1. Missed the live Ask the Expert event?
    Catch up on the conversation with Ken Hutcheson, President of U.S. Lawns in the Franchising forum plus sign up to receive a FREE eBook on how to grow your landscape business.

    Dismiss Notice

no threads in Kohler SV470 engine mount holes

Discussion in 'Mechanic and Repair' started by redeye1964, Aug 17, 2013.

  1. redeye1964

    redeye1964 LawnSite Member
    Messages: 44

    I'm fitting a SV470 into a ride-on, went to screw the bolts into the engine mounting holes - they are unthreaded......is this normal with these engines, do I have to tap threads into them? Seems crazy to me, wondering if it is a casting error?? Please help, I need to get this going, I'm a contractor :confused:


    as you can see, 3 holes are blind, no way to use nut/bolts, except for 1
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    Most equipment makers use self tapping screws when installing engines so no threads is normal, Cut your own with a tap or use the factory equipment bolts...... But....Be careful, I snapped a self tapper off in a brand new aluminum spindle housing ONCE......
  3. BigFish

    BigFish LawnSite Gold Member
    Messages: 3,778

    As was mentioned, you'd be better off to cut new threads using a tap. You can prolly get by with just a " plug tap" which will cut almost to the bottom of the blind holes. If ya don't have a plug tap, you can grind some of the lead/ point off a regular taper tap.
    Use plenty of lube and blow out the chips, shouldn't have any problems.
    Last edited: Aug 17, 2013
  4. dutch1

    dutch1 LawnSite Silver Member
    from Jayhawk
    Messages: 2,247

    This is just another process the manufacturers eliminate to reduce the cost of production. I've never attempted to use self tappers on a new block--I always tap threads since breaking one off while removing an engine. Grade 5 and 242(blue) Loctite works for me.
  5. redeye1964

    redeye1964 LawnSite Member
    Messages: 44

    thanks for the advice, I'll tap threads rather than risk self threaders
  6. redeye1964

    redeye1964 LawnSite Member
    Messages: 44

    finally fitted, was a big job - best part of 3 days, where I usually do an engine swap in a matter of hours - all due to the mounting arrangement......mower is a Cox, made in Oz
  7. gnobles

    gnobles LawnSite Member
    Messages: 4

    I had good success today tapping threads with this technique:




  8. Valk

    Valk LawnSite Silver Member
    Messages: 2,711

    Is the above method preferable to a self tapping screw/bolt? Mechanics??
  9. gnobles

    gnobles LawnSite Member
    Messages: 4

    I should have also mentioned that I inserted the thread cutting tool only 3 to 5 threads deep, then pulled it out, blew it off with air, blew the hole out with air, and then repeated until finished. I also lubricated the hole with WD-40.

    I had never done this before, but found it to be a surprising easy process.
  10. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    As I mentioned above, After snapping one off...... ALL un-threaded holes get tapped......

Share This Page