just leave one bank empty and it ran like an inline three with good pulse tuning. It was the dominant engine in the engine. As the boats got older and heaver, along the the drivers, the Mod SST60 was very strong. We build those for the inflatable guys at 115 hp with stock carbs.
    Inflatable as in thundercat?

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. Bill Fales' 6 Cylinder/Yamaha 6 Cylinder
    By Steve Fales in forum Outboard Racing History
    Replies: 7
    Last Post: 08-27-2013, 05:18 PM
  2. WTB: OMC - CCC / RS Trim Cylinder
    By RogerH in forum Parts and Accessories
    Replies: 0
    Last Post: 12-13-2012, 06:16 PM
  3. Six Cylinder and 4 cylinder Looper Show Down
    By jimmy robb in forum Boat Racing Encyclopedia
    Replies: 1
    Last Post: 09-13-2012, 08:03 PM
  4. Cylinder for 125/250/500 VRP
    By Bill Van Steenwyk in forum Racing Parts
    Replies: 2
    Last Post: 06-02-2012, 05:29 PM

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •