Merc 4.3 v6 /alpha - stripped starter bolts

Discussion in 'Gas Engines' started by wood45s, Aug 6, 2017.

  1. wood45s
    Joined: May 2017
    Posts: 10
    Likes: 0, Points: 1
    Location: ga

    wood45s Junior Member

    Merc 4.3 v6 with alpha drive - recently acquired with multiple previous owner induced problems.
    New problem when cranking after alignment with still no stern drive installed – I think the timing may have been advanced too much. It appeared to kick back and stripped the starter bolts out. The distributor wasn’t tight and appears to have been accidentally advanced while lifting the engine for alignment. So now I think I will be ordering a timesert 1535 kit or similar to restore threads ++ TIME-SERT MANUFACTURER KITS - GENERAL MOTORS ++ northstar headbolt thread repair, cadillac northstar head gasket repair,cadillac northstar thread repair, cadillac northstar headbolt thread repair, GM headbolt thread repair, general motors cadillac head bolt thread repair. http://www.timesert.com/html/gm.html I found that the small block Chevs once included a brace on front of starter to stabilize the starter. That seems to have been discontinued when the gear drive starters came into use. I can’t seem to find anything that might work on this. The thread inserts may fix the problem, but I think the brace should be installed also.

    I can’t find a brace for the gear drive starters. The brace for the older starters will not fit.
    Has anybody seen one or have a suggestion?

    The starter was loose when I first got the boat, so this may be partly a preexisting condition. I replaced the starter drive and it cranked ok until the bolts stripped out.
    Also got some 93 octane gas – no idea what the compression is now. It was bored 60 thousandths and heads probably shaved.

    Thx,
    wood
     
  2. PAR
    Joined: Nov 2003
    Posts: 19,133
    Likes: 470, Points: 93, Legacy Rep: 3967
    Location: Eustis, FL

    PAR Yacht Designer/Builder

    If that block was drilled to .60, it's not going to last very long. This block is exactly the same as a first gen SBC (350), just missing a few cylinders. .30" is the recommended over bore on a street 350, while you can get by with a .40" over drilling, a .60" over bore is reserved for race engines that will be disassembled regularly and a lifespan that is measured in minutes. Simply put, with the deck (or heads) shaved and the bore .60" over, you're going to have a hot running engine. These puppies are well know to develop cracks in the lifter valley and have oil pressure issues. Toss some extra heat and compression at them and they don't last long. Given how common these things are, you might consider a junkyard 4.3 long block, swap out the cam and other stuff from the current engine and move on. You have to remember this is a 2 bolt main, two piece rear main seal, dainty webbed block. It's not a hefty webbed, 4 bolt, with a one piece rear seal block.

    The starter brace deal seems to have come and gone over the years. I have a 1996 350 in a truck, with the brace, but I also have another 1992 with no brace. The diagonal bolt pattern may have something to do with this, as well as duty service. For example the 1996 was ordered with the trailer towing package, which is likely why the brace was installed. The 1992 of the same vehicle didn't have the factory trailer package, but just a dealer installed hitch.

    The brace is easy to make and some 1" angle stock will get it done quickly. As to kick back, well I don't think is what caused you stripped bolts. The Bendix drive will not let the drive gear do anything other than disengage, if the engine backfires or otherwise tries to turn the wrong way. They bolts strip if over torqued or left in sloppy. A HeliCoil kit will fix it, assuming you'll keep this block.
     
  3. wood45s
    Joined: May 2017
    Posts: 10
    Likes: 0, Points: 1
    Location: ga

    wood45s Junior Member

    I checked the parts list for engine build and it has 40 over pistons etc, not 60 over like I was told, so that’s something of a relief.
    There’s not even a hole in the block that I can find for attaching a starter brace. I don’t know if drilling a hole is a good/bad idea. I’d be really nervous about that, since I don’t know how thick the block is in that area. Making the bracket wouldn’t be that hard.

    So now i’m about to lift the engine for installing the Timesert inserts for that starter bolt holes. While doing that I will pull the flywheel and replace the ring gear, which has one tooth missing. As already mentioned, the starter was loose when I got the boat and starter drive gear teeth worn off. I'll have to check, but i think this is the 168 tooth flywheel. I'm assuming i can use an automotive ring gear - please let me know if i'm wrong about that.
    I’ll check the drive coupler and engine mounts. Also, general inspection / bolt checking of everything behind the engine.
    Are there any suggestions of anything else I should replace at this time while the engine is out?

    I think i’ll change oil and filter while it’s convenient. Supposedly engine only had a couple of hours since build running with a hose hooked to it before I got the boat. I’ve run it probably run it 30 min checking the new manifolds and for water leaks. I’ll have to get a suction gun or something to change oil in the future.

    Thx,
    wood
     
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